diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 2220 |
1 files changed, 1563 insertions, 657 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6e604caa870c..a7d6e0c5928b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -322,6 +322,7 @@ struct bpf_kfunc_call_arg_meta { struct btf *arg_btf; u32 arg_btf_id; bool arg_owning_ref; + bool arg_prog; struct { struct btf_field *field; @@ -456,7 +457,7 @@ static bool subprog_is_exc_cb(struct bpf_verifier_env *env, int subprog) static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg) { - return btf_record_has_field(reg_btf_record(reg), BPF_SPIN_LOCK); + return btf_record_has_field(reg_btf_record(reg), BPF_SPIN_LOCK | BPF_RES_SPIN_LOCK); } static bool type_is_rdonly_mem(u32 type) @@ -579,6 +580,13 @@ static bool is_cmpxchg_insn(const struct bpf_insn *insn) insn->imm == BPF_CMPXCHG; } +static bool is_atomic_load_insn(const struct bpf_insn *insn) +{ + return BPF_CLASS(insn->code) == BPF_STX && + BPF_MODE(insn->code) == BPF_ATOMIC && + insn->imm == BPF_LOAD_ACQ; +} + static int __get_spi(s32 off) { return (-off - 1) / BPF_REG_SIZE; @@ -1148,7 +1156,8 @@ static int release_irq_state(struct bpf_verifier_state *state, int id); static int mark_stack_slot_irq_flag(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta, - struct bpf_reg_state *reg, int insn_idx) + struct bpf_reg_state *reg, int insn_idx, + int kfunc_class) { struct bpf_func_state *state = func(env, reg); struct bpf_stack_state *slot; @@ -1170,6 +1179,7 @@ static int mark_stack_slot_irq_flag(struct bpf_verifier_env *env, st->type = PTR_TO_STACK; /* we don't have dedicated reg type */ st->live |= REG_LIVE_WRITTEN; st->ref_obj_id = id; + st->irq.kfunc_class = kfunc_class; for (i = 0; i < BPF_REG_SIZE; i++) slot->slot_type[i] = STACK_IRQ_FLAG; @@ -1178,7 +1188,8 @@ static int mark_stack_slot_irq_flag(struct bpf_verifier_env *env, return 0; } -static int unmark_stack_slot_irq_flag(struct bpf_verifier_env *env, struct bpf_reg_state *reg) +static int unmark_stack_slot_irq_flag(struct bpf_verifier_env *env, struct bpf_reg_state *reg, + int kfunc_class) { struct bpf_func_state *state = func(env, reg); struct bpf_stack_state *slot; @@ -1192,6 +1203,15 @@ static int unmark_stack_slot_irq_flag(struct bpf_verifier_env *env, struct bpf_r slot = &state->stack[spi]; st = &slot->spilled_ptr; + if (st->irq.kfunc_class != kfunc_class) { + const char *flag_kfunc = st->irq.kfunc_class == IRQ_NATIVE_KFUNC ? "native" : "lock"; + const char *used_kfunc = kfunc_class == IRQ_NATIVE_KFUNC ? "native" : "lock"; + + verbose(env, "irq flag acquired by %s kfuncs cannot be restored with %s kfuncs\n", + flag_kfunc, used_kfunc); + return -EINVAL; + } + err = release_irq_state(env->cur_state, st->ref_obj_id); WARN_ON_ONCE(err && err != -EACCES); if (err) { @@ -1409,6 +1429,8 @@ static int copy_reference_state(struct bpf_verifier_state *dst, const struct bpf dst->active_preempt_locks = src->active_preempt_locks; dst->active_rcu_lock = src->active_rcu_lock; dst->active_irq_id = src->active_irq_id; + dst->active_lock_id = src->active_lock_id; + dst->active_lock_ptr = src->active_lock_ptr; return 0; } @@ -1508,6 +1530,8 @@ static int acquire_lock_state(struct bpf_verifier_env *env, int insn_idx, enum r s->ptr = ptr; state->active_locks++; + state->active_lock_id = id; + state->active_lock_ptr = ptr; return 0; } @@ -1545,18 +1569,37 @@ static void release_reference_state(struct bpf_verifier_state *state, int idx) return; } +static bool find_reference_state(struct bpf_verifier_state *state, int ptr_id) +{ + int i; + + for (i = 0; i < state->acquired_refs; i++) + if (state->refs[i].id == ptr_id) + return true; + + return false; +} + static int release_lock_state(struct bpf_verifier_state *state, int type, int id, void *ptr) { + void *prev_ptr = NULL; + u32 prev_id = 0; int i; for (i = 0; i < state->acquired_refs; i++) { - if (state->refs[i].type != type) - continue; - if (state->refs[i].id == id && state->refs[i].ptr == ptr) { + if (state->refs[i].type == type && state->refs[i].id == id && + state->refs[i].ptr == ptr) { release_reference_state(state, i); state->active_locks--; + /* Reassign active lock (id, ptr). */ + state->active_lock_id = prev_id; + state->active_lock_ptr = prev_ptr; return 0; } + if (state->refs[i].type & REF_TYPE_LOCK_MASK) { + prev_id = state->refs[i].id; + prev_ptr = state->refs[i].ptr; + } } return -EINVAL; } @@ -1591,7 +1634,7 @@ static struct bpf_reference_state *find_lock_state(struct bpf_verifier_state *st for (i = 0; i < state->acquired_refs; i++) { struct bpf_reference_state *s = &state->refs[i]; - if (s->type != type) + if (!(s->type & type)) continue; if (s->id == id && s->ptr == ptr) @@ -1600,6 +1643,14 @@ static struct bpf_reference_state *find_lock_state(struct bpf_verifier_state *st return NULL; } +static void update_peak_states(struct bpf_verifier_env *env) +{ + u32 cur_states; + + cur_states = env->explored_states_size + env->free_list_size; + env->peak_states = max(env->peak_states, cur_states); +} + static void free_func_state(struct bpf_func_state *state) { if (!state) @@ -1622,6 +1673,50 @@ static void free_verifier_state(struct bpf_verifier_state *state, kfree(state); } +/* struct bpf_verifier_state->{parent,loop_entry} refer to states + * that are in either of env->{expored_states,free_list}. + * In both cases the state is contained in struct bpf_verifier_state_list. + */ +static struct bpf_verifier_state_list *state_parent_as_list(struct bpf_verifier_state *st) +{ + if (st->parent) + return container_of(st->parent, struct bpf_verifier_state_list, state); + return NULL; +} + +static struct bpf_verifier_state_list *state_loop_entry_as_list(struct bpf_verifier_state *st) +{ + if (st->loop_entry) + return container_of(st->loop_entry, struct bpf_verifier_state_list, state); + return NULL; +} + +/* A state can be freed if it is no longer referenced: + * - is in the env->free_list; + * - has no children states; + * - is not used as loop_entry. + * + * Freeing a state can make it's loop_entry free-able. + */ +static void maybe_free_verifier_state(struct bpf_verifier_env *env, + struct bpf_verifier_state_list *sl) +{ + struct bpf_verifier_state_list *loop_entry_sl; + + while (sl && sl->in_free_list && + sl->state.branches == 0 && + sl->state.used_as_loop_entry == 0) { + loop_entry_sl = state_loop_entry_as_list(&sl->state); + if (loop_entry_sl) + loop_entry_sl->state.used_as_loop_entry--; + list_del(&sl->node); + free_verifier_state(&sl->state, false); + kfree(sl); + env->free_list_size--; + sl = loop_entry_sl; + } +} + /* copy verifier state from src to dst growing dst stack space * when necessary to accommodate larger src stack */ @@ -1661,6 +1756,7 @@ static int copy_verifier_state(struct bpf_verifier_state *dst_state, dst_state->callback_unroll_depth = src->callback_unroll_depth; dst_state->used_as_loop_entry = src->used_as_loop_entry; dst_state->may_goto_depth = src->may_goto_depth; + dst_state->loop_entry = src->loop_entry; for (i = 0; i <= src->curframe; i++) { dst = dst_state->frame[i]; if (!dst) { @@ -1681,7 +1777,7 @@ static u32 state_htab_size(struct bpf_verifier_env *env) return env->prog->len; } -static struct bpf_verifier_state_list **explored_state(struct bpf_verifier_env *env, int idx) +static struct list_head *explored_state(struct bpf_verifier_env *env, int idx) { struct bpf_verifier_state *cur = env->cur_state; struct bpf_func_state *state = cur->frame[cur->curframe]; @@ -1789,16 +1885,13 @@ static bool same_callsites(struct bpf_verifier_state *a, struct bpf_verifier_sta * # Find outermost loop entry known for n * def get_loop_entry(n): * h = entries.get(n, None) - * while h in entries and entries[h] != h: + * while h in entries: * h = entries[h] * return h * - * # Update n's loop entry if h's outermost entry comes - * # before n's outermost entry in current DFS path. + * # Update n's loop entry if h comes before n in current DFS path. * def update_loop_entry(n, h): - * n1 = get_loop_entry(n) or n - * h1 = get_loop_entry(h) or h - * if h1 in path and depths[h1] <= depths[n1]: + * if h in path and depths[entries.get(n, n)] < depths[n]: * entries[n] = h1 * * def dfs(n, depth): @@ -1810,7 +1903,7 @@ static bool same_callsites(struct bpf_verifier_state *a, struct bpf_verifier_sta * # Case A: explore succ and update cur's loop entry * # only if succ's entry is in current DFS path. * dfs(succ, depth + 1) - * h = get_loop_entry(succ) + * h = entries.get(succ, None) * update_loop_entry(n, h) * else: * # Case B or C depending on `h1 in path` check in update_loop_entry(). @@ -1822,46 +1915,46 @@ static bool same_callsites(struct bpf_verifier_state *a, struct bpf_verifier_sta * and cur's loop entry has to be updated (case A), handle this in * update_branch_counts(); * - use st->branch > 0 as a signal that st is in the current DFS path; - * - handle cases B and C in is_state_visited(); - * - update topmost loop entry for intermediate states in get_loop_entry(). + * - handle cases B and C in is_state_visited(). */ -static struct bpf_verifier_state *get_loop_entry(struct bpf_verifier_state *st) +static struct bpf_verifier_state *get_loop_entry(struct bpf_verifier_env *env, + struct bpf_verifier_state *st) { - struct bpf_verifier_state *topmost = st->loop_entry, *old; + struct bpf_verifier_state *topmost = st->loop_entry; + u32 steps = 0; - while (topmost && topmost->loop_entry && topmost != topmost->loop_entry) + while (topmost && topmost->loop_entry) { + if (verifier_bug_if(steps++ > st->dfs_depth, env, "infinite loop")) + return ERR_PTR(-EFAULT); topmost = topmost->loop_entry; - /* Update loop entries for intermediate states to avoid this - * traversal in future get_loop_entry() calls. - */ - while (st && st->loop_entry != topmost) { - old = st->loop_entry; - st->loop_entry = topmost; - st = old; } return topmost; } -static void update_loop_entry(struct bpf_verifier_state *cur, struct bpf_verifier_state *hdr) +static void update_loop_entry(struct bpf_verifier_env *env, + struct bpf_verifier_state *cur, struct bpf_verifier_state *hdr) { - struct bpf_verifier_state *cur1, *hdr1; - - cur1 = get_loop_entry(cur) ?: cur; - hdr1 = get_loop_entry(hdr) ?: hdr; - /* The head1->branches check decides between cases B and C in - * comment for get_loop_entry(). If hdr1->branches == 0 then + /* The hdr->branches check decides between cases B and C in + * comment for get_loop_entry(). If hdr->branches == 0 then * head's topmost loop entry is not in current DFS path, * hence 'cur' and 'hdr' are not in the same loop and there is * no need to update cur->loop_entry. */ - if (hdr1->branches && hdr1->dfs_depth <= cur1->dfs_depth) { + if (hdr->branches && hdr->dfs_depth < (cur->loop_entry ?: cur)->dfs_depth) { + if (cur->loop_entry) { + cur->loop_entry->used_as_loop_entry--; + maybe_free_verifier_state(env, state_loop_entry_as_list(cur)); + } cur->loop_entry = hdr; - hdr->used_as_loop_entry = true; + hdr->used_as_loop_entry++; } } static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st) { + struct bpf_verifier_state_list *sl = NULL, *parent_sl; + struct bpf_verifier_state *parent; + while (st) { u32 br = --st->branches; @@ -1871,7 +1964,7 @@ static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifi * This is a part of 'case A' in get_loop_entry() comment. */ if (br == 0 && st->parent && st->loop_entry) - update_loop_entry(st->parent, st->loop_entry); + update_loop_entry(env, st->parent, st->loop_entry); /* WARN_ON(br > 1) technically makes sense here, * but see comment in push_stack(), hence: @@ -1881,7 +1974,12 @@ static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifi br); if (br) break; - st = st->parent; + parent = st->parent; + parent_sl = state_parent_as_list(st); + if (sl) + maybe_free_verifier_state(env, sl); + st = parent; + sl = parent_sl; } } @@ -3206,6 +3304,21 @@ bpf_jit_find_kfunc_model(const struct bpf_prog *prog, return res ? &res->func_model : NULL; } +static int add_kfunc_in_insns(struct bpf_verifier_env *env, + struct bpf_insn *insn, int cnt) +{ + int i, ret; + + for (i = 0; i < cnt; i++, insn++) { + if (bpf_pseudo_kfunc_call(insn)) { + ret = add_kfunc_call(env, insn->imm, insn->off); + if (ret < 0) + return ret; + } + } + return 0; +} + static int add_subprog_and_kfunc(struct bpf_verifier_env *env) { struct bpf_subprog_info *subprog = env->subprog_info; @@ -3269,6 +3382,15 @@ static int add_subprog_and_kfunc(struct bpf_verifier_env *env) return 0; } +static int jmp_offset(struct bpf_insn *insn) +{ + u8 code = insn->code; + + if (code == (BPF_JMP32 | BPF_JA)) + return insn->imm; + return insn->off; +} + static int check_subprogs(struct bpf_verifier_env *env) { int i, subprog_start, subprog_end, off, cur_subprog = 0; @@ -3295,10 +3417,7 @@ static int check_subprogs(struct bpf_verifier_env *env) goto next; if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL) goto next; - if (code == (BPF_JMP32 | BPF_JA)) - off = i + insn[i].imm + 1; - else - off = i + insn[i].off + 1; + off = i + jmp_offset(&insn[i]) + 1; if (off < subprog_start || off >= subprog_end) { verbose(env, "jump out of range from insn %d to %d\n", i, off); return -EINVAL; @@ -3338,12 +3457,11 @@ static int mark_reg_read(struct bpf_verifier_env *env, /* if read wasn't screened by an earlier write ... */ if (writes && state->live & REG_LIVE_WRITTEN) break; - if (parent->live & REG_LIVE_DONE) { - verbose(env, "verifier BUG type %s var_off %lld off %d\n", - reg_type_str(env, parent->type), - parent->var_off.value, parent->off); + if (verifier_bug_if(parent->live & REG_LIVE_DONE, env, + "type %s var_off %lld off %d", + reg_type_str(env, parent->type), + parent->var_off.value, parent->off)) return -EFAULT; - } /* The first condition is more likely to be true than the * second, checked it first. */ @@ -3483,7 +3601,7 @@ static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn, } if (class == BPF_STX) { - /* BPF_STX (including atomic variants) has multiple source + /* BPF_STX (including atomic variants) has one or more source * operands, one of which is a ptr. Check whether the caller is * asking about it. */ @@ -3528,16 +3646,16 @@ static int insn_def_regno(const struct bpf_insn *insn) case BPF_ST: return -1; case BPF_STX: - if ((BPF_MODE(insn->code) == BPF_ATOMIC || - BPF_MODE(insn->code) == BPF_PROBE_ATOMIC) && - (insn->imm & BPF_FETCH)) { + if (BPF_MODE(insn->code) == BPF_ATOMIC || + BPF_MODE(insn->code) == BPF_PROBE_ATOMIC) { if (insn->imm == BPF_CMPXCHG) return BPF_REG_0; - else + else if (insn->imm == BPF_LOAD_ACQ) + return insn->dst_reg; + else if (insn->imm & BPF_FETCH) return insn->src_reg; - } else { - return -1; } + return -1; default: return insn->dst_reg; } @@ -3736,14 +3854,14 @@ static int push_insn_history(struct bpf_verifier_env *env, struct bpf_verifier_s /* atomic instructions push insn_flags twice, for READ and * WRITE sides, but they should agree on stack slot */ - WARN_ONCE((env->cur_hist_ent->flags & insn_flags) && - (env->cur_hist_ent->flags & insn_flags) != insn_flags, - "verifier insn history bug: insn_idx %d cur flags %x new flags %x\n", - env->insn_idx, env->cur_hist_ent->flags, insn_flags); + verifier_bug_if((env->cur_hist_ent->flags & insn_flags) && + (env->cur_hist_ent->flags & insn_flags) != insn_flags, + env, "insn history: insn_idx %d cur flags %x new flags %x", + env->insn_idx, env->cur_hist_ent->flags, insn_flags); env->cur_hist_ent->flags |= insn_flags; - WARN_ONCE(env->cur_hist_ent->linked_regs != 0, - "verifier insn history bug: insn_idx %d linked_regs != 0: %#llx\n", - env->insn_idx, env->cur_hist_ent->linked_regs); + verifier_bug_if(env->cur_hist_ent->linked_regs != 0, env, + "insn history: insn_idx %d linked_regs: %#llx", + env->insn_idx, env->cur_hist_ent->linked_regs); env->cur_hist_ent->linked_regs = linked_regs; return 0; } @@ -3828,6 +3946,17 @@ static const char *disasm_kfunc_name(void *data, const struct bpf_insn *insn) return btf_name_by_offset(desc_btf, func->name_off); } +static void verbose_insn(struct bpf_verifier_env *env, struct bpf_insn *insn) +{ + const struct bpf_insn_cbs cbs = { + .cb_call = disasm_kfunc_name, + .cb_print = verbose, + .private_data = env, + }; + + print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); +} + static inline void bt_init(struct backtrack_state *bt, u32 frame) { bt->frame = frame; @@ -3855,8 +3984,7 @@ static inline u32 bt_empty(struct backtrack_state *bt) static inline int bt_subprog_enter(struct backtrack_state *bt) { if (bt->frame == MAX_CALL_FRAMES - 1) { - verbose(bt->env, "BUG subprog enter from frame %d\n", bt->frame); - WARN_ONCE(1, "verifier backtracking bug"); + verifier_bug(bt->env, "subprog enter from frame %d", bt->frame); return -EFAULT; } bt->frame++; @@ -3866,8 +3994,7 @@ static inline int bt_subprog_enter(struct backtrack_state *bt) static inline int bt_subprog_exit(struct backtrack_state *bt) { if (bt->frame == 0) { - verbose(bt->env, "BUG subprog exit from frame 0\n"); - WARN_ONCE(1, "verifier backtracking bug"); + verifier_bug(bt->env, "subprog exit from frame 0"); return -EFAULT; } bt->frame--; @@ -4028,11 +4155,6 @@ static bool calls_callback(struct bpf_verifier_env *env, int insn_idx); static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, struct bpf_insn_hist_entry *hist, struct backtrack_state *bt) { - const struct bpf_insn_cbs cbs = { - .cb_call = disasm_kfunc_name, - .cb_print = verbose, - .private_data = env, - }; struct bpf_insn *insn = env->prog->insnsi + idx; u8 class = BPF_CLASS(insn->code); u8 opcode = BPF_OP(insn->code); @@ -4050,7 +4172,7 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, fmt_stack_mask(env->tmp_str_buf, TMP_STR_BUF_LEN, bt_stack_mask(bt)); verbose(env, "stack=%s before ", env->tmp_str_buf); verbose(env, "%d: ", idx); - print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); + verbose_insn(env, insn); } /* If there is a history record that some registers gained range at this insn, @@ -4097,7 +4219,7 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, * dreg still needs precision before this insn */ } - } else if (class == BPF_LDX) { + } else if (class == BPF_LDX || is_atomic_load_insn(insn)) { if (!bt_is_reg_set(bt, dreg)) return 0; bt_clear_reg(bt, dreg); @@ -4150,14 +4272,15 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, * should be literally next instruction in * caller program */ - WARN_ONCE(idx + 1 != subseq_idx, "verifier backtracking bug"); + verifier_bug_if(idx + 1 != subseq_idx, env, + "extra insn from subprog"); /* r1-r5 are invalidated after subprog call, * so for global func call it shouldn't be set * anymore */ if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) { - verbose(env, "BUG regs %x\n", bt_reg_mask(bt)); - WARN_ONCE(1, "verifier backtracking bug"); + verifier_bug(env, "global subprog unexpected regs %x", + bt_reg_mask(bt)); return -EFAULT; } /* global subprog always sets R0 */ @@ -4171,16 +4294,17 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, * the current frame should be zero by now */ if (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) { - verbose(env, "BUG regs %x\n", bt_reg_mask(bt)); - WARN_ONCE(1, "verifier backtracking bug"); + verifier_bug(env, "static subprog unexpected regs %x", + bt_reg_mask(bt)); return -EFAULT; } /* we are now tracking register spills correctly, * so any instance of leftover slots is a bug */ if (bt_stack_mask(bt) != 0) { - verbose(env, "BUG stack slots %llx\n", bt_stack_mask(bt)); - WARN_ONCE(1, "verifier backtracking bug (subprog leftover stack slots)"); + verifier_bug(env, + "static subprog leftover stack slots %llx", + bt_stack_mask(bt)); return -EFAULT; } /* propagate r1-r5 to the caller */ @@ -4203,13 +4327,13 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, * not actually arguments passed directly to callback subprogs */ if (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) { - verbose(env, "BUG regs %x\n", bt_reg_mask(bt)); - WARN_ONCE(1, "verifier backtracking bug"); + verifier_bug(env, "callback unexpected regs %x", + bt_reg_mask(bt)); return -EFAULT; } if (bt_stack_mask(bt) != 0) { - verbose(env, "BUG stack slots %llx\n", bt_stack_mask(bt)); - WARN_ONCE(1, "verifier backtracking bug (callback leftover stack slots)"); + verifier_bug(env, "callback leftover stack slots %llx", + bt_stack_mask(bt)); return -EFAULT; } /* clear r1-r5 in callback subprog's mask */ @@ -4228,11 +4352,11 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, /* regular helper call sets R0 */ bt_clear_reg(bt, BPF_REG_0); if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) { - /* if backtracing was looking for registers R1-R5 + /* if backtracking was looking for registers R1-R5 * they should have been found already. */ - verbose(env, "BUG regs %x\n", bt_reg_mask(bt)); - WARN_ONCE(1, "verifier backtracking bug"); + verifier_bug(env, "backtracking call unexpected regs %x", + bt_reg_mask(bt)); return -EFAULT; } } else if (opcode == BPF_EXIT) { @@ -4250,8 +4374,8 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, for (i = BPF_REG_1; i <= BPF_REG_5; i++) bt_clear_reg(bt, i); if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) { - verbose(env, "BUG regs %x\n", bt_reg_mask(bt)); - WARN_ONCE(1, "verifier backtracking bug"); + verifier_bug(env, "backtracking exit unexpected regs %x", + bt_reg_mask(bt)); return -EFAULT; } @@ -4286,8 +4410,10 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, * before it would be equally necessary to * propagate it to dreg. */ - bt_set_reg(bt, dreg); - bt_set_reg(bt, sreg); + if (!hist || !(hist->flags & INSN_F_SRC_REG_STACK)) + bt_set_reg(bt, sreg); + if (!hist || !(hist->flags & INSN_F_DST_REG_STACK)) + bt_set_reg(bt, dreg); } else if (BPF_SRC(insn->code) == BPF_K) { /* dreg <cond> K * Only dreg still needs precision before @@ -4592,9 +4718,8 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) return 0; } - verbose(env, "BUG backtracking func entry subprog %d reg_mask %x stack_mask %llx\n", - st->frame[0]->subprogno, bt_reg_mask(bt), bt_stack_mask(bt)); - WARN_ONCE(1, "verifier backtracking bug"); + verifier_bug(env, "backtracking func entry subprog %d reg_mask %x stack_mask %llx", + st->frame[0]->subprogno, bt_reg_mask(bt), bt_stack_mask(bt)); return -EFAULT; } @@ -4630,8 +4755,7 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) * It means the backtracking missed the spot where * particular register was initialized with a constant. */ - verbose(env, "BUG backtracking idx %d\n", i); - WARN_ONCE(1, "verifier backtracking bug"); + verifier_bug(env, "backtracking idx %d", i); return -EFAULT; } } @@ -4656,12 +4780,10 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) bitmap_from_u64(mask, bt_frame_stack_mask(bt, fr)); for_each_set_bit(i, mask, 64) { - if (i >= func->allocated_stack / BPF_REG_SIZE) { - verbose(env, "BUG backtracking (stack slot %d, total slots %d)\n", - i, func->allocated_stack / BPF_REG_SIZE); - WARN_ONCE(1, "verifier backtracking bug (stack slot out of bounds)"); + if (verifier_bug_if(i >= func->allocated_stack / BPF_REG_SIZE, + env, "stack slot %d, total slots %d", + i, func->allocated_stack / BPF_REG_SIZE)) return -EFAULT; - } if (!is_spilled_scalar_reg(&func->stack[i])) { bt_clear_frame_slot(bt, fr, i); @@ -5982,18 +6104,10 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, /* check access to 'struct bpf_context' fields. Supports fixed offsets only */ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size, - enum bpf_access_type t, enum bpf_reg_type *reg_type, - struct btf **btf, u32 *btf_id, bool *is_retval, bool is_ldsx) + enum bpf_access_type t, struct bpf_insn_access_aux *info) { - struct bpf_insn_access_aux info = { - .reg_type = *reg_type, - .log = &env->log, - .is_retval = false, - .is_ldsx = is_ldsx, - }; - if (env->ops->is_valid_access && - env->ops->is_valid_access(off, size, t, env->prog, &info)) { + env->ops->is_valid_access(off, size, t, env->prog, info)) { /* A non zero info.ctx_field_size indicates that this field is a * candidate for later verifier transformation to load the whole * field and then apply a mask when accessed with a narrower @@ -6001,14 +6115,15 @@ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, * will only allow for whole field access and rejects any other * type of narrower access. */ - *reg_type = info.reg_type; - *is_retval = info.is_retval; - - if (base_type(*reg_type) == PTR_TO_BTF_ID) { - *btf = info.btf; - *btf_id = info.btf_id; + if (base_type(info->reg_type) == PTR_TO_BTF_ID) { + if (info->ref_obj_id && + !find_reference_state(env->cur_state, info->ref_obj_id)) { + verbose(env, "invalid bpf_context access off=%d. Reference may already be released\n", + off); + return -EACCES; + } } else { - env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size; + env->insn_aux_data[insn_idx].ctx_field_size = info->ctx_field_size; } /* remember the offset of last byte accessed in ctx */ if (env->prog->aux->max_ctx_offset < off + size) @@ -6118,6 +6233,26 @@ static bool is_arena_reg(struct bpf_verifier_env *env, int regno) return reg->type == PTR_TO_ARENA; } +/* Return false if @regno contains a pointer whose type isn't supported for + * atomic instruction @insn. + */ +static bool atomic_ptr_type_ok(struct bpf_verifier_env *env, int regno, + struct bpf_insn *insn) +{ + if (is_ctx_reg(env, regno)) + return false; + if (is_pkt_reg(env, regno)) + return false; + if (is_flow_key_reg(env, regno)) + return false; + if (is_sk_reg(env, regno)) + return false; + if (is_arena_reg(env, regno)) + return bpf_jit_supports_insn(insn, true); + + return true; +} + static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = { #ifdef CONFIG_NET [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK], @@ -6421,21 +6556,18 @@ continue_func: /* find the callee */ next_insn = i + insn[i].imm + 1; sidx = find_subprog(env, next_insn); - if (sidx < 0) { - WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", - next_insn); + if (verifier_bug_if(sidx < 0, env, "callee not found at insn %d", next_insn)) return -EFAULT; - } if (subprog[sidx].is_async_cb) { if (subprog[sidx].has_tail_call) { - verbose(env, "verifier bug. subprog has tail_call and async cb\n"); + verifier_bug(env, "subprog has tail_call and async cb"); return -EFAULT; } /* async callbacks don't increase bpf prog stack size unless called directly */ if (!bpf_pseudo_call(insn + i)) continue; if (subprog[sidx].is_exception_cb) { - verbose(env, "insn %d cannot call exception cb directly\n", i); + verbose(env, "insn %d cannot call exception cb directly", i); return -EINVAL; } } @@ -6535,11 +6667,8 @@ static int get_callee_stack_depth(struct bpf_verifier_env *env, int start = idx + insn->imm + 1, subprog; subprog = find_subprog(env, start); - if (subprog < 0) { - WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", - start); + if (verifier_bug_if(subprog < 0, env, "get stack depth: no program at insn %d", start)) return -EFAULT; - } return env->subprog_info[subprog].stack_depth; } #endif @@ -7365,11 +7494,12 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn if (!err && value_regno >= 0 && (t == BPF_READ || rdonly_mem)) mark_reg_unknown(env, regs, value_regno); } else if (reg->type == PTR_TO_CTX) { - bool is_retval = false; struct bpf_retval_range range; - enum bpf_reg_type reg_type = SCALAR_VALUE; - struct btf *btf = NULL; - u32 btf_id = 0; + struct bpf_insn_access_aux info = { + .reg_type = SCALAR_VALUE, + .is_ldsx = is_ldsx, + .log = &env->log, + }; if (t == BPF_WRITE && value_regno >= 0 && is_pointer_value(env, value_regno)) { @@ -7381,8 +7511,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn if (err < 0) return err; - err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf, - &btf_id, &is_retval, is_ldsx); + err = check_ctx_access(env, insn_idx, off, size, t, &info); if (err) verbose_linfo(env, insn_idx, "; "); if (!err && t == BPF_READ && value_regno >= 0) { @@ -7390,8 +7519,8 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn * PTR_TO_PACKET[_META,_END]. In the latter * case, we know the offset is zero. */ - if (reg_type == SCALAR_VALUE) { - if (is_retval && get_func_retval_range(env->prog, &range)) { + if (info.reg_type == SCALAR_VALUE) { + if (info.is_retval && get_func_retval_range(env->prog, &range)) { err = __mark_reg_s32_range(env, regs, value_regno, range.minval, range.maxval); if (err) @@ -7402,7 +7531,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn } else { mark_reg_known_zero(env, regs, value_regno); - if (type_may_be_null(reg_type)) + if (type_may_be_null(info.reg_type)) regs[value_regno].id = ++env->id_gen; /* A load of ctx field could have different * actual load size with the one encoded in the @@ -7410,12 +7539,13 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn * a sub-register. */ regs[value_regno].subreg_def = DEF_NOT_SUBREG; - if (base_type(reg_type) == PTR_TO_BTF_ID) { - regs[value_regno].btf = btf; - regs[value_regno].btf_id = btf_id; + if (base_type(info.reg_type) == PTR_TO_BTF_ID) { + regs[value_regno].btf = info.btf; + regs[value_regno].btf_id = info.btf_id; + regs[value_regno].ref_obj_id = info.ref_obj_id; } } - regs[value_regno].type = reg_type; + regs[value_regno].type = info.reg_type; } } else if (reg->type == PTR_TO_STACK) { @@ -7518,27 +7648,72 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn static int save_aux_ptr_type(struct bpf_verifier_env *env, enum bpf_reg_type type, bool allow_trust_mismatch); -static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn) +static int check_load_mem(struct bpf_verifier_env *env, struct bpf_insn *insn, + bool strict_alignment_once, bool is_ldsx, + bool allow_trust_mismatch, const char *ctx) { - int load_reg; + struct bpf_reg_state *regs = cur_regs(env); + enum bpf_reg_type src_reg_type; int err; - switch (insn->imm) { - case BPF_ADD: - case BPF_ADD | BPF_FETCH: - case BPF_AND: - case BPF_AND | BPF_FETCH: - case BPF_OR: - case BPF_OR | BPF_FETCH: - case BPF_XOR: - case BPF_XOR | BPF_FETCH: - case BPF_XCHG: - case BPF_CMPXCHG: - break; - default: - verbose(env, "BPF_ATOMIC uses invalid atomic opcode %02x\n", insn->imm); - return -EINVAL; - } + /* check src operand */ + err = check_reg_arg(env, insn->src_reg, SRC_OP); + if (err) + return err; + + /* check dst operand */ + err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); + if (err) + return err; + + src_reg_type = regs[insn->src_reg].type; + + /* Check if (src_reg + off) is readable. The state of dst_reg will be + * updated by this call. + */ + err = check_mem_access(env, env->insn_idx, insn->src_reg, insn->off, + BPF_SIZE(insn->code), BPF_READ, insn->dst_reg, + strict_alignment_once, is_ldsx); + err = err ?: save_aux_ptr_type(env, src_reg_type, + allow_trust_mismatch); + err = err ?: reg_bounds_sanity_check(env, ®s[insn->dst_reg], ctx); + + return err; +} + +static int check_store_reg(struct bpf_verifier_env *env, struct bpf_insn *insn, + bool strict_alignment_once) +{ + struct bpf_reg_state *regs = cur_regs(env); + enum bpf_reg_type dst_reg_type; + int err; + + /* check src1 operand */ + err = check_reg_arg(env, insn->src_reg, SRC_OP); + if (err) + return err; + + /* check src2 operand */ + err = check_reg_arg(env, insn->dst_reg, SRC_OP); + if (err) + return err; + + dst_reg_type = regs[insn->dst_reg].type; + + /* Check if (dst_reg + off) is writeable. */ + err = check_mem_access(env, env->insn_idx, insn->dst_reg, insn->off, + BPF_SIZE(insn->code), BPF_WRITE, insn->src_reg, + strict_alignment_once, false); + err = err ?: save_aux_ptr_type(env, dst_reg_type, false); + + return err; +} + +static int check_atomic_rmw(struct bpf_verifier_env *env, + struct bpf_insn *insn) +{ + int load_reg; + int err; if (BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) { verbose(env, "invalid atomic operand size\n"); @@ -7574,11 +7749,7 @@ static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_i return -EACCES; } - if (is_ctx_reg(env, insn->dst_reg) || - is_pkt_reg(env, insn->dst_reg) || - is_flow_key_reg(env, insn->dst_reg) || - is_sk_reg(env, insn->dst_reg) || - (is_arena_reg(env, insn->dst_reg) && !bpf_jit_supports_insn(insn, true))) { + if (!atomic_ptr_type_ok(env, insn->dst_reg, insn)) { verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n", insn->dst_reg, reg_type_str(env, reg_state(env, insn->dst_reg)->type)); @@ -7605,12 +7776,12 @@ static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_i /* Check whether we can read the memory, with second call for fetch * case to simulate the register fill. */ - err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, + err = check_mem_access(env, env->insn_idx, insn->dst_reg, insn->off, BPF_SIZE(insn->code), BPF_READ, -1, true, false); if (!err && load_reg >= 0) - err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, - BPF_SIZE(insn->code), BPF_READ, load_reg, - true, false); + err = check_mem_access(env, env->insn_idx, insn->dst_reg, + insn->off, BPF_SIZE(insn->code), + BPF_READ, load_reg, true, false); if (err) return err; @@ -7620,13 +7791,86 @@ static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_i return err; } /* Check whether we can write into the same memory. */ - err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off, + err = check_mem_access(env, env->insn_idx, insn->dst_reg, insn->off, BPF_SIZE(insn->code), BPF_WRITE, -1, true, false); if (err) return err; return 0; } +static int check_atomic_load(struct bpf_verifier_env *env, + struct bpf_insn *insn) +{ + int err; + + err = check_load_mem(env, insn, true, false, false, "atomic_load"); + if (err) + return err; + + if (!atomic_ptr_type_ok(env, insn->src_reg, insn)) { + verbose(env, "BPF_ATOMIC loads from R%d %s is not allowed\n", + insn->src_reg, + reg_type_str(env, reg_state(env, insn->src_reg)->type)); + return -EACCES; + } + + return 0; +} + +static int check_atomic_store(struct bpf_verifier_env *env, + struct bpf_insn *insn) +{ + int err; + + err = check_store_reg(env, insn, true); + if (err) + return err; + + if (!atomic_ptr_type_ok(env, insn->dst_reg, insn)) { + verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n", + insn->dst_reg, + reg_type_str(env, reg_state(env, insn->dst_reg)->type)); + return -EACCES; + } + + return 0; +} + +static int check_atomic(struct bpf_verifier_env *env, struct bpf_insn *insn) +{ + switch (insn->imm) { + case BPF_ADD: + case BPF_ADD | BPF_FETCH: + case BPF_AND: + case BPF_AND | BPF_FETCH: + case BPF_OR: + case BPF_OR | BPF_FETCH: + case BPF_XOR: + case BPF_XOR | BPF_FETCH: + case BPF_XCHG: + case BPF_CMPXCHG: + return check_atomic_rmw(env, insn); + case BPF_LOAD_ACQ: + if (BPF_SIZE(insn->code) == BPF_DW && BITS_PER_LONG != 64) { + verbose(env, + "64-bit load-acquires are only supported on 64-bit arches\n"); + return -EOPNOTSUPP; + } + return check_atomic_load(env, insn); + case BPF_STORE_REL: + if (BPF_SIZE(insn->code) == BPF_DW && BITS_PER_LONG != 64) { + verbose(env, + "64-bit store-releases are only supported on 64-bit arches\n"); + return -EOPNOTSUPP; + } + return check_atomic_store(env, insn); + default: + verbose(env, "BPF_ATOMIC uses invalid atomic opcode %02x\n", + insn->imm); + return -EINVAL; + } +} + /* When register 'regno' is used to read the stack (either directly or through * a helper function) make sure that it's within stack boundary and, depending * on the access type and privileges, that all elements of the stack are @@ -7729,7 +7973,7 @@ static int check_stack_range_initialized( slot = -i - 1; spi = slot / BPF_REG_SIZE; if (state->allocated_stack <= slot) { - verbose(env, "verifier bug: allocated_stack too small\n"); + verbose(env, "allocated_stack too small\n"); return -EFAULT; } @@ -7985,6 +8229,12 @@ static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg return err; } +enum { + PROCESS_SPIN_LOCK = (1 << 0), + PROCESS_RES_LOCK = (1 << 1), + PROCESS_LOCK_IRQ = (1 << 2), +}; + /* Implementation details: * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL. * bpf_obj_new returns PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL. @@ -8007,30 +8257,33 @@ static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg * env->cur_state->active_locks remembers which map value element or allocated * object got locked and clears it after bpf_spin_unlock. */ -static int process_spin_lock(struct bpf_verifier_env *env, int regno, - bool is_lock) +static int process_spin_lock(struct bpf_verifier_env *env, int regno, int flags) { + bool is_lock = flags & PROCESS_SPIN_LOCK, is_res_lock = flags & PROCESS_RES_LOCK; + const char *lock_str = is_res_lock ? "bpf_res_spin" : "bpf_spin"; struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; struct bpf_verifier_state *cur = env->cur_state; bool is_const = tnum_is_const(reg->var_off); + bool is_irq = flags & PROCESS_LOCK_IRQ; u64 val = reg->var_off.value; struct bpf_map *map = NULL; struct btf *btf = NULL; struct btf_record *rec; + u32 spin_lock_off; int err; if (!is_const) { verbose(env, - "R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n", - regno); + "R%d doesn't have constant offset. %s_lock has to be at the constant offset\n", + regno, lock_str); return -EINVAL; } if (reg->type == PTR_TO_MAP_VALUE) { map = reg->map_ptr; if (!map->btf) { verbose(env, - "map '%s' has to have BTF in order to use bpf_spin_lock\n", - map->name); + "map '%s' has to have BTF in order to use %s_lock\n", + map->name, lock_str); return -EINVAL; } } else { @@ -8038,36 +8291,53 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, } rec = reg_btf_record(reg); - if (!btf_record_has_field(rec, BPF_SPIN_LOCK)) { - verbose(env, "%s '%s' has no valid bpf_spin_lock\n", map ? "map" : "local", - map ? map->name : "kptr"); + if (!btf_record_has_field(rec, is_res_lock ? BPF_RES_SPIN_LOCK : BPF_SPIN_LOCK)) { + verbose(env, "%s '%s' has no valid %s_lock\n", map ? "map" : "local", + map ? map->name : "kptr", lock_str); return -EINVAL; } - if (rec->spin_lock_off != val + reg->off) { - verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock' that is at %d\n", - val + reg->off, rec->spin_lock_off); + spin_lock_off = is_res_lock ? rec->res_spin_lock_off : rec->spin_lock_off; + if (spin_lock_off != val + reg->off) { + verbose(env, "off %lld doesn't point to 'struct %s_lock' that is at %d\n", + val + reg->off, lock_str, spin_lock_off); return -EINVAL; } if (is_lock) { void *ptr; + int type; if (map) ptr = map; else ptr = btf; - if (cur->active_locks) { - verbose(env, - "Locking two bpf_spin_locks are not allowed\n"); - return -EINVAL; + if (!is_res_lock && cur->active_locks) { + if (find_lock_state(env->cur_state, REF_TYPE_LOCK, 0, NULL)) { + verbose(env, + "Locking two bpf_spin_locks are not allowed\n"); + return -EINVAL; + } + } else if (is_res_lock && cur->active_locks) { + if (find_lock_state(env->cur_state, REF_TYPE_RES_LOCK | REF_TYPE_RES_LOCK_IRQ, reg->id, ptr)) { + verbose(env, "Acquiring the same lock again, AA deadlock detected\n"); + return -EINVAL; + } } - err = acquire_lock_state(env, env->insn_idx, REF_TYPE_LOCK, reg->id, ptr); + + if (is_res_lock && is_irq) + type = REF_TYPE_RES_LOCK_IRQ; + else if (is_res_lock) + type = REF_TYPE_RES_LOCK; + else + type = REF_TYPE_LOCK; + err = acquire_lock_state(env, env->insn_idx, type, reg->id, ptr); if (err < 0) { verbose(env, "Failed to acquire lock state\n"); return err; } } else { void *ptr; + int type; if (map) ptr = map; @@ -8075,12 +8345,26 @@ static int process_spin_lock(struct bpf_verifier_env *env, int regno, ptr = btf; if (!cur->active_locks) { - verbose(env, "bpf_spin_unlock without taking a lock\n"); + verbose(env, "%s_unlock without taking a lock\n", lock_str); return -EINVAL; } - if (release_lock_state(env->cur_state, REF_TYPE_LOCK, reg->id, ptr)) { - verbose(env, "bpf_spin_unlock of different lock\n"); + if (is_res_lock && is_irq) + type = REF_TYPE_RES_LOCK_IRQ; + else if (is_res_lock) + type = REF_TYPE_RES_LOCK; + else + type = REF_TYPE_LOCK; + if (!find_lock_state(cur, type, reg->id, ptr)) { + verbose(env, "%s_unlock of different lock\n", lock_str); + return -EINVAL; + } + if (reg->id != cur->active_lock_id || ptr != cur->active_lock_ptr) { + verbose(env, "%s_unlock cannot be out of order\n", lock_str); + return -EINVAL; + } + if (release_lock_state(cur, type, reg->id, ptr)) { + verbose(env, "%s_unlock of different lock\n", lock_str); return -EINVAL; } @@ -8118,7 +8402,7 @@ static int process_timer_func(struct bpf_verifier_env *env, int regno, return -EINVAL; } if (meta->map_ptr) { - verbose(env, "verifier bug. Two map pointers in a timer helper\n"); + verifier_bug(env, "Two map pointers in a timer helper"); return -EFAULT; } meta->map_uid = reg->map_uid; @@ -8431,10 +8715,12 @@ static struct bpf_verifier_state *find_prev_entry(struct bpf_verifier_env *env, { struct bpf_verifier_state_list *sl; struct bpf_verifier_state *st; + struct list_head *pos, *head; /* Explored states are pushed in stack order, most recent states come first */ - sl = *explored_state(env, insn_idx); - for (; sl; sl = sl->next) { + head = explored_state(env, insn_idx); + list_for_each(pos, head) { + sl = container_of(pos, struct bpf_verifier_state_list, node); /* If st->branches != 0 state is a part of current DFS verification path, * hence cur & st for a loop. */ @@ -9404,11 +9690,11 @@ skip_type_check: return -EACCES; } if (meta->func_id == BPF_FUNC_spin_lock) { - err = process_spin_lock(env, regno, true); + err = process_spin_lock(env, regno, PROCESS_SPIN_LOCK); if (err) return err; } else if (meta->func_id == BPF_FUNC_spin_unlock) { - err = process_spin_lock(env, regno, false); + err = process_spin_lock(env, regno, 0); if (err) return err; } else { @@ -9666,7 +9952,7 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) goto error; if (env->subprog_cnt > 1 && !allow_tail_call_in_subprogs(env)) { - verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n"); + verbose(env, "mixing of tail_calls and bpf-to-bpf calls is not supported\n"); return -EINVAL; } break; @@ -9988,8 +10274,7 @@ static int setup_func_entry(struct bpf_verifier_env *env, int subprog, int calls } if (state->frame[state->curframe + 1]) { - verbose(env, "verifier bug. Frame %d already allocated\n", - state->curframe + 1); + verifier_bug(env, "Frame %d already allocated", state->curframe + 1); return -EFAULT; } @@ -10103,8 +10388,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, if (err) return err; } else { - bpf_log(log, "verifier bug: unrecognized arg#%d type %d\n", - i, arg->arg_type); + verifier_bug(env, "unrecognized arg#%d type %d", i, arg->arg_type); return -EFAULT; } } @@ -10167,13 +10451,13 @@ static int push_callback_call(struct bpf_verifier_env *env, struct bpf_insn *ins env->subprog_info[subprog].is_cb = true; if (bpf_pseudo_kfunc_call(insn) && !is_callback_calling_kfunc(insn->imm)) { - verbose(env, "verifier bug: kfunc %s#%d not marked as callback-calling\n", - func_id_name(insn->imm), insn->imm); + verifier_bug(env, "kfunc %s#%d not marked as callback-calling", + func_id_name(insn->imm), insn->imm); return -EFAULT; } else if (!bpf_pseudo_kfunc_call(insn) && !is_callback_calling_function(insn->imm)) { /* helper */ - verbose(env, "verifier bug: helper %s#%d not marked as callback-calling\n", - func_id_name(insn->imm), insn->imm); + verifier_bug(env, "helper %s#%d not marked as callback-calling", + func_id_name(insn->imm), insn->imm); return -EFAULT; } @@ -10225,10 +10509,9 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, target_insn = *insn_idx + insn->imm + 1; subprog = find_subprog(env, target_insn); - if (subprog < 0) { - verbose(env, "verifier bug. No program starts at insn %d\n", target_insn); + if (verifier_bug_if(subprog < 0, env, "target of func call at insn %d is not a program", + target_insn)) return -EFAULT; - } caller = state->frame[state->curframe]; err = btf_check_subprog_call(env, subprog, caller->regs); @@ -10237,23 +10520,18 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (subprog_is_global(env, subprog)) { const char *sub_name = subprog_name(env, subprog); - /* Only global subprogs cannot be called with a lock held. */ if (env->cur_state->active_locks) { verbose(env, "global function calls are not allowed while holding a lock,\n" "use static function instead\n"); return -EINVAL; } - /* Only global subprogs cannot be called with preemption disabled. */ - if (env->cur_state->active_preempt_locks) { - verbose(env, "global function calls are not allowed with preemption disabled,\n" - "use static function instead\n"); - return -EINVAL; - } - - if (env->cur_state->active_irq_id) { - verbose(env, "global function calls are not allowed with IRQs disabled,\n" - "use static function instead\n"); + if (env->subprog_info[subprog].might_sleep && + (env->cur_state->active_rcu_lock || env->cur_state->active_preempt_locks || + env->cur_state->active_irq_id || !in_sleepable(env))) { + verbose(env, "global functions that may sleep are not allowed in non-sleepable context,\n" + "i.e., in a RCU/IRQ/preempt-disabled section, or in\n" + "a non-sleepable BPF program context\n"); return -EINVAL; } @@ -10752,6 +11030,8 @@ record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, static int check_reference_leak(struct bpf_verifier_env *env, bool exception_exit) { struct bpf_verifier_state *state = env->cur_state; + enum bpf_prog_type type = resolve_prog_type(env->prog); + struct bpf_reg_state *reg = reg_state(env, BPF_REG_0); bool refs_lingering = false; int i; @@ -10761,6 +11041,12 @@ static int check_reference_leak(struct bpf_verifier_env *env, bool exception_exi for (i = 0; i < state->acquired_refs; i++) { if (state->refs[i].type != REF_TYPE_PTR) continue; + /* Allow struct_ops programs to return a referenced kptr back to + * kernel. Type checks are performed later in check_return_code. + */ + if (type == BPF_PROG_TYPE_STRUCT_OPS && !exception_exit && + reg->ref_obj_id == state->refs[i].id) + continue; verbose(env, "Unreleased reference id=%d alloc_insn=%d\n", state->refs[i].id, state->refs[i].insn_idx); refs_lingering = true; @@ -10824,7 +11110,7 @@ static int check_bpf_snprintf_call(struct bpf_verifier_env *env, err = fmt_map->ops->map_direct_value_addr(fmt_map, &fmt_addr, fmt_map_off); if (err) { - verbose(env, "verifier bug\n"); + verbose(env, "failed to retrieve map value address\n"); return -EFAULT; } fmt = (char *)(long)fmt_addr + fmt_map_off; @@ -11287,7 +11573,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn regs[BPF_REG_0].map_uid = meta.map_uid; regs[BPF_REG_0].type = PTR_TO_MAP_VALUE | ret_flag; if (!type_may_be_null(ret_flag) && - btf_record_has_field(meta.map_ptr->record, BPF_SPIN_LOCK)) { + btf_record_has_field(meta.map_ptr->record, BPF_SPIN_LOCK | BPF_RES_SPIN_LOCK)) { regs[BPF_REG_0].id = ++env->id_gen; } break; @@ -11459,10 +11745,10 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn /* mark_btf_func_reg_size() is used when the reg size is determined by * the BTF func_proto's return value size and argument. */ -static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno, - size_t reg_size) +static void __mark_btf_func_reg_size(struct bpf_verifier_env *env, struct bpf_reg_state *regs, + u32 regno, size_t reg_size) { - struct bpf_reg_state *reg = &cur_regs(env)[regno]; + struct bpf_reg_state *reg = ®s[regno]; if (regno == BPF_REG_0) { /* Function return value */ @@ -11480,6 +11766,12 @@ static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno, } } +static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno, + size_t reg_size) +{ + return __mark_btf_func_reg_size(env, cur_regs(env), regno, reg_size); +} + static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta) { return meta->kfunc_flags & KF_ACQUIRE; @@ -11591,6 +11883,11 @@ static bool is_kfunc_arg_irq_flag(const struct btf *btf, const struct btf_param return btf_param_match_suffix(btf, arg, "__irq_flag"); } +static bool is_kfunc_arg_prog(const struct btf *btf, const struct btf_param *arg) +{ + return btf_param_match_suffix(btf, arg, "__prog"); +} + static bool is_kfunc_arg_scalar_with_name(const struct btf *btf, const struct btf_param *arg, const char *name) @@ -11617,6 +11914,7 @@ enum { KF_ARG_RB_ROOT_ID, KF_ARG_RB_NODE_ID, KF_ARG_WORKQUEUE_ID, + KF_ARG_RES_SPIN_LOCK_ID, }; BTF_ID_LIST(kf_arg_btf_ids) @@ -11626,6 +11924,7 @@ BTF_ID(struct, bpf_list_node) BTF_ID(struct, bpf_rb_root) BTF_ID(struct, bpf_rb_node) BTF_ID(struct, bpf_wq) +BTF_ID(struct, bpf_res_spin_lock) static bool __is_kfunc_ptr_arg_type(const struct btf *btf, const struct btf_param *arg, int type) @@ -11674,6 +11973,21 @@ static bool is_kfunc_arg_wq(const struct btf *btf, const struct btf_param *arg) return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_WORKQUEUE_ID); } +static bool is_kfunc_arg_res_spin_lock(const struct btf *btf, const struct btf_param *arg) +{ + return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RES_SPIN_LOCK_ID); +} + +static bool is_rbtree_node_type(const struct btf_type *t) +{ + return t == btf_type_by_id(btf_vmlinux, kf_arg_btf_ids[KF_ARG_RB_NODE_ID]); +} + +static bool is_list_node_type(const struct btf_type *t) +{ + return t == btf_type_by_id(btf_vmlinux, kf_arg_btf_ids[KF_ARG_LIST_NODE_ID]); +} + static bool is_kfunc_arg_callback(struct bpf_verifier_env *env, const struct btf *btf, const struct btf_param *arg) { @@ -11745,6 +12059,7 @@ enum kfunc_ptr_arg_type { KF_ARG_PTR_TO_MAP, KF_ARG_PTR_TO_WORKQUEUE, KF_ARG_PTR_TO_IRQ_FLAG, + KF_ARG_PTR_TO_RES_SPIN_LOCK, }; enum special_kfunc_type { @@ -11755,6 +12070,8 @@ enum special_kfunc_type { KF_bpf_list_push_back_impl, KF_bpf_list_pop_front, KF_bpf_list_pop_back, + KF_bpf_list_front, + KF_bpf_list_back, KF_bpf_cast_to_kern_ctx, KF_bpf_rdonly_cast, KF_bpf_rcu_read_lock, @@ -11762,6 +12079,9 @@ enum special_kfunc_type { KF_bpf_rbtree_remove, KF_bpf_rbtree_add_impl, KF_bpf_rbtree_first, + KF_bpf_rbtree_root, + KF_bpf_rbtree_left, + KF_bpf_rbtree_right, KF_bpf_dynptr_from_skb, KF_bpf_dynptr_from_xdp, KF_bpf_dynptr_slice, @@ -11781,37 +12101,15 @@ enum special_kfunc_type { KF_bpf_iter_num_new, KF_bpf_iter_num_next, KF_bpf_iter_num_destroy, + KF_bpf_set_dentry_xattr, + KF_bpf_remove_dentry_xattr, + KF_bpf_res_spin_lock, + KF_bpf_res_spin_unlock, + KF_bpf_res_spin_lock_irqsave, + KF_bpf_res_spin_unlock_irqrestore, + KF___bpf_trap, }; -BTF_SET_START(special_kfunc_set) -BTF_ID(func, bpf_obj_new_impl) -BTF_ID(func, bpf_obj_drop_impl) -BTF_ID(func, bpf_refcount_acquire_impl) -BTF_ID(func, bpf_list_push_front_impl) -BTF_ID(func, bpf_list_push_back_impl) -BTF_ID(func, bpf_list_pop_front) -BTF_ID(func, bpf_list_pop_back) -BTF_ID(func, bpf_cast_to_kern_ctx) -BTF_ID(func, bpf_rdonly_cast) -BTF_ID(func, bpf_rbtree_remove) -BTF_ID(func, bpf_rbtree_add_impl) -BTF_ID(func, bpf_rbtree_first) -#ifdef CONFIG_NET -BTF_ID(func, bpf_dynptr_from_skb) -BTF_ID(func, bpf_dynptr_from_xdp) -#endif -BTF_ID(func, bpf_dynptr_slice) -BTF_ID(func, bpf_dynptr_slice_rdwr) -BTF_ID(func, bpf_dynptr_clone) -BTF_ID(func, bpf_percpu_obj_new_impl) -BTF_ID(func, bpf_percpu_obj_drop_impl) -BTF_ID(func, bpf_throw) -BTF_ID(func, bpf_wq_set_callback_impl) -#ifdef CONFIG_CGROUPS -BTF_ID(func, bpf_iter_css_task_new) -#endif -BTF_SET_END(special_kfunc_set) - BTF_ID_LIST(special_kfunc_list) BTF_ID(func, bpf_obj_new_impl) BTF_ID(func, bpf_obj_drop_impl) @@ -11820,6 +12118,8 @@ BTF_ID(func, bpf_list_push_front_impl) BTF_ID(func, bpf_list_push_back_impl) BTF_ID(func, bpf_list_pop_front) BTF_ID(func, bpf_list_pop_back) +BTF_ID(func, bpf_list_front) +BTF_ID(func, bpf_list_back) BTF_ID(func, bpf_cast_to_kern_ctx) BTF_ID(func, bpf_rdonly_cast) BTF_ID(func, bpf_rcu_read_lock) @@ -11827,6 +12127,9 @@ BTF_ID(func, bpf_rcu_read_unlock) BTF_ID(func, bpf_rbtree_remove) BTF_ID(func, bpf_rbtree_add_impl) BTF_ID(func, bpf_rbtree_first) +BTF_ID(func, bpf_rbtree_root) +BTF_ID(func, bpf_rbtree_left) +BTF_ID(func, bpf_rbtree_right) #ifdef CONFIG_NET BTF_ID(func, bpf_dynptr_from_skb) BTF_ID(func, bpf_dynptr_from_xdp) @@ -11859,6 +12162,18 @@ BTF_ID(func, bpf_local_irq_restore) BTF_ID(func, bpf_iter_num_new) BTF_ID(func, bpf_iter_num_next) BTF_ID(func, bpf_iter_num_destroy) +#ifdef CONFIG_BPF_LSM +BTF_ID(func, bpf_set_dentry_xattr) +BTF_ID(func, bpf_remove_dentry_xattr) +#else +BTF_ID_UNUSED +BTF_ID_UNUSED +#endif +BTF_ID(func, bpf_res_spin_lock) +BTF_ID(func, bpf_res_spin_unlock) +BTF_ID(func, bpf_res_spin_lock_irqsave) +BTF_ID(func, bpf_res_spin_unlock_irqrestore) +BTF_ID(func, __bpf_trap) static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta) { @@ -11952,6 +12267,9 @@ get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, if (is_kfunc_arg_irq_flag(meta->btf, &args[argno])) return KF_ARG_PTR_TO_IRQ_FLAG; + if (is_kfunc_arg_res_spin_lock(meta->btf, &args[argno])) + return KF_ARG_PTR_TO_RES_SPIN_LOCK; + if ((base_type(reg->type) == PTR_TO_BTF_ID || reg2btf_ids[base_type(reg->type)])) { if (!btf_type_is_struct(ref_t)) { verbose(env, "kernel function %s args#%d pointer type %s %s is not supported\n", @@ -12059,13 +12377,19 @@ static int process_irq_flag(struct bpf_verifier_env *env, int regno, struct bpf_kfunc_call_arg_meta *meta) { struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; + int err, kfunc_class = IRQ_NATIVE_KFUNC; bool irq_save; - int err; - if (meta->func_id == special_kfunc_list[KF_bpf_local_irq_save]) { + if (meta->func_id == special_kfunc_list[KF_bpf_local_irq_save] || + meta->func_id == special_kfunc_list[KF_bpf_res_spin_lock_irqsave]) { irq_save = true; - } else if (meta->func_id == special_kfunc_list[KF_bpf_local_irq_restore]) { + if (meta->func_id == special_kfunc_list[KF_bpf_res_spin_lock_irqsave]) + kfunc_class = IRQ_LOCK_KFUNC; + } else if (meta->func_id == special_kfunc_list[KF_bpf_local_irq_restore] || + meta->func_id == special_kfunc_list[KF_bpf_res_spin_unlock_irqrestore]) { irq_save = false; + if (meta->func_id == special_kfunc_list[KF_bpf_res_spin_unlock_irqrestore]) + kfunc_class = IRQ_LOCK_KFUNC; } else { verbose(env, "verifier internal error: unknown irq flags kfunc\n"); return -EFAULT; @@ -12081,7 +12405,7 @@ static int process_irq_flag(struct bpf_verifier_env *env, int regno, if (err) return err; - err = mark_stack_slot_irq_flag(env, meta, reg, env->insn_idx); + err = mark_stack_slot_irq_flag(env, meta, reg, env->insn_idx, kfunc_class); if (err) return err; } else { @@ -12095,7 +12419,7 @@ static int process_irq_flag(struct bpf_verifier_env *env, int regno, if (err) return err; - err = unmark_stack_slot_irq_flag(env, reg); + err = unmark_stack_slot_irq_flag(env, reg, kfunc_class); if (err) return err; } @@ -12222,7 +12546,7 @@ static int check_reg_allocation_locked(struct bpf_verifier_env *env, struct bpf_ if (!env->cur_state->active_locks) return -EINVAL; - s = find_lock_state(env->cur_state, REF_TYPE_LOCK, id, ptr); + s = find_lock_state(env->cur_state, REF_TYPE_LOCK_MASK, id, ptr); if (!s) { verbose(env, "held lock and object are not in the same allocation\n"); return -EINVAL; @@ -12235,14 +12559,19 @@ static bool is_bpf_list_api_kfunc(u32 btf_id) return btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] || btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] || btf_id == special_kfunc_list[KF_bpf_list_pop_front] || - btf_id == special_kfunc_list[KF_bpf_list_pop_back]; + btf_id == special_kfunc_list[KF_bpf_list_pop_back] || + btf_id == special_kfunc_list[KF_bpf_list_front] || + btf_id == special_kfunc_list[KF_bpf_list_back]; } static bool is_bpf_rbtree_api_kfunc(u32 btf_id) { return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl] || btf_id == special_kfunc_list[KF_bpf_rbtree_remove] || - btf_id == special_kfunc_list[KF_bpf_rbtree_first]; + btf_id == special_kfunc_list[KF_bpf_rbtree_first] || + btf_id == special_kfunc_list[KF_bpf_rbtree_root] || + btf_id == special_kfunc_list[KF_bpf_rbtree_left] || + btf_id == special_kfunc_list[KF_bpf_rbtree_right]; } static bool is_bpf_iter_num_api_kfunc(u32 btf_id) @@ -12258,9 +12587,18 @@ static bool is_bpf_graph_api_kfunc(u32 btf_id) btf_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]; } +static bool is_bpf_res_spin_lock_kfunc(u32 btf_id) +{ + return btf_id == special_kfunc_list[KF_bpf_res_spin_lock] || + btf_id == special_kfunc_list[KF_bpf_res_spin_unlock] || + btf_id == special_kfunc_list[KF_bpf_res_spin_lock_irqsave] || + btf_id == special_kfunc_list[KF_bpf_res_spin_unlock_irqrestore]; +} + static bool kfunc_spin_allowed(u32 btf_id) { - return is_bpf_graph_api_kfunc(btf_id) || is_bpf_iter_num_api_kfunc(btf_id); + return is_bpf_graph_api_kfunc(btf_id) || is_bpf_iter_num_api_kfunc(btf_id) || + is_bpf_res_spin_lock_kfunc(btf_id); } static bool is_sync_callback_calling_kfunc(u32 btf_id) @@ -12333,7 +12671,9 @@ static bool check_kfunc_is_graph_node_api(struct bpf_verifier_env *env, break; case BPF_RB_NODE: ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_remove] || - kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl]); + kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl] || + kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_left] || + kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_right]); break; default: verbose(env, "verifier internal error: unexpected graph node argument type %s\n", @@ -12553,6 +12893,17 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ if (is_kfunc_arg_ignore(btf, &args[i])) continue; + if (is_kfunc_arg_prog(btf, &args[i])) { + /* Used to reject repeated use of __prog. */ + if (meta->arg_prog) { + verbose(env, "Only 1 prog->aux argument supported per-kfunc\n"); + return -EFAULT; + } + meta->arg_prog = true; + cur_aux(env)->arg_prog = regno; + continue; + } + if (btf_type_is_scalar(t)) { if (reg->type != SCALAR_VALUE) { verbose(env, "R%d is not a scalar\n", regno); @@ -12692,6 +13043,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ case KF_ARG_PTR_TO_CONST_STR: case KF_ARG_PTR_TO_WORKQUEUE: case KF_ARG_PTR_TO_IRQ_FLAG: + case KF_ARG_PTR_TO_RES_SPIN_LOCK: break; default: WARN_ON_ONCE(1); @@ -12846,22 +13198,22 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ return ret; break; case KF_ARG_PTR_TO_RB_NODE: - if (meta->func_id == special_kfunc_list[KF_bpf_rbtree_remove]) { - if (!type_is_non_owning_ref(reg->type) || reg->ref_obj_id) { - verbose(env, "rbtree_remove node input must be non-owning ref\n"); + if (meta->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) { + if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) { + verbose(env, "arg#%d expected pointer to allocated object\n", i); return -EINVAL; } - if (in_rbtree_lock_required_cb(env)) { - verbose(env, "rbtree_remove not allowed in rbtree cb\n"); + if (!reg->ref_obj_id) { + verbose(env, "allocated object must be referenced\n"); return -EINVAL; } } else { - if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) { - verbose(env, "arg#%d expected pointer to allocated object\n", i); + if (!type_is_non_owning_ref(reg->type) && !reg->ref_obj_id) { + verbose(env, "%s can only take non-owning or refcounted bpf_rb_node pointer\n", func_name); return -EINVAL; } - if (!reg->ref_obj_id) { - verbose(env, "allocated object must be referenced\n"); + if (in_rbtree_lock_required_cb(env)) { + verbose(env, "%s not allowed in rbtree cb\n", func_name); return -EINVAL; } } @@ -12990,6 +13342,28 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ if (ret < 0) return ret; break; + case KF_ARG_PTR_TO_RES_SPIN_LOCK: + { + int flags = PROCESS_RES_LOCK; + + if (reg->type != PTR_TO_MAP_VALUE && reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) { + verbose(env, "arg#%d doesn't point to map value or allocated object\n", i); + return -EINVAL; + } + + if (!is_bpf_res_spin_lock_kfunc(meta->func_id)) + return -EFAULT; + if (meta->func_id == special_kfunc_list[KF_bpf_res_spin_lock] || + meta->func_id == special_kfunc_list[KF_bpf_res_spin_lock_irqsave]) + flags |= PROCESS_SPIN_LOCK; + if (meta->func_id == special_kfunc_list[KF_bpf_res_spin_lock_irqsave] || + meta->func_id == special_kfunc_list[KF_bpf_res_spin_unlock_irqrestore]) + flags |= PROCESS_LOCK_IRQ; + ret = process_spin_lock(env, regno, flags); + if (ret < 0) + return ret; + break; + } } } @@ -13044,6 +13418,178 @@ static int fetch_kfunc_meta(struct bpf_verifier_env *env, return 0; } +/* check special kfuncs and return: + * 1 - not fall-through to 'else' branch, continue verification + * 0 - fall-through to 'else' branch + * < 0 - not fall-through to 'else' branch, return error + */ +static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta, + struct bpf_reg_state *regs, struct bpf_insn_aux_data *insn_aux, + const struct btf_type *ptr_type, struct btf *desc_btf) +{ + const struct btf_type *ret_t; + int err = 0; + + if (meta->btf != btf_vmlinux) + return 0; + + if (meta->func_id == special_kfunc_list[KF_bpf_obj_new_impl] || + meta->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { + struct btf_struct_meta *struct_meta; + struct btf *ret_btf; + u32 ret_btf_id; + + if (meta->func_id == special_kfunc_list[KF_bpf_obj_new_impl] && !bpf_global_ma_set) + return -ENOMEM; + + if (((u64)(u32)meta->arg_constant.value) != meta->arg_constant.value) { + verbose(env, "local type ID argument must be in range [0, U32_MAX]\n"); + return -EINVAL; + } + + ret_btf = env->prog->aux->btf; + ret_btf_id = meta->arg_constant.value; + + /* This may be NULL due to user not supplying a BTF */ + if (!ret_btf) { + verbose(env, "bpf_obj_new/bpf_percpu_obj_new requires prog BTF\n"); + return -EINVAL; + } + + ret_t = btf_type_by_id(ret_btf, ret_btf_id); + if (!ret_t || !__btf_type_is_struct(ret_t)) { + verbose(env, "bpf_obj_new/bpf_percpu_obj_new type ID argument must be of a struct\n"); + return -EINVAL; + } + + if (meta->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { + if (ret_t->size > BPF_GLOBAL_PERCPU_MA_MAX_SIZE) { + verbose(env, "bpf_percpu_obj_new type size (%d) is greater than %d\n", + ret_t->size, BPF_GLOBAL_PERCPU_MA_MAX_SIZE); + return -EINVAL; + } + + if (!bpf_global_percpu_ma_set) { + mutex_lock(&bpf_percpu_ma_lock); + if (!bpf_global_percpu_ma_set) { + /* Charge memory allocated with bpf_global_percpu_ma to + * root memcg. The obj_cgroup for root memcg is NULL. + */ + err = bpf_mem_alloc_percpu_init(&bpf_global_percpu_ma, NULL); + if (!err) + bpf_global_percpu_ma_set = true; + } + mutex_unlock(&bpf_percpu_ma_lock); + if (err) + return err; + } + + mutex_lock(&bpf_percpu_ma_lock); + err = bpf_mem_alloc_percpu_unit_init(&bpf_global_percpu_ma, ret_t->size); + mutex_unlock(&bpf_percpu_ma_lock); + if (err) + return err; + } + + struct_meta = btf_find_struct_meta(ret_btf, ret_btf_id); + if (meta->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { + if (!__btf_type_is_scalar_struct(env, ret_btf, ret_t, 0)) { + verbose(env, "bpf_percpu_obj_new type ID argument must be of a struct of scalars\n"); + return -EINVAL; + } + + if (struct_meta) { + verbose(env, "bpf_percpu_obj_new type ID argument must not contain special fields\n"); + return -EINVAL; + } + } + + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC; + regs[BPF_REG_0].btf = ret_btf; + regs[BPF_REG_0].btf_id = ret_btf_id; + if (meta->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) + regs[BPF_REG_0].type |= MEM_PERCPU; + + insn_aux->obj_new_size = ret_t->size; + insn_aux->kptr_struct_meta = struct_meta; + } else if (meta->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) { + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC; + regs[BPF_REG_0].btf = meta->arg_btf; + regs[BPF_REG_0].btf_id = meta->arg_btf_id; + + insn_aux->kptr_struct_meta = + btf_find_struct_meta(meta->arg_btf, + meta->arg_btf_id); + } else if (is_list_node_type(ptr_type)) { + struct btf_field *field = meta->arg_list_head.field; + + mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root); + } else if (is_rbtree_node_type(ptr_type)) { + struct btf_field *field = meta->arg_rbtree_root.field; + + mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root); + } else if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) { + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_TRUSTED; + regs[BPF_REG_0].btf = desc_btf; + regs[BPF_REG_0].btf_id = meta->ret_btf_id; + } else if (meta->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) { + ret_t = btf_type_by_id(desc_btf, meta->arg_constant.value); + if (!ret_t || !btf_type_is_struct(ret_t)) { + verbose(env, + "kfunc bpf_rdonly_cast type ID argument must be of a struct\n"); + return -EINVAL; + } + + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED; + regs[BPF_REG_0].btf = desc_btf; + regs[BPF_REG_0].btf_id = meta->arg_constant.value; + } else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_slice] || + meta->func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) { + enum bpf_type_flag type_flag = get_dynptr_type_flag(meta->initialized_dynptr.type); + + mark_reg_known_zero(env, regs, BPF_REG_0); + + if (!meta->arg_constant.found) { + verbose(env, "verifier internal error: bpf_dynptr_slice(_rdwr) no constant size\n"); + return -EFAULT; + } + + regs[BPF_REG_0].mem_size = meta->arg_constant.value; + + /* PTR_MAYBE_NULL will be added when is_kfunc_ret_null is checked */ + regs[BPF_REG_0].type = PTR_TO_MEM | type_flag; + + if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_slice]) { + regs[BPF_REG_0].type |= MEM_RDONLY; + } else { + /* this will set env->seen_direct_write to true */ + if (!may_access_direct_pkt_data(env, NULL, BPF_WRITE)) { + verbose(env, "the prog does not allow writes to packet data\n"); + return -EINVAL; + } + } + + if (!meta->initialized_dynptr.id) { + verbose(env, "verifier internal error: no dynptr id\n"); + return -EFAULT; + } + regs[BPF_REG_0].dynptr_id = meta->initialized_dynptr.id; + + /* we don't need to set BPF_REG_0's ref obj id + * because packet slices are not refcounted (see + * dynptr_type_refcounted) + */ + } else { + return 0; + } + + return 1; +} + static int check_return_code(struct bpf_verifier_env *env, int regno, const char *reg_name); static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, @@ -13058,7 +13604,6 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, struct bpf_insn_aux_data *insn_aux; int err, insn_idx = *insn_idx_p; const struct btf_param *args; - const struct btf_type *ret_t; struct btf *desc_btf; /* skip for now, but return error when we find this in fixup_kfunc_call */ @@ -13075,6 +13620,36 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, insn_aux->is_iter_next = is_iter_next_kfunc(&meta); + if (!insn->off && + (insn->imm == special_kfunc_list[KF_bpf_res_spin_lock] || + insn->imm == special_kfunc_list[KF_bpf_res_spin_lock_irqsave])) { + struct bpf_verifier_state *branch; + struct bpf_reg_state *regs; + + branch = push_stack(env, env->insn_idx + 1, env->insn_idx, false); + if (!branch) { + verbose(env, "failed to push state for failed lock acquisition\n"); + return -ENOMEM; + } + + regs = branch->frame[branch->curframe]->regs; + + /* Clear r0-r5 registers in forked state */ + for (i = 0; i < CALLER_SAVED_REGS; i++) + mark_reg_not_init(env, regs, caller_saved[i]); + + mark_reg_unknown(env, regs, BPF_REG_0); + err = __mark_reg_s32_range(env, regs, BPF_REG_0, -MAX_ERRNO, -1); + if (err) { + verbose(env, "failed to mark s32 range for retval in forked state for lock\n"); + return err; + } + __mark_btf_func_reg_size(env, regs, BPF_REG_0, sizeof(u32)); + } else if (!insn->off && insn->imm == special_kfunc_list[KF___bpf_trap]) { + verbose(env, "unexpected __bpf_trap() due to uninitialized variable?\n"); + return -EFAULT; + } + if (is_kfunc_destructive(&meta) && !capable(CAP_SYS_BOOT)) { verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capability\n"); return -EACCES; @@ -13245,168 +13820,16 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (btf_type_is_scalar(t)) { mark_reg_unknown(env, regs, BPF_REG_0); + if (meta.btf == btf_vmlinux && (meta.func_id == special_kfunc_list[KF_bpf_res_spin_lock] || + meta.func_id == special_kfunc_list[KF_bpf_res_spin_lock_irqsave])) + __mark_reg_const_zero(env, ®s[BPF_REG_0]); mark_btf_func_reg_size(env, BPF_REG_0, t->size); } else if (btf_type_is_ptr(t)) { ptr_type = btf_type_skip_modifiers(desc_btf, t->type, &ptr_type_id); - - if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) { - if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl] || - meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { - struct btf_struct_meta *struct_meta; - struct btf *ret_btf; - u32 ret_btf_id; - - if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl] && !bpf_global_ma_set) - return -ENOMEM; - - if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) { - verbose(env, "local type ID argument must be in range [0, U32_MAX]\n"); - return -EINVAL; - } - - ret_btf = env->prog->aux->btf; - ret_btf_id = meta.arg_constant.value; - - /* This may be NULL due to user not supplying a BTF */ - if (!ret_btf) { - verbose(env, "bpf_obj_new/bpf_percpu_obj_new requires prog BTF\n"); - return -EINVAL; - } - - ret_t = btf_type_by_id(ret_btf, ret_btf_id); - if (!ret_t || !__btf_type_is_struct(ret_t)) { - verbose(env, "bpf_obj_new/bpf_percpu_obj_new type ID argument must be of a struct\n"); - return -EINVAL; - } - - if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { - if (ret_t->size > BPF_GLOBAL_PERCPU_MA_MAX_SIZE) { - verbose(env, "bpf_percpu_obj_new type size (%d) is greater than %d\n", - ret_t->size, BPF_GLOBAL_PERCPU_MA_MAX_SIZE); - return -EINVAL; - } - - if (!bpf_global_percpu_ma_set) { - mutex_lock(&bpf_percpu_ma_lock); - if (!bpf_global_percpu_ma_set) { - /* Charge memory allocated with bpf_global_percpu_ma to - * root memcg. The obj_cgroup for root memcg is NULL. - */ - err = bpf_mem_alloc_percpu_init(&bpf_global_percpu_ma, NULL); - if (!err) - bpf_global_percpu_ma_set = true; - } - mutex_unlock(&bpf_percpu_ma_lock); - if (err) - return err; - } - - mutex_lock(&bpf_percpu_ma_lock); - err = bpf_mem_alloc_percpu_unit_init(&bpf_global_percpu_ma, ret_t->size); - mutex_unlock(&bpf_percpu_ma_lock); - if (err) - return err; - } - - struct_meta = btf_find_struct_meta(ret_btf, ret_btf_id); - if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) { - if (!__btf_type_is_scalar_struct(env, ret_btf, ret_t, 0)) { - verbose(env, "bpf_percpu_obj_new type ID argument must be of a struct of scalars\n"); - return -EINVAL; - } - - if (struct_meta) { - verbose(env, "bpf_percpu_obj_new type ID argument must not contain special fields\n"); - return -EINVAL; - } - } - - mark_reg_known_zero(env, regs, BPF_REG_0); - regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC; - regs[BPF_REG_0].btf = ret_btf; - regs[BPF_REG_0].btf_id = ret_btf_id; - if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) - regs[BPF_REG_0].type |= MEM_PERCPU; - - insn_aux->obj_new_size = ret_t->size; - insn_aux->kptr_struct_meta = struct_meta; - } else if (meta.func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) { - mark_reg_known_zero(env, regs, BPF_REG_0); - regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC; - regs[BPF_REG_0].btf = meta.arg_btf; - regs[BPF_REG_0].btf_id = meta.arg_btf_id; - - insn_aux->kptr_struct_meta = - btf_find_struct_meta(meta.arg_btf, - meta.arg_btf_id); - } else if (meta.func_id == special_kfunc_list[KF_bpf_list_pop_front] || - meta.func_id == special_kfunc_list[KF_bpf_list_pop_back]) { - struct btf_field *field = meta.arg_list_head.field; - - mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root); - } else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_remove] || - meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) { - struct btf_field *field = meta.arg_rbtree_root.field; - - mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root); - } else if (meta.func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) { - mark_reg_known_zero(env, regs, BPF_REG_0); - regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_TRUSTED; - regs[BPF_REG_0].btf = desc_btf; - regs[BPF_REG_0].btf_id = meta.ret_btf_id; - } else if (meta.func_id == special_kfunc_list[KF_bpf_rdonly_cast]) { - ret_t = btf_type_by_id(desc_btf, meta.arg_constant.value); - if (!ret_t || !btf_type_is_struct(ret_t)) { - verbose(env, - "kfunc bpf_rdonly_cast type ID argument must be of a struct\n"); - return -EINVAL; - } - - mark_reg_known_zero(env, regs, BPF_REG_0); - regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED; - regs[BPF_REG_0].btf = desc_btf; - regs[BPF_REG_0].btf_id = meta.arg_constant.value; - } else if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice] || - meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) { - enum bpf_type_flag type_flag = get_dynptr_type_flag(meta.initialized_dynptr.type); - - mark_reg_known_zero(env, regs, BPF_REG_0); - - if (!meta.arg_constant.found) { - verbose(env, "verifier internal error: bpf_dynptr_slice(_rdwr) no constant size\n"); - return -EFAULT; - } - - regs[BPF_REG_0].mem_size = meta.arg_constant.value; - - /* PTR_MAYBE_NULL will be added when is_kfunc_ret_null is checked */ - regs[BPF_REG_0].type = PTR_TO_MEM | type_flag; - - if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice]) { - regs[BPF_REG_0].type |= MEM_RDONLY; - } else { - /* this will set env->seen_direct_write to true */ - if (!may_access_direct_pkt_data(env, NULL, BPF_WRITE)) { - verbose(env, "the prog does not allow writes to packet data\n"); - return -EINVAL; - } - } - - if (!meta.initialized_dynptr.id) { - verbose(env, "verifier internal error: no dynptr id\n"); - return -EFAULT; - } - regs[BPF_REG_0].dynptr_id = meta.initialized_dynptr.id; - - /* we don't need to set BPF_REG_0's ref obj id - * because packet slices are not refcounted (see - * dynptr_type_refcounted) - */ - } else { - verbose(env, "kernel function %s unhandled dynamic return type\n", - meta.func_name); - return -EFAULT; - } + err = check_special_kfunc(env, &meta, regs, insn_aux, ptr_type, desc_btf); + if (err) { + if (err < 0) + return err; } else if (btf_type_is_void(ptr_type)) { /* kfunc returning 'void *' is equivalent to returning scalar */ mark_reg_unknown(env, regs, BPF_REG_0); @@ -13475,14 +13898,14 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (is_kfunc_ret_null(&meta)) regs[BPF_REG_0].id = id; regs[BPF_REG_0].ref_obj_id = id; - } else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) { + } else if (is_rbtree_node_type(ptr_type) || is_list_node_type(ptr_type)) { ref_set_non_owning(env, ®s[BPF_REG_0]); } if (reg_may_point_to_spin_lock(®s[BPF_REG_0]) && !regs[BPF_REG_0].id) regs[BPF_REG_0].id = ++env->id_gen; } else if (btf_type_is_void(t)) { - if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) { + if (meta.btf == btf_vmlinux) { if (meta.func_id == special_kfunc_list[KF_bpf_obj_drop_impl] || meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_drop_impl]) { insn_aux->kptr_struct_meta = @@ -15971,6 +16394,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, struct bpf_reg_state *eq_branch_regs; struct linked_regs linked_regs = {}; u8 opcode = BPF_OP(insn->code); + int insn_flags = 0; bool is_jmp32; int pred = -1; int err; @@ -16029,6 +16453,11 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, insn->src_reg); return -EACCES; } + + if (src_reg->type == PTR_TO_STACK) + insn_flags |= INSN_F_SRC_REG_STACK; + if (dst_reg->type == PTR_TO_STACK) + insn_flags |= INSN_F_DST_REG_STACK; } else { if (insn->src_reg != BPF_REG_0) { verbose(env, "BPF_JMP/JMP32 uses reserved fields\n"); @@ -16038,6 +16467,15 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, memset(src_reg, 0, sizeof(*src_reg)); src_reg->type = SCALAR_VALUE; __mark_reg_known(src_reg, insn->imm); + + if (dst_reg->type == PTR_TO_STACK) + insn_flags |= INSN_F_DST_REG_STACK; + } + + if (insn_flags) { + err = push_insn_history(env, this_branch, insn_flags, 0); + if (err) + return err; } is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32; @@ -16399,13 +16837,14 @@ static int check_return_code(struct bpf_verifier_env *env, int regno, const char const char *exit_ctx = "At program exit"; struct tnum enforce_attach_type_range = tnum_unknown; const struct bpf_prog *prog = env->prog; - struct bpf_reg_state *reg; + struct bpf_reg_state *reg = reg_state(env, regno); struct bpf_retval_range range = retval_range(0, 1); enum bpf_prog_type prog_type = resolve_prog_type(env->prog); int err; struct bpf_func_state *frame = env->cur_state->frame[0]; const bool is_subprog = frame->subprogno; bool return_32bit = false; + const struct btf_type *reg_type, *ret_type = NULL; /* LSM and struct_ops func-ptr's return type could be "void" */ if (!is_subprog || frame->in_exception_callback_fn) { @@ -16414,10 +16853,26 @@ static int check_return_code(struct bpf_verifier_env *env, int regno, const char if (prog->expected_attach_type == BPF_LSM_CGROUP) /* See below, can be 0 or 0-1 depending on hook. */ break; - fallthrough; + if (!prog->aux->attach_func_proto->type) + return 0; + break; case BPF_PROG_TYPE_STRUCT_OPS: if (!prog->aux->attach_func_proto->type) return 0; + + if (frame->in_exception_callback_fn) + break; + + /* Allow a struct_ops program to return a referenced kptr if it + * matches the operator's return type and is in its unmodified + * form. A scalar zero (i.e., a null pointer) is also allowed. + */ + reg_type = reg->btf ? btf_type_by_id(reg->btf, reg->btf_id) : NULL; + ret_type = btf_type_resolve_ptr(prog->aux->attach_btf, + prog->aux->attach_func_proto->type, + NULL); + if (ret_type && ret_type == reg_type && reg->ref_obj_id) + return __check_ptr_off_reg(env, reg, regno, false); break; default: break; @@ -16439,8 +16894,6 @@ static int check_return_code(struct bpf_verifier_env *env, int regno, const char return -EACCES; } - reg = cur_regs(env) + regno; - if (frame->in_async_callback_fn) { /* enforce return zero from async callbacks like timer */ exit_ctx = "At async callback return"; @@ -16539,6 +16992,11 @@ static int check_return_code(struct bpf_verifier_env *env, int regno, const char case BPF_PROG_TYPE_NETFILTER: range = retval_range(NF_DROP, NF_ACCEPT); break; + case BPF_PROG_TYPE_STRUCT_OPS: + if (!ret_type) + return 0; + range = retval_range(0, 0); + break; case BPF_PROG_TYPE_EXT: /* freplace program can return anything as its return value * depends on the to-be-replaced kernel func or bpf program. @@ -16582,6 +17040,14 @@ static void mark_subprog_changes_pkt_data(struct bpf_verifier_env *env, int off) subprog->changes_pkt_data = true; } +static void mark_subprog_might_sleep(struct bpf_verifier_env *env, int off) +{ + struct bpf_subprog_info *subprog; + + subprog = find_containing_subprog(env, off); + subprog->might_sleep = true; +} + /* 't' is an index of a call-site. * 'w' is a callee entry point. * Eventually this function would be called when env->cfg.insn_state[w] == EXPLORED. @@ -16595,6 +17061,7 @@ static void merge_callee_effects(struct bpf_verifier_env *env, int t, int w) caller = find_containing_subprog(env, t); callee = find_containing_subprog(env, w); caller->changes_pkt_data |= callee->changes_pkt_data; + caller->might_sleep |= callee->might_sleep; } /* non-recursive DFS pseudo code @@ -16753,27 +17220,6 @@ static int visit_func_call_insn(int t, struct bpf_insn *insns, /* Bitmask with 1s for all caller saved registers */ #define ALL_CALLER_SAVED_REGS ((1u << CALLER_SAVED_REGS) - 1) -/* Return a bitmask specifying which caller saved registers are - * clobbered by a call to a helper *as if* this helper follows - * bpf_fastcall contract: - * - includes R0 if function is non-void; - * - includes R1-R5 if corresponding parameter has is described - * in the function prototype. - */ -static u32 helper_fastcall_clobber_mask(const struct bpf_func_proto *fn) -{ - u32 mask; - int i; - - mask = 0; - if (fn->ret_type != RET_VOID) - mask |= BIT(BPF_REG_0); - for (i = 0; i < ARRAY_SIZE(fn->arg_type); ++i) - if (fn->arg_type[i] != ARG_DONTCARE) - mask |= BIT(BPF_REG_1 + i); - return mask; -} - /* True if do_misc_fixups() replaces calls to helper number 'imm', * replacement patch is presumed to follow bpf_fastcall contract * (see mark_fastcall_pattern_for_call() below). @@ -16790,24 +17236,54 @@ static bool verifier_inlines_helper_call(struct bpf_verifier_env *env, s32 imm) } } -/* Same as helper_fastcall_clobber_mask() but for kfuncs, see comment above */ -static u32 kfunc_fastcall_clobber_mask(struct bpf_kfunc_call_arg_meta *meta) +struct call_summary { + u8 num_params; + bool is_void; + bool fastcall; +}; + +/* If @call is a kfunc or helper call, fills @cs and returns true, + * otherwise returns false. + */ +static bool get_call_summary(struct bpf_verifier_env *env, struct bpf_insn *call, + struct call_summary *cs) { - u32 vlen, i, mask; + struct bpf_kfunc_call_arg_meta meta; + const struct bpf_func_proto *fn; + int i; - vlen = btf_type_vlen(meta->func_proto); - mask = 0; - if (!btf_type_is_void(btf_type_by_id(meta->btf, meta->func_proto->type))) - mask |= BIT(BPF_REG_0); - for (i = 0; i < vlen; ++i) - mask |= BIT(BPF_REG_1 + i); - return mask; -} + if (bpf_helper_call(call)) { -/* Same as verifier_inlines_helper_call() but for kfuncs, see comment above */ -static bool is_fastcall_kfunc_call(struct bpf_kfunc_call_arg_meta *meta) -{ - return meta->kfunc_flags & KF_FASTCALL; + if (get_helper_proto(env, call->imm, &fn) < 0) + /* error would be reported later */ + return false; + cs->fastcall = fn->allow_fastcall && + (verifier_inlines_helper_call(env, call->imm) || + bpf_jit_inlines_helper_call(call->imm)); + cs->is_void = fn->ret_type == RET_VOID; + cs->num_params = 0; + for (i = 0; i < ARRAY_SIZE(fn->arg_type); ++i) { + if (fn->arg_type[i] == ARG_DONTCARE) + break; + cs->num_params++; + } + return true; + } + + if (bpf_pseudo_kfunc_call(call)) { + int err; + + err = fetch_kfunc_meta(env, call, &meta, NULL); + if (err < 0) + /* error would be reported later */ + return false; + cs->num_params = btf_type_vlen(meta.func_proto); + cs->fastcall = meta.kfunc_flags & KF_FASTCALL; + cs->is_void = btf_type_is_void(btf_type_by_id(meta.btf, meta.func_proto->type)); + return true; + } + + return false; } /* LLVM define a bpf_fastcall function attribute. @@ -16890,39 +17366,23 @@ static void mark_fastcall_pattern_for_call(struct bpf_verifier_env *env, { struct bpf_insn *insns = env->prog->insnsi, *stx, *ldx; struct bpf_insn *call = &env->prog->insnsi[insn_idx]; - const struct bpf_func_proto *fn; - u32 clobbered_regs_mask = ALL_CALLER_SAVED_REGS; + u32 clobbered_regs_mask; + struct call_summary cs; u32 expected_regs_mask; - bool can_be_inlined = false; s16 off; int i; - if (bpf_helper_call(call)) { - if (get_helper_proto(env, call->imm, &fn) < 0) - /* error would be reported later */ - return; - clobbered_regs_mask = helper_fastcall_clobber_mask(fn); - can_be_inlined = fn->allow_fastcall && - (verifier_inlines_helper_call(env, call->imm) || - bpf_jit_inlines_helper_call(call->imm)); - } - - if (bpf_pseudo_kfunc_call(call)) { - struct bpf_kfunc_call_arg_meta meta; - int err; - - err = fetch_kfunc_meta(env, call, &meta, NULL); - if (err < 0) - /* error would be reported later */ - return; - - clobbered_regs_mask = kfunc_fastcall_clobber_mask(&meta); - can_be_inlined = is_fastcall_kfunc_call(&meta); - } - - if (clobbered_regs_mask == ALL_CALLER_SAVED_REGS) + if (!get_call_summary(env, call, &cs)) return; + /* A bitmask specifying which caller saved registers are clobbered + * by a call to a helper/kfunc *as if* this helper/kfunc follows + * bpf_fastcall contract: + * - includes R0 if function is non-void; + * - includes R1-R5 if corresponding parameter has is described + * in the function prototype. + */ + clobbered_regs_mask = GENMASK(cs.num_params, cs.is_void ? 1 : 0); /* e.g. if helper call clobbers r{0,1}, expect r{2,3,4,5} in the pattern */ expected_regs_mask = ~clobbered_regs_mask & ALL_CALLER_SAVED_REGS; @@ -16980,7 +17440,7 @@ static void mark_fastcall_pattern_for_call(struct bpf_verifier_env *env, * don't set 'fastcall_spills_num' for call B so that remove_fastcall_spills_fills() * does not remove spill/fill pair {4,6}. */ - if (can_be_inlined) + if (cs.fastcall) env->insn_aux_data[insn_idx].fastcall_spills_num = i - 1; else subprog->keep_fastcall_stack = 1; @@ -17062,9 +17522,20 @@ static int visit_insn(int t, struct bpf_verifier_env *env) mark_prune_point(env, t); mark_jmp_point(env, t); } - if (bpf_helper_call(insn) && bpf_helper_changes_pkt_data(insn->imm)) - mark_subprog_changes_pkt_data(env, t); - if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) { + if (bpf_helper_call(insn)) { + const struct bpf_func_proto *fp; + + ret = get_helper_proto(env, insn->imm, &fp); + /* If called in a non-sleepable context program will be + * rejected anyway, so we should end up with precise + * sleepable marks on subprogs, except for dead code + * elimination. + */ + if (ret == 0 && fp->might_sleep) + mark_subprog_might_sleep(env, t); + if (bpf_helper_changes_pkt_data(insn->imm)) + mark_subprog_changes_pkt_data(env, t); + } else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) { struct bpf_kfunc_call_arg_meta meta; ret = fetch_kfunc_meta(env, insn, &meta, NULL); @@ -17083,6 +17554,13 @@ static int visit_insn(int t, struct bpf_verifier_env *env) */ mark_force_checkpoint(env, t); } + /* Same as helpers, if called in a non-sleepable context + * program will be rejected anyway, so we should end up + * with precise sleepable marks on subprogs, except for + * dead code elimination. + */ + if (ret == 0 && is_kfunc_sleepable(&meta)) + mark_subprog_might_sleep(env, t); } return visit_func_call_insn(t, insns, env, insn->src_reg == BPF_PSEUDO_CALL); @@ -17125,9 +17603,8 @@ static int visit_insn(int t, struct bpf_verifier_env *env) static int check_cfg(struct bpf_verifier_env *env) { int insn_cnt = env->prog->len; - int *insn_stack, *insn_state; + int *insn_stack, *insn_state, *insn_postorder; int ex_insn_beg, i, ret = 0; - bool ex_done = false; insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); if (!insn_state) @@ -17139,6 +17616,17 @@ static int check_cfg(struct bpf_verifier_env *env) return -ENOMEM; } + insn_postorder = env->cfg.insn_postorder = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); + if (!insn_postorder) { + kvfree(insn_state); + kvfree(insn_stack); + return -ENOMEM; + } + + ex_insn_beg = env->exception_callback_subprog + ? env->subprog_info[env->exception_callback_subprog].start + : 0; + insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */ insn_stack[0] = 0; /* 0 is the first instruction */ env->cfg.cur_stack = 1; @@ -17152,6 +17640,7 @@ walk_cfg: case DONE_EXPLORING: insn_state[t] = EXPLORED; env->cfg.cur_stack--; + insn_postorder[env->cfg.cur_postorder++] = t; break; case KEEP_EXPLORING: break; @@ -17170,13 +17659,10 @@ walk_cfg: goto err_free; } - if (env->exception_callback_subprog && !ex_done) { - ex_insn_beg = env->subprog_info[env->exception_callback_subprog].start; - + if (ex_insn_beg && insn_state[ex_insn_beg] != EXPLORED) { insn_state[ex_insn_beg] = DISCOVERED; insn_stack[0] = ex_insn_beg; env->cfg.cur_stack = 1; - ex_done = true; goto walk_cfg; } @@ -17199,6 +17685,7 @@ walk_cfg: } ret = 0; /* cfg looks good */ env->prog->aux->changes_pkt_data = env->subprog_info[0].changes_pkt_data; + env->prog->aux->might_sleep = env->subprog_info[0].might_sleep; err_free: kvfree(insn_state); @@ -17815,18 +18302,22 @@ static void clean_verifier_state(struct bpf_verifier_env *env, static void clean_live_states(struct bpf_verifier_env *env, int insn, struct bpf_verifier_state *cur) { + struct bpf_verifier_state *loop_entry; struct bpf_verifier_state_list *sl; + struct list_head *pos, *head; - sl = *explored_state(env, insn); - while (sl) { + head = explored_state(env, insn); + list_for_each(pos, head) { + sl = container_of(pos, struct bpf_verifier_state_list, node); if (sl->state.branches) - goto next; + continue; + loop_entry = get_loop_entry(env, &sl->state); + if (!IS_ERR_OR_NULL(loop_entry) && loop_entry->branches) + continue; if (sl->state.insn_idx != insn || !same_callsites(&sl->state, cur)) - goto next; + continue; clean_verifier_state(env, &sl->state); -next: - sl = sl->next; } } @@ -18127,7 +18618,8 @@ static bool stacksafe(struct bpf_verifier_env *env, struct bpf_func_state *old, case STACK_IRQ_FLAG: old_reg = &old->stack[spi].spilled_ptr; cur_reg = &cur->stack[spi].spilled_ptr; - if (!check_ids(old_reg->ref_obj_id, cur_reg->ref_obj_id, idmap)) + if (!check_ids(old_reg->ref_obj_id, cur_reg->ref_obj_id, idmap) || + old_reg->irq.kfunc_class != cur_reg->irq.kfunc_class) return false; break; case STACK_MISC: @@ -18162,6 +18654,10 @@ static bool refsafe(struct bpf_verifier_state *old, struct bpf_verifier_state *c if (!check_ids(old->active_irq_id, cur->active_irq_id, idmap)) return false; + if (!check_ids(old->active_lock_id, cur->active_lock_id, idmap) || + old->active_lock_ptr != cur->active_lock_ptr) + return false; + for (i = 0; i < old->acquired_refs; i++) { if (!check_ids(old->refs[i].id, cur->refs[i].id, idmap) || old->refs[i].type != cur->refs[i].type) @@ -18171,6 +18667,8 @@ static bool refsafe(struct bpf_verifier_state *old, struct bpf_verifier_state *c case REF_TYPE_IRQ: break; case REF_TYPE_LOCK: + case REF_TYPE_RES_LOCK: + case REF_TYPE_RES_LOCK_IRQ: if (old->refs[i].ptr != cur->refs[i].ptr) return false; break; @@ -18210,15 +18708,17 @@ static bool refsafe(struct bpf_verifier_state *old, struct bpf_verifier_state *c * the current state will reach 'bpf_exit' instruction safely */ static bool func_states_equal(struct bpf_verifier_env *env, struct bpf_func_state *old, - struct bpf_func_state *cur, enum exact_level exact) + struct bpf_func_state *cur, u32 insn_idx, enum exact_level exact) { - int i; + u16 live_regs = env->insn_aux_data[insn_idx].live_regs_before; + u16 i; if (old->callback_depth > cur->callback_depth) return false; for (i = 0; i < MAX_BPF_REG; i++) - if (!regsafe(env, &old->regs[i], &cur->regs[i], + if (((1 << i) & live_regs) && + !regsafe(env, &old->regs[i], &cur->regs[i], &env->idmap_scratch, exact)) return false; @@ -18239,6 +18739,7 @@ static bool states_equal(struct bpf_verifier_env *env, struct bpf_verifier_state *cur, enum exact_level exact) { + u32 insn_idx; int i; if (old->curframe != cur->curframe) @@ -18262,9 +18763,12 @@ static bool states_equal(struct bpf_verifier_env *env, * and all frame states need to be equivalent */ for (i = 0; i <= old->curframe; i++) { + insn_idx = i == old->curframe + ? env->insn_idx + : old->frame[i + 1]->callsite; if (old->frame[i]->callsite != cur->frame[i]->callsite) return false; - if (!func_states_equal(env, old->frame[i], cur->frame[i], exact)) + if (!func_states_equal(env, old->frame[i], cur->frame[i], insn_idx, exact)) return false; } return true; @@ -18517,10 +19021,11 @@ static bool iter_active_depths_differ(struct bpf_verifier_state *old, struct bpf static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) { struct bpf_verifier_state_list *new_sl; - struct bpf_verifier_state_list *sl, **pprev; + struct bpf_verifier_state_list *sl; struct bpf_verifier_state *cur = env->cur_state, *new, *loop_entry; int i, j, n, err, states_cnt = 0; bool force_new_state, add_new_state, force_exact; + struct list_head *pos, *tmp, *head; force_new_state = env->test_state_freq || is_force_checkpoint(env, insn_idx) || /* Avoid accumulating infinitely long jmp history */ @@ -18539,15 +19044,14 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) env->insn_processed - env->prev_insn_processed >= 8) add_new_state = true; - pprev = explored_state(env, insn_idx); - sl = *pprev; - clean_live_states(env, insn_idx, cur); - while (sl) { + head = explored_state(env, insn_idx); + list_for_each_safe(pos, tmp, head) { + sl = container_of(pos, struct bpf_verifier_state_list, node); states_cnt++; if (sl->state.insn_idx != insn_idx) - goto next; + continue; if (sl->state.branches) { struct bpf_func_state *frame = sl->state.frame[sl->state.curframe]; @@ -18621,7 +19125,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) spi = __get_spi(iter_reg->off + iter_reg->var_off.value); iter_state = &func(env, iter_reg)->stack[spi].spilled_ptr; if (iter_state->iter.state == BPF_ITER_STATE_ACTIVE) { - update_loop_entry(cur, &sl->state); + update_loop_entry(env, cur, &sl->state); goto hit; } } @@ -18630,7 +19134,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) if (is_may_goto_insn_at(env, insn_idx)) { if (sl->state.may_goto_depth != cur->may_goto_depth && states_equal(env, &sl->state, cur, RANGE_WITHIN)) { - update_loop_entry(cur, &sl->state); + update_loop_entry(env, cur, &sl->state); goto hit; } } @@ -18697,11 +19201,13 @@ skip_inf_loop_check: * * Additional details are in the comment before get_loop_entry(). */ - loop_entry = get_loop_entry(&sl->state); + loop_entry = get_loop_entry(env, &sl->state); + if (IS_ERR(loop_entry)) + return PTR_ERR(loop_entry); force_exact = loop_entry && loop_entry->branches > 0; if (states_equal(env, &sl->state, cur, force_exact ? RANGE_WITHIN : NOT_EXACT)) { if (force_exact) - update_loop_entry(cur, loop_entry); + update_loop_entry(env, cur, loop_entry); hit: sl->hit_cnt++; /* reached equivalent register/stack state, @@ -18750,31 +19256,13 @@ miss: /* the state is unlikely to be useful. Remove it to * speed up verification */ - *pprev = sl->next; - if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE && - !sl->state.used_as_loop_entry) { - u32 br = sl->state.branches; - - WARN_ONCE(br, - "BUG live_done but branches_to_explore %d\n", - br); - free_verifier_state(&sl->state, false); - kfree(sl); - env->peak_states--; - } else { - /* cannot free this state, since parentage chain may - * walk it later. Add it for free_list instead to - * be freed at the end of verification - */ - sl->next = env->free_list; - env->free_list = sl; - } - sl = *pprev; - continue; + sl->in_free_list = true; + list_del(&sl->node); + list_add(&sl->node, &env->free_list); + env->free_list_size++; + env->explored_states_size--; + maybe_free_verifier_state(env, sl); } -next: - pprev = &sl->next; - sl = *pprev; } if (env->max_states_per_insn < states_cnt) @@ -18799,7 +19287,8 @@ next: if (!new_sl) return -ENOMEM; env->total_states++; - env->peak_states++; + env->explored_states_size++; + update_peak_states(env); env->prev_jmps_processed = env->jmps_processed; env->prev_insn_processed = env->insn_processed; @@ -18823,8 +19312,8 @@ next: cur->first_insn_idx = insn_idx; cur->insn_hist_start = cur->insn_hist_end; cur->dfs_depth = new->dfs_depth + 1; - new_sl->next = *explored_state(env, insn_idx); - *explored_state(env, insn_idx) = new_sl; + list_add(&new_sl->node, head); + /* connect new state to parentage chain. Current frame needs all * registers connected. Only r6 - r9 of the callers are alive (pushed * to the stack implicitly by JITs) so in callers' frames connect just @@ -19011,19 +19500,13 @@ static int do_check(struct bpf_verifier_env *env) } if (env->log.level & BPF_LOG_LEVEL) { - const struct bpf_insn_cbs cbs = { - .cb_call = disasm_kfunc_name, - .cb_print = verbose, - .private_data = env, - }; - if (verifier_state_scratched(env)) print_insn_state(env, state, state->curframe); verbose_linfo(env, env->insn_idx, "; "); env->prev_log_pos = env->log.end_pos; verbose(env, "%d: ", env->insn_idx); - print_bpf_insn(&cbs, insn, env->allow_ptr_leaks); + verbose_insn(env, insn); env->prev_insn_print_pos = env->log.end_pos - env->prev_log_pos; env->prev_log_pos = env->log.end_pos; } @@ -19045,37 +19528,18 @@ static int do_check(struct bpf_verifier_env *env) return err; } else if (class == BPF_LDX) { - enum bpf_reg_type src_reg_type; - - /* check for reserved fields is already done */ - - /* check src operand */ - err = check_reg_arg(env, insn->src_reg, SRC_OP); - if (err) - return err; - - err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); - if (err) - return err; + bool is_ldsx = BPF_MODE(insn->code) == BPF_MEMSX; - src_reg_type = regs[insn->src_reg].type; - - /* check that memory (src_reg + off) is readable, - * the state of dst_reg will be updated by this func + /* Check for reserved fields is already done in + * resolve_pseudo_ldimm64(). */ - err = check_mem_access(env, env->insn_idx, insn->src_reg, - insn->off, BPF_SIZE(insn->code), - BPF_READ, insn->dst_reg, false, - BPF_MODE(insn->code) == BPF_MEMSX); - err = err ?: save_aux_ptr_type(env, src_reg_type, true); - err = err ?: reg_bounds_sanity_check(env, ®s[insn->dst_reg], "ldx"); + err = check_load_mem(env, insn, false, is_ldsx, true, + "ldx"); if (err) return err; } else if (class == BPF_STX) { - enum bpf_reg_type dst_reg_type; - if (BPF_MODE(insn->code) == BPF_ATOMIC) { - err = check_atomic(env, env->insn_idx, insn); + err = check_atomic(env, insn); if (err) return err; env->insn_idx++; @@ -19087,25 +19551,7 @@ static int do_check(struct bpf_verifier_env *env) return -EINVAL; } - /* check src1 operand */ - err = check_reg_arg(env, insn->src_reg, SRC_OP); - if (err) - return err; - /* check src2 operand */ - err = check_reg_arg(env, insn->dst_reg, SRC_OP); - if (err) - return err; - - dst_reg_type = regs[insn->dst_reg].type; - - /* check that memory (dst_reg + off) is writeable */ - err = check_mem_access(env, env->insn_idx, insn->dst_reg, - insn->off, BPF_SIZE(insn->code), - BPF_WRITE, insn->src_reg, false, false); - if (err) - return err; - - err = save_aux_ptr_type(env, dst_reg_type, false); + err = check_store_reg(env, insn, false); if (err) return err; } else if (class == BPF_ST) { @@ -19245,6 +19691,9 @@ process_bpf_exit: return err; break; } else { + if (verifier_bug_if(env->cur_state->loop_entry, env, + "broken loop detection")) + return -EFAULT; do_print_state = true; continue; } @@ -19504,7 +19953,7 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env, } } - if (btf_record_has_field(map->record, BPF_SPIN_LOCK)) { + if (btf_record_has_field(map->record, BPF_SPIN_LOCK | BPF_RES_SPIN_LOCK)) { if (prog_type == BPF_PROG_TYPE_SOCKET_FILTER) { verbose(env, "socket filter progs cannot use bpf_spin_lock yet\n"); return -EINVAL; @@ -20302,10 +20751,9 @@ static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env, if (bpf_pseudo_kfunc_call(&insn)) continue; - if (WARN_ON(load_reg == -1)) { - verbose(env, "verifier bug. zext_dst is set, but no reg is defined\n"); + if (verifier_bug_if(load_reg == -1, env, + "zext_dst is set, but no reg is defined")) return -EFAULT; - } zext_patch[0] = insn; zext_patch[1].dst_reg = load_reg; @@ -20334,7 +20782,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) { struct bpf_subprog_info *subprogs = env->subprog_info; const struct bpf_verifier_ops *ops = env->ops; - int i, cnt, size, ctx_field_size, delta = 0, epilogue_cnt = 0; + int i, cnt, size, ctx_field_size, ret, delta = 0, epilogue_cnt = 0; const int insn_cnt = env->prog->len; struct bpf_insn *epilogue_buf = env->epilogue_buf; struct bpf_insn *insn_buf = env->insn_buf; @@ -20363,6 +20811,10 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) return -ENOMEM; env->prog = new_prog; delta += cnt - 1; + + ret = add_kfunc_in_insns(env, epilogue_buf, epilogue_cnt - 1); + if (ret < 0) + return ret; } } @@ -20383,6 +20835,10 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) env->prog = new_prog; delta += cnt - 1; + + ret = add_kfunc_in_insns(env, insn_buf, cnt - 1); + if (ret < 0) + return ret; } } @@ -20415,7 +20871,9 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) insn->code == (BPF_ST | BPF_MEM | BPF_W) || insn->code == (BPF_ST | BPF_MEM | BPF_DW)) { type = BPF_WRITE; - } else if ((insn->code == (BPF_STX | BPF_ATOMIC | BPF_W) || + } else if ((insn->code == (BPF_STX | BPF_ATOMIC | BPF_B) || + insn->code == (BPF_STX | BPF_ATOMIC | BPF_H) || + insn->code == (BPF_STX | BPF_ATOMIC | BPF_W) || insn->code == (BPF_STX | BPF_ATOMIC | BPF_DW)) && env->insn_aux_data[i + delta].ptr_type == PTR_TO_ARENA) { insn->code = BPF_STX | BPF_PROBE_ATOMIC | BPF_SIZE(insn->code); @@ -20612,11 +21070,9 @@ static int jit_subprogs(struct bpf_verifier_env *env) * propagated in any case. */ subprog = find_subprog(env, i + insn->imm + 1); - if (subprog < 0) { - WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", - i + insn->imm + 1); + if (verifier_bug_if(subprog < 0, env, "No program to jit at insn %d", + i + insn->imm + 1)) return -EFAULT; - } /* temporarily remember subprog id inside insn instead of * aux_data, since next loop will split up all insns into funcs */ @@ -20723,6 +21179,7 @@ static int jit_subprogs(struct bpf_verifier_env *env) func[i]->aux->tail_call_reachable = env->subprog_info[i].tail_call_reachable; func[i]->aux->exception_cb = env->subprog_info[i].is_exception_cb; func[i]->aux->changes_pkt_data = env->subprog_info[i].changes_pkt_data; + func[i]->aux->might_sleep = env->subprog_info[i].might_sleep; if (!i) func[i]->aux->exception_boundary = env->seen_exception; func[i] = bpf_int_jit_compile(func[i]); @@ -20939,6 +21396,14 @@ static void specialize_kfunc(struct bpf_verifier_env *env, */ env->seen_direct_write = seen_direct_write; } + + if (func_id == special_kfunc_list[KF_bpf_set_dentry_xattr] && + bpf_lsm_has_d_inode_locked(prog)) + *addr = (unsigned long)bpf_set_dentry_xattr_locked; + + if (func_id == special_kfunc_list[KF_bpf_remove_dentry_xattr] && + bpf_lsm_has_d_inode_locked(prog)) + *addr = (unsigned long)bpf_remove_dentry_xattr_locked; } static void __fixup_collection_insert_kfunc(struct bpf_insn_aux_data *insn_aux, @@ -21050,13 +21515,17 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, desc->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) { insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1); *cnt = 1; - } else if (is_bpf_wq_set_callback_impl_kfunc(desc->func_id)) { - struct bpf_insn ld_addrs[2] = { BPF_LD_IMM64(BPF_REG_4, (long)env->prog->aux) }; + } - insn_buf[0] = ld_addrs[0]; - insn_buf[1] = ld_addrs[1]; - insn_buf[2] = *insn; - *cnt = 3; + if (env->insn_aux_data[insn_idx].arg_prog) { + u32 regno = env->insn_aux_data[insn_idx].arg_prog; + struct bpf_insn ld_addrs[2] = { BPF_LD_IMM64(regno, (long)env->prog->aux) }; + int idx = *cnt; + + insn_buf[idx++] = ld_addrs[0]; + insn_buf[idx++] = ld_addrs[1]; + insn_buf[idx++] = *insn; + *cnt = idx; } return 0; } @@ -21373,7 +21842,50 @@ static int do_misc_fixups(struct bpf_verifier_env *env) goto next_insn; } - if (is_may_goto_insn(insn)) { + if (is_may_goto_insn(insn) && bpf_jit_supports_timed_may_goto()) { + int stack_off_cnt = -stack_depth - 16; + + /* + * Two 8 byte slots, depth-16 stores the count, and + * depth-8 stores the start timestamp of the loop. + * + * The starting value of count is BPF_MAX_TIMED_LOOPS + * (0xffff). Every iteration loads it and subs it by 1, + * until the value becomes 0 in AX (thus, 1 in stack), + * after which we call arch_bpf_timed_may_goto, which + * either sets AX to 0xffff to keep looping, or to 0 + * upon timeout. AX is then stored into the stack. In + * the next iteration, we either see 0 and break out, or + * continue iterating until the next time value is 0 + * after subtraction, rinse and repeat. + */ + stack_depth_extra = 16; + insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_AX, BPF_REG_10, stack_off_cnt); + if (insn->off >= 0) + insn_buf[1] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_AX, 0, insn->off + 5); + else + insn_buf[1] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_AX, 0, insn->off - 1); + insn_buf[2] = BPF_ALU64_IMM(BPF_SUB, BPF_REG_AX, 1); + insn_buf[3] = BPF_JMP_IMM(BPF_JNE, BPF_REG_AX, 0, 2); + /* + * AX is used as an argument to pass in stack_off_cnt + * (to add to r10/fp), and also as the return value of + * the call to arch_bpf_timed_may_goto. + */ + insn_buf[4] = BPF_MOV64_IMM(BPF_REG_AX, stack_off_cnt); + insn_buf[5] = BPF_EMIT_CALL(arch_bpf_timed_may_goto); + insn_buf[6] = BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_AX, stack_off_cnt); + cnt = 7; + + new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); + if (!new_prog) + return -ENOMEM; + + delta += cnt - 1; + env->prog = prog = new_prog; + insn = new_prog->insnsi + i + delta; + goto next_insn; + } else if (is_may_goto_insn(insn)) { int stack_off = -stack_depth - 8; stack_depth_extra = 8; @@ -21897,6 +22409,13 @@ next_insn: if (subprogs[cur_subprog + 1].start == i + delta + 1) { subprogs[cur_subprog].stack_depth += stack_depth_extra; subprogs[cur_subprog].stack_extra = stack_depth_extra; + + stack_depth = subprogs[cur_subprog].stack_depth; + if (stack_depth > MAX_BPF_STACK && !prog->jit_requested) { + verbose(env, "stack size %d(extra %d) is too large\n", + stack_depth, stack_depth_extra); + return -EINVAL; + } cur_subprog++; stack_depth = subprogs[cur_subprog].stack_depth; stack_depth_extra = 0; @@ -21907,23 +22426,33 @@ next_insn: env->prog->aux->stack_depth = subprogs[0].stack_depth; for (i = 0; i < env->subprog_cnt; i++) { + int delta = bpf_jit_supports_timed_may_goto() ? 2 : 1; int subprog_start = subprogs[i].start; int stack_slots = subprogs[i].stack_extra / 8; + int slots = delta, cnt = 0; if (!stack_slots) continue; - if (stack_slots > 1) { - verbose(env, "verifier bug: stack_slots supports may_goto only\n"); + /* We need two slots in case timed may_goto is supported. */ + if (stack_slots > slots) { + verifier_bug(env, "stack_slots supports may_goto only"); return -EFAULT; } - /* Add ST insn to subprog prologue to init extra stack */ - insn_buf[0] = BPF_ST_MEM(BPF_DW, BPF_REG_FP, - -subprogs[i].stack_depth, BPF_MAX_LOOPS); + stack_depth = subprogs[i].stack_depth; + if (bpf_jit_supports_timed_may_goto()) { + insn_buf[cnt++] = BPF_ST_MEM(BPF_DW, BPF_REG_FP, -stack_depth, + BPF_MAX_TIMED_LOOPS); + insn_buf[cnt++] = BPF_ST_MEM(BPF_DW, BPF_REG_FP, -stack_depth + 8, 0); + } else { + /* Add ST insn to subprog prologue to init extra stack */ + insn_buf[cnt++] = BPF_ST_MEM(BPF_DW, BPF_REG_FP, -stack_depth, + BPF_MAX_LOOPS); + } /* Copy first actual insn to preserve it */ - insn_buf[1] = env->prog->insnsi[subprog_start]; + insn_buf[cnt++] = env->prog->insnsi[subprog_start]; - new_prog = bpf_patch_insn_data(env, subprog_start, insn_buf, 2); + new_prog = bpf_patch_insn_data(env, subprog_start, insn_buf, cnt); if (!new_prog) return -ENOMEM; env->prog = prog = new_prog; @@ -21933,7 +22462,7 @@ next_insn: * to insn after BPF_ST that inits may_goto count. * Adjustment will succeed because bpf_patch_insn_data() didn't fail. */ - WARN_ON(adjust_jmp_off(env->prog, subprog_start, 1)); + WARN_ON(adjust_jmp_off(env->prog, subprog_start, delta)); } /* Since poke tab is now finalized, publish aux to tracker. */ @@ -22131,31 +22660,29 @@ static int remove_fastcall_spills_fills(struct bpf_verifier_env *env) static void free_states(struct bpf_verifier_env *env) { - struct bpf_verifier_state_list *sl, *sln; + struct bpf_verifier_state_list *sl; + struct list_head *head, *pos, *tmp; int i; - sl = env->free_list; - while (sl) { - sln = sl->next; + list_for_each_safe(pos, tmp, &env->free_list) { + sl = container_of(pos, struct bpf_verifier_state_list, node); free_verifier_state(&sl->state, false); kfree(sl); - sl = sln; } - env->free_list = NULL; + INIT_LIST_HEAD(&env->free_list); if (!env->explored_states) return; for (i = 0; i < state_htab_size(env); i++) { - sl = env->explored_states[i]; + head = &env->explored_states[i]; - while (sl) { - sln = sl->next; + list_for_each_safe(pos, tmp, head) { + sl = container_of(pos, struct bpf_verifier_state_list, node); free_verifier_state(&sl->state, false); kfree(sl); - sl = sln; } - env->explored_states[i] = NULL; + INIT_LIST_HEAD(&env->explored_states[i]); } } @@ -22163,6 +22690,7 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) { bool pop_log = !(env->log.level & BPF_LOG_LEVEL2); struct bpf_subprog_info *sub = subprog_info(env, subprog); + struct bpf_prog_aux *aux = env->prog->aux; struct bpf_verifier_state *state; struct bpf_reg_state *regs; int ret, i; @@ -22270,6 +22798,13 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) mark_reg_known_zero(env, regs, BPF_REG_1); } + /* Acquire references for struct_ops program arguments tagged with "__ref" */ + if (!subprog && env->prog->type == BPF_PROG_TYPE_STRUCT_OPS) { + for (i = 0; i < aux->ctx_arg_info_size; i++) + aux->ctx_arg_info[i].ref_obj_id = aux->ctx_arg_info[i].refcounted ? + acquire_reference(env, 0) : 0; + } + ret = do_check(env); out: /* check for NULL is necessary, since cur_state can be freed inside @@ -22392,6 +22927,15 @@ static void print_verification_stats(struct bpf_verifier_env *env) env->peak_states, env->longest_mark_read_walk); } +int bpf_prog_ctx_arg_info_init(struct bpf_prog *prog, + const struct bpf_ctx_arg_aux *info, u32 cnt) +{ + prog->aux->ctx_arg_info = kmemdup_array(info, cnt, sizeof(*info), GFP_KERNEL); + prog->aux->ctx_arg_info_size = cnt; + + return prog->aux->ctx_arg_info ? 0 : -ENOMEM; +} + static int check_struct_ops_btf_id(struct bpf_verifier_env *env) { const struct btf_type *t, *func_proto; @@ -22399,10 +22943,11 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) const struct bpf_struct_ops *st_ops; const struct btf_member *member; struct bpf_prog *prog = env->prog; - u32 btf_id, member_idx; + bool has_refcounted_arg = false; + u32 btf_id, member_idx, member_off; struct btf *btf; const char *mname; - int err; + int i, err; if (!prog->gpl_compatible) { verbose(env, "struct ops programs must have a GPL compatible license\n"); @@ -22450,7 +22995,8 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) return -EINVAL; } - err = bpf_struct_ops_supported(st_ops, __btf_member_bit_offset(t, member) / 8); + member_off = __btf_member_bit_offset(t, member) / 8; + err = bpf_struct_ops_supported(st_ops, member_off); if (err) { verbose(env, "attach to unsupported member %s of struct %s\n", mname, st_ops->name); @@ -22472,17 +23018,32 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) return -EACCES; } - /* btf_ctx_access() used this to provide argument type info */ - prog->aux->ctx_arg_info = - st_ops_desc->arg_info[member_idx].info; - prog->aux->ctx_arg_info_size = - st_ops_desc->arg_info[member_idx].cnt; + for (i = 0; i < st_ops_desc->arg_info[member_idx].cnt; i++) { + if (st_ops_desc->arg_info[member_idx].info->refcounted) { + has_refcounted_arg = true; + break; + } + } + + /* Tail call is not allowed for programs with refcounted arguments since we + * cannot guarantee that valid refcounted kptrs will be passed to the callee. + */ + for (i = 0; i < env->subprog_cnt; i++) { + if (has_refcounted_arg && env->subprog_info[i].has_tail_call) { + verbose(env, "program with __ref argument cannot tail call\n"); + return -EINVAL; + } + } + + prog->aux->st_ops = st_ops; + prog->aux->attach_st_ops_member_off = member_off; prog->aux->attach_func_proto = func_proto; prog->aux->attach_func_name = mname; env->ops = st_ops->verifier_ops; - return 0; + return bpf_prog_ctx_arg_info_init(prog, st_ops_desc->arg_info[member_idx].info, + st_ops_desc->arg_info[member_idx].cnt); } #define SECURITY_PREFIX "security_" @@ -22558,6 +23119,7 @@ int bpf_check_attach_target(struct bpf_verifier_log *log, if (tgt_prog) { struct bpf_prog_aux *aux = tgt_prog->aux; bool tgt_changes_pkt_data; + bool tgt_might_sleep; if (bpf_prog_is_dev_bound(prog->aux) && !bpf_prog_dev_bound_match(prog, tgt_prog)) { @@ -22600,6 +23162,15 @@ int bpf_check_attach_target(struct bpf_verifier_log *log, "Extension program changes packet data, while original does not\n"); return -EINVAL; } + + tgt_might_sleep = aux->func + ? aux->func[subprog]->aux->might_sleep + : aux->might_sleep; + if (prog->aux->might_sleep && !tgt_might_sleep) { + bpf_log(log, + "Extension program may sleep, while original does not\n"); + return -EINVAL; + } } if (!tgt_prog->jited) { bpf_log(log, "Can attach to only JITed progs\n"); @@ -22856,6 +23427,33 @@ BTF_ID(func, __rcu_read_unlock) #endif BTF_SET_END(btf_id_deny) +/* fexit and fmod_ret can't be used to attach to __noreturn functions. + * Currently, we must manually list all __noreturn functions here. Once a more + * robust solution is implemented, this workaround can be removed. + */ +BTF_SET_START(noreturn_deny) +#ifdef CONFIG_IA32_EMULATION +BTF_ID(func, __ia32_sys_exit) +BTF_ID(func, __ia32_sys_exit_group) +#endif +#ifdef CONFIG_KUNIT +BTF_ID(func, __kunit_abort) +BTF_ID(func, kunit_try_catch_throw) +#endif +#ifdef CONFIG_MODULES +BTF_ID(func, __module_put_and_kthread_exit) +#endif +#ifdef CONFIG_X86_64 +BTF_ID(func, __x64_sys_exit) +BTF_ID(func, __x64_sys_exit_group) +#endif +BTF_ID(func, do_exit) +BTF_ID(func, do_group_exit) +BTF_ID(func, kthread_complete_and_exit) +BTF_ID(func, kthread_exit) +BTF_ID(func, make_task_dead) +BTF_SET_END(noreturn_deny) + static bool can_be_sleepable(struct bpf_prog *prog) { if (prog->type == BPF_PROG_TYPE_TRACING) { @@ -22932,9 +23530,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) prog->aux->attach_btf_trace = true; return 0; } else if (prog->expected_attach_type == BPF_TRACE_ITER) { - if (!bpf_iter_prog_supported(prog)) - return -EINVAL; - return 0; + return bpf_iter_prog_supported(prog); } if (prog->type == BPF_PROG_TYPE_LSM) { @@ -22944,6 +23540,11 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) } else if (prog->type == BPF_PROG_TYPE_TRACING && btf_id_set_contains(&btf_id_deny, btf_id)) { return -EINVAL; + } else if ((prog->expected_attach_type == BPF_TRACE_FEXIT || + prog->expected_attach_type == BPF_MODIFY_RETURN) && + btf_id_set_contains(&noreturn_deny, btf_id)) { + verbose(env, "Attaching fexit/fmod_ret to __noreturn functions is rejected.\n"); + return -EINVAL; } key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id); @@ -23036,6 +23637,302 @@ static int process_fd_array(struct bpf_verifier_env *env, union bpf_attr *attr, return 0; } +static bool can_fallthrough(struct bpf_insn *insn) +{ + u8 class = BPF_CLASS(insn->code); + u8 opcode = BPF_OP(insn->code); + + if (class != BPF_JMP && class != BPF_JMP32) + return true; + + if (opcode == BPF_EXIT || opcode == BPF_JA) + return false; + + return true; +} + +static bool can_jump(struct bpf_insn *insn) +{ + u8 class = BPF_CLASS(insn->code); + u8 opcode = BPF_OP(insn->code); + + if (class != BPF_JMP && class != BPF_JMP32) + return false; + + switch (opcode) { + case BPF_JA: + case BPF_JEQ: + case BPF_JNE: + case BPF_JLT: + case BPF_JLE: + case BPF_JGT: + case BPF_JGE: + case BPF_JSGT: + case BPF_JSGE: + case BPF_JSLT: + case BPF_JSLE: + case BPF_JCOND: + return true; + } + + return false; +} + +static int insn_successors(struct bpf_prog *prog, u32 idx, u32 succ[2]) +{ + struct bpf_insn *insn = &prog->insnsi[idx]; + int i = 0, insn_sz; + u32 dst; + + insn_sz = bpf_is_ldimm64(insn) ? 2 : 1; + if (can_fallthrough(insn) && idx + 1 < prog->len) + succ[i++] = idx + insn_sz; + + if (can_jump(insn)) { + dst = idx + jmp_offset(insn) + 1; + if (i == 0 || succ[0] != dst) + succ[i++] = dst; + } + + return i; +} + +/* Each field is a register bitmask */ +struct insn_live_regs { + u16 use; /* registers read by instruction */ + u16 def; /* registers written by instruction */ + u16 in; /* registers that may be alive before instruction */ + u16 out; /* registers that may be alive after instruction */ +}; + +/* Bitmask with 1s for all caller saved registers */ +#define ALL_CALLER_SAVED_REGS ((1u << CALLER_SAVED_REGS) - 1) + +/* Compute info->{use,def} fields for the instruction */ +static void compute_insn_live_regs(struct bpf_verifier_env *env, + struct bpf_insn *insn, + struct insn_live_regs *info) +{ + struct call_summary cs; + u8 class = BPF_CLASS(insn->code); + u8 code = BPF_OP(insn->code); + u8 mode = BPF_MODE(insn->code); + u16 src = BIT(insn->src_reg); + u16 dst = BIT(insn->dst_reg); + u16 r0 = BIT(0); + u16 def = 0; + u16 use = 0xffff; + + switch (class) { + case BPF_LD: + switch (mode) { + case BPF_IMM: + if (BPF_SIZE(insn->code) == BPF_DW) { + def = dst; + use = 0; + } + break; + case BPF_LD | BPF_ABS: + case BPF_LD | BPF_IND: + /* stick with defaults */ + break; + } + break; + case BPF_LDX: + switch (mode) { + case BPF_MEM: + case BPF_MEMSX: + def = dst; + use = src; + break; + } + break; + case BPF_ST: + switch (mode) { + case BPF_MEM: + def = 0; + use = dst; + break; + } + break; + case BPF_STX: + switch (mode) { + case BPF_MEM: + def = 0; + use = dst | src; + break; + case BPF_ATOMIC: + switch (insn->imm) { + case BPF_CMPXCHG: + use = r0 | dst | src; + def = r0; + break; + case BPF_LOAD_ACQ: + def = dst; + use = src; + break; + case BPF_STORE_REL: + def = 0; + use = dst | src; + break; + default: + use = dst | src; + if (insn->imm & BPF_FETCH) + def = src; + else + def = 0; + } + break; + } + break; + case BPF_ALU: + case BPF_ALU64: + switch (code) { + case BPF_END: + use = dst; + def = dst; + break; + case BPF_MOV: + def = dst; + if (BPF_SRC(insn->code) == BPF_K) + use = 0; + else + use = src; + break; + default: + def = dst; + if (BPF_SRC(insn->code) == BPF_K) + use = dst; + else + use = dst | src; + } + break; + case BPF_JMP: + case BPF_JMP32: + switch (code) { + case BPF_JA: + case BPF_JCOND: + def = 0; + use = 0; + break; + case BPF_EXIT: + def = 0; + use = r0; + break; + case BPF_CALL: + def = ALL_CALLER_SAVED_REGS; + use = def & ~BIT(BPF_REG_0); + if (get_call_summary(env, insn, &cs)) + use = GENMASK(cs.num_params, 1); + break; + default: + def = 0; + if (BPF_SRC(insn->code) == BPF_K) + use = dst; + else + use = dst | src; + } + break; + } + + info->def = def; + info->use = use; +} + +/* Compute may-live registers after each instruction in the program. + * The register is live after the instruction I if it is read by some + * instruction S following I during program execution and is not + * overwritten between I and S. + * + * Store result in env->insn_aux_data[i].live_regs. + */ +static int compute_live_registers(struct bpf_verifier_env *env) +{ + struct bpf_insn_aux_data *insn_aux = env->insn_aux_data; + struct bpf_insn *insns = env->prog->insnsi; + struct insn_live_regs *state; + int insn_cnt = env->prog->len; + int err = 0, i, j; + bool changed; + + /* Use the following algorithm: + * - define the following: + * - I.use : a set of all registers read by instruction I; + * - I.def : a set of all registers written by instruction I; + * - I.in : a set of all registers that may be alive before I execution; + * - I.out : a set of all registers that may be alive after I execution; + * - insn_successors(I): a set of instructions S that might immediately + * follow I for some program execution; + * - associate separate empty sets 'I.in' and 'I.out' with each instruction; + * - visit each instruction in a postorder and update + * state[i].in, state[i].out as follows: + * + * state[i].out = U [state[s].in for S in insn_successors(i)] + * state[i].in = (state[i].out / state[i].def) U state[i].use + * + * (where U stands for set union, / stands for set difference) + * - repeat the computation while {in,out} fields changes for + * any instruction. + */ + state = kvcalloc(insn_cnt, sizeof(*state), GFP_KERNEL); + if (!state) { + err = -ENOMEM; + goto out; + } + + for (i = 0; i < insn_cnt; ++i) + compute_insn_live_regs(env, &insns[i], &state[i]); + + changed = true; + while (changed) { + changed = false; + for (i = 0; i < env->cfg.cur_postorder; ++i) { + int insn_idx = env->cfg.insn_postorder[i]; + struct insn_live_regs *live = &state[insn_idx]; + int succ_num; + u32 succ[2]; + u16 new_out = 0; + u16 new_in = 0; + + succ_num = insn_successors(env->prog, insn_idx, succ); + for (int s = 0; s < succ_num; ++s) + new_out |= state[succ[s]].in; + new_in = (new_out & ~live->def) | live->use; + if (new_out != live->out || new_in != live->in) { + live->in = new_in; + live->out = new_out; + changed = true; + } + } + } + + for (i = 0; i < insn_cnt; ++i) + insn_aux[i].live_regs_before = state[i].in; + + if (env->log.level & BPF_LOG_LEVEL2) { + verbose(env, "Live regs before insn:\n"); + for (i = 0; i < insn_cnt; ++i) { + verbose(env, "%3d: ", i); + for (j = BPF_REG_0; j < BPF_REG_10; ++j) + if (insn_aux[i].live_regs_before & BIT(j)) + verbose(env, "%d", j); + else + verbose(env, "."); + verbose(env, " "); + verbose_insn(env, &insns[i]); + if (bpf_is_ldimm64(&insns[i])) + i++; + } + } + +out: + kvfree(state); + kvfree(env->cfg.insn_postorder); + env->cfg.insn_postorder = NULL; + env->cfg.cur_postorder = 0; + return err; +} + int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size) { u64 start_time = ktime_get_ns(); @@ -23113,12 +24010,16 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3 env->test_reg_invariants = attr->prog_flags & BPF_F_TEST_REG_INVARIANTS; env->explored_states = kvcalloc(state_htab_size(env), - sizeof(struct bpf_verifier_state_list *), + sizeof(struct list_head), GFP_USER); ret = -ENOMEM; if (!env->explored_states) goto skip_full_check; + for (i = 0; i < state_htab_size(env); i++) + INIT_LIST_HEAD(&env->explored_states[i]); + INIT_LIST_HEAD(&env->free_list); + ret = check_btf_info_early(env, attr, uattr); if (ret < 0) goto skip_full_check; @@ -23153,6 +24054,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3 if (ret) goto skip_full_check; + ret = compute_live_registers(env); + if (ret < 0) + goto skip_full_check; + ret = mark_fastcall_patterns(env); if (ret < 0) goto skip_full_check; @@ -23291,6 +24196,7 @@ err_unlock: vfree(env->insn_aux_data); kvfree(env->insn_hist); err_free_env: + kvfree(env->cfg.insn_postorder); kvfree(env); return ret; } |