diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/helpers.c | 6 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 20 |
2 files changed, 24 insertions, 2 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index e45e72676f5a..9e8a5557ea8d 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1884,6 +1884,11 @@ void *bpf_cast_to_kern_ctx(void *obj) return obj; } +void *bpf_rdonly_cast(void *obj__ign, u32 btf_id__k) +{ + return obj__ign; +} + __diag_pop(); BTF_SET8_START(generic_btf_ids) @@ -1913,6 +1918,7 @@ BTF_ID(func, bpf_task_release) BTF_SET8_START(common_btf_ids) BTF_ID_FLAGS(func, bpf_cast_to_kern_ctx) +BTF_ID_FLAGS(func, bpf_rdonly_cast) BTF_SET8_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index d63cc0fb0a9c..f07bec227fef 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8153,6 +8153,7 @@ enum special_kfunc_type { KF_bpf_list_pop_front, KF_bpf_list_pop_back, KF_bpf_cast_to_kern_ctx, + KF_bpf_rdonly_cast, }; BTF_SET_START(special_kfunc_set) @@ -8163,6 +8164,7 @@ BTF_ID(func, bpf_list_push_back) 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_SET_END(special_kfunc_set) BTF_ID_LIST(special_kfunc_list) @@ -8173,6 +8175,7 @@ BTF_ID(func, bpf_list_push_back) 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) static enum kfunc_ptr_arg_type get_kfunc_ptr_arg_type(struct bpf_verifier_env *env, @@ -8809,6 +8812,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, u32 i, nargs, func_id, ptr_type_id; int err, insn_idx = *insn_idx_p; const struct btf_param *args; + const struct btf_type *ret_t; struct btf *desc_btf; u32 *kfunc_flags; @@ -8888,7 +8892,6 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, 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]) { - const struct btf_type *ret_t; struct btf *ret_btf; u32 ret_btf_id; @@ -8941,6 +8944,18 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, 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 { verbose(env, "kernel function %s unhandled dynamic return type\n", meta.func_name); @@ -15194,7 +15209,8 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, insn_buf[1] = addr[1]; insn_buf[2] = *insn; *cnt = 3; - } else if (desc->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) { + } else if (desc->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx] || + desc->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) { insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1); *cnt = 1; } |