diff options
| -rw-r--r-- | arch/riscv/include/asm/cfi.h | 16 | ||||
| -rw-r--r-- | arch/riscv/kernel/cfi.c | 24 | ||||
| -rw-r--r-- | arch/x86/include/asm/cfi.h | 10 | ||||
| -rw-r--r-- | arch/x86/kernel/alternative.c | 12 | ||||
| -rw-r--r-- | include/linux/cfi.h | 47 | ||||
| -rw-r--r-- | kernel/cfi.c | 15 |
6 files changed, 56 insertions, 68 deletions
diff --git a/arch/riscv/include/asm/cfi.h b/arch/riscv/include/asm/cfi.h index fb9696d7a3f2..4508aaa7a2fd 100644 --- a/arch/riscv/include/asm/cfi.h +++ b/arch/riscv/include/asm/cfi.h @@ -14,27 +14,11 @@ struct pt_regs; #ifdef CONFIG_CFI_CLANG enum bug_trap_type handle_cfi_failure(struct pt_regs *regs); #define __bpfcall -static inline int cfi_get_offset(void) -{ - return 4; -} - -#define cfi_get_offset cfi_get_offset -extern u32 cfi_bpf_hash; -extern u32 cfi_bpf_subprog_hash; -extern u32 cfi_get_func_hash(void *func); #else static inline enum bug_trap_type handle_cfi_failure(struct pt_regs *regs) { return BUG_TRAP_TYPE_NONE; } - -#define cfi_bpf_hash 0U -#define cfi_bpf_subprog_hash 0U -static inline u32 cfi_get_func_hash(void *func) -{ - return 0; -} #endif /* CONFIG_CFI_CLANG */ #endif /* _ASM_RISCV_CFI_H */ diff --git a/arch/riscv/kernel/cfi.c b/arch/riscv/kernel/cfi.c index e7aec5f36dd5..6ec9dbd7292e 100644 --- a/arch/riscv/kernel/cfi.c +++ b/arch/riscv/kernel/cfi.c @@ -4,7 +4,6 @@ * * Copyright (C) 2023 Google LLC */ -#include <linux/cfi_types.h> #include <linux/cfi.h> #include <asm/insn.h> @@ -76,26 +75,3 @@ enum bug_trap_type handle_cfi_failure(struct pt_regs *regs) return report_cfi_failure(regs, regs->epc, &target, type); } - -#ifdef CONFIG_CFI_CLANG -struct bpf_insn; - -/* Must match bpf_func_t / DEFINE_BPF_PROG_RUN() */ -extern unsigned int __bpf_prog_runX(const void *ctx, - const struct bpf_insn *insn); -DEFINE_CFI_TYPE(cfi_bpf_hash, __bpf_prog_runX); - -/* Must match bpf_callback_t */ -extern u64 __bpf_callback_fn(u64, u64, u64, u64, u64); -DEFINE_CFI_TYPE(cfi_bpf_subprog_hash, __bpf_callback_fn); - -u32 cfi_get_func_hash(void *func) -{ - u32 hash; - - if (get_kernel_nofault(hash, func - cfi_get_offset())) - return 0; - - return hash; -} -#endif diff --git a/arch/x86/include/asm/cfi.h b/arch/x86/include/asm/cfi.h index 3e51ba459154..1751f1eb95ef 100644 --- a/arch/x86/include/asm/cfi.h +++ b/arch/x86/include/asm/cfi.h @@ -116,8 +116,6 @@ struct pt_regs; #ifdef CONFIG_CFI_CLANG enum bug_trap_type handle_cfi_failure(struct pt_regs *regs); #define __bpfcall -extern u32 cfi_bpf_hash; -extern u32 cfi_bpf_subprog_hash; static inline int cfi_get_offset(void) { @@ -135,6 +133,8 @@ static inline int cfi_get_offset(void) #define cfi_get_offset cfi_get_offset extern u32 cfi_get_func_hash(void *func); +#define cfi_get_func_hash cfi_get_func_hash + extern int cfi_get_func_arity(void *func); #ifdef CONFIG_FINEIBT @@ -153,12 +153,6 @@ static inline enum bug_trap_type handle_cfi_failure(struct pt_regs *regs) { return BUG_TRAP_TYPE_NONE; } -#define cfi_bpf_hash 0U -#define cfi_bpf_subprog_hash 0U -static inline u32 cfi_get_func_hash(void *func) -{ - return 0; -} static inline int cfi_get_func_arity(void *func) { return 0; diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index a555665b4d9c..9f6b7dab2d9a 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -2,7 +2,6 @@ #define pr_fmt(fmt) "SMP alternatives: " fmt #include <linux/mmu_context.h> -#include <linux/cfi_types.h> #include <linux/perf_event.h> #include <linux/vmalloc.h> #include <linux/memory.h> @@ -1185,17 +1184,6 @@ bool cfi_bhi __ro_after_init = false; #endif #ifdef CONFIG_CFI_CLANG -struct bpf_insn; - -/* Must match bpf_func_t / DEFINE_BPF_PROG_RUN() */ -extern unsigned int __bpf_prog_runX(const void *ctx, - const struct bpf_insn *insn); -DEFINE_CFI_TYPE(cfi_bpf_hash, __bpf_prog_runX); - -/* Must match bpf_callback_t */ -extern u64 __bpf_callback_fn(u64, u64, u64, u64, u64); -DEFINE_CFI_TYPE(cfi_bpf_subprog_hash, __bpf_callback_fn); - u32 cfi_get_func_hash(void *func) { u32 hash; diff --git a/include/linux/cfi.h b/include/linux/cfi.h index 1db17ecbb86c..52a98886a455 100644 --- a/include/linux/cfi.h +++ b/include/linux/cfi.h @@ -11,16 +11,9 @@ #include <linux/module.h> #include <asm/cfi.h> +#ifdef CONFIG_CFI_CLANG extern bool cfi_warn; -#ifndef cfi_get_offset -static inline int cfi_get_offset(void) -{ - return 0; -} -#endif - -#ifdef CONFIG_CFI_CLANG enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr, unsigned long *target, u32 type); @@ -29,6 +22,44 @@ static inline enum bug_trap_type report_cfi_failure_noaddr(struct pt_regs *regs, { return report_cfi_failure(regs, addr, NULL, 0); } + +#ifndef cfi_get_offset +/* + * Returns the CFI prefix offset. By default, the compiler emits only + * a 4-byte CFI type hash before the function. If an architecture + * uses -fpatchable-function-entry=N,M where M>0 to change the prefix + * offset, they must override this function. + */ +static inline int cfi_get_offset(void) +{ + return 4; +} +#endif + +#ifndef cfi_get_func_hash +static inline u32 cfi_get_func_hash(void *func) +{ + u32 hash; + + if (get_kernel_nofault(hash, func - cfi_get_offset())) + return 0; + + return hash; +} +#endif + +/* CFI type hashes for BPF function types */ +extern u32 cfi_bpf_hash; +extern u32 cfi_bpf_subprog_hash; + +#else /* CONFIG_CFI_CLANG */ + +static inline int cfi_get_offset(void) { return 0; } +static inline u32 cfi_get_func_hash(void *func) { return 0; } + +#define cfi_bpf_hash 0U +#define cfi_bpf_subprog_hash 0U + #endif /* CONFIG_CFI_CLANG */ #ifdef CONFIG_ARCH_USES_CFI_TRAPS diff --git a/kernel/cfi.c b/kernel/cfi.c index 422fa4f958ae..4dad04ead06c 100644 --- a/kernel/cfi.c +++ b/kernel/cfi.c @@ -5,6 +5,8 @@ * Copyright (C) 2022 Google LLC */ +#include <linux/bpf.h> +#include <linux/cfi_types.h> #include <linux/cfi.h> bool cfi_warn __ro_after_init = IS_ENABLED(CONFIG_CFI_PERMISSIVE); @@ -27,6 +29,19 @@ enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr, return BUG_TRAP_TYPE_BUG; } +/* + * Declare two non-existent functions with types that match bpf_func_t and + * bpf_callback_t pointers, and use DEFINE_CFI_TYPE to define type hash + * variables for each function type. The cfi_bpf_* variables are used by + * arch-specific BPF JIT implementations to ensure indirectly callable JIT + * code has matching CFI type hashes. + */ +extern typeof(*(bpf_func_t)0) __bpf_prog_runX; +DEFINE_CFI_TYPE(cfi_bpf_hash, __bpf_prog_runX); + +extern typeof(*(bpf_callback_t)0) __bpf_callback_fn; +DEFINE_CFI_TYPE(cfi_bpf_subprog_hash, __bpf_callback_fn); + #ifdef CONFIG_ARCH_USES_CFI_TRAPS static inline unsigned long trap_address(s32 *p) { |