diff options
| -rw-r--r-- | arch/x86/include/asm/cfi.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/alternative.c | 18 | ||||
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 18 |
3 files changed, 30 insertions, 8 deletions
diff --git a/arch/x86/include/asm/cfi.h b/arch/x86/include/asm/cfi.h index 7a7b0b823a98..8779abd217b7 100644 --- a/arch/x86/include/asm/cfi.h +++ b/arch/x86/include/asm/cfi.h @@ -106,6 +106,7 @@ struct pt_regs; 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) { @@ -128,6 +129,7 @@ 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 #endif /* CONFIG_CFI_CLANG */ #endif /* _ASM_X86_CFI_H */ diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index d808d3aaec7e..cb393efd5ccd 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -866,6 +866,23 @@ asm ( " .size cfi_bpf_hash, 4 \n" " .popsection \n" ); + +/* Must match bpf_callback_t */ +extern u64 __bpf_callback_fn(u64, u64, u64, u64, u64); + +__ADDRESSABLE(__bpf_callback_fn); + +/* u32 __ro_after_init cfi_bpf_subprog_hash = __kcfi_typeid___bpf_callback_fn; */ +asm ( +" .pushsection .data..ro_after_init,\"aw\",@progbits \n" +" .type cfi_bpf_subprog_hash,@object \n" +" .globl cfi_bpf_subprog_hash \n" +" .p2align 2, 0x0 \n" +"cfi_bpf_subprog_hash: \n" +" .long __kcfi_typeid___bpf_callback_fn \n" +" .size cfi_bpf_subprog_hash, 4 \n" +" .popsection \n" +); #endif #ifdef CONFIG_FINEIBT @@ -1181,6 +1198,7 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline, if (builtin) { cfi_seed = get_random_u32(); cfi_bpf_hash = cfi_rehash(cfi_bpf_hash); + cfi_bpf_subprog_hash = cfi_rehash(cfi_bpf_subprog_hash); } ret = cfi_rand_preamble(start_cfi, end_cfi); diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 5d5b967b111d..43b8c08fdf8d 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -312,12 +312,13 @@ static void pop_callee_regs(u8 **pprog, bool *callee_regs_used) * in arch/x86/kernel/alternative.c */ -static void emit_fineibt(u8 **pprog) +static void emit_fineibt(u8 **pprog, bool is_subprog) { + u32 hash = is_subprog ? cfi_bpf_subprog_hash : cfi_bpf_hash; u8 *prog = *pprog; EMIT_ENDBR(); - EMIT3_off32(0x41, 0x81, 0xea, cfi_bpf_hash); /* subl $hash, %r10d */ + EMIT3_off32(0x41, 0x81, 0xea, hash); /* subl $hash, %r10d */ EMIT2(0x74, 0x07); /* jz.d8 +7 */ EMIT2(0x0f, 0x0b); /* ud2 */ EMIT1(0x90); /* nop */ @@ -326,11 +327,12 @@ static void emit_fineibt(u8 **pprog) *pprog = prog; } -static void emit_kcfi(u8 **pprog) +static void emit_kcfi(u8 **pprog, bool is_subprog) { + u32 hash = is_subprog ? cfi_bpf_subprog_hash : cfi_bpf_hash; u8 *prog = *pprog; - EMIT1_off32(0xb8, cfi_bpf_hash); /* movl $hash, %eax */ + EMIT1_off32(0xb8, hash); /* movl $hash, %eax */ #ifdef CONFIG_CALL_PADDING EMIT1(0x90); EMIT1(0x90); @@ -349,17 +351,17 @@ static void emit_kcfi(u8 **pprog) *pprog = prog; } -static void emit_cfi(u8 **pprog) +static void emit_cfi(u8 **pprog, bool is_subprog) { u8 *prog = *pprog; switch (cfi_mode) { case CFI_FINEIBT: - emit_fineibt(&prog); + emit_fineibt(&prog, is_subprog); break; case CFI_KCFI: - emit_kcfi(&prog); + emit_kcfi(&prog, is_subprog); break; default: @@ -381,7 +383,7 @@ static void emit_prologue(u8 **pprog, u32 stack_depth, bool ebpf_from_cbpf, { u8 *prog = *pprog; - emit_cfi(&prog); + emit_cfi(&prog, is_subprog); /* BPF trampoline can be made to work without these nops, * but let's waste 5 bytes for now and optimize later */ |