[compiler-rt] Fix interceptors with AArch64 BTI #84061
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@llvm/pr-subscribers-compiler-rt-sanitizer Author: Marco Elver (melver) ChangesOn AArch64 with BTI and/or PAC, we have to prefix the function body with the appropriate hints/checks. PACIASP is an implicit branch target identification instructions which is equivalent to BTI c. Full diff: https://github.com/llvm/llvm-project/pull/84061.diff 2 Files Affected:
diff --git a/compiler-rt/lib/interception/interception.h b/compiler-rt/lib/interception/interception.h
index 00bcd979638b53..5a8fb24a9ccb2c 100644
--- a/compiler-rt/lib/interception/interception.h
+++ b/compiler-rt/lib/interception/interception.h
@@ -205,6 +205,7 @@ const interpose_substitution substitution_##func_name[] \
ASM_TYPE_FUNCTION_STR "\n" \
SANITIZER_STRINGIFY(TRAMPOLINE(func)) ":\n" \
SANITIZER_STRINGIFY(CFI_STARTPROC) "\n" \
+ SANITIZER_STRINGIFY(ASM_PAC_STARTPROC) "\n" \
C_ASM_TAIL_CALL(SANITIZER_STRINGIFY(TRAMPOLINE(func)), \
"__interceptor_" \
SANITIZER_STRINGIFY(ASM_PREEMPTIBLE_SYM(func))) "\n" \
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_asm.h b/compiler-rt/lib/sanitizer_common/sanitizer_asm.h
index 3af66a4e449988..bd4421b1991c2b 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_asm.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_asm.h
@@ -42,6 +42,12 @@
# define CFI_RESTORE(reg)
#endif
+#if defined(__aarch64__)
+# define ASM_PAC_STARTPROC paciasp
+#else
+# define ASM_PAC_STARTPROC
+#endif
+
#if defined(__x86_64__) || defined(__i386__) || defined(__sparc__)
# define ASM_TAIL_CALL jmp
#elif defined(__arm__) || defined(__aarch64__) || defined(__mips__) || \
@@ -115,6 +121,7 @@
ASM_TYPE_FUNCTION(__interceptor_trampoline_##name); \
__interceptor_trampoline_##name: \
CFI_STARTPROC; \
+ ASM_PAC_STARTPROC; \
ASM_TAIL_CALL ASM_PREEMPTIBLE_SYM(__interceptor_##name); \
CFI_ENDPROC; \
ASM_SIZE(__interceptor_trampoline_##name)
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You can test this locally with the following command:git-clang-format --diff 17162b61c2e6968482fab928f89bdca8b4ac06d9 f6f0c2a3ad24651decaa739893c17a75e49550ef -- compiler-rt/lib/interception/interception.h compiler-rt/lib/sanitizer_common/sanitizer_asm.hView the diff from clang-format here.diff --git a/compiler-rt/lib/interception/interception.h b/compiler-rt/lib/interception/interception.h
index 38c152952e..029a1d7de3 100644
--- a/compiler-rt/lib/interception/interception.h
+++ b/compiler-rt/lib/interception/interception.h
@@ -191,12 +191,12 @@ const interpose_substitution substitution_##func_name[] \
# define ASM_TYPE_FUNCTION_STR "@function"
# endif
// Keep trampoline implementation in sync with sanitizer_common/sanitizer_asm.h
-# define DECLARE_WRAPPER(ret_type, func, ...) \
- extern "C" ret_type func(__VA_ARGS__); \
- extern "C" ret_type TRAMPOLINE(func)(__VA_ARGS__); \
- extern "C" ret_type __interceptor_##func(__VA_ARGS__) \
- INTERCEPTOR_ATTRIBUTE __attribute__((weak)) ALIAS(WRAP(func)); \
- asm( \
+# define DECLARE_WRAPPER(ret_type, func, ...) \
+ extern "C" ret_type func(__VA_ARGS__); \
+ extern "C" ret_type TRAMPOLINE(func)(__VA_ARGS__); \
+ extern "C" ret_type __interceptor_##func(__VA_ARGS__) \
+ INTERCEPTOR_ATTRIBUTE __attribute__((weak)) ALIAS(WRAP(func)); \
+ asm( \
".text\n" \
__ASM_WEAK_WRAPPER(func) \
".set " #func ", " SANITIZER_STRINGIFY(TRAMPOLINE(func)) "\n" \
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_asm.h b/compiler-rt/lib/sanitizer_common/sanitizer_asm.h
index 30e9d15184..ac8b497ac6 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_asm.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_asm.h
@@ -43,11 +43,13 @@
#endif
#if defined(__aarch64__) && defined(__ARM_FEATURE_BTI_DEFAULT)
-# define ASM_STARTPROC CFI_STARTPROC; hint #34
-# define C_ASM_STARTPROC SANITIZER_STRINGIFY(CFI_STARTPROC) "\nhint #34"
+# define ASM_STARTPROC \
+ CFI_STARTPROC; \
+ hint #34
+# define C_ASM_STARTPROC SANITIZER_STRINGIFY(CFI_STARTPROC) "\nhint #34"
#else
-# define ASM_STARTPROC CFI_STARTPROC
-# define C_ASM_STARTPROC SANITIZER_STRINGIFY(CFI_STARTPROC)
+# define ASM_STARTPROC CFI_STARTPROC
+# define C_ASM_STARTPROC SANITIZER_STRINGIFY(CFI_STARTPROC)
#endif
#define ASM_ENDPROC CFI_ENDPROC
#define C_ASM_ENDPROC SANITIZER_STRINGIFY(CFI_ENDPROC)
@@ -118,17 +120,16 @@
# define ASM_TRAMPOLINE_ALIAS(symbol, name) \
.weak symbol; \
.set symbol, __interceptor_trampoline_##name
-# define ASM_INTERCEPTOR_TRAMPOLINE(name) \
- .weak __interceptor_##name; \
- .set __interceptor_##name, ASM_WRAPPER_NAME(name); \
- .globl __interceptor_trampoline_##name; \
- ASM_TYPE_FUNCTION(__interceptor_trampoline_##name); \
- __interceptor_trampoline_##name: \
- ASM_STARTPROC; \
- ASM_TAIL_CALL ASM_PREEMPTIBLE_SYM(__interceptor_##name); \
- ASM_ENDPROC; \
- ASM_SIZE(__interceptor_trampoline_##name)
-# define ASM_INTERCEPTOR_TRAMPOLINE_SUPPORT 1
+# define ASM_INTERCEPTOR_TRAMPOLINE(name) \
+ .weak __interceptor_##name; \
+ .set __interceptor_##name, ASM_WRAPPER_NAME(name); \
+ .globl __interceptor_trampoline_##name; \
+ ASM_TYPE_FUNCTION(__interceptor_trampoline_##name); \
+ __interceptor_trampoline_##name : ASM_STARTPROC; \
+ ASM_TAIL_CALL ASM_PREEMPTIBLE_SYM(__interceptor_##name); \
+ ASM_ENDPROC; \
+ ASM_SIZE(__interceptor_trampoline_##name)
+# define ASM_INTERCEPTOR_TRAMPOLINE_SUPPORT 1
# endif // Architecture supports interceptor trampoline
#else
# define ASM_HIDDEN(symbol)
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Question: Do we need both PACIASP or just BTI hint? |
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It has to be |
On AArch64 with BTI, we have to start functions with the appropriate BTI hint to indicate that the function is a valid call target. To support interceptors with AArch64 BTI, add "BTI c".
melver
changed the title
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PTAL |
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LGTM, thanks! |
vitalybuka
approved these changes
Mar 12, 2024
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On AArch64 with BTI, we have to start functions with the appropriate
BTI hint to indicate that the function is a valid call target.
To support interceptors with AArch64 BTI, add "BTI c".