release/19.x: [Sanitizers] Avoid overload ambiguity for interceptors (#100986) #101150
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@vitalybuka What do you think about merging this PR to the release branch? |
vitalybuka
approved these changes
Jul 31, 2024
Since glibc 2.40 some functions like openat make use of overloads when built with `-D_FORTIFY_SOURCE=2`, see: https://github.com/bminor/glibc/blob/master/io/bits/fcntl2.h This means that doing something like `(uintptr_t) openat` or `(void *) openat` is now ambiguous, breaking the compiler-rt build on new glibc versions. Fix this by explicitly casting the symbol to the expected function type before casting it to an intptr. The expected type is obtained as `decltype(REAL(func))` so we don't have to repeat the signature from INTERCEPTOR in the INTERCEPT_FUNTION macro. Fixes llvm#100754. (cherry picked from commit 155b7a1)
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@llvm/pr-subscribers-compiler-rt-sanitizer Author: None (llvmbot) ChangesBackport 155b7a1 Requested by: @nikic Full diff: https://github.com/llvm/llvm-project/pull/101150.diff 1 Files Affected:
diff --git a/compiler-rt/lib/interception/interception_linux.h b/compiler-rt/lib/interception/interception_linux.h
index 433a3d9bd7fa7..2e01ff44578c3 100644
--- a/compiler-rt/lib/interception/interception_linux.h
+++ b/compiler-rt/lib/interception/interception_linux.h
@@ -28,12 +28,14 @@ bool InterceptFunction(const char *name, const char *ver, uptr *ptr_to_real,
uptr func, uptr trampoline);
} // namespace __interception
-#define INTERCEPT_FUNCTION_LINUX_OR_FREEBSD(func) \
- ::__interception::InterceptFunction( \
- #func, \
- (::__interception::uptr *)&REAL(func), \
- (::__interception::uptr)&(func), \
- (::__interception::uptr)&TRAMPOLINE(func))
+// Cast func to type of REAL(func) before casting to uptr in case it is an
+// overloaded function, which is the case for some glibc functions when
+// _FORTIFY_SOURCE is used. This disambiguates which overload to use.
+#define INTERCEPT_FUNCTION_LINUX_OR_FREEBSD(func) \
+ ::__interception::InterceptFunction( \
+ #func, (::__interception::uptr *)&REAL(func), \
+ (::__interception::uptr)(decltype(REAL(func)))&(func), \
+ (::__interception::uptr) &TRAMPOLINE(func))
// dlvsym is a GNU extension supported by some other platforms.
#if SANITIZER_GLIBC || SANITIZER_FREEBSD || SANITIZER_NETBSD
@@ -41,7 +43,7 @@ bool InterceptFunction(const char *name, const char *ver, uptr *ptr_to_real,
::__interception::InterceptFunction( \
#func, symver, \
(::__interception::uptr *)&REAL(func), \
- (::__interception::uptr)&(func), \
+ (::__interception::uptr)(decltype(REAL(func)))&(func), \
(::__interception::uptr)&TRAMPOLINE(func))
#else
#define INTERCEPT_FUNCTION_VER_LINUX_OR_FREEBSD(func, symver) \
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@nikic (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR. |
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Release note:
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Backport 155b7a1
Requested by: @nikic