[compiler-rt] 4e1a6c0 - [msan] Add stat-family interceptors on Linux

[Evgenii Stepanov via llvm-commits]

Author: Nikita Malyavin
Date: 2021-10-20T17:14:43-07:00
New Revision: 4e1a6c07052b466a2a1cd0c3ff150e4e89a6d87a

URL: https://github.com/llvm/llvm-project/commit/4e1a6c07052b466a2a1cd0c3ff150e4e89a6d87a
DIFF: https://github.com/llvm/llvm-project/commit/4e1a6c07052b466a2a1cd0c3ff150e4e89a6d87a.diff

LOG: [msan] Add stat-family interceptors on Linux

Add following interceptors on Linux: stat, lstat, fstat, fstatat.

This fixes use-of-uninitialized value on platforms with GLIBC 2.33+.
In particular: Arch Linux, Ubuntu hirsute/impish.

The tests should have also been failing during the release on the mentioned platforms, but I cannot find any related discussion.

Most likely, the regression was introduced by glibc commit [[ https://github.com/bminor/glibc/commit/8ed005daf0ab03e142500324a34087ce179ae78e | 8ed005daf0ab03e14250032 ]]:
all stat-family functions are now exported as shared functions.

Before, some of them (namely stat, lstat, fstat, fstatat) were provided as a part of libc_noshared.a and called their __xstat dopplegangers. This is still true for Debian Sid and earlier Ubuntu's. stat interceptors may be safely provided for them, no problem with that.

Closes https://github.com/google/sanitizers/issues/1452.
See also https://jira.mariadb.org/browse/MDEV-24841

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D111984

Added: 
    

Modified: 
    compiler-rt/lib/msan/msan_interceptors.cpp
    compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/msan/msan_interceptors.cpp b/compiler-rt/lib/msan/msan_interceptors.cpp
index e61b24fd47ea6..830190916ed70 100644
--- a/compiler-rt/lib/msan/msan_interceptors.cpp
+++ b/compiler-rt/lib/msan/msan_interceptors.cpp
@@ -658,7 +658,8 @@ INTERCEPTOR(int, putenv, char *string) {
   return res;
 }
 
-#if SANITIZER_FREEBSD || SANITIZER_NETBSD
+#define SANITIZER_STAT_LINUX (SANITIZER_LINUX && __GLIBC_PREREQ(2, 33))
+#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_STAT_LINUX
 INTERCEPTOR(int, fstat, int fd, void *buf) {
   ENSURE_MSAN_INITED();
   int res = REAL(fstat)(fd, buf);
@@ -666,7 +667,7 @@ INTERCEPTOR(int, fstat, int fd, void *buf) {
     __msan_unpoison(buf, __sanitizer::struct_stat_sz);
   return res;
 }
-#define MSAN_MAYBE_INTERCEPT_FSTAT INTERCEPT_FUNCTION(fstat)
+#  define MSAN_MAYBE_INTERCEPT_FSTAT MSAN_INTERCEPT_FUNC(fstat)
 #else
 #define MSAN_MAYBE_INTERCEPT_FSTAT
 #endif
@@ -679,7 +680,7 @@ INTERCEPTOR(int, __fxstat, int magic, int fd, void *buf) {
     __msan_unpoison(buf, __sanitizer::struct_stat_sz);
   return res;
 }
-#define MSAN_MAYBE_INTERCEPT___FXSTAT INTERCEPT_FUNCTION(__fxstat)
+#  define MSAN_MAYBE_INTERCEPT___FXSTAT MSAN_INTERCEPT_FUNC(__fxstat)
 #else
 #define MSAN_MAYBE_INTERCEPT___FXSTAT
 #endif
@@ -692,20 +693,24 @@ INTERCEPTOR(int, __fxstat64, int magic, int fd, void *buf) {
     __msan_unpoison(buf, __sanitizer::struct_stat64_sz);
   return res;
 }
-#define MSAN_MAYBE_INTERCEPT___FXSTAT64 INTERCEPT_FUNCTION(__fxstat64)
+#  define MSAN_MAYBE_INTERCEPT___FXSTAT64 MSAN_INTERCEPT_FUNC(__fxstat64)
 #else
-#define MSAN_MAYBE_INTERCEPT___FXSTAT64
+#  define MSAN_MAYBE_INTERCEPT___FXSTAT64
 #endif
 
-#if SANITIZER_FREEBSD || SANITIZER_NETBSD
+#if SANITIZER_FREEBSD || SANITIZER_NETBSD || SANITIZER_STAT_LINUX
 INTERCEPTOR(int, fstatat, int fd, char *pathname, void *buf, int flags) {
   ENSURE_MSAN_INITED();
   int res = REAL(fstatat)(fd, pathname, buf, flags);
   if (!res) __msan_unpoison(buf, __sanitizer::struct_stat_sz);
   return res;
 }
-# define MSAN_INTERCEPT_FSTATAT INTERCEPT_FUNCTION(fstatat)
+#  define MSAN_MAYBE_INTERCEPT_FSTATAT MSAN_INTERCEPT_FUNC(fstatat)
 #else
+#  define MSAN_MAYBE_INTERCEPT_FSTATAT
+#endif
+
+#if !SANITIZER_FREEBSD && !SANITIZER_NETBSD
 INTERCEPTOR(int, __fxstatat, int magic, int fd, char *pathname, void *buf,
             int flags) {
   ENSURE_MSAN_INITED();
@@ -713,7 +718,9 @@ INTERCEPTOR(int, __fxstatat, int magic, int fd, char *pathname, void *buf,
   if (!res) __msan_unpoison(buf, __sanitizer::struct_stat_sz);
   return res;
 }
-# define MSAN_INTERCEPT_FSTATAT INTERCEPT_FUNCTION(__fxstatat)
+#  define MSAN_MAYBE_INTERCEPT___FXSTATAT MSAN_INTERCEPT_FUNC(__fxstatat)
+#else
+#  define MSAN_MAYBE_INTERCEPT___FXSTATAT
 #endif
 
 #if !SANITIZER_FREEBSD && !SANITIZER_NETBSD
@@ -724,9 +731,9 @@ INTERCEPTOR(int, __fxstatat64, int magic, int fd, char *pathname, void *buf,
   if (!res) __msan_unpoison(buf, __sanitizer::struct_stat64_sz);
   return res;
 }
-#define MSAN_MAYBE_INTERCEPT___FXSTATAT64 INTERCEPT_FUNCTION(__fxstatat64)
+#  define MSAN_MAYBE_INTERCEPT___FXSTATAT64 MSAN_INTERCEPT_FUNC(__fxstatat64)
 #else
-#define MSAN_MAYBE_INTERCEPT___FXSTATAT64
+#  define MSAN_MAYBE_INTERCEPT___FXSTATAT64
 #endif
 
 INTERCEPTOR(int, pipe, int pipefd[2]) {
@@ -1690,7 +1697,8 @@ void InitializeInterceptors() {
   MSAN_MAYBE_INTERCEPT_FCVT;
   MSAN_MAYBE_INTERCEPT_FSTAT;
   MSAN_MAYBE_INTERCEPT___FXSTAT;
-  MSAN_INTERCEPT_FSTATAT;
+  MSAN_MAYBE_INTERCEPT_FSTATAT;
+  MSAN_MAYBE_INTERCEPT___FXSTATAT;
   MSAN_MAYBE_INTERCEPT___FXSTAT64;
   MSAN_MAYBE_INTERCEPT___FXSTATAT64;
   INTERCEPT_FUNCTION(pipe);

diff  --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
index 4e6efcad44d11..4da53ca1ab98d 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
@@ -460,10 +460,13 @@
 #define SANITIZER_INTERCEPT_SEND_SENDTO SI_POSIX
 #define SANITIZER_INTERCEPT_EVENTFD_READ_WRITE SI_LINUX
 
-#define SANITIZER_INTERCEPT_STAT \
-  (SI_FREEBSD || SI_MAC || SI_ANDROID || SI_NETBSD || SI_SOLARIS)
+#define SI_STAT_LINUX (SI_LINUX && __GLIBC_PREREQ(2, 33))
+#define SANITIZER_INTERCEPT_STAT                                        \
+  (SI_FREEBSD || SI_MAC || SI_ANDROID || SI_NETBSD || SI_SOLARIS ||     \
+   SI_STAT_LINUX)
 #define SANITIZER_INTERCEPT_LSTAT (SI_NETBSD || SI_FREEBSD)
-#define SANITIZER_INTERCEPT___XSTAT (!SANITIZER_INTERCEPT_STAT && SI_POSIX)
+#define SANITIZER_INTERCEPT___XSTAT                             \
+  (!SANITIZER_INTERCEPT_STAT && SI_POSIX) || SI_STAT_LINUX
 #define SANITIZER_INTERCEPT___XSTAT64 SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT___LXSTAT SANITIZER_INTERCEPT___XSTAT
 #define SANITIZER_INTERCEPT___LXSTAT64 SI_LINUX_NOT_ANDROID