[compiler-rt] acf0a64 - [sanitizer] Fix __sanitizer_kernel_sigset_t endianness issue

[Ilya Leoshkevich via llvm-commits]

Author: Ilya Leoshkevich
Date: 2021-07-15T12:18:46+02:00
New Revision: acf0a6428681dccac803984bfbb1e3e54248f090

URL: https://github.com/llvm/llvm-project/commit/acf0a6428681dccac803984bfbb1e3e54248f090
DIFF: https://github.com/llvm/llvm-project/commit/acf0a6428681dccac803984bfbb1e3e54248f090.diff

LOG: [sanitizer] Fix __sanitizer_kernel_sigset_t endianness issue

setuid(0) hangs on SystemZ under TSan because TSan's BackgroundThread
ignores SIGSETXID. This in turn happens because internal_sigdelset()
messes up the mask bits on big-endian system due to how
__sanitizer_kernel_sigset_t is defined.

Commit d9a1a53b8d80 ("[ESan] [MIPS] Fix workingset-signal-posix.cpp on
MIPS") fixed this for MIPS by adjusting the __sanitizer_kernel_sigset_t
definition. Generalize this by defining __SANITIZER_KERNEL_NSIG based
on kernel's _NSIG and using uptr[] for __sanitizer_kernel_sigset_t.sig
on all platforms.

Reviewed By: dvyukov

Differential Revision: https://reviews.llvm.org/D105629

Added: 
    

Modified: 
    compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
    compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
index cc4dfd7dfe06..ac0bb9586a79 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
@@ -878,7 +878,7 @@ void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {
   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
-  k_set->sig[idx] &= ~(1 << bit);
+  k_set->sig[idx] &= ~((uptr)1 << bit);
 }
 
 bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
@@ -888,7 +888,7 @@ bool internal_sigismember(__sanitizer_sigset_t *set, int signum) {
   __sanitizer_kernel_sigset_t *k_set = (__sanitizer_kernel_sigset_t *)set;
   const uptr idx = signum / (sizeof(k_set->sig[0]) * 8);
   const uptr bit = signum % (sizeof(k_set->sig[0]) * 8);
-  return k_set->sig[idx] & (1 << bit);
+  return k_set->sig[idx] & ((uptr)1 << bit);
 }
 #elif SANITIZER_FREEBSD
 void internal_sigdelset(__sanitizer_sigset_t *set, int signum) {

diff  --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
index 8a156b7fcb80..4dd27644ed11 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.h
@@ -650,14 +650,14 @@ struct __sanitizer_sigaction {
 #endif // !SANITIZER_ANDROID
 
 #if defined(__mips__)
-struct __sanitizer_kernel_sigset_t {
-  uptr sig[2];
-};
+#define __SANITIZER_KERNEL_NSIG 128
 #else
+#define __SANITIZER_KERNEL_NSIG 64
+#endif
+
 struct __sanitizer_kernel_sigset_t {
-  u8 sig[8];
+  uptr sig[__SANITIZER_KERNEL_NSIG / (sizeof(uptr) * 8)];
 };
-#endif
 
 // Linux system headers define the 'sa_handler' and 'sa_sigaction' macros.
 #if SANITIZER_MIPS