Hi,
in OS X 10.11+ or iOS 9.0+, dyld will interpose even if
DYLD_INSERT_LIBRARIES is not set. This means, that it's not safe to use
"setenv" function to set DYLD_INSERT_LIBRARIES in MaybeReexec, because
ASan interceptors already established and we can easily end up with
something like this:
AsanInitInternal -> MaybeReexec -> setenv -> some intercepted function
(say, memmove) -> BOOM.
In fact, there is no need to reexec at all on such platforms, because we
already have working interceptors. Thus, for now we have completely
broken ASan for OS X 10.11+ and iOS 9.0+ with GCC 5.
Upstream ASan already has a fix for the issue, as well as GCC 6, so the
proper solution would be just cherry-picking corresponding commits
(r224315 and r241487) from upstream to gcc-5-branch.
Regtested and bootstrapped on x86_64-unknown-linux-gnu by myself and on
x86_64-apple-darwin15.2.0 by Dominique
(https://gcc.gnu.org/ml/gcc-testresults/2016-01/msg01115.html).
Ok for gcc-5-branch?
-Maxim
libsanitizer/ChangeLog:
2016-01-13 Maxim Ostapenko <m.ostape...@partner.samsung.com>
* PR sanitizer/69147
* asan/asan_mac.cc: Cherry pick upstream r241487.
* sanitizer_common/sanitizer_mac.cc: Cherry pick upstream r224315.
* sanitizer_common/sanitizer_mac.h: Likewise.
diff --git a/libsanitizer/asan/asan_mac.cc b/libsanitizer/asan/asan_mac.cc
index 70823bd..22f3f70 100644
--- a/libsanitizer/asan/asan_mac.cc
+++ b/libsanitizer/asan/asan_mac.cc
@@ -99,6 +99,23 @@ void LeakyResetEnv(const char *name, const char *name_value) {
}
}
+bool DyldNeedsEnvVariable() {
+// If running on OS X 10.11+ or iOS 9.0+, dyld will interpose even if
+// DYLD_INSERT_LIBRARIES is not set.
+
+#if SANITIZER_IOSSIM
+ // GetMacosVersion will not work for the simulator, whose kernel version
+ // is tied to the host. Use a weak linking hack for the simulator.
+ // This API was introduced in the same version of the OS as the dyld
+ // optimization.
+
+ // Check for presence of a symbol that is available on OS X 10.11+, iOS 9.0+.
+ return (dlsym(RTLD_NEXT, "mach_memory_info") == nullptr);
+#else
+ return (GetMacosVersion() <= MACOS_VERSION_YOSEMITE);
+#endif
+}
+
void MaybeReexec() {
if (!flags()->allow_reexec) return;
// Make sure the dynamic ASan runtime library is preloaded so that the
@@ -111,8 +128,9 @@ void MaybeReexec() {
uptr old_env_len = dyld_insert_libraries ?
internal_strlen(dyld_insert_libraries) : 0;
uptr fname_len = internal_strlen(info.dli_fname);
- if (!dyld_insert_libraries ||
- !REAL(strstr)(dyld_insert_libraries, info.dli_fname)) {
+ bool lib_is_in_env =
+ dyld_insert_libraries && REAL(strstr)(dyld_insert_libraries, info.dli_fname);
+ if (DyldNeedsEnvVariable() && !lib_is_in_env) {
// DYLD_INSERT_LIBRARIES is not set or does not contain the runtime
// library.
char program_name[1024];
@@ -141,6 +159,10 @@ void MaybeReexec() {
VReport(1, "Set ASAN_OPTIONS=allow_reexec=0 to disable this.\n");
execv(program_name, *_NSGetArgv());
} else {
+
+ if (!lib_is_in_env)
+ return;
+
// DYLD_INSERT_LIBRARIES is set and contains the runtime library.
if (old_env_len == fname_len) {
// It's just the runtime library name - fine to unset the variable.
diff --git a/libsanitizer/sanitizer_common/sanitizer_mac.cc b/libsanitizer/sanitizer_common/sanitizer_mac.cc
index 17b931c..b53ffba 100644
--- a/libsanitizer/sanitizer_common/sanitizer_mac.cc
+++ b/libsanitizer/sanitizer_common/sanitizer_mac.cc
@@ -296,7 +296,11 @@ MacosVersion GetMacosVersionInternal() {
case '2': return MACOS_VERSION_MOUNTAIN_LION;
case '3': return MACOS_VERSION_MAVERICKS;
case '4': return MACOS_VERSION_YOSEMITE;
- default: return MACOS_VERSION_UNKNOWN;
+ default:
+ if (IsDigit(version[1]))
+ return MACOS_VERSION_UNKNOWN_NEWER;
+ else
+ return MACOS_VERSION_UNKNOWN;
}
}
default: return MACOS_VERSION_UNKNOWN;
diff --git a/libsanitizer/sanitizer_common/sanitizer_mac.h b/libsanitizer/sanitizer_common/sanitizer_mac.h
index 47739f7..46a7b44 100644
--- a/libsanitizer/sanitizer_common/sanitizer_mac.h
+++ b/libsanitizer/sanitizer_common/sanitizer_mac.h
@@ -25,6 +25,7 @@ enum MacosVersion {
MACOS_VERSION_MOUNTAIN_LION,
MACOS_VERSION_MAVERICKS,
MACOS_VERSION_YOSEMITE,
+ MACOS_VERSION_UNKNOWN_NEWER
};
MacosVersion GetMacosVersion();
