[compiler-rt] r298305 - Bypass potential libc's sysconf wrappers for sysconf(_SC_PAGESIZE) call
Alex Shlyapnikov via llvm-commits
llvm-commits at lists.llvm.org
Mon Mar 20 14:03:28 PDT 2017
Author: alekseyshl
Date: Mon Mar 20 16:03:28 2017
New Revision: 298305
URL: http://llvm.org/viewvc/llvm-project?rev=298305&view=rev
Log:
Bypass potential libc's sysconf wrappers for sysconf(_SC_PAGESIZE) call
Summary:
sysconf(_SC_PAGESIZE) is called very early, during sanitizer init and
any instrumented code (a wrapper/interceptor will likely be instrumented)
calling back to sanitizer before init is done will most surely crash.
Reviewers: eugenis
Subscribers: llvm-commits, kubamracek
Differential Revision: https://reviews.llvm.org/D31092
Added:
compiler-rt/trunk/test/sanitizer_common/TestCases/Linux/sysconf_interceptor_bypass_test.cc
Modified:
compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc?rev=298305&r1=298304&r2=298305&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc Mon Mar 20 16:03:28 2017
@@ -78,6 +78,7 @@ extern char **environ; // provided by c
#endif
#if SANITIZER_LINUX
+#include <sys/auxv.h>
// <linux/time.h>
struct kernel_timeval {
long tv_sec;
@@ -805,6 +806,8 @@ uptr GetPageSize() {
return 4096;
#elif SANITIZER_LINUX && (defined(__x86_64__) || defined(__i386__))
return EXEC_PAGESIZE;
+#elif SANITIZER_LINUX
+ return getauxval(AT_PAGESZ);
#else
return sysconf(_SC_PAGESIZE); // EXEC_PAGESIZE may not be trustworthy.
#endif
Added: compiler-rt/trunk/test/sanitizer_common/TestCases/Linux/sysconf_interceptor_bypass_test.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/sanitizer_common/TestCases/Linux/sysconf_interceptor_bypass_test.cc?rev=298305&view=auto
==============================================================================
--- compiler-rt/trunk/test/sanitizer_common/TestCases/Linux/sysconf_interceptor_bypass_test.cc (added)
+++ compiler-rt/trunk/test/sanitizer_common/TestCases/Linux/sysconf_interceptor_bypass_test.cc Mon Mar 20 16:03:28 2017
@@ -0,0 +1,21 @@
+// RUN: %clangxx -O2 %s -o %t && %run %t 2>&1 | FileCheck %s
+
+#include <stdio.h>
+
+extern "C" long sysconf(int name) {
+ fprintf(stderr, "sysconf wrapper called\n");
+ return 0;
+}
+
+int main() {
+ // All we need to check is that the sysconf() interceptor defined above was
+ // not called. Should it get called, it will crash right there, any
+ // instrumented code executed before sanitizer init is finished will crash
+ // accessing non-initialized sanitizer internals. Even if it will not crash
+ // in some configuration, it should never be called anyway.
+ fprintf(stderr, "Passed\n");
+ // CHECK-NOT: sysconf wrapper called
+ // CHECK: Passed
+ // CHECK-NOT: sysconf wrapper called
+ return 0;
+}
More information about the llvm-commits
mailing list