[PATCH] D68168: [msan] Intercept __getrlimit.

[Evgenii Stepanov via Phabricator via llvm-commits]

eugenis created this revision.
eugenis added reviewers: vitalybuka, pcc.
Herald added subscribers: Sanitizers, jfb.
Herald added projects: Sanitizers, LLVM.

This interceptor is useful on its own, but the main purpose of this
change is to intercept libpthread initialization on linux/glibc in
order to run __msan_init before any .preinit_array constructors.

We used to trigger on pthread_initialize_minimal -> getrlimit(), but
that call has changed to __getrlimit at some point.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D68168

Files:
  compiler-rt/lib/msan/msan_interceptors.cpp
  compiler-rt/test/msan/preinit_array.cpp


Index: compiler-rt/test/msan/preinit_array.cpp
===================================================================
--- /dev/null
+++ compiler-rt/test/msan/preinit_array.cpp
@@ -0,0 +1,16 @@
+// RUN: %clangxx_msan -O0 %s -o %t && %run %t
+
+#include <sanitizer/msan_interface.h>
+
+volatile int global;
+static void pre_ctor() {
+  volatile int local;
+  global = 42;
+  local = 42;
+}
+
+__attribute__((section(".preinit_array"), used)) void(*__local_pre_ctor)(void) = pre_ctor;
+
+int main(void) {
+  return 0;
+}
Index: compiler-rt/lib/msan/msan_interceptors.cpp
===================================================================
--- compiler-rt/lib/msan/msan_interceptors.cpp
+++ compiler-rt/lib/msan/msan_interceptors.cpp
@@ -765,17 +765,24 @@
 #define MSAN_MAYBE_INTERCEPT_FGETS_UNLOCKED
 #endif
 
+#define INTERCEPTOR_GETRLIMIT_BODY(func, resource, rlim)  \
+  if (msan_init_is_running)                               \
+    return REAL(getrlimit)(resource, rlim);               \
+  ENSURE_MSAN_INITED();                                   \
+  int res = REAL(func)(resource, rlim);                   \
+  if (!res)                                               \
+    __msan_unpoison(rlim, __sanitizer::struct_rlimit_sz); \
+  return res
+
 INTERCEPTOR(int, getrlimit, int resource, void *rlim) {
-  if (msan_init_is_running)
-    return REAL(getrlimit)(resource, rlim);
-  ENSURE_MSAN_INITED();
-  int res = REAL(getrlimit)(resource, rlim);
-  if (!res)
-    __msan_unpoison(rlim, __sanitizer::struct_rlimit_sz);
-  return res;
+  INTERCEPTOR_GETRLIMIT_BODY(getrlimit, resource, rlim);
 }
 
 #if !SANITIZER_FREEBSD && !SANITIZER_NETBSD
+INTERCEPTOR(int, __getrlimit, int resource, void *rlim) {
+  INTERCEPTOR_GETRLIMIT_BODY(__getrlimit, resource, rlim);
+}
+
 INTERCEPTOR(int, getrlimit64, int resource, void *rlim) {
   if (msan_init_is_running) return REAL(getrlimit64)(resource, rlim);
   ENSURE_MSAN_INITED();
@@ -806,10 +813,12 @@
   return res;
 }
 
+#define MSAN_MAYBE_INTERCEPT___GETRLIMIT INTERCEPT_FUNCTION(__getrlimit)
 #define MSAN_MAYBE_INTERCEPT_GETRLIMIT64 INTERCEPT_FUNCTION(getrlimit64)
 #define MSAN_MAYBE_INTERCEPT_PRLIMIT INTERCEPT_FUNCTION(prlimit)
 #define MSAN_MAYBE_INTERCEPT_PRLIMIT64 INTERCEPT_FUNCTION(prlimit64)
 #else
+#define MSAN_MAYBE_INTERCEPT___GETRLIMIT
 #define MSAN_MAYBE_INTERCEPT_GETRLIMIT64
 #define MSAN_MAYBE_INTERCEPT_PRLIMIT
 #define MSAN_MAYBE_INTERCEPT_PRLIMIT64
@@ -1678,6 +1687,7 @@
   INTERCEPT_FUNCTION(socketpair);
   MSAN_MAYBE_INTERCEPT_FGETS_UNLOCKED;
   INTERCEPT_FUNCTION(getrlimit);
+  MSAN_MAYBE_INTERCEPT___GETRLIMIT;
   MSAN_MAYBE_INTERCEPT_GETRLIMIT64;
   MSAN_MAYBE_INTERCEPT_PRLIMIT;
   MSAN_MAYBE_INTERCEPT_PRLIMIT64;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D68168.222263.patch
Type: text/x-patch
Size: 2691 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20190927/0c11ff56/attachment.bin>