release/19.x: [lsan] Fix free(NULL) interception during initialization

[llvmbot]

Backport 1797174 ae0ed3d d9ed8b0

Requested by: @nikic

[llvmbot]

@tmiasko @vitalybuka @vitalybuka What do you think about merging this PR to the release branch?

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: None (llvmbot)

Changes

Backport 1797174 ae0ed3d d9ed8b0

Requested by: @nikic

---

Full diff: https://github.com/llvm/llvm-project/pull/121100.diff

2 Files Affected:

• (modified) compiler-rt/lib/lsan/lsan_interceptors.cpp (+2)
• (added) compiler-rt/test/sanitizer_common/TestCases/dlsym_alloc.c (+60)

diff --git a/compiler-rt/lib/lsan/lsan_interceptors.cpp b/compiler-rt/lib/lsan/lsan_interceptors.cpp
index b569c337e97641..efbf2fdfb0ab3f 100644
--- a/compiler-rt/lib/lsan/lsan_interceptors.cpp
+++ b/compiler-rt/lib/lsan/lsan_interceptors.cpp
@@ -77,6 +77,8 @@ INTERCEPTOR(void*, malloc, uptr size) {
 }
 
 INTERCEPTOR(void, free, void *p) {
+  if (UNLIKELY(!p))
+    return;
   if (DlsymAlloc::PointerIsMine(p))
     return DlsymAlloc::Free(p);
   ENSURE_LSAN_INITED;
diff --git a/compiler-rt/test/sanitizer_common/TestCases/dlsym_alloc.c b/compiler-rt/test/sanitizer_common/TestCases/dlsym_alloc.c
new file mode 100644
index 00000000000000..7b5b9cf34a90f9
--- /dev/null
+++ b/compiler-rt/test/sanitizer_common/TestCases/dlsym_alloc.c
@@ -0,0 +1,60 @@
+// RUN: %clang -O0 %s -o %t && %run %t
+
+// FIXME: TSAN does not use DlsymAlloc.
+// UNSUPPORTED: tsan
+// FIXME: investigate why this fails on macos
+// UNSUPPORTED: darwin
+
+#include <stdlib.h>
+
+const char *test() __attribute__((disable_sanitizer_instrumentation)) {
+  void *volatile p = malloc(3);
+  p = realloc(p, 7);
+  free(p);
+
+  p = calloc(3, 7);
+  free(p);
+
+  free(NULL);
+
+  return "";
+}
+
+const char *__asan_default_options()
+    __attribute__((disable_sanitizer_instrumentation)) {
+  return test();
+}
+const char *__hwasan_default_options()
+    __attribute__((disable_sanitizer_instrumentation)) {
+  return test();
+}
+const char *__lsan_default_options()
+    __attribute__((disable_sanitizer_instrumentation)) {
+  return test();
+}
+const char *__memprof_default_options()
+    __attribute__((disable_sanitizer_instrumentation)) {
+  return test();
+}
+const char *__msan_default_options()
+    __attribute__((disable_sanitizer_instrumentation)) {
+  return test();
+}
+const char *__nsan_default_options()
+    __attribute__((disable_sanitizer_instrumentation)) {
+  return test();
+}
+const char *__rtsan_default_options()
+    __attribute__((disable_sanitizer_instrumentation)) {
+  return test();
+}
+const char *__tsan_default_options()
+    __attribute__((disable_sanitizer_instrumentation)) {
+  return test();
+}
+const char *__ubsan_default_options()
+    __attribute__((disable_sanitizer_instrumentation)) {
+  return test();
+}
+
+int main(int argc, char **argv) { return 0; }

[github-actions]

@nikic (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.