[PATCH] D56125: [Sanitizer] Intercept arc4random_buf on FreeBSD/NetBSD

[David CARLIER via Phabricator via llvm-commits]

devnexen created this revision.
devnexen added reviewers: vitalybuka, krytarowski.
devnexen created this object with visibility "All Users".
Herald added subscribers: Sanitizers, llvm-commits, fedor.sergeev, kubamracek, srhines.

- Disabled on purpose on Android and Darwin platform (for now). Darwin might be pretty easily feasible though.


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D56125

Files:
  lib/sanitizer_common/sanitizer_common_interceptors.inc
  lib/sanitizer_common/sanitizer_platform_interceptors.h
  test/asan/TestCases/Posix/arc4random.cc


Index: test/asan/TestCases/Posix/arc4random.cc
===================================================================
--- /dev/null
+++ test/asan/TestCases/Posix/arc4random.cc
@@ -0,0 +1,23 @@
+// RUN: %clangxx_asan -O0 -g %s -o %t && not %run %t 2>&1 | FileCheck %s
+//
+// Darwin supports it, would need interception in its specific code before enabling it.
+// Linux does not support it but only via third party library.
+// Android supports it via bionic however it is known to have issue with older versions
+// of the implementations. Can be enabled by an Android committer later on if necessary
+// once there is more 'certainity'/been more tested.
+// UNSUPPORTED: linux, darwin, solaris
+
+#include <stdlib.h>
+
+int main(void) {
+  printf("arc4random\n");
+  char buf[10];
+  char *p = &buf[0];
+
+  arc4random_buf(p, sizeof(buf));
+  char *p = &buf[1];
+  arc4random_buf(p, sizeof(buf));
+  return 0;
+  // CHECK: arc4random
+  // CHECK: {{AddressSanitizer: stack-buffer-overflow}}
+}
Index: lib/sanitizer_common/sanitizer_platform_interceptors.h
===================================================================
--- lib/sanitizer_common/sanitizer_platform_interceptors.h
+++ lib/sanitizer_common/sanitizer_platform_interceptors.h
@@ -546,5 +546,6 @@
 #define SANITIZER_INTERCEPT_CDB SI_NETBSD
 #define SANITIZER_INTERCEPT_VIS (SI_NETBSD || SI_FREEBSD)
 #define SANITIZER_INTERCEPT_GETFSENT (SI_FREEBSD || SI_NETBSD)
+#define SANITIZER_INTERCEPT_ARC4RANDOM (SI_FREEBSD || SI_NETBSD)
 
 #endif  // #ifndef SANITIZER_PLATFORM_INTERCEPTORS_H
Index: lib/sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -9084,6 +9084,24 @@
 #else
 #define INIT_GETFSENT
 #endif
+
+#if SANITIZER_INTERCEPT_ARC4RANDOM
+INTERCEPTOR(void, arc4random_buf, void *buf, SIZE_T len) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, arc4random_buf, buf, len);
+  if (buf)
+    COMMON_INTERCEPTOR_READ_RANGE(ctx, buf, len);
+  REAL(arc4random_buf)(buf, len);
+  if (buf)
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, buf, len);
+}
+
+#define INIT_ARC4RANDOM \
+  COMMON_INTERCEPT_FUNCTION(arc4random_buf);
+#else
+#define INIT_ARC4RANDOM
+#endif
+
 static void InitializeCommonInterceptors() {
   static u64 metadata_mem[sizeof(MetadataHashMap) / sizeof(u64) + 1];
   interceptor_metadata_map =
@@ -9365,6 +9383,7 @@
   INIT_VIS;
   INIT_CDB;
   INIT_GETFSENT;
+  INIT_ARC4RANDOM;
 
   INIT___PRINTF_CHK;
 }


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