[HWASAN] Implement memcmp interceptor in HWASAN

DON NOT SUBMIT - NEED TO TEST ON ARM

Author: kstoimenov

compiler-rt/lib/hwasan/hwasan_interceptors.cpp

@@ -31,6 +31,21 @@
 
 using namespace __hwasan;
 
+struct HWAsanInterceptorContext {
+  const char *interceptor_name;
+};
+
+#  define ACCESS_MEMORY_RANGE(ctx, offset, size, access)                    \
+    do {                                                                    \
+      __hwasan::CheckAddressSized<ErrorAction::Abort, access>((uptr)offset, \
+                                                              size);        \
+    } while (0)
+
+#define HWASAN_READ_RANGE(ctx, offset, size) \
+  ACCESS_MEMORY_RANGE(ctx, offset, size, AccessType::Load)
+#define HWASAN_WRITE_RANGE(ctx, offset, size) \
+  ACCESS_MEMORY_RANGE(ctx, offset, size, AccessType::Store)
+
 #  if !SANITIZER_APPLE
 #    define HWASAN_INTERCEPT_FUNC(name)                                        \
       do {                                                                     \
@@ -79,13 +94,11 @@ using namespace __hwasan;
       } while (false)
 
 #    define COMMON_INTERCEPTOR_READ_RANGE(ctx, ptr, size) \
-      do {                                                \
-        (void)(ctx);                                      \
-        (void)(ptr);                                      \
-        (void)(size);                                     \
-      } while (false)
+      HWASAN_READ_RANGE(ctx, ptr, size)
 
 #    define COMMON_INTERCEPTOR_ENTER(ctx, func, ...) \
+      HWAsanInterceptorContext _ctx = {#func};       \
+      ctx = (void *)&_ctx;                           \
       do {                                           \
         (void)(ctx);                                 \
         (void)(func);                                \

compiler-rt/lib/hwasan/hwasan_platform_interceptors.h

@@ -66,7 +66,7 @@
 #define SANITIZER_INTERCEPT_MEMCPY 0
 
 #undef SANITIZER_INTERCEPT_MEMCMP
-#define SANITIZER_INTERCEPT_MEMCMP 0
+#define SANITIZER_INTERCEPT_MEMCMP 1
 
 #undef SANITIZER_INTERCEPT_BCMP
 #define SANITIZER_INTERCEPT_BCMP 0

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

@@ -445,11 +445,13 @@ INTERCEPTOR(char*, textdomain, const char *domainname) {
 #define INIT_TEXTDOMAIN
 #endif
 
-#if SANITIZER_INTERCEPT_STRCMP
+#if SANITIZER_INTERCEPT_STRCMP || SANITIZER_INTERCEPT_MEMCMP
 static inline int CharCmpX(unsigned char c1, unsigned char c2) {
   return (c1 == c2) ? 0 : (c1 < c2) ? -1 : 1;
 }
+#endif
 
+#if SANITIZER_INTERCEPT_STRCMP
 DECLARE_WEAK_INTERCEPTOR_HOOK(__sanitizer_weak_hook_strcmp, uptr called_pc,
                               const char *s1, const char *s2, int result)
 

compiler-rt/test/hwasan/TestCases/memcmp.cpp

@@ -0,0 +1,17 @@
+// RUN: %clangxx_hwasan -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_hwasan -O1 %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_hwasan -O2 %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clangxx_hwasan -O3 %s -o %t && not %run %t 2>&1 | FileCheck %s
+
+// REQUIRES: arm
+
+#include <string.h>
+int main(int argc, char **argv) {
+  char a1[] = {static_cast<char>(argc), 2, 3, 4};
+  char a2[] = {1, static_cast<char>(2*argc), 3, 4};
+  int res = memcmp(a1, a2, 4 + argc);  // BOOM
+  // CHECK: AddressSanitizer: stack-buffer-overflow
+  // CHECK: {{#[0-9]+ .*memcmp}}
+  // CHECK: {{#[0-9]+ .*main}}
+  return res;
+}