[sanitizer] add a weak hook for strncmp interceptor, both to dfsan and other sanitizers. Hide the declaration and the calls in better macros

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@243610 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 45 insertions, 19 deletions

diff --git a/include/sanitizer/common_interface_defs.h b/include/sanitizer/common_interface_defs.h
index 47df81b68..4cba61a49 100644
--- a/include/sanitizer/common_interface_defs.h
+++ b/include/sanitizer/common_interface_defs.h
@@ -120,6 +120,8 @@ extern "C" {
   // FIXME: implement more hooks.
   void __sanitizer_weak_hook_memcmp(void *called_pc, const void *s1,
                                     const void *s2, size_t n);
+  void __sanitizer_weak_hook_strncmp(void *called_pc, const char *s1,
+                                    const char *s2, size_t n);
 #ifdef __cplusplus
 }  // extern "C"
 #endif
diff --git a/include/sanitizer/dfsan_interface.h b/include/sanitizer/dfsan_interface.h
index 84ffd49f8..05666f736 100644
--- a/include/sanitizer/dfsan_interface.h
+++ b/include/sanitizer/dfsan_interface.h
@@ -91,16 +91,18 @@ void dfsan_set_write_callback(dfsan_write_callback_t labeled_write_callback);
 /// <label> <parent label 1> <parent label 2> <label description if any>
 void dfsan_dump_labels(int fd);
 
+/// Interceptor hooks.
 /// Whenever a dfsan's custom function is called the corresponding
 /// hook is called it non-zero. The hooks should be defined by the user.
 /// The primary use case is taint-guided fuzzing, where the fuzzer
 /// needs to see the parameters of the function and the labels.
 /// FIXME: implement more hooks.
-
-/// memcmp hook.
 void dfsan_weak_hook_memcmp(void *caller_pc, const void *s1, const void *s2,
                             size_t n, dfsan_label s1_label,
                             dfsan_label s2_label, dfsan_label n_label);
+void dfsan_weak_hook_strncmp(void *caller_pc, const char *s1, const char *s2,
+                             size_t n, dfsan_label s1_label,
+                             dfsan_label s2_label, dfsan_label n_label);
 #ifdef __cplusplus
 }  // extern "C"
 
diff --git a/lib/dfsan/dfsan_custom.cc b/lib/dfsan/dfsan_custom.cc
index c58b471db..d9a303e6d 100644
--- a/lib/dfsan/dfsan_custom.cc
+++ b/lib/dfsan/dfsan_custom.cc
@@ -43,6 +43,14 @@
 
 using namespace __dfsan;
 
+#define CALL_WEAK_INTERCEPTOR_HOOK(f, ...)                                     \
+  do {                                                                         \
+    if (f)                                                                     \
+      f(__VA_ARGS__);                                                          \
+  } while (false)
+#define DECLARE_WEAK_INTERCEPTOR_HOOK(f, ...) \
+SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE void f(__VA_ARGS__);
+
 extern "C" {
 SANITIZER_INTERFACE_ATTRIBUTE int
 __dfsw_stat(const char *path, struct stat *buf, dfsan_label path_label,
@@ -82,20 +90,18 @@ SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strchr(const char *s, int c,
   }
 }
 
-SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
-void
-dfsan_weak_hook_memcmp(uptr caller_pc, const void *s1, const void *s2, size_t n,
-                       dfsan_label s1_label, dfsan_label s2_label,
-                       dfsan_label n_label);
+DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_memcmp, uptr caller_pc,
+                              const void *s1, const void *s2, size_t n,
+                              dfsan_label s1_label, dfsan_label s2_label,
+                              dfsan_label n_label);
 
 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_memcmp(const void *s1, const void *s2,
                                                 size_t n, dfsan_label s1_label,
                                                 dfsan_label s2_label,
                                                 dfsan_label n_label,
                                                 dfsan_label *ret_label) {
-  if (dfsan_weak_hook_memcmp)
-    dfsan_weak_hook_memcmp(GET_CALLER_PC(), s1, s2, n, s1_label, s2_label,
-                           n_label);
+  CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_memcmp, GET_CALLER_PC(), s1, s2, n,
+                             s1_label, s2_label, n_label);
   const char *cs1 = (const char *) s1, *cs2 = (const char *) s2;
   for (size_t i = 0; i != n; ++i) {
     if (cs1[i] != cs2[i]) {
@@ -153,6 +159,11 @@ __dfsw_strcasecmp(const char *s1, const char *s2, dfsan_label s1_label,
   return 0;
 }
 
+DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strncmp, uptr caller_pc,
+                              const char *s1, const char *s2, size_t n,
+                              dfsan_label s1_label, dfsan_label s2_label,
+                              dfsan_label n_label);
+
 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strncmp(const char *s1, const char *s2,
                                                  size_t n, dfsan_label s1_label,
                                                  dfsan_label s2_label,
@@ -163,6 +174,9 @@ SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strncmp(const char *s1, const char *s2,
     return 0;
   }
 
+  CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strncmp, GET_CALLER_PC(), s1, s2,
+                             n, s1_label, s2_label, n_label);
+
   for (size_t i = 0;; ++i) {
     if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0 || i == n - 1) {
       if (flags().strict_data_dependencies) {
diff --git a/lib/sanitizer_common/sanitizer_common_interceptors.inc b/lib/sanitizer_common/sanitizer_common_interceptors.inc
index f5e96708c..a595efa7a 100644
--- a/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -40,13 +40,19 @@
 #include <stdarg.h>
 
 #if SANITIZER_INTERCEPTOR_HOOKS
-#define CALL_WEAK_INTERCEPTOR_HOOK4(f, ...)                                    \
+#define CALL_WEAK_INTERCEPTOR_HOOK(f, ...)                                     \
   do {                                                                         \
     if (f)                                                                     \
       f(__VA_ARGS__);                                                          \
   } while (false);
+#define DECLARE_WEAK_INTERCEPTOR_HOOK(f, ...)                                  \
+  extern "C" {                                                                 \
+  SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE void f(__VA_ARGS__);  \
+  } // extern "C"
 #else
-#define CALL_WEAK_INTERCEPTOR_HOOK4(f, a1, a2, a3, a4)
+#define DECLARE_WEAK_INTERCEPTOR_HOOK(f, ...)
+#define CALL_WEAK_INTERCEPTOR_HOOK(f, a1, a2, a3, a4)
+
 #endif  // SANITIZER_INTERCEPTOR_HOOKS
 
 #if SANITIZER_WINDOWS && !defined(va_copy)
@@ -213,11 +219,16 @@ INTERCEPTOR(int, strcmp, const char *s1, const char *s2) {
   return CharCmpX(c1, c2);
 }
 
+DECLARE_WEAK_INTERCEPTOR_HOOK(__sanitizer_weak_hook_strncmp, uptr called_pc,
+                              const char *s1, const char *s2, uptr n);
+
 INTERCEPTOR(int, strncmp, const char *s1, const char *s2, uptr size) {
   if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
     return internal_strncmp(s1, s2, size);
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, strncmp, s1, s2, size);
+  CALL_WEAK_INTERCEPTOR_HOOK(__sanitizer_weak_hook_strncmp, GET_CALLER_PC(), s1,
+                             s2, size);
   unsigned char c1 = 0, c2 = 0;
   uptr i;
   for (i = 0; i < size; i++) {
@@ -374,19 +385,16 @@ INTERCEPTOR(char *, strpbrk, const char *s1, const char *s2) {
 
 #if SANITIZER_INTERCEPT_MEMCMP
 
-extern "C" {
-SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
-void __sanitizer_weak_hook_memcmp(uptr called_pc, const void *s1,
-                                  const void *s2, uptr n);
-}  // extern "C"
+DECLARE_WEAK_INTERCEPTOR_HOOK(__sanitizer_weak_hook_memcmp, uptr called_pc,
+                              const void *s1, const void *s2, uptr n);
 
 INTERCEPTOR(int, memcmp, const void *a1, const void *a2, uptr size) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, memcmp, a1, a2, size);
   if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
     return internal_memcmp(a1, a2, size);
-  CALL_WEAK_INTERCEPTOR_HOOK4(__sanitizer_weak_hook_memcmp, GET_CALLER_PC(), a1,
-                              a2, size);
+  CALL_WEAK_INTERCEPTOR_HOOK(__sanitizer_weak_hook_memcmp, GET_CALLER_PC(), a1,
+                             a2, size);
   if (common_flags()->intercept_memcmp) {
     if (common_flags()->strict_memcmp) {
       // Check the entire regions even if the first bytes of the buffers are