sanitizer_common: don't write into .rodata

[dvyukov]

Summary

setlocale interceptor imitates a write into result,
which may be located in .rodata section.
This is the only interceptor that tries to do this and
I think the intention was to initialize the range for msan.
So do that instead. Writing into .rodata shouldn't happen
(without crashing later on the actual write) and this
traps on my local tsan experiments.

[vitalybuka]

Can you make compiler-rt/test/sanitizer_common/TestCases/setlocale.cpp to fail without patch?

[dvyukov]

In D102161#2752759, @vitalybuka wrote:

Can you make compiler-rt/test/sanitizer_common/TestCases/setlocale.cpp to fail without patch?

It's not possible now. Currently tsan handles it and that's why we did not notice it earlier (it would crash on our internal codebase otherwise).
I noticed it only while making some significant changes to tsan runtime.

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

enum {
     CIMT_FILE
   } type;
   union {
     FileMetadata file;
   };
 };
 
 #if SI_POSIX
 typedef AddrHashMap<CommonInterceptorMetadata, 31051> MetadataHashMap;
 
 static MetadataHashMap *interceptor_metadata_map;
 
 UNUSED static void SetInterceptorMetadata(__sanitizer_FILE *addr,
                                           const FileMetadata &file) {
   MetadataHashMap::Handle h(interceptor_metadata_map, (uptr)addr);
   CHECK(h.created());
   h->type = CommonInterceptorMetadata::CIMT_FILE;
   h->file = file;
 }
 
 UNUSED static const FileMetadata *GetInterceptorMetadata(
     __sanitizer_FILE *addr) {

 
 UNUSED static void DeleteInterceptorMetadata(void *addr) {
   MetadataHashMap::Handle h(interceptor_metadata_map, (uptr)addr, true);
   CHECK(h.exists());
 }
 #endif  // SI_POSIX
 
 #if SANITIZER_INTERCEPT_STRLEN
 INTERCEPTOR(SIZE_T, strlen, const char *s) {
   // Sometimes strlen is called prior to InitializeCommonInterceptors,
   // in which case the REAL(strlen) typically used in
   // COMMON_INTERCEPTOR_ENTER will fail.  We use internal_strlen here
   // to handle that.
   if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
     return internal_strlen(s);
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, strlen, s);
   SIZE_T result = REAL(strlen)(s);
   if (common_flags()->intercept_strlen)
     COMMON_INTERCEPTOR_READ_RANGE(ctx, s, result + 1);
   return result;
 }
 #define INIT_STRLEN COMMON_INTERCEPT_FUNCTION(strlen)
 #else
 #define INIT_STRLEN
 #endif
 
 #if SANITIZER_INTERCEPT_STRNLEN
 INTERCEPTOR(SIZE_T, strnlen, const char *s, SIZE_T maxlen) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, strnlen, s, maxlen);
   SIZE_T length = REAL(strnlen)(s, maxlen);
   if (common_flags()->intercept_strlen)
     COMMON_INTERCEPTOR_READ_RANGE(ctx, s, Min(length + 1, maxlen));
   return length;
 }
 #define INIT_STRNLEN COMMON_INTERCEPT_FUNCTION(strnlen)
 #else
 #define INIT_STRNLEN
 #endif
 
 #if SANITIZER_INTERCEPT_STRNDUP
 INTERCEPTOR(char*, strndup, const char *s, uptr size) {
   void *ctx;
   COMMON_INTERCEPTOR_STRNDUP_IMPL(ctx, s, size);
 }
 #define INIT_STRNDUP COMMON_INTERCEPT_FUNCTION(strndup)
 #else
 #define INIT_STRNDUP
 #endif // SANITIZER_INTERCEPT_STRNDUP
 

 
 INTERCEPTOR(char *, setlocale, int category, char *locale) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, setlocale, category, locale);
   if (locale)
     COMMON_INTERCEPTOR_READ_RANGE(ctx, locale, REAL(strlen)(locale) + 1);
   char *res = REAL(setlocale)(category, locale);
   if (res) {
-    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, res, REAL(strlen)(res) + 1);
+    COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, REAL(strlen)(res) + 1);
     unpoison_ctype_arrays(ctx);
   }
   return res;
 }
 
 #define INIT_SETLOCALE COMMON_INTERCEPT_FUNCTION(setlocale);
 #else
 #define INIT_SETLOCALE