Add hardening for strrchr

1 files changed, 11 insertions, 0 deletions

diff --git a/include/string.h b/include/string.h
index 1fba9d9..4a3426a 100644
--- a/include/string.h
+++ b/include/string.h
@@ -102,6 +102,17 @@ _FORTIFY_FN(strchr) char *strchr(const char * _FORTIFY_POS0 __s, int __c)
         return __r;
 }
 
+__access(read_only, 1, 2)
+_FORTIFY_FN(strrchr) char *strrchr(const char * _FORTIFY_POS0 __s, int __c)
+{
+        size_t __b = __bos(__s, 0);
+
+        char* __r = __builtin_strrchr(__s, __c);
+        if (__r - __s > __b)
+                __builtin_trap();
+        return __r;
+}
+
 #if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
  || defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
  || defined(_BSD_SOURCE)