libhfuzz: fix strlcat wrapper

google · Nov 24, 2023 · 1912660 · 1912660
1 parent 88709ce
commit 1912660
Showing 1 changed file with 9 additions and 2 deletions.
diff --git a/libhfuzz/memorycmp.c b/libhfuzz/memorycmp.c
@@ -225,8 +225,15 @@ static inline size_t HF_strlcpy(char* dest, const char* src, size_t sz, uintptr_
 }
 
 static inline size_t HF_strlcat(char* dest, const char* src, size_t sz, uintptr_t addr) {
- size_t len = __builtin_strlen(dest);
- return HF_strlcpy(dest + len, src, sz, addr);
+ size_t dstlen = __builtin_strlen(dest);
+
+ if (dstlen >= sz) {
+ return dstlen + __builtin_strlen(src);
+ }
+
+ size_t left = sz - dstlen;
+
+ return dstlen + HF_strlcpy(dest + dstlen, src, left, addr);
 }
 
 /* Define a weak function x, as well as __wrap_x pointing to x */