diff options
| -rw-r--r-- | src/commonlib/bsd/string.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/src/commonlib/bsd/string.c b/src/commonlib/bsd/string.c index 56670e8862..6482279713 100644 --- a/src/commonlib/bsd/string.c +++ b/src/commonlib/bsd/string.c @@ -15,10 +15,19 @@ size_t strlen(const char *str) size_t strnlen(const char *str, size_t maxlen) { - size_t len = 0; - while (*str++ && len < maxlen) - len++; - return len; + const char *ptr = str; + const char *end = str + maxlen; + + if (!maxlen) + return 0; + + while (*ptr++) { + /* Make sure this checks for ==, not >=, because the calculation + for `end` may overflow in some edge cases. */ + if (ptr == end) + return maxlen; + } + return ptr - str - 1; } char *strcat(char *dst, const char *src) |