diff options
| author | Yu-Ping Wu <yupingso@chromium.org> | 2024-08-15 10:17:38 +0800 |
|---|---|---|
| committer | Julius Werner <jwerner@chromium.org> | 2024-08-15 18:16:23 +0000 |
| commit | 078a5a0e7ca006f6536d3a72e94f49f4d52f8953 (patch) | |
| tree | a4e0abb654700dbda3149270ab60c16b4c6a13cc /src | |
| parent | 0b2f9c9582af96fa3de82e2e7ab7c4f99119e1a4 (diff) | |
commonlib/bsd/string: Fix pointer overflow for strnlen()
When `maxlen` is large (such as SIZE_MAX), the `end` pointer will
overflow, causing strnlen() to incorrectly return 0.
To not make the implementation over-complicated, fix the problem by
using a counter.
BUG=b:359951393
TEST=make unit-tests -j
BRANCH=none
Change-Id: Ic9d983b11391f5e05c2bceb262682aced5206f94
Signed-off-by: Yu-Ping Wu <yupingso@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83914
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/commonlib/bsd/string.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/src/commonlib/bsd/string.c b/src/commonlib/bsd/string.c index 16cd4b5e1d..56670e8862 100644 --- a/src/commonlib/bsd/string.c +++ b/src/commonlib/bsd/string.c @@ -15,12 +15,10 @@ size_t strlen(const char *str) size_t strnlen(const char *str, size_t maxlen) { - const char *ptr = str; - const char *end = str + maxlen + 1; - - while (*ptr++ && ptr < end) - ; - return ptr - str - 1; + size_t len = 0; + while (*str++ && len < maxlen) + len++; + return len; } char *strcat(char *dst, const char *src) |