On 23.10.23 21:35, Justin Stitt wrote:
strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.
We expect chid to be NUL-terminated based on its use with format
strings:
CTCM_DBF_TEXT_(SETUP, CTC_DBF_INFO, "%s(%s) %s", CTCM_FUNTAIL,
chid, ok ? "OK" : "failed");
Moreover, NUL-padding is not required as it is _only_ used in this one
instance with a format string.
Considering the above, a suitable replacement is `strscpy` [2] due to
the fact that it guarantees NUL-termination on the destination buffer
without unnecessarily NUL-padding.
We can also drop the +1 from chid's declaration as we no longer need to
be cautious about leaving a spot for a NUL-byte. Let's use the more
idiomatic strscpy usage of (dest, src, sizeof(dest)) as this more
closely ties the destination buffer to the length.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@xxxxxxxxxxxxxxx
Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx>
LGTM, thank you!
Reviewed-by: Thorsten Winkler <twinkler@xxxxxxxxxxxxx>
Tested-by: Thorsten Winkler <twinkler@xxxxxxxxxxxxx>
---
Note: build-tested only.
Found with: $ rg "strncpy\("
---
drivers/s390/net/ctcm_main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c
index 6faf27136024..ac15d7c2b200 100644
--- a/drivers/s390/net/ctcm_main.c
+++ b/drivers/s390/net/ctcm_main.c
@@ -200,13 +200,13 @@ static void channel_free(struct channel *ch)
static void channel_remove(struct channel *ch)
{
struct channel **c = &channels;
- char chid[CTCM_ID_SIZE+1];
+ char chid[CTCM_ID_SIZE];
int ok = 0;
if (ch == NULL)
return;
else
- strncpy(chid, ch->id, CTCM_ID_SIZE);
+ strscpy(chid, ch->id, sizeof(chid));
channel_free(ch);
while (*c) {
---
base-commit: 9c5d00cb7b6bbc5a7965d9ab7d223b5402d1f02c
change-id: 20231023-strncpy-drivers-s390-net-ctcm_main-c-f9180f470c69
Best regards,
--
Justin Stitt <justinstitt@xxxxxxxxxx>
