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| author | Justin Stitt <justinstitt@google.com> | 2023-08-07 21:22:30 +0300 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2023-08-16 23:50:37 +0300 |
| commit | 30bed99e0c6335b711119b9fda806da7b4031dfb (patch) | |
| tree | 49d71f6d95fb526262498da883f647f816d90388 /arch/um | |
| parent | 967afdf808cf66908a55c55b8ec5937cc20676ce (diff) | |
| download | linux-30bed99e0c6335b711119b9fda806da7b4031dfb.tar.xz | |
um: vector: refactor deprecated strncpy
`strncpy` is deprecated for use on NUL-terminated destination strings [1].
A suitable replacement is `strscpy` [2] due to the fact that it
guarantees NUL-termination on its destination buffer argument which is
_not_ the case for `strncpy`!
In this case, we are able to drop the now superfluous `... - 1`
instances because `strscpy` will automatically truncate the last byte by
setting it to a NUL byte if the source size exceeds the destination size
or if the source string is not NUL-terminated.
I've also opted to remove the seemingly useless char* casts. I'm not
sure why they're present at all since (after expanding the `ifr_name`
macro) `ifr.ifr_ifrn.ifrn_name` is a char* already.
All in all, `strscpy` is a more robust and less ambiguous interface
while also letting us remove some `... -1`'s which cleans things up a
bit.
[1]: www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
[2]: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Link: https://lore.kernel.org/r/20230807-arch-um-drivers-v1-1-10d602c5577a@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'arch/um')
| -rw-r--r-- | arch/um/drivers/vector_user.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/um/drivers/vector_user.c b/arch/um/drivers/vector_user.c index c650e428432b..c719e1ec4645 100644 --- a/arch/um/drivers/vector_user.c +++ b/arch/um/drivers/vector_user.c @@ -141,7 +141,7 @@ static int create_tap_fd(char *iface) } memset(&ifr, 0, sizeof(ifr)); ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR; - strncpy((char *)&ifr.ifr_name, iface, sizeof(ifr.ifr_name) - 1); + strscpy(ifr.ifr_name, iface, sizeof(ifr.ifr_name)); err = ioctl(fd, TUNSETIFF, (void *) &ifr); if (err != 0) { @@ -171,7 +171,7 @@ static int create_raw_fd(char *iface, int flags, int proto) goto raw_fd_cleanup; } memset(&ifr, 0, sizeof(ifr)); - strncpy((char *)&ifr.ifr_name, iface, sizeof(ifr.ifr_name) - 1); + strscpy(ifr.ifr_name, iface, sizeof(ifr.ifr_name)); if (ioctl(fd, SIOCGIFINDEX, (void *) &ifr) < 0) { err = -errno; goto raw_fd_cleanup; |