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authorJustin Stitt <justinstitt@google.com>2023-08-07 21:22:30 +0300
committerKees Cook <keescook@chromium.org>2023-08-16 23:50:37 +0300
commit30bed99e0c6335b711119b9fda806da7b4031dfb (patch)
tree49d71f6d95fb526262498da883f647f816d90388 /arch/um
parent967afdf808cf66908a55c55b8ec5937cc20676ce (diff)
downloadlinux-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.c4
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;