| Message ID | 20230925-strncpy-drivers-md-dm-ioctl-c-v1-1-f0bfa093ef14@google.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
| Series | dm ioctl: replace deprecated strncpy with strscpy_pad | expand |
On Mon, 25 Sep 2023 06:54:51 +0000, 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 `spec->target_type` to be NUL-terminated based on its use with > a format string after `dm_table_add_target()` is called > | r = dm_table_add_target(table, spec->target_type, > | (sector_t) spec->sector_start, > | (sector_t) spec->length, > | target_params); > ... wherein `spec->target_type` is passed as parameter `type` and later > printed with DMERR: > | DMERR("%s: %s: unknown target type", dm_device_name(t->md), type); > > [...] Applied to for-next/hardening, thanks! [1/1] dm ioctl: replace deprecated strncpy with strscpy_pad https://git.kernel.org/kees/c/0f3f34ea3798 Take care,
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 21ebb6c39394..e65058e0ed06 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1295,8 +1295,8 @@ static void retrieve_status(struct dm_table *table, spec->status = 0; spec->sector_start = ti->begin; spec->length = ti->len; - strncpy(spec->target_type, ti->type->name, - sizeof(spec->target_type) - 1); + strscpy_pad(spec->target_type, ti->type->name, + sizeof(spec->target_type)); outptr += sizeof(struct dm_target_spec); remaining = len - (outptr - outbuf);
`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 `spec->target_type` to be NUL-terminated based on its use with a format string after `dm_table_add_target()` is called | r = dm_table_add_target(table, spec->target_type, | (sector_t) spec->sector_start, | (sector_t) spec->length, | target_params); ... wherein `spec->target_type` is passed as parameter `type` and later printed with DMERR: | DMERR("%s: %s: unknown target type", dm_device_name(t->md), type); It appears that `spec` is not zero-allocated and thus NUL-padding may be required in this ioctl context. Considering the above, a suitable replacement is `strscpy_pad` due to the fact that it guarantees NUL-termination whilst maintaining the NUL-padding behavior that strncpy provides. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> --- Note: build-tested only. --- drivers/md/dm-ioctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- base-commit: 6465e260f48790807eef06b583b38ca9789b6072 change-id: 20230925-strncpy-drivers-md-dm-ioctl-c-ea5c10e77981 Best regards, -- Justin Stitt <justinstitt@google.com> -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel