From 0ffb645ea821fbad4215b6a5681b823639c24660 Mon Sep 17 00:00:00 2001 From: Justin Stitt Date: Mon, 25 Sep 2023 06:54:51 +0000 Subject: [PATCH] dm ioctl: replace deprecated strncpy with strscpy_pad `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 Reviewed-by: Kees Cook Signed-off-by: Justin Stitt Signed-off-by: Mike Snitzer --- drivers/md/dm-ioctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) 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);