From b60528d9e68113e2c297c3a45102332cb1d3e608 Mon Sep 17 00:00:00 2001 From: Demi Marie Obenour Date: Sat, 3 Jun 2023 10:52:39 -0400 Subject: dm ioctl: Check dm_target_spec is sufficiently aligned Otherwise subsequent code, if given malformed input, could dereference a misaligned 'struct dm_target_spec *'. Signed-off-by: Demi Marie Obenour Signed-off-by: Stephen Rothwell # use %zu Reviewed-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- drivers/md/dm-ioctl.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers/md') diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 8ba4cbb92351..3a6989b7817d 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1394,6 +1394,15 @@ static inline blk_mode_t get_mode(struct dm_ioctl *param) static int next_target(struct dm_target_spec *last, uint32_t next, void *end, struct dm_target_spec **spec, char **target_params) { + static_assert(__alignof__(struct dm_target_spec) <= 8, + "struct dm_target_spec must not require more than 8-byte alignment"); + + if (next % __alignof__(struct dm_target_spec)) { + DMERR("Next dm_target_spec (offset %u) is not %zu-byte aligned", + next, __alignof__(struct dm_target_spec)); + return -EINVAL; + } + *spec = (struct dm_target_spec *) ((unsigned char *) last + next); *target_params = (char *) (*spec + 1); -- cgit v1.2.3