diff options
author | Al Viro <viro@ZenIV.linux.org.uk> | 2017-02-19 07:15:27 +0000 |
---|---|---|
committer | Sasha Levin <alexander.levin@verizon.com> | 2017-03-06 17:31:14 -0500 |
commit | 4f5f648b4f5b008da04dcef644369b58d24ab9b6 (patch) | |
tree | 94d8230fd7c48e9dd38bc445f86d038d6b1cd6e8 | |
parent | cfb109399f07eb9fe536659dc36e58114c3a02cb (diff) |
Fix missing sanity check in /dev/sg
[ Upstream commit 137d01df511b3afe1f05499aea05f3bafc0fb221 ]
What happens is that a write to /dev/sg is given a request with non-zero
->iovec_count combined with zero ->dxfer_len. Or with ->dxferp pointing
to an array full of empty iovecs.
Having write permission to /dev/sg shouldn't be equivalent to the
ability to trigger BUG_ON() while holding spinlocks...
Found by Dmitry Vyukov and syzkaller.
[ The BUG_ON() got changed to a WARN_ON_ONCE(), but this fixes the
underlying issue. - Linus ]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
-rw-r--r-- | drivers/scsi/sg.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 26bc4e9c7441..0cc067ce5715 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -1757,6 +1757,10 @@ sg_start_req(Sg_request *srp, unsigned char *cmd) return res; iov_iter_truncate(&i, hp->dxfer_len); + if (!iov_iter_count(&i)) { + kfree(iov); + return -EINVAL; + } res = blk_rq_map_user_iov(q, rq, md, &i, GFP_ATOMIC); kfree(iov); |