diff options
| author | Al Viro <viro@ZenIV.linux.org.uk> | 2017-02-19 07:15:27 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-02-23 17:43:09 +0100 |
| commit | 65de8bfbbe20cf53871852c3c57162ac4d87d6c8 (patch) | |
| tree | c7e2ed4d7eff985e9db4b0aaa3897ad949318462 /drivers | |
| parent | 8107096d243d8c0429513582da8919bfed5cd03d (diff) | |
Fix missing sanity check in /dev/sg
commit 137d01df511b3afe1f05499aea05f3bafc0fb221 upstream.
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -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 a1c29b0afb22..dedcff9cabb5 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -1763,6 +1763,10 @@ 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); |