Messages in this thread | | | Date | Fri, 4 Nov 2011 19:06:16 +0000 | From | Ben Hutchings <> | Subject | Re: [050/107] block: check for proper length of iov entries earlier in blk_rq_map_user_iov() |
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On Fri, Nov 04, 2011 at 10:14:26AM -0700, Greg KH wrote: > On Fri, Nov 04, 2011 at 03:24:16PM +0000, Ben Hutchings wrote: > > On Wed, 2011-11-02 at 15:14 -0700, Greg KH wrote: > > > 2.6.32-longterm review patch. If anyone has any objections, please let us know. > > > > > > ------------------ > > > > > > From: Xiaotian Feng <dfeng@redhat.com> > > > > > > commit 5478755616ae2ef1ce144dded589b62b2a50d575 upstream. > > > > > > commit 9284bcf checks for proper length of iov entries in > > > blk_rq_map_user_iov(). But if the map is unaligned, kernel > > > will break out the loop without checking for the proper length. > > > So we need to check the proper length before the unalign check. > > > > This will catch an unaligned zero-length entry. But there's still no > > check for zero-length iov entries *after* the unaligned entry. > > > > [...] > > > --- a/block/blk-map.c > > > +++ b/block/blk-map.c > > > @@ -201,12 +201,13 @@ int blk_rq_map_user_iov(struct request_q > > > for (i = 0; i < iov_count; i++) { > > > unsigned long uaddr = (unsigned long)iov[i].iov_base; > > > > > > + if (!iov[i].iov_len) > > > + return -EINVAL; > > > + > > > if (uaddr & queue_dma_alignment(q)) { > > > unaligned = 1; > > > break; > > > > I think the correct fix is just to remove the 'break'. > > Then the fix should go upstream first :)
But if I'm right, this is a non-fix and doesn't belong in the longterm update.
Ben.
-- Ben Hutchings We get into the habit of living before acquiring the habit of thinking. - Albert Camus
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