From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Goyal Subject: Re: [dm-devel] [PATCH v3 01/26] block: Fix a buffer overrun in bio_integrity_split() Date: Mon, 1 Oct 2012 17:23:36 -0400 Message-ID: <20121001212336.GA17165@redhat.com> References: <1348526106-17074-1-git-send-email-koverstreet@google.com> <1348526106-17074-2-git-send-email-koverstreet@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1348526106-17074-2-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Kent Overstreet Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, "Martin K. Petersen" , tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org List-Id: dm-devel.ids On Mon, Sep 24, 2012 at 03:34:41PM -0700, Kent Overstreet wrote: > bio_integrity_split() seemed to be confusing pointers and arrays - > bip_vec in bio_integrity_payload is an array appended to the end of the > payload, so the bio_vecs in struct bio_pair need to come immediately > after the bio_integrity_payload they're for, and there was an assignment > in bio_integrity_split() that didn't make any sense. > > Signed-off-by: Kent Overstreet > CC: Jens Axboe > CC: Martin K. Petersen > --- > fs/bio-integrity.c | 3 --- > include/linux/bio.h | 6 ++++-- > 2 files changed, 4 insertions(+), 5 deletions(-) > > diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c > index a3f28f3..c7b6b52 100644 > --- a/fs/bio-integrity.c > +++ b/fs/bio-integrity.c > @@ -697,9 +697,6 @@ void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors) > bp->iv1 = bip->bip_vec[0]; > bp->iv2 = bip->bip_vec[0]; > > - bp->bip1.bip_vec[0] = bp->iv1; > - bp->bip2.bip_vec[0] = bp->iv2; > - > bp->iv1.bv_len = sectors * bi->tuple_size; > bp->iv2.bv_offset += sectors * bi->tuple_size; > bp->iv2.bv_len -= sectors * bi->tuple_size; > diff --git a/include/linux/bio.h b/include/linux/bio.h > index b31036f..8e2d108 100644 > --- a/include/linux/bio.h > +++ b/include/linux/bio.h > @@ -200,8 +200,10 @@ struct bio_pair { > struct bio bio1, bio2; > struct bio_vec bv1, bv2; > #if defined(CONFIG_BLK_DEV_INTEGRITY) > - struct bio_integrity_payload bip1, bip2; > - struct bio_vec iv1, iv2; > + struct bio_integrity_payload bip1; > + struct bio_vec iv1; > + struct bio_integrity_payload bip2; > + struct bio_vec iv2; > #endif I think it probably is a good idea to put a comment here so that we know that certain elements of structure assume ordering. Also I am wondering that what's the gurantee that there are no padding bytes between bipi1 and iv1 (or bip2 or iv2). I think if there are padding bytes then the assumption that bio_vec is always following bip will be broken? Also had a general question about split logic. We seem to have only one global pool for bio pair (bio_split_pool). So in the IO stack if we split a bio more than once, we have the deadlock possibility again? Thanks Vivek