From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kent Overstreet Subject: Re: [dm-devel] [PATCH v3 01/26] block: Fix a buffer overrun in bio_integrity_split() Date: Mon, 1 Oct 2012 14:42:41 -0700 Message-ID: <20121001214241.GE26488@google.com> References: <1348526106-17074-1-git-send-email-koverstreet@google.com> <1348526106-17074-2-git-send-email-koverstreet@google.com> <20121001212336.GA17165@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20121001212336.GA17165-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Vivek Goyal 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, Oct 01, 2012 at 05:23:36PM -0400, Vivek Goyal wrote: > 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? Here's the new patch: commit e270c9ca843b5c86d59431b0d7a676b7846946d6 Author: Kent Overstreet Date: Mon Oct 1 14:41:08 2012 -0700 block: Fix a buffer overrun in bio_integrity_split() 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. Also, changed bio_integrity_split() to not refer to the bvecs embedded in struct bio_pair, in case there's padding between them and bip->bip_vec. Signed-off-by: Kent Overstreet CC: Jens Axboe CC: Martin K. Petersen diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c index a3f28f3..4ae22a8 100644 --- a/fs/bio-integrity.c +++ b/fs/bio-integrity.c @@ -694,15 +694,12 @@ void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors) bp->bio1.bi_integrity = &bp->bip1; bp->bio2.bi_integrity = &bp->bip2; - bp->iv1 = bip->bip_vec[0]; - bp->iv2 = bip->bip_vec[0]; + *bp->bip1.bip_vec = bip->bip_vec[0]; + *bp->bip2.bip_vec = 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; + bp->bip1.bip_vec->bv_len = sectors * bi->tuple_size; + bp->bip2.bip_vec->bv_offset += sectors * bi->tuple_size; + bp->bip2.bip_vec->bv_len -= sectors * bi->tuple_size; bp->bip1.bip_sector = bio->bi_integrity->bip_sector; bp->bip2.bip_sector = bio->bi_integrity->bip_sector + nr_sectors; 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 atomic_t cnt; int error;