linux-kernel - Re: bio_integrity_verify() bug causing READ verify to be silently skipped

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <yq1sit4zv23.fsf@sermon.lab.mkp.net>
Date:	Fri, 03 Jan 2014 15:09:40 -0500
From:	"Martin K. Petersen" <martin.petersen@...cle.com>
To:	"Nicholas A. Bellinger" <nab@...ux-iscsi.org>
Cc:	"Martin K. Petersen" <martin.petersen@...cle.com>,
	linux-scsi <linux-scsi@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Jens Axboe <axboe@...nel.dk>, Christoph Hellwig <hch@....de>,
	Hannes Reinecke <hare@...e.de>,
	James Bottomley <James.Bottomley@...senPartnership.com>
Subject: Re: bio_integrity_verify() bug causing READ verify to be silently skipped

>>>>> "nab" == Nicholas A Bellinger <nab@...ux-iscsi.org> writes:

nab> Given that bio_integrity_verify() is using bio_for_each_segment(),
nab> the loop starts from the updated bio->bi_idx, and not a zero value,
nab> which ends up skipping individual bio segment calls to
nab> bi->verify_fn().

That's botched. Verify is meant to be called with the completed bytes
before the index is tampered with.

nab> The following patch changes bio_integrity_verify() to use
nab> bio_for_each_segment_all() instead of bio_for_each_segment() to
nab> ensure that the segment walk always starts from zero, regardless of
nab> the current bio->bi_idx value after bio_advance().

That breaks partial completion, though. I'll take a look at Kent's
changes...

-- 
Martin K. Petersen	Oracle Linux Engineering
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/