From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B5CD63F86F7; Fri, 15 May 2026 16:07:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778861244; cv=none; b=Oy+RKgK5BEBgpaDXsqKuMX/WjcHLCHcUeNF4U2UEYSyVhavRdhczCTjfDSORDNc0lU7Fs3R0Pn97kDoyyd+wjSw1los2R2trP7JamTma8xg94Tc+olB/GINVjf+D1badIvSLUoFpLRWVYUWhyvxQjMeCjphZKIqF1ue1T6cQQoA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778861244; c=relaxed/simple; bh=JU8CBn4PXW42IwnSr/jo5ZytZFh6kXH4fuK/MCJ3dHs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DSTk+FF0ilpkv/ZKnVZmq42rBAQBtDFZCk+phJDCVflVISTnHDg8rUKdw+iqtEspljCPNg/dJ4dJ4dTRqORHzmdpjdWj5VYcXgofXUWcllzxpXoFzRZHuP0g2LxRj1A05RsyyPkF9OITSrpJvo6ulTh3DAv2XZYccn4OR1ZTxXg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fjpdcn1z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="fjpdcn1z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D547C2BCB0; Fri, 15 May 2026 16:07:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778861244; bh=JU8CBn4PXW42IwnSr/jo5ZytZFh6kXH4fuK/MCJ3dHs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fjpdcn1zXngEhfqFgZnsEvp1Tu4pj3HSNQSMwgmjSxkcExfwjy3A+Qxthj6u0yB2o 6kmPg8mtnuVNDq7Apmh84mXqTlczj31un16P4TNL0lqob7cyLRw3jKO3DNRlv+C26m Jy3xanvXcbz4gdWENIz8QcOEJv/lfOAuQ7EzLnbY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Biggers , Mikulas Patocka Subject: [PATCH 6.6 255/474] dm-verity-fec: correctly reject too-small FEC devices Date: Fri, 15 May 2026 17:46:04 +0200 Message-ID: <20260515154720.518311180@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260515154715.053014143@linuxfoundation.org> References: <20260515154715.053014143@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit 2b14e0bb63cc671120e7791658f5c494fc66d072 upstream. Fix verity_fec_ctr() to reject too-small FEC devices by correctly computing the number of parity blocks as 'f->rounds * f->roots'. Previously it incorrectly used 'div64_u64(f->rounds * f->roots, v->fec->roots << SECTOR_SHIFT)' which is a much smaller value. Note that the units of 'rounds' are blocks, not bytes. This matches the units of the value returned by dm_bufio_get_device_size(), which are also blocks. A later commit will give 'rounds' a clearer name. Fixes: a739ff3f543a ("dm verity: add support for forward error correction") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Mikulas Patocka Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-verity-fec.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/drivers/md/dm-verity-fec.c +++ b/drivers/md/dm-verity-fec.c @@ -688,7 +688,7 @@ int verity_fec_ctr(struct dm_verity *v) { struct dm_verity_fec *f = v->fec; struct dm_target *ti = v->ti; - u64 hash_blocks, fec_blocks; + u64 hash_blocks; int ret; if (!verity_fec_is_enabled(v)) { @@ -769,8 +769,7 @@ int verity_fec_ctr(struct dm_verity *v) dm_bufio_set_sector_offset(f->bufio, f->start << (v->data_dev_block_bits - SECTOR_SHIFT)); - fec_blocks = div64_u64(f->rounds * f->roots, v->fec->roots << SECTOR_SHIFT); - if (dm_bufio_get_device_size(f->bufio) < fec_blocks) { + if (dm_bufio_get_device_size(f->bufio) < f->rounds * f->roots) { ti->error = "FEC device is too small"; return -E2BIG; }