From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3CEEEB64D9 for ; Mon, 19 Jun 2023 10:59:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232469AbjFSK7K (ORCPT ); Mon, 19 Jun 2023 06:59:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60838 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232366AbjFSK6n (ORCPT ); Mon, 19 Jun 2023 06:58:43 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 817131723 for ; Mon, 19 Jun 2023 03:57:11 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0DAA960B5F for ; Mon, 19 Jun 2023 10:57:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25A70C433C0; Mon, 19 Jun 2023 10:57:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1687172230; bh=tyw/1INzvYwlkUZF5NwSsxLIo63T8sqs8Ids4I6zJ1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BmrFfqwrVg81K3dMUO0ZUFiSkUm9VH20+d3b/cVRx5n8aWGAui06ho6kxmB3F06i+ QAPS6NoMF/TI5WRWkBu5ARguGZS+n9iq7TPxvJ9yF/hITr2blUeIZdinhxvlfluMtv 0zwvGMe24Tmf+DeGZNx4r7F4uhcM5L9fhySJcCXY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ryusuke Konishi , syzbot+7d50f1e54a12ba3aeae2@syzkaller.appspotmail.com, Andrew Morton Subject: [PATCH 5.10 83/89] nilfs2: reject devices with insufficient block count Date: Mon, 19 Jun 2023 12:31:11 +0200 Message-ID: <20230619102142.066600154@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230619102138.279161276@linuxfoundation.org> References: <20230619102138.279161276@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ryusuke Konishi commit 92c5d1b860e9581d64baca76779576c0ab0d943d upstream. The current sanity check for nilfs2 geometry information lacks checks for the number of segments stored in superblocks, so even for device images that have been destructively truncated or have an unusually high number of segments, the mount operation may succeed. This causes out-of-bounds block I/O on file system block reads or log writes to the segments, the latter in particular causing "a_ops->writepages" to repeatedly fail, resulting in sync_inodes_sb() to hang. Fix this issue by checking the number of segments stored in the superblock and avoiding mounting devices that can cause out-of-bounds accesses. To eliminate the possibility of overflow when calculating the number of blocks required for the device from the number of segments, this also adds a helper function to calculate the upper bound on the number of segments and inserts a check using it. Link: https://lkml.kernel.org/r/20230526021332.3431-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi Reported-by: syzbot+7d50f1e54a12ba3aeae2@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=7d50f1e54a12ba3aeae2 Tested-by: Ryusuke Konishi Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/nilfs2/the_nilfs.c | 44 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 43 insertions(+), 1 deletion(-) --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -405,6 +405,18 @@ unsigned long nilfs_nrsvsegs(struct the_ 100)); } +/** + * nilfs_max_segment_count - calculate the maximum number of segments + * @nilfs: nilfs object + */ +static u64 nilfs_max_segment_count(struct the_nilfs *nilfs) +{ + u64 max_count = U64_MAX; + + do_div(max_count, nilfs->ns_blocks_per_segment); + return min_t(u64, max_count, ULONG_MAX); +} + void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs) { nilfs->ns_nsegments = nsegs; @@ -414,6 +426,8 @@ void nilfs_set_nsegments(struct the_nilf static int nilfs_store_disk_layout(struct the_nilfs *nilfs, struct nilfs_super_block *sbp) { + u64 nsegments, nblocks; + if (le32_to_cpu(sbp->s_rev_level) < NILFS_MIN_SUPP_REV) { nilfs_err(nilfs->ns_sb, "unsupported revision (superblock rev.=%d.%d, current rev.=%d.%d). Please check the version of mkfs.nilfs(2).", @@ -457,7 +471,35 @@ static int nilfs_store_disk_layout(struc return -EINVAL; } - nilfs_set_nsegments(nilfs, le64_to_cpu(sbp->s_nsegments)); + nsegments = le64_to_cpu(sbp->s_nsegments); + if (nsegments > nilfs_max_segment_count(nilfs)) { + nilfs_err(nilfs->ns_sb, + "segment count %llu exceeds upper limit (%llu segments)", + (unsigned long long)nsegments, + (unsigned long long)nilfs_max_segment_count(nilfs)); + return -EINVAL; + } + + nblocks = (u64)i_size_read(nilfs->ns_sb->s_bdev->bd_inode) >> + nilfs->ns_sb->s_blocksize_bits; + if (nblocks) { + u64 min_block_count = nsegments * nilfs->ns_blocks_per_segment; + /* + * To avoid failing to mount early device images without a + * second superblock, exclude that block count from the + * "min_block_count" calculation. + */ + + if (nblocks < min_block_count) { + nilfs_err(nilfs->ns_sb, + "total number of segment blocks %llu exceeds device size (%llu blocks)", + (unsigned long long)min_block_count, + (unsigned long long)nblocks); + return -EINVAL; + } + } + + nilfs_set_nsegments(nilfs, nsegments); nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed); return 0; }