From: "Darrick J. Wong" Date: Thu, 22 Aug 2019 20:55:28 -0700 Subject: xfs: fix missing ILOCK unlock when xfs_setattr_nonsize fails due to EDQUOT Origin: https://git.kernel.org/linus/1fb254aa983bf190cfd685d40c64a480a9bafaee Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2019-15538 Benjamin Moody reported to Debian that XFS partially wedges when a chgrp fails on account of being out of disk quota. I ran his reproducer script: # adduser dummy # adduser dummy plugdev # dd if=/dev/zero bs=1M count=100 of=test.img # mkfs.xfs test.img # mount -t xfs -o gquota test.img /mnt # mkdir -p /mnt/dummy # chown -c dummy /mnt/dummy # xfs_quota -xc 'limit -g bsoft=100k bhard=100k plugdev' /mnt (and then as user dummy) $ dd if=/dev/urandom bs=1M count=50 of=/mnt/dummy/foo $ chgrp plugdev /mnt/dummy/foo and saw: ================================================ WARNING: lock held when returning to user space! 5.3.0-rc5 #rc5 Tainted: G W ------------------------------------------------ chgrp/47006 is leaving the kernel with locks still held! 1 lock held by chgrp/47006: #0: 000000006664ea2d (&xfs_nondir_ilock_class){++++}, at: xfs_ilock+0xd2/0x290 [xfs] ...which is clearly caused by xfs_setattr_nonsize failing to unlock the ILOCK after the xfs_qm_vop_chown_reserve call fails. Add the missing unlock. Reported-by: benjamin.moody@gmail.com Fixes: 253f4911f297 ("xfs: better xfs_trans_alloc interface") Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner Tested-by: Salvatore Bonaccorso --- fs/xfs/xfs_iops.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c index ff3c1fae5357..fe285d123d69 100644 --- a/fs/xfs/xfs_iops.c +++ b/fs/xfs/xfs_iops.c @@ -793,6 +793,7 @@ xfs_setattr_nonsize( out_cancel: xfs_trans_cancel(tp); + xfs_iunlock(ip, XFS_ILOCK_EXCL); out_dqrele: xfs_qm_dqrele(udqp); xfs_qm_dqrele(gdqp); -- 2.23.0