[Ocfs2-devel] + ocfs2-fix-use-after-free-when-unmounting-read-only-filesystem.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: ocfs2: fix use-after-free when unmounting read-only filesystem
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     ocfs2-fix-use-after-free-when-unmounting-read-only-filesystem.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ocfs2-fix-use-after-free-when-unmounting-read-only-filesystem.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Luís Henriques <ocfs2-devel at oss.oracle.com>
Subject: ocfs2: fix use-after-free when unmounting read-only filesystem
Date: Mon, 22 May 2023 11:21:12 +0100

It's trivial to trigger a use-after-free bug in the ocfs2 quotas code
using fstest generic/452.  After mounting a filesystem as read-only,
quotas are suspended and ocfs2_mem_dqinfo is freed through
->ocfs2_local_free_info().  When unmounting the filesystem, an UAF access
to the oinfo will eventually cause a crash.

Link: https://lkml.kernel.org/r/20230522102112.9031-1-lhenriques@suse.de
Signed-off-by: Luís Henriques <lhenriques at suse.de>
Reviewed-by: Joseph Qi <joseph.qi at linux.alibaba.com>
Tested-by: Joseph Qi <joseph.qi at linux.alibaba.com>
Cc: Mark Fasheh <mark at fasheh.com>
Cc: Joel Becker <jlbec at evilplan.org>
Cc: Junxiao Bi <junxiao.bi at oracle.com>
Cc: Changwei Ge <gechangwei at live.cn>
Cc: Gang He <ghe at suse.com>
Cc: Jun Piao <piaojun at huawei.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
---

 fs/ocfs2/super.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/fs/ocfs2/super.c~ocfs2-fix-use-after-free-when-unmounting-read-only-filesystem
+++ a/fs/ocfs2/super.c
@@ -952,8 +952,10 @@ static void ocfs2_disable_quotas(struct
 	for (type = 0; type < OCFS2_MAXQUOTAS; type++) {
 		if (!sb_has_quota_loaded(sb, type))
 			continue;
-		oinfo = sb_dqinfo(sb, type)->dqi_priv;
-		cancel_delayed_work_sync(&oinfo->dqi_sync_work);
+		if (!sb_has_quota_suspended(sb, type)) {
+			oinfo = sb_dqinfo(sb, type)->dqi_priv;
+			cancel_delayed_work_sync(&oinfo->dqi_sync_work);
+		}
 		inode = igrab(sb->s_dquot.files[type]);
 		/* Turn off quotas. This will remove all dquot structures from
 		 * memory and so they will be automatically synced to global
_

Patches currently in -mm which might be from ocfs2-devel at oss.oracle.com are

ocfs2-fix-use-after-free-when-unmounting-read-only-filesystem.patch