Patch "ocfs2: fix slab-use-after-free due to dangling pointer dqi_priv" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ocfs2: fix slab-use-after-free due to dangling pointer dqi_priv

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ocfs2-fix-slab-use-after-free-due-to-dangling-pointe.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit f1755a0e8fb7dc81f0b45ad804e8ce03229da454
Author: Dennis Lam <dennis.lamerice@xxxxxxxxx>
Date:   Tue Dec 17 21:39:25 2024 -0500

    ocfs2: fix slab-use-after-free due to dangling pointer dqi_priv
    
    [ Upstream commit 5f3fd772d152229d94602bca243fbb658068a597 ]
    
    When mounting ocfs2 and then remounting it as read-only, a
    slab-use-after-free occurs after the user uses a syscall to
    quota_getnextquota.  Specifically, sb_dqinfo(sb, type)->dqi_priv is the
    dangling pointer.
    
    During the remounting process, the pointer dqi_priv is freed but is never
    set as null leaving it to be accessed.  Additionally, the read-only option
    for remounting sets the DQUOT_SUSPENDED flag instead of setting the
    DQUOT_USAGE_ENABLED flags.  Moreover, later in the process of getting the
    next quota, the function ocfs2_get_next_id is called and only checks the
    quota usage flags and not the quota suspended flags.
    
    To fix this, I set dqi_priv to null when it is freed after remounting with
    read-only and put a check for DQUOT_SUSPENDED in ocfs2_get_next_id.
    
    [akpm@xxxxxxxxxxxxxxxxxxxx: coding-style cleanups]
    Link: https://lkml.kernel.org/r/20241218023924.22821-2-dennis.lamerice@xxxxxxxxx
    Fixes: 8f9e8f5fcc05 ("ocfs2: Fix Q_GETNEXTQUOTA for filesystem without quotas")
    Signed-off-by: Dennis Lam <dennis.lamerice@xxxxxxxxx>
    Reported-by: syzbot+d173bf8a5a7faeede34c@xxxxxxxxxxxxxxxxxxxxxxxxx
    Tested-by: syzbot+d173bf8a5a7faeede34c@xxxxxxxxxxxxxxxxxxxxxxxxx
    Closes: https://lore.kernel.org/all/6731d26f.050a0220.1fb99c.014b.GAE@xxxxxxxxxx/T/
    Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
    Cc: Mark Fasheh <mark@xxxxxxxxxx>
    Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
    Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
    Cc: Changwei Ge <gechangwei@xxxxxxx>
    Cc: Jun Piao <piaojun@xxxxxxxxxx>
    Cc: <stable@xxxxxxxxxxxxxxx>
    Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c
index eda83487c9ec..1ce3780e8b49 100644
--- a/fs/ocfs2/quota_global.c
+++ b/fs/ocfs2/quota_global.c
@@ -881,7 +881,7 @@ static int ocfs2_get_next_id(struct super_block *sb, struct kqid *qid)
 	int status = 0;
 
 	trace_ocfs2_get_next_id(from_kqid(&init_user_ns, *qid), type);
-	if (!sb_has_quota_loaded(sb, type)) {
+	if (!sb_has_quota_active(sb, type)) {
 		status = -ESRCH;
 		goto out;
 	}
diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
index fbab536741e2..77d5aa90338f 100644
--- a/fs/ocfs2/quota_local.c
+++ b/fs/ocfs2/quota_local.c
@@ -864,6 +864,7 @@ static int ocfs2_local_free_info(struct super_block *sb, int type)
 	brelse(oinfo->dqi_libh);
 	brelse(oinfo->dqi_lqi_bh);
 	kfree(oinfo);
+	info->dqi_priv = NULL;
 	return status;
 }