From: Theodore Ts'o tytso@mit.edu
stable inclusion from stable-v4.19.283 commit 37302d4c2724dc92be5f90a3718eafa29834d586 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I7J5UF CVE: NA
Reference:https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
--------------------------------
commit 4c0b4818b1f636bc96359f7817a2d8bab6370162 upstream.
If there are failures while changing the mount options in __ext4_remount(), we need to restore the old mount options.
This commit fixes two problem. The first is there is a chance that we will free the old quota file names before a potential failure leading to a use-after-free. The second problem addressed in this commit is if there is a failed read/write to read-only transition, if the quota has already been suspended, we need to renable quota handling.
Cc: stable@kernel.org Link: https://lore.kernel.org/r/20230506142419.984260-2-tytso@mit.edu Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
Conflicts: fs/ext4/super.c
Signed-off-by: Baokun Li libaokun1@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- fs/ext4/super.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index d11a300c31f5..571eaf1ed971 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5813,9 +5813,6 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) }
#ifdef CONFIG_QUOTA - /* Release old quota file names */ - for (i = 0; i < EXT4_MAXQUOTAS; i++) - kfree(old_opts.s_qf_names[i]); if (enable_quota) { if (sb_any_quota_suspended(sb)) dquot_resume(sb, -1); @@ -5825,6 +5822,9 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) goto restore_opts; } } + /* Release old quota file names */ + for (i = 0; i < EXT4_MAXQUOTAS; i++) + kfree(old_opts.s_qf_names[i]); #endif if (!test_opt(sb, BLOCK_VALIDITY) && sbi->system_blks) ext4_release_system_zone(sb); @@ -5844,6 +5844,14 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) return 0;
restore_opts: + /* + * If there was a failing r/w to ro transition, we may need to + * re-enable quota + */ + if ((sb->s_flags & SB_RDONLY) && !(old_sb_flags & SB_RDONLY) && + sb_any_quota_suspended(sb)) + dquot_resume(sb, -1); + percpu_down_write(&sbi->s_writepages_rwsem); sb->s_flags = old_sb_flags; sbi->s_mount_opt = old_opts.s_mount_opt;