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| author | Theodore Ts'o <tytso@mit.edu> | 2023-05-05 22:20:29 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-17 11:53:58 +0200 |
| commit | 25c9fca7b71c5045d6dc537430af5b2e79598fa1 (patch) | |
| tree | efb67403960c39863ab9fde7f7068fe462f79ed1 | |
| parent | 748e4bb27d2e3cb455ed2b75afd6cceee876b378 (diff) | |
| download | linux-25c9fca7b71c5045d6dc537430af5b2e79598fa1.tar.gz | |
ext4: improve error recovery code paths in __ext4_remount()
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>
| -rw-r--r-- | fs/ext4/super.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index feb862ab3f65..d542f068ca99 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -6566,9 +6566,6 @@ static int __ext4_remount(struct fs_context *fc, struct super_block *sb) } #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); @@ -6578,6 +6575,9 @@ static int __ext4_remount(struct fs_context *fc, struct super_block *sb) 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->s_system_blks) ext4_release_system_zone(sb); @@ -6588,6 +6588,13 @@ static int __ext4_remount(struct fs_context *fc, struct super_block *sb) 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); sb->s_flags = old_sb_flags; sbi->s_mount_opt = old_opts.s_mount_opt; sbi->s_mount_opt2 = old_opts.s_mount_opt2; |