kernel.git/fs/ext4/super.c, branch linux-6.4.y

ext4: turn quotas off if mount failed after enabling quotas

2023-07-23T11:53:57Z

commit d13f99632748462c32fc95d729f5e754bab06064 upstream. Yi found during a review of the patch "ext4: don't BUG on inconsistent journal feature" that when ext4_mark_recovery_complete() returns an error value, the error handling path does not turn off the enabled quotas, which triggers the following kmemleak: ================================================================ unreferenced object 0xffff8cf68678e7c0 (size 64): comm "mount", pid 746, jiffies 4294871231 (age 11.540s) hex dump (first 32 bytes): 00 90 ef 82 f6 8c ff ff 00 00 00 00 41 01 00 00 ............A... c7 00 00 00 bd 00 00 00 0a 00 00 00 48 00 00 00 ............H... backtrace: [<00000000c561ef24>] __kmem_cache_alloc_node+0x4d4/0x880 [<00000000d4e621d7>] kmalloc_trace+0x39/0x140 [<00000000837eee74>] v2_read_file_info+0x18a/0x3a0 [<0000000088f6c877>] dquot_load_quota_sb+0x2ed/0x770 [<00000000340a4782>] dquot_load_quota_inode+0xc6/0x1c0 [<0000000089a18bd5>] ext4_enable_quotas+0x17e/0x3a0 [ext4] [<000000003a0268fa>] __ext4_fill_super+0x3448/0x3910 [ext4] [<00000000b0f2a8a8>] ext4_fill_super+0x13d/0x340 [ext4] [<000000004a9489c4>] get_tree_bdev+0x1dc/0x370 [<000000006e723bf1>] ext4_get_tree+0x1d/0x30 [ext4] [<00000000c7cb663d>] vfs_get_tree+0x31/0x160 [<00000000320e1bed>] do_new_mount+0x1d5/0x480 [<00000000c074654c>] path_mount+0x22e/0xbe0 [<0000000003e97a8e>] do_mount+0x95/0xc0 [<000000002f3d3736>] __x64_sys_mount+0xc4/0x160 [<0000000027d2140c>] do_syscall_64+0x3f/0x90 ================================================================ To solve this problem, we add a "failed_mount10" tag, and call ext4_quota_off_umount() in this tag to release the enabled qoutas. Fixes: 11215630aada ("ext4: don't BUG on inconsistent journal feature") Cc: stable@kernel.org Signed-off-by: Zhang Yi Signed-off-by: Baokun Li Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20230327141630.156875-2-libaokun1@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: avoid updating the superblock on a r/o mount if not needed

2023-07-23T11:53:56Z

commit 2ef6c32a914b85217b44a0a2418e830e520b085e upstream. This was noticed by a user who noticied that the mtime of a file backing a loopback device was getting bumped when the loopback device is mounted read/only. Note: This doesn't show up when doing a loopback mount of a file directly, via "mount -o ro /tmp/foo.img /mnt", since the loop device is set read-only when mount automatically creates loop device. However, this is noticeable for a LUKS loop device like this: % cryptsetup luksOpen /tmp/foo.img test % mount -o ro /dev/loop0 /mnt ; umount /mnt or, if LUKS is not in use, if the user manually creates the loop device like this: % losetup /dev/loop0 /tmp/foo.img % mount -o ro /dev/loop0 /mnt ; umount /mnt The modified mtime causes rsync to do a rolling checksum scan of the file on the local and remote side, incrementally increasing the time to rsync the not-modified-but-touched image file. Fixes: eee00237fa5e ("ext4: commit super block if fs record error when journal record without error") Cc: stable@kernel.org Link: https://lore.kernel.org/r/ZIauBR7YiV3rVAHL@glitch Reported-by: Sean Greenslade Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: Fix reusing stale buffer heads from last failed mounting

2023-07-23T11:53:56Z

commit 26fb5290240dc31cae99b8b4dd2af7f46dfcba6b upstream. Following process makes ext4 load stale buffer heads from last failed mounting in a new mounting operation: mount_bdev ext4_fill_super | ext4_load_and_init_journal | ext4_load_journal | jbd2_journal_load | load_superblock | journal_get_superblock | set_buffer_verified(bh) // buffer head is verified | jbd2_journal_recover // failed caused by EIO | goto failed_mount3a // skip 'sb->s_root' initialization deactivate_locked_super kill_block_super generic_shutdown_super if (sb->s_root) // false, skip ext4_put_super->invalidate_bdev-> // invalidate_mapping_pages->mapping_evict_folio-> // filemap_release_folio->try_to_free_buffers, which // cannot drop buffer head. blkdev_put blkdev_put_whole if (atomic_dec_and_test(&bdev->bd_openers)) // false, systemd-udev happens to open the device. Then // blkdev_flush_mapping->kill_bdev->truncate_inode_pages-> // truncate_inode_folio->truncate_cleanup_folio-> // folio_invalidate->block_invalidate_folio-> // filemap_release_folio->try_to_free_buffers will be skipped, // dropping buffer head is missed again. Second mount: ext4_fill_super ext4_load_and_init_journal ext4_load_journal ext4_get_journal jbd2_journal_init_inode journal_init_common bh = getblk_unmovable bh = __find_get_block // Found stale bh in last failed mounting journal->j_sb_buffer = bh jbd2_journal_load load_superblock journal_get_superblock if (buffer_verified(bh)) // true, skip journal->j_format_version = 2, value is 0 jbd2_journal_recover do_one_pass next_log_block += count_tags(journal, bh) // According to journal_tag_bytes(), 'tag_bytes' calculating is // affected by jbd2_has_feature_csum3(), jbd2_has_feature_csum3() // returns false because 'j->j_format_version >= 2' is not true, // then we get wrong next_log_block. The do_one_pass may exit // early whenoccuring non JBD2_MAGIC_NUMBER in 'next_log_block'. The filesystem is corrupted here, journal is partially replayed, and new journal sequence number actually is already used by last mounting. The invalidate_bdev() can drop all buffer heads even racing with bare reading block device(eg. systemd-udev), so we can fix it by invalidating bdev in error handling path in __ext4_fill_super(). Fetch a reproducer in [Link]. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217171 Fixes: 25ed6e8a54df ("jbd2: enable journal clients to enable v2 checksumming") Cc: stable@vger.kernel.org # v3.5 Signed-off-by: Zhihao Cheng Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20230315013128.3911115-2-chengzhihao1@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

Revert "ext4: don't clear SB_RDONLY when remounting r/w until quota is re-enabled"

2023-06-08T13:57:04Z

This reverts commit a44be64bbecb15a452496f60db6eacfee2b59c79. Link: https://lore.kernel.org/r/653b3359-2005-21b1-039d-c55ca4cffdcc@gmail.com Signed-off-by: Theodore Ts'o

ext4: enable the lazy init thread when remounting read/write

2023-05-30T19:33:57Z

In commit a44be64bbecb ("ext4: don't clear SB_RDONLY when remounting r/w until quota is re-enabled") we defer clearing tyhe SB_RDONLY flag in struct super. However, we didn't defer when we checked sb_rdonly() to determine the lazy itable init thread should be enabled, with the next result that the lazy inode table initialization would not be properly started. This can cause generic/231 to fail in ext4's nojournal mode. Fix this by moving when we decide to start or stop the lazy itable init thread to after we clear the SB_RDONLY flag when we are remounting the file system read/write. Fixes a44be64bbecb ("ext4: don't clear SB_RDONLY when remounting r/w until...") Signed-off-by: Theodore Ts'o Link: https://lore.kernel.org/r/20230527035729.1001605-1-tytso@mit.edu Signed-off-by: Theodore Ts'o

ext4: add indication of ro vs r/w mounts in the mount message

2023-05-13T22:05:05Z

Whether the file system is mounted read-only or read/write is more important than the quota mode, which we are already printing. Add the ro vs r/w indication since this can be helpful in debugging problems from the console log. Signed-off-by: Theodore Ts'o

ext4: improve error recovery code paths in __ext4_remount()

2023-05-13T22:05:05Z

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

ext4: don't clear SB_RDONLY when remounting r/w until quota is re-enabled

2023-05-13T22:05:05Z

When a file system currently mounted read/only is remounted read/write, if we clear the SB_RDONLY flag too early, before the quota is initialized, and there is another process/thread constantly attempting to create a directory, it's possible to trigger the WARN_ON_ONCE(dquot_initialize_needed(inode)); in ext4_xattr_block_set(), with the following stack trace: WARNING: CPU: 0 PID: 5338 at fs/ext4/xattr.c:2141 ext4_xattr_block_set+0x2ef2/0x3680 RIP: 0010:ext4_xattr_block_set+0x2ef2/0x3680 fs/ext4/xattr.c:2141 Call Trace: ext4_xattr_set_handle+0xcd4/0x15c0 fs/ext4/xattr.c:2458 ext4_initxattrs+0xa3/0x110 fs/ext4/xattr_security.c:44 security_inode_init_security+0x2df/0x3f0 security/security.c:1147 __ext4_new_inode+0x347e/0x43d0 fs/ext4/ialloc.c:1324 ext4_mkdir+0x425/0xce0 fs/ext4/namei.c:2992 vfs_mkdir+0x29d/0x450 fs/namei.c:4038 do_mkdirat+0x264/0x520 fs/namei.c:4061 __do_sys_mkdirat fs/namei.c:4076 [inline] __se_sys_mkdirat fs/namei.c:4074 [inline] __x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4074 Cc: stable@kernel.org Link: https://lore.kernel.org/r/20230506142419.984260-1-tytso@mit.edu Reported-by: syzbot+6385d7d3065524c5ca6d@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=6513f6cb5cd6b5fc9f37e3bb70d273b94be9c34c Signed-off-by: Theodore Ts'o

ext4: avoid a potential slab-out-of-bounds in ext4_group_desc_csum

2023-05-13T22:05:04Z

When modifying the block device while it is mounted by the filesystem, syzbot reported the following: BUG: KASAN: slab-out-of-bounds in crc16+0x206/0x280 lib/crc16.c:58 Read of size 1 at addr ffff888075f5c0a8 by task syz-executor.2/15586 CPU: 1 PID: 15586 Comm: syz-executor.2 Not tainted 6.2.0-rc5-syzkaller-00205-gc96618275234 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106 print_address_description+0x74/0x340 mm/kasan/report.c:306 print_report+0x107/0x1f0 mm/kasan/report.c:417 kasan_report+0xcd/0x100 mm/kasan/report.c:517 crc16+0x206/0x280 lib/crc16.c:58 ext4_group_desc_csum+0x81b/0xb20 fs/ext4/super.c:3187 ext4_group_desc_csum_set+0x195/0x230 fs/ext4/super.c:3210 ext4_mb_clear_bb fs/ext4/mballoc.c:6027 [inline] ext4_free_blocks+0x191a/0x2810 fs/ext4/mballoc.c:6173 ext4_remove_blocks fs/ext4/extents.c:2527 [inline] ext4_ext_rm_leaf fs/ext4/extents.c:2710 [inline] ext4_ext_remove_space+0x24ef/0x46a0 fs/ext4/extents.c:2958 ext4_ext_truncate+0x177/0x220 fs/ext4/extents.c:4416 ext4_truncate+0xa6a/0xea0 fs/ext4/inode.c:4342 ext4_setattr+0x10c8/0x1930 fs/ext4/inode.c:5622 notify_change+0xe50/0x1100 fs/attr.c:482 do_truncate+0x200/0x2f0 fs/open.c:65 handle_truncate fs/namei.c:3216 [inline] do_open fs/namei.c:3561 [inline] path_openat+0x272b/0x2dd0 fs/namei.c:3714 do_filp_open+0x264/0x4f0 fs/namei.c:3741 do_sys_openat2+0x124/0x4e0 fs/open.c:1310 do_sys_open fs/open.c:1326 [inline] __do_sys_creat fs/open.c:1402 [inline] __se_sys_creat fs/open.c:1396 [inline] __x64_sys_creat+0x11f/0x160 fs/open.c:1396 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f72f8a8c0c9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f72f97e3168 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007f72f8bac050 RCX: 00007f72f8a8c0c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000280 RBP: 00007f72f8ae7ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd165348bf R14: 00007f72f97e3300 R15: 0000000000022000 Replace le16_to_cpu(sbi->s_es->s_desc_size) with sbi->s_desc_size It reduces ext4's compiled text size, and makes the code more efficient (we remove an extra indirect reference and a potential byte swap on big endian systems), and there is no downside. It also avoids the potential KASAN / syzkaller failure, as a bonus. Reported-by: syzbot+fc51227e7100c9294894@syzkaller.appspotmail.com Reported-by: syzbot+8785e41224a3afd04321@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=70d28d11ab14bd7938f3e088365252aa923cff42 Link: https://syzkaller.appspot.com/bug?id=b85721b38583ecc6b5e72ff524c67302abbc30f3 Link: https://lore.kernel.org/all/000000000000ece18705f3b20934@google.com/ Fixes: 717d50e4971b ("Ext4: Uninitialized Block Groups") Cc: stable@vger.kernel.org Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20230504121525.3275886-1-tudor.ambarus@linaro.org Signed-off-by: Theodore Ts'o

ext4: allow ext4_get_group_info() to fail

2023-05-13T22:02:46Z

Previously, ext4_get_group_info() would treat an invalid group number as BUG(), since in theory it should never happen. However, if a malicious attaker (or fuzzer) modifies the superblock via the block device while it is the file system is mounted, it is possible for s_first_data_block to get set to a very large number. In that case, when calculating the block group of some block number (such as the starting block of a preallocation region), could result in an underflow and very large block group number. Then the BUG_ON check in ext4_get_group_info() would fire, resutling in a denial of service attack that can be triggered by root or someone with write access to the block device. For a quality of implementation perspective, it's best that even if the system administrator does something that they shouldn't, that it will not trigger a BUG. So instead of BUG'ing, ext4_get_group_info() will call ext4_error and return NULL. We also add fallback code in all of the callers of ext4_get_group_info() that it might NULL. Also, since ext4_get_group_info() was already borderline to be an inline function, un-inline it. The results in a next reduction of the compiled text size of ext4 by roughly 2k. Cc: stable@kernel.org Link: https://lore.kernel.org/r/20230430154311.579720-2-tytso@mit.edu Reported-by: syzbot+e2efa3efc15a1c9e95c3@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=69b28112e098b070f639efb356393af3ffec4220 Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara