Pull ext4 fixes from Ted Ts'o: "Fix some syzbot-detected bugs, as well as other bugs found by I/O injection testing. Change ext4's fallocate to consistently drop set[ug]id bits when an fallocate operation might possibly change the user-visible contents of a file. Also, improve handling of potentially invalid values in the the s_overhead_cluster superblock field to avoid ext4 returning a negative number of free blocks" * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: jbd2: fix a potential race while discarding reserved buffers after an abort ext4: update the cached overhead value in the superblock ext4: force overhead calculation if the s_overhead_cluster makes no sense ext4: fix overhead calculation to account for the reserved gdt blocks ext4, doc: fix incorrect h_reserved size ext4: limit length to bitmap_maxbytes - blocksize in punch_hole ext4: fix use-after-free in ext4_search_dir ext4: fix bug_on in start_this_handle during umount filesystem ext4: fix symlink file size not match to file content ext4: fix fallocate to use file_modified to update permissions consistently
If we (re-)calculate the file system overhead amount and it's different from the on-disk s_overhead_clusters value, update the on-disk version since this can take potentially quite a while on bigalloc file systems. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
If the file system does not use bigalloc, calculating the overhead is cheap, so force the recalculation of the overhead so we don't have to trust the precalculated overhead in the superblock. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
The kernel calculation was underestimating the overhead by not taking into account the reserved gdt blocks. With this change, the overhead calculated by the kernel matches the overhead calculation in mke2fs. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
Syzbot found an issue [1] in ext4_fallocate().
The C reproducer [2] calls fallocate(), passing size 0xffeffeff000ul,
and offset 0x1000000ul, which, when added together exceed the
bitmap_maxbytes for the inode. This triggers a BUG in
ext4_ind_remove_space(). According to the comments in this function
the 'end' parameter needs to be one block after the last block to be
removed. In the case when the BUG is triggered it points to the last
block. Modify the ext4_punch_hole() function and add constraint that
caps the length to satisfy the one before laster block requirement.
LINK: [1] https://syzkaller.appspot.com/bug?id=b80bd9cf348aac724a4f4dff251800106d721331
LINK: [2] https://syzkaller.appspot.com/text?tag=ReproC&x=14ba0238700000
Fixes: a4bb6b64e39a ("ext4: enable "punch hole" functionality")
Reported-by: syzbot+7a806094edd5d07ba029@syzkaller.appspotmail.com
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Link: https://lore.kernel.org/r/20220331200515.153214-1-tadeusz.struk@linaro.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
We got issue as follows:
EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
==================================================================
BUG: KASAN: use-after-free in ext4_search_dir fs/ext4/namei.c:1394 [inline]
BUG: KASAN: use-after-free in search_dirblock fs/ext4/namei.c:1199 [inline]
BUG: KASAN: use-after-free in __ext4_find_entry+0xdca/0x1210 fs/ext4/namei.c:1553
Read of size 1 at addr ffff8881317c3005 by task syz-executor117/2331
CPU: 1 PID: 2331 Comm: syz-executor117 Not tainted 5.10.0+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
__dump_stack lib/dump_stack.c:83 [inline]
dump_stack+0x144/0x187 lib/dump_stack.c:124
print_address_description+0x7d/0x630 mm/kasan/report.c:387
__kasan_report+0x132/0x190 mm/kasan/report.c:547
kasan_report+0x47/0x60 mm/kasan/report.c:564
ext4_search_dir fs/ext4/namei.c:1394 [inline]
search_dirblock fs/ext4/namei.c:1199 [inline]
__ext4_find_entry+0xdca/0x1210 fs/ext4/namei.c:1553
ext4_lookup_entry fs/ext4/namei.c:1622 [inline]
ext4_lookup+0xb8/0x3a0 fs/ext4/namei.c:1690
__lookup_hash+0xc5/0x190 fs/namei.c:1451
do_rmdir+0x19e/0x310 fs/namei.c:3760
do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x445e59
Code: 4d c7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 1b c7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff2277fac8 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 0000000000400280 RCX: 0000000000445e59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200000c0
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000002
R10: 00007fff2277f990 R11: 0000000000000246 R12: 0000000000000000
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
The buggy address belongs to the page:
page:0000000048cd3304 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1317c3
flags: 0x200000000000000()
raw: 0200000000000000 ffffea0004526588 ffffea0004528088 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8881317c2f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881317c2f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881317c3000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff8881317c3080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff8881317c3100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
ext4_search_dir:
...
de = (struct ext4_dir_entry_2 *)search_buf;
dlimit = search_buf + buf_size;
while ((char *) de < dlimit) {
...
if ((char *) de + de->name_len <= dlimit &&
ext4_match(dir, fname, de)) {
...
}
...
de_len = ext4_rec_len_from_disk(de->rec_len, dir->i_sb->s_blocksize);
if (de_len <= 0)
return -1;
offset += de_len;
de = (struct ext4_dir_entry_2 *) ((char *) de + de_len);
}
Assume:
de=0xffff8881317c2fff
dlimit=0x0xffff8881317c3000
If read 'de->name_len' which address is 0xffff8881317c3005, obviously is
out of range, then will trigger use-after-free.
To solve this issue, 'dlimit' must reserve 8 bytes, as we will read
'de->name_len' to judge if '(char *) de + de->name_len' out of range.
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220324064816.1209985-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
We got issue as follows:
------------[ cut here ]------------
kernel BUG at fs/jbd2/transaction.c:389!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 9 PID: 131 Comm: kworker/9:1 Not tainted 5.17.0-862.14.0.6.x86_64-00001-g23f87daf7d74-dirty #197
Workqueue: events flush_stashed_error_work
RIP: 0010:start_this_handle+0x41c/0x1160
RSP: 0018:ffff888106b47c20 EFLAGS: 00010202
RAX: ffffed10251b8400 RBX: ffff888128dc204c RCX: ffffffffb52972ac
RDX: 0000000000000200 RSI: 0000000000000004 RDI: ffff888128dc2050
RBP: 0000000000000039 R08: 0000000000000001 R09: ffffed10251b840a
R10: ffff888128dc204f R11: ffffed10251b8409 R12: ffff888116d78000
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff888128dc2000
FS: 0000000000000000(0000) GS:ffff88839d680000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001620068 CR3: 0000000376c0e000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
jbd2__journal_start+0x38a/0x790
jbd2_journal_start+0x19/0x20
flush_stashed_error_work+0x110/0x2b3
process_one_work+0x688/0x1080
worker_thread+0x8b/0xc50
kthread+0x26f/0x310
ret_from_fork+0x22/0x30
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
Above issue may happen as follows:
umount read procfs error_work
ext4_put_super
flush_work(&sbi->s_error_work);
ext4_mb_seq_groups_show
ext4_mb_load_buddy_gfp
ext4_mb_init_group
ext4_mb_init_cache
ext4_read_block_bitmap_nowait
ext4_validate_block_bitmap
ext4_error
ext4_handle_error
schedule_work(&EXT4_SB(sb)->s_error_work);
ext4_unregister_sysfs(sb);
jbd2_journal_destroy(sbi->s_journal);
journal_kill_thread
journal->j_flags |= JBD2_UNMOUNT;
flush_stashed_error_work
jbd2_journal_start
start_this_handle
BUG_ON(journal->j_flags & JBD2_UNMOUNT);
To solve this issue, we call 'ext4_unregister_sysfs() before flushing
s_error_work in ext4_put_super().
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20220322012419.725457-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
We got issue as follows: [home]# fsck.ext4 -fn ram0yb e2fsck 1.45.6 (20-Mar-2020) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Symlink /p3/d14/d1a/l3d (inode #3494) is invalid. Clear? no Entry 'l3d' in /p3/d14/d1a (3383) has an incorrect filetype (was 7, should be 0). Fix? no As the symlink file size does not match the file content. If the writeback of the symlink data block failed, ext4_finish_bio() handles the end of IO. However this function fails to mark the buffer with BH_write_io_error and so when unmount does journal checkpoint it cannot detect the writeback error and will cleanup the journal. Thus we've lost the correct data in the journal area. To solve this issue, mark the buffer as BH_write_io_error in ext4_finish_bio(). Cc: stable@kernel.org Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20220321144438.201685-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Since the initial introduction of (posix) fallocate back at the turn of the century, it has been possible to use this syscall to change the user-visible contents of files. This can happen by extending the file size during a preallocation, or through any of the newer modes (punch, zero, collapse, insert range). Because the call can be used to change file contents, we should treat it like we do any other modification to a file -- update the mtime, and drop set[ug]id privileges/capabilities. The VFS function file_modified() does all this for us if pass it a locked inode, so let's make fallocate drop permissions correctly. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Link: https://lore.kernel.org/r/20220308185043.GA117678@magnolia Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
This should use the new folio_buffers() instead of page_has_buffers(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Al Viro <viro@zeniv.linux.org.uk>