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  1. 28 Apr, 2023 4 commits
    • Theodore Ts'o's avatar
      ext4: fix lost error code reporting in __ext4_fill_super() · d5e72c4e
      Theodore Ts'o authored 
      When code was factored out of __ext4_fill_super() into
ext4_percpu_param_init() the error return was discarded.  This meant
that it was possible for __ext4_fill_super() to return zero,
indicating success, without the struct super getting completely filled
in, leading to a potential NULL pointer dereference.

Reported-by: syzbot+bbf0f9a213c94f283a5c@syzkaller.appspotmail.com
Fixes: 1f79467c ("ext4: factor out ext4_percpu_param_init() ...")
Link: https://syzkaller.appspot.com/bug?id=6dac47d5e58af770c0055f680369586ec32e144cSigned-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarJason Yan <yanaijie@huawei.com>
      d5e72c4e
    • Nathan Chancellor's avatar
      ext4: fix unused iterator variable warnings · 856dd6c5
      Nathan Chancellor authored 
      When CONFIG_QUOTA is disabled, there are warnings around unused iterator
variables:

  fs/ext4/super.c: In function 'ext4_put_super':
  fs/ext4/super.c:1262:13: error: unused variable 'i' [-Werror=unused-variable]
   1262 |         int i, err;
        |             ^
  fs/ext4/super.c: In function '__ext4_fill_super':
  fs/ext4/super.c:5200:22: error: unused variable 'i' [-Werror=unused-variable]
   5200 |         unsigned int i;
        |                      ^
  cc1: all warnings being treated as errors

The kernel has updated to GNU11, allowing the variables to be declared
within the for loop.  Do so to clear up the warnings.

Fixes: dcbf8758 ("ext4: factor out ext4_flex_groups_free()")
Signed-off-by: default avatarNathan Chancellor <nathan@kernel.org>
Reviewed-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarJason Yan <yanaijie@huawei.com>
Link: https://lore.kernel.org/r/20230420-ext4-unused-variables-super-c-v1-1-138b6db6c21c@kernel.orgSigned-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
      856dd6c5
    • Ye Bin's avatar
      ext4: fix use-after-free read in ext4_find_extent for bigalloc + inline · 83565959
      Ye Bin authored 
      Syzbot found the following issue:
loop0: detected capacity change from 0 to 2048
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: none.
==================================================================
BUG: KASAN: use-after-free in ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]
BUG: KASAN: use-after-free in ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931
Read of size 4 at addr ffff888073644750 by task syz-executor420/5067

CPU: 0 PID: 5067 Comm: syz-executor420 Not tainted 6.2.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __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
 ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]
 ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931
 ext4_clu_mapped+0x117/0x970 fs/ext4/extents.c:5809
 ext4_insert_delayed_block fs/ext4/inode.c:1696 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1806 [inline]
 ext4_da_get_block_prep+0x9e8/0x13c0 fs/ext4/inode.c:1870
 ext4_block_write_begin+0x6a8/0x2290 fs/ext4/inode.c:1098
 ext4_da_write_begin+0x539/0x760 fs/ext4/inode.c:3082
 generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772
 ext4_buffered_write_iter+0x122/0x3a0 fs/ext4/file.c:285
 ext4_file_write_iter+0x1d0/0x18f0
 call_write_iter include/linux/fs.h:2186 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x7dc/0xc50 fs/read_write.c:584
 ksys_write+0x177/0x2a0 fs/read_write.c:637
 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: 0033:0x7f4b7a9737b9
RSP: 002b:00007ffc5cac3668 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4b7a9737b9
RDX: 00000000175d9003 RSI: 0000000020000200 RDI: 0000000000000004
RBP: 00007f4b7a933050 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000079f R11: 0000000000000246 R12: 00007f4b7a9330e0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Above issue is happens when enable bigalloc and inline data feature. As
commit 131294c3 fixed delayed allocation bug in ext4_clu_mapped for
bigalloc + inline. But it only resolved issue when has inline data, if
inline data has been converted to extent(ext4_da_convert_inline_data_to_extent)
before writepages, there is no EXT4_STATE_MAY_INLINE_DATA flag. However
i_data is still store inline data in this scene. Then will trigger UAF
when find extent.
To resolve above issue, there is need to add judge "ext4_has_inline_data(inode)"
in ext4_clu_mapped().

Fixes: 131294c3 ("ext4: fix delayed allocation bug in ext4_clu_mapped for bigalloc + inline")
Reported-by: syzbot+bf4bb7731ef73b83a3b4@syzkaller.appspotmail.com
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarYe Bin <yebin10@huawei.com>
Reviewed-by: default avatarTudor Ambarus <tudor.ambarus@linaro.org>
Tested-by: default avatarTudor Ambarus <tudor.ambarus@linaro.org>
Link: https://lore.kernel.org/r/20230406111627.1916759-1-tudor.ambarus@linaro.orgSigned-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
      83565959
    • Zhihao Cheng's avatar
      ext4: fix i_disksize exceeding i_size problem in paritally written case · 1dedde69
      Zhihao Cheng authored 
      It is possible for i_disksize can exceed i_size, triggering a warning.

generic_perform_write
 copied = iov_iter_copy_from_user_atomic(len) // copied < len
 ext4_da_write_end
 | ext4_update_i_disksize
 |  new_i_size = pos + copied;
 |  WRITE_ONCE(EXT4_I(inode)->i_disksize, newsize) // update i_disksize
 | generic_write_end
 |  copied = block_write_end(copied, len) // copied = 0
 |   if (unlikely(copied < len))
 |    if (!PageUptodate(page))
 |     copied = 0;
 |  if (pos + copied > inode->i_size) // return false
 if (unlikely(copied == 0))
  goto again;
 if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
  status = -EFAULT;
  break;
 }

We get i_disksize greater than i_size here, which could trigger WARNING
check 'i_size_read(inode) < EXT4_I(inode)->i_disksize' while doing dio:

ext4_dio_write_iter
 iomap_dio_rw
  __iomap_dio_rw // return err, length is not aligned to 512
 ext4_handle_inode_extension
  WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize) // Oops

 WARNING: CPU: 2 PID: 2609 at fs/ext4/file.c:319
 CPU: 2 PID: 2609 Comm: aa Not tainted 6.3.0-rc2
 RIP: 0010:ext4_file_write_iter+0xbc7
 Call Trace:
  vfs_write+0x3b1
  ksys_write+0x77
  do_syscall_64+0x39

Fix it by updating 'copied' value before updating i_disksize just like
ext4_write_inline_data_end() does.

A reproducer can be found in the buganizer link below.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217209
Fixes: 64769240 ("ext4: Add delayed allocation support in data=writeback mode")
Signed-off-by: default avatarZhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230321013721.89818-1-chengzhihao1@huawei.comSigned-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
      1dedde69
  3. 20 Apr, 2023 3 commits
  5. 15 Apr, 2023 9 commits
  7. 14 Apr, 2023 12 commits
  9. 06 Apr, 2023 12 commits
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