Re: [syzbot] [crypto?] KMSAN: uninit-value in aes_encrypt (5)

[Herbert Xu]

On Thu, May 09, 2024 at 09:02:27PM -0700, syzbot wrote:
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    45db3ab70092 Merge tag '6.9-rc7-ksmbd-fixes' of git://git...
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=14d9bfdf180000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=617171361dd3cd47
> dashboard link: https://syzkaller.appspot.com/bug?extid=aeb14e2539ffb6d21130
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1617adb8980000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=112f45d4980000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/232e7c2a73a5/disk-45db3ab7.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/7e9bf7c936ab/vmlinux-45db3ab7.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/5e8f98ee02d8/bzImage-45db3ab7.xz
> mounted in repro: https://storage.googleapis.com/syzbot-assets/fcc88c919ed9/mount_1.gz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+aeb14e2539ffb6d21130@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> fscrypt: AES-256-XTS using implementation "xts(ecb(aes-fixed-time))"
> =====================================================
> BUG: KMSAN: uninit-value in subshift lib/crypto/aes.c:149 [inline]
> BUG: KMSAN: uninit-value in aes_encrypt+0x15cc/0x1db0 lib/crypto/aes.c:282
>  subshift lib/crypto/aes.c:149 [inline]
>  aes_encrypt+0x15cc/0x1db0 lib/crypto/aes.c:282
>  aesti_encrypt+0x7d/0xf0 crypto/aes_ti.c:31
>  crypto_ecb_crypt crypto/ecb.c:23 [inline]
>  crypto_ecb_encrypt2+0x18a/0x300 crypto/ecb.c:40
>  crypto_lskcipher_crypt_sg+0x36b/0x7f0 crypto/lskcipher.c:228
>  crypto_lskcipher_encrypt_sg+0x8a/0xc0 crypto/lskcipher.c:247
>  crypto_skcipher_encrypt+0x119/0x1e0 crypto/skcipher.c:669
>  xts_encrypt+0x3c4/0x550 crypto/xts.c:269
>  crypto_skcipher_encrypt+0x1a0/0x1e0 crypto/skcipher.c:671
>  fscrypt_crypt_data_unit+0x4ee/0x8f0 fs/crypto/crypto.c:144
>  fscrypt_encrypt_pagecache_blocks+0x422/0x900 fs/crypto/crypto.c:207
>  ext4_bio_write_folio+0x13db/0x2e40 fs/ext4/page-io.c:526
>  mpage_submit_folio+0x351/0x4a0 fs/ext4/inode.c:1869
>  mpage_process_page_bufs+0xb92/0xe30 fs/ext4/inode.c:1982
>  mpage_prepare_extent_to_map+0x1702/0x22c0 fs/ext4/inode.c:2490
>  ext4_do_writepages+0x1117/0x62e0 fs/ext4/inode.c:2632
>  ext4_writepages+0x312/0x830 fs/ext4/inode.c:2768
>  do_writepages+0x427/0xc30 mm/page-writeback.c:2612
>  filemap_fdatawrite_wbc+0x1d8/0x270 mm/filemap.c:397
>  __filemap_fdatawrite_range mm/filemap.c:430 [inline]
>  file_write_and_wait_range+0x1bf/0x370 mm/filemap.c:788
>  generic_buffers_fsync_noflush+0x84/0x3e0 fs/buffer.c:602
>  ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
>  ext4_sync_file+0x5ba/0x13a0 fs/ext4/fsync.c:151
>  vfs_fsync_range+0x20d/0x270 fs/sync.c:188
>  generic_write_sync include/linux/fs.h:2795 [inline]
>  ext4_buffered_write_iter+0x9ad/0xaa0 fs/ext4/file.c:305
>  ext4_file_write_iter+0x208/0x3450
>  call_write_iter include/linux/fs.h:2110 [inline]
>  new_sync_write fs/read_write.c:497 [inline]
>  vfs_write+0xb63/0x1520 fs/read_write.c:590
>  ksys_write+0x20f/0x4c0 fs/read_write.c:643
>  __do_sys_write fs/read_write.c:655 [inline]
>  __se_sys_write fs/read_write.c:652 [inline]
>  __x64_sys_write+0x93/0xe0 fs/read_write.c:652
>  x64_sys_call+0x3062/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:2
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> Uninit was stored to memory at:
>  le128_xor include/crypto/b128ops.h:69 [inline]
>  xts_xor_tweak+0x4ae/0xbf0 crypto/xts.c:123
>  xts_xor_tweak_pre crypto/xts.c:135 [inline]
>  xts_encrypt+0x296/0x550 crypto/xts.c:268
>  crypto_skcipher_encrypt+0x1a0/0x1e0 crypto/skcipher.c:671
>  fscrypt_crypt_data_unit+0x4ee/0x8f0 fs/crypto/crypto.c:144
>  fscrypt_encrypt_pagecache_blocks+0x422/0x900 fs/crypto/crypto.c:207
>  ext4_bio_write_folio+0x13db/0x2e40 fs/ext4/page-io.c:526
>  mpage_submit_folio+0x351/0x4a0 fs/ext4/inode.c:1869
>  mpage_process_page_bufs+0xb92/0xe30 fs/ext4/inode.c:1982
>  mpage_prepare_extent_to_map+0x1702/0x22c0 fs/ext4/inode.c:2490
>  ext4_do_writepages+0x1117/0x62e0 fs/ext4/inode.c:2632
>  ext4_writepages+0x312/0x830 fs/ext4/inode.c:2768
>  do_writepages+0x427/0xc30 mm/page-writeback.c:2612
>  filemap_fdatawrite_wbc+0x1d8/0x270 mm/filemap.c:397
>  __filemap_fdatawrite_range mm/filemap.c:430 [inline]
>  file_write_and_wait_range+0x1bf/0x370 mm/filemap.c:788
>  generic_buffers_fsync_noflush+0x84/0x3e0 fs/buffer.c:602
>  ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
>  ext4_sync_file+0x5ba/0x13a0 fs/ext4/fsync.c:151
>  vfs_fsync_range+0x20d/0x270 fs/sync.c:188
>  generic_write_sync include/linux/fs.h:2795 [inline]
>  ext4_buffered_write_iter+0x9ad/0xaa0 fs/ext4/file.c:305
>  ext4_file_write_iter+0x208/0x3450
>  call_write_iter include/linux/fs.h:2110 [inline]
>  new_sync_write fs/read_write.c:497 [inline]
>  vfs_write+0xb63/0x1520 fs/read_write.c:590
>  ksys_write+0x20f/0x4c0 fs/read_write.c:643
>  __do_sys_write fs/read_write.c:655 [inline]
>  __se_sys_write fs/read_write.c:652 [inline]
>  __x64_sys_write+0x93/0xe0 fs/read_write.c:652
>  x64_sys_call+0x3062/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:2
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> Uninit was created at:
>  __alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598
>  alloc_pages_mpol+0x299/0x990 mm/mempolicy.c:2264
>  alloc_pages mm/mempolicy.c:2335 [inline]
>  folio_alloc+0x1d0/0x230 mm/mempolicy.c:2342
>  filemap_alloc_folio+0xa6/0x440 mm/filemap.c:984
>  __filemap_get_folio+0xa10/0x14b0 mm/filemap.c:1926
>  ext4_write_begin+0x3e5/0x2230 fs/ext4/inode.c:1159
>  generic_perform_write+0x400/0xc60 mm/filemap.c:3974
>  ext4_buffered_write_iter+0x564/0xaa0 fs/ext4/file.c:299
>  ext4_file_write_iter+0x208/0x3450
>  call_write_iter include/linux/fs.h:2110 [inline]
>  new_sync_write fs/read_write.c:497 [inline]
>  vfs_write+0xb63/0x1520 fs/read_write.c:590
>  ksys_write+0x20f/0x4c0 fs/read_write.c:643
>  __do_sys_write fs/read_write.c:655 [inline]
>  __se_sys_write fs/read_write.c:652 [inline]
>  __x64_sys_write+0x93/0xe0 fs/read_write.c:652
>  x64_sys_call+0x3062/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:2
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> CPU: 0 PID: 5048 Comm: syz-executor132 Not tainted 6.9.0-rc7-syzkaller-00056-g45db3ab70092 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
> =====================================================
> 
> 
> ---
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.

#syz set subsystems: ext4

These reports have been coming in for a while, previously they were
merged incorrectly with reports coming from networking, see for
example:

https://syzkaller.appspot.com/bug?id=6eb713b7107c62e9f6c259adf944c96efc3cd524
https://syzkaller.appspot.com/text?tag=CrashReport&x=11e16a77a80000

The networking bug disappeared mysteriously in July 2023.

Thanks,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt