KASAN: use-after-free Read in crypto_poly1305_update

Status: fixed on 2025/09/04 16:57
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+d587b24799bd8c2d32f4@syzkaller.appspotmail.com
Fix commit: d89a34b14df5 bcachefs: Move bset size check before csum check
First crash: 525d, last: 404d
Cause bisection: introduced by (bisect log) :
commit 03ef80b469d5d83530ce1ce15be78a40e5300f9b
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date: Sat Sep 23 22:41:51 2023 +0000

  bcachefs: Ignore unknown mount options

Crash: BUG: unable to handle kernel paging request in bch2_fs_btree_iter_exit (log)
Repro: C syz .config
  
Fix bisection: fixed by (bisect log) :
commit d89a34b14df5c205de698c23c3950b2b947cdb97
Author: Alan Huang <mmpgouride@gmail.com>
Date: Sat Jun 14 09:18:07 2025 +0000

  bcachefs: Move bset size check before csum check

  
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [crypto?] KASAN: use-after-free Read in crypto_poly1305_update 1 (5) 2025/07/17 21:45
▶ ▼ Last patch testing requests (3)
Created Duration User Patch Repo Result
2025/07/03 09:16 20m retest repro upstream OK log
2025/04/25 10:19 13m retest repro upstream report log
2025/04/24 08:31 14m retest repro upstream report log
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2025/07/17 11:11 9h36m bisect fix upstream OK (1) job log
2025/06/16 05:43 2h14m bisect fix upstream OK (0) job log log
2025/05/13 21:48 2h04m bisect fix upstream OK (0) job log log

Sample crash report:
bcachefs (loop0): Version upgrade required:
Version upgrade from 0.19: freespace to 1.7: mi_btree_bitmap incomplete
Doing incompatible version upgrade from 0.19: freespace to 1.20: directory_size
  running recovery passes: check_allocations,check_alloc_info,check_lrus,check_btree_backpointers,check_backpointers_to_extents,check_extents_to_backpointers,check_alloc_to_lru_refs,bucket_gens_init,check_snapshot_trees,check_snapshots,check_subvols,check_subvol_children,delete_dead_snapshots,check_inodes,check_extents,check_indirect_extents,check_dirents,check_xattrs,check_root,check_unreachable_inodes,check_subvolume_structure,check_directory_structure,check_nlinks,set_fs_needs_rebalance
==================================================================
BUG: KASAN: use-after-free in crypto_poly1305_update+0x28/0x40 arch/x86/crypto/poly1305_glue.c:230
Read of size 8 at addr ffff8880722b7390 by task syz-executor360/5822

CPU: 1 UID: 0 PID: 5822 Comm: syz-executor360 Not tainted 6.14.0-rc3-syzkaller-00012-g2408a807bfc3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
 crypto_poly1305_update+0x28/0x40 arch/x86/crypto/poly1305_glue.c:230
 bch2_checksum+0x5fa/0x780 fs/bcachefs/checksum.c:239
 bch2_btree_node_read_done+0x1402/0x6180 fs/bcachefs/btree_io.c:1130
 btree_node_read_work+0x6dc/0x1380 fs/bcachefs/btree_io.c:1358
 bch2_btree_node_read+0x2433/0x29f0
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1789 [inline]
 bch2_btree_root_read+0x626/0x7b0 fs/bcachefs/btree_io.c:1811
 read_btree_roots+0x3d3/0xa70 fs/bcachefs/recovery.c:581
 bch2_fs_recovery+0x260f/0x3de0 fs/bcachefs/recovery.c:928
 bch2_fs_start+0x37c/0x610 fs/bcachefs/super.c:1041
 bch2_fs_get_tree+0xdb7/0x17a0 fs/bcachefs/fs.c:2203
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3560
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa91570a73a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa9156c0088 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fa9156c00a0 RCX: 00007fa91570a73a
RDX: 0000400000000000 RSI: 0000400000000200 RDI: 00007fa9156c00a0
RBP: 0000400000000000 R08: 00007fa9156c00e0 R09: 000000000000f634
R10: 0000000002a08414 R11: 0000000000000282 R12: 0000400000000200
R13: 00007fa9156c00e0 R14: 0000000000000003 R15: 0000000002a08414
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x722b7
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xcc0(GFP_KERNEL), pid 1, tgid 1 (swapper/0), ts 14383469870, free_ts 15548215805
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
 split_free_pages+0xe1/0x2d0 mm/page_alloc.c:6355
 alloc_contig_range_noprof+0x10eb/0x1770 mm/page_alloc.c:6532
 __alloc_contig_pages mm/page_alloc.c:6562 [inline]
 alloc_contig_pages_noprof+0x4b3/0x5c0 mm/page_alloc.c:6644
 debug_vm_pgtable_alloc_huge_page+0xaf/0x100 mm/debug_vm_pgtable.c:1084
 init_args+0x83b/0xb20 mm/debug_vm_pgtable.c:1266
 debug_vm_pgtable+0xe4/0x590 mm/debug_vm_pgtable.c:1304
 do_one_initcall+0x248/0x930 init/main.c:1257
 do_initcall_level+0x157/0x210 init/main.c:1319
 do_initcalls+0x71/0xd0 init/main.c:1335
 kernel_init_freeable+0x435/0x5d0 init/main.c:1568
 kernel_init+0x1d/0x2b0 init/main.c:1457
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0xe04/0x10e0 mm/page_alloc.c:2660
 free_contig_range+0x14c/0x430 mm/page_alloc.c:6678
 destroy_args+0x94/0x4b0 mm/debug_vm_pgtable.c:1017
 debug_vm_pgtable+0x551/0x590 mm/debug_vm_pgtable.c:1397
 do_one_initcall+0x248/0x930 init/main.c:1257
 do_initcall_level+0x157/0x210 init/main.c:1319
 do_initcalls+0x71/0xd0 init/main.c:1335
 kernel_init_freeable+0x435/0x5d0 init/main.c:1568
 kernel_init+0x1d/0x2b0 init/main.c:1457
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Memory state around the buggy address:
 ffff8880722b7280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880722b7300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880722b7380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff8880722b7400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880722b7480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (20):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/18 08:09 upstream 2408a807bfc3 429ea007 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs KASAN: use-after-free Read in crypto_poly1305_update
2025/04/10 07:30 upstream 3b07108ada81 988b336c .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/04/07 01:39 upstream 0af2f6be1b42 1c65791e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/03/30 10:05 upstream 93d52288679e d3999433 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/03/28 22:58 upstream acb4f33713b9 9a1a9e31 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/03/27 03:09 upstream f6e0150b2003 20510e88 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/03/23 11:53 upstream 183601b78a9b 4e8d3850 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/03/16 20:09 upstream cb82ca153949 e2826670 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/03/11 04:09 upstream 4d872d51bc9d 16256247 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/03/08 05:28 upstream 21e4543a2e2f 7e3bd60d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/03/06 16:30 upstream 848e07631744 831e3629 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/03/02 11:05 upstream ece144f151ac c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/03/01 08:45 upstream 276f98efb64a 67cf5345 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/02/27 16:19 upstream dd83757f6e68 6a8fcbc4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/02/26 12:54 upstream ac9c34d1e45a d34966d1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/02/21 05:22 upstream e9a8cac0bf89 0808a665 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/02/20 09:47 upstream 87a132e73910 50668798 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/02/17 00:41 upstream ba643b6d8440 40a34ec9 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/02/17 00:15 upstream ba643b6d8440 40a34ec9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
2025/02/15 06:13 upstream 04f41cbf03ec 40a34ec9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in crypto_poly1305_update
* Struck through repros no longer work on HEAD.