syzbot


KASAN: use-after-free Read in udf_new_inode

Status: upstream: reported on 2022/11/28 13:37
Reported-by: syzbot+4740808fef2bdfd0e75f@syzkaller.appspotmail.com
First crash: 69d, last: 53d

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in udf_new_inode+0xdfe/0xf30
Read of size 4 at addr ffff88803a88db90 by task syz-executor.3/16719

CPU: 1 PID: 16719 Comm: syz-executor.3 Not tainted 6.1.0-syzkaller-09941-ge2ca6ba6ba01 #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+0x1b1/0x28e 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
 udf_new_inode+0xdfe/0xf30
 udf_tmpfile+0x1f/0x170 fs/udf/namei.c:631
 vfs_tmpfile+0x337/0x490 fs/namei.c:3608
 do_tmpfile+0x11e/0x320 fs/namei.c:3671
 path_openat+0x27a6/0x2dd0 fs/namei.c:3705
 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_openat fs/open.c:1342 [inline]
 __se_sys_openat fs/open.c:1337 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1337
 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: 0033:0x7f26ede8c0d9
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:00007f26eeb3a168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f26edfabf80 RCX: 00007f26ede8c0d9
RDX: 0000000000418006 RSI: 0000000020000040 RDI: ffffffffffffff9c
RBP: 00007f26edee7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffeb97c70df R14: 00007f26eeb3a300 R15: 0000000000022000
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0000ea2340 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x3a88d
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 16207, tgid 16206 (syz-executor.3), ts 594035905851, free_ts 594940797251
 prep_new_page mm/page_alloc.c:2531 [inline]
 get_page_from_freelist+0x742/0x7c0 mm/page_alloc.c:4283
 __alloc_pages+0x259/0x560 mm/page_alloc.c:5549
 __folio_alloc+0xf/0x30 mm/page_alloc.c:5581
 vma_alloc_folio+0x660/0xb60 mm/mempolicy.c:2246
 shmem_alloc_folio mm/shmem.c:1571 [inline]
 shmem_alloc_and_acct_folio+0x594/0xd70 mm/shmem.c:1595
 shmem_get_folio_gfp+0xd00/0x36e0 mm/shmem.c:1922
 shmem_get_folio mm/shmem.c:2053 [inline]
 shmem_write_begin+0x133/0x480 mm/shmem.c:2545
 generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772
 __generic_file_write_iter+0x176/0x400 mm/filemap.c:3900
 generic_file_write_iter+0xab/0x310 mm/filemap.c:3932
 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
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1446 [inline]
 free_pcp_prepare+0x751/0x780 mm/page_alloc.c:1496
 free_unref_page_prepare mm/page_alloc.c:3369 [inline]
 free_unref_page_list+0xb2/0x830 mm/page_alloc.c:3510
 release_pages+0x233e/0x25e0 mm/swap.c:1076
 __pagevec_release+0x7d/0xf0 mm/swap.c:1096
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 shmem_undo_range+0x6d0/0x1fe0 mm/shmem.c:949
 shmem_truncate_range mm/shmem.c:1044 [inline]
 shmem_evict_inode+0x276/0xa10 mm/shmem.c:1153
 evict+0x2a4/0x620 fs/inode.c:664
 __dentry_kill+0x3b1/0x5b0 fs/dcache.c:607
 dentry_kill+0xbb/0x290
 dput+0x1f3/0x410 fs/dcache.c:913
 __fput+0x5e4/0x880 fs/file_table.c:328
 task_work_run+0x243/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x124/0x150 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0xb2/0x140 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x26/0x60 kernel/entry/common.c:296
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86

Memory state around the buggy address:
 ffff88803a88da80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88803a88db00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88803a88db80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff88803a88dc00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88803a88dc80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-upstream-fs 2022/12/14 23:11 upstream e2ca6ba6ba01 b18f0a64 .config console log report info [disk image] [vmlinux] [kernel image] KASAN: use-after-free Read in udf_new_inode
ci2-upstream-fs 2022/11/28 13:02 upstream b7b275e60bcd 247de55b .config console log report info [disk image] [vmlinux] [kernel image] KASAN: use-after-free Read in udf_new_inode
* Struck through repros no longer work on HEAD.