KASAN: slab-use-after-free Read in v4l2_fh_open

KASAN: slab-use-after-free Read in v4l2_fh_open

[sanan.hasanou]

Good day, dear maintainers,

We found a bug using a modified version of syzkaller.

Kernel Branch: 7.0-rc1
Kernel Config: <https://drive.google.com/open?id=173DLEAEPKPhhR1TcqofdnkLpdoK7PMFl>
Reproducer: <https://drive.google.com/open?id=1R8QMlaB0Uwrt1BIzqQvRrMo6VYbmX3qK>
Thank you!

Best regards,
Sanan Hasanov

==================================================================
BUG: KASAN: slab-use-after-free in v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline]
BUG: KASAN: slab-use-after-free in v4l2_fh_open+0x144/0x550 drivers/media/v4l2-core/v4l2-fh.c:64
Read of size 8 at addr ffff8880570245b8 by task v4l_id/31950

CPU: 0 UID: 0 PID: 31950 Comm: v4l_id Not tainted 7.0.0-rc1 #1 PREEMPT(full) 
Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcb/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline]
 v4l2_fh_open+0x144/0x550 drivers/media/v4l2-core/v4l2-fh.c:64
 em28xx_v4l2_open+0x15a/0x990 drivers/media/usb/em28xx/em28xx-video.c:2153
 v4l2_open+0x1bc/0x390 drivers/media/v4l2-core/v4l2-dev.c:433
 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411
 do_dentry_open+0x777/0x14d0 fs/open.c:949
 vfs_open+0x3d/0x340 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x2d8a/0x37e0 fs/namei.c:4830
 do_file_open+0x208/0x440 fs/namei.c:4859
 do_sys_openat2+0x10a/0x1e0 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x13d/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x19a/0x7b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7fdfdd774127
Code: 25 00 00 41 00 3d 00 00 41 00 74 47 64 8b 04 25 18 00 00 00 85 c0 75 6b 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 95 00 00 00 48 8b 4c 24 28 64 48 2b 0c 25
RSP: 002b:00007ffd4df65430 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007ffd4df65628 RCX: 00007fdfdd774127
RDX: 0000000000000000 RSI: 00007ffd4df65f19 RDI: 00000000ffffff9c
RBP: 00007ffd4df65f19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 12368:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x70 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xa0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x27b/0x3e0 mm/slub.c:5339
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1200 [inline]
 em28xx_v4l2_init+0x16b/0x2ef0 drivers/media/usb/em28xx/em28xx-video.c:2532
 em28xx_init_extension+0x11f/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1117
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0x811/0xf10 kernel/workqueue.c:3358
 worker_thread+0x9c1/0xeb0 kernel/workqueue.c:3439
 kthread+0x3c1/0x4d0 kernel/kthread.c:467
 ret_from_fork+0x608/0xc40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:245

Freed by task 12368:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x70 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2687 [inline]
 slab_free mm/slub.c:6124 [inline]
 kfree+0x1f8/0x4f0 mm/slub.c:6442
 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2118 [inline]
 kref_put include/linux/kref.h:65 [inline]
 em28xx_v4l2_init+0x16d4/0x2ef0 drivers/media/usb/em28xx/em28xx-video.c:2901
 em28xx_init_extension+0x11f/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1117
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0x811/0xf10 kernel/workqueue.c:3358
 worker_thread+0x9c1/0xeb0 kernel/workqueue.c:3439
 kthread+0x3c1/0x4d0 kernel/kthread.c:467
 ret_from_fork+0x608/0xc40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888057024000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 1464 bytes inside of
 freed 8192-byte region [ffff888057024000, ffff888057026000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x57020
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888057022011
flags: 0x2000000000000040(head|zone=1)
page_type: f5(slab)
raw: 2000000000000040 ffff888012c42280 dead000000000100 dead000000000122
raw: 0000000000000000 0000400000020002 00000000f5000000 ffff888057022011
head: 2000000000000040 ffff888012c42280 dead000000000100 dead000000000122
head: 0000000000000000 0000400000020002 00000000f5000000 ffff888057022011
head: 2000000000000003 ffffea00015c0801 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 12836, tgid 12836 (kworker/1:8), ts 148781064900, free_ts 148779833020
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x253/0x480 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x2240/0x2330 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x20e/0x3d0 mm/page_alloc.c:5250
 alloc_slab_page+0x5e/0x120 mm/slub.c:-1
 allocate_slab+0x77/0x540 mm/slub.c:3444
 new_slab mm/slub.c:3502 [inline]
 refill_objects+0x229/0x680 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x1cf/0x430 mm/slub.c:4578
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 __kmalloc_cache_noprof+0x377/0x3e0 mm/slub.c:5334
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1200 [inline]
 snd_mixer_oss_notify_handler+0x1bc/0x1150 sound/core/oss/mixer_oss.c:1318
 snd_card_register+0x5df/0x750 sound/core/init.c:923
 try_to_register_card+0x2a1/0x330 sound/usb/card.c:-1
 usb_audio_probe+0x145d/0x1e80 sound/usb/card.c:1045
 usb_probe_interface+0x6c8/0xcf0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x46f/0xbb0 drivers/base/dd.c:661
 __driver_probe_device+0x1ad/0x330 drivers/base/dd.c:803
 driver_probe_device+0x54/0x240 drivers/base/dd.c:833
page last free pid 12836 tgid 12836 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xb5e/0x1200 mm/page_alloc.c:2978
 __slab_free+0x2d2/0x2e0 mm/slub.c:5532
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9e/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14a/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 kmem_cache_alloc_noprof+0x223/0x3d0 mm/slub.c:4837
 __kernfs_new_node+0x15c/0x7a0 fs/kernfs/dir.c:637
 kernfs_new_node+0x158/0x270 fs/kernfs/dir.c:718
 __kernfs_create_file+0x50/0x270 fs/kernfs/file.c:1057
 sysfs_add_file_mode_ns+0x1bd/0x250 fs/sysfs/file.c:313
 sysfs_merge_group+0x17c/0x310 fs/sysfs/group.c:382
 dpm_sysfs_add+0xd7/0x270 drivers/base/power/sysfs.c:704
 device_add+0x548/0xba0 drivers/base/core.c:3649
 snd_register_device+0x3db/0x560 sound/core/sound.c:278
 snd_ctl_dev_register+0x79/0x180 sound/core/control.c:2296
 __snd_device_register sound/core/device.c:149 [inline]
 snd_device_register_all+0xd1/0x1a0 sound/core/device.c:197

Memory state around the buggy address:
 ffff888057024480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888057024500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888057024580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff888057024600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888057024680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

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