Re: KASAN: use-after-free Write in snd_rawmidi_receive

[Takashi Iwai]

On Thu, 22 Sep 2022 13:27:22 +0200,
Rondreis wrote:
> 
> Hello,
> 
> When fuzzing the Linux kernel driver v5.18.0, the following crash was
> triggered.
> 
> HEAD commit: 4b0986a3613c92f4ec1bdc7f60ec66fea135991f
> git tree: upstream

A too old kernel for testing such things.

Please try with the newer kernel.  There have been a couple of
(possibly) relevant fixes already in the recent kernel (around
sound/core/rawmidi.c).


thanks,

Takashi

> 
> kernel config: https://pastebin.com/raw/KecL2gaG
> console output: https://pastebin.com/raw/aJGZYGs4
> 
> Sorry for failing to extract the reproducer. But on other versions of
> Linux, I also triggered this crash.
> 
> I would appreciate it if you have any idea how to solve this bug.
> 
> The crash report is as follows:
> ==================================================================
> BUG: KASAN: use-after-free in snd_rawmidi_receive+0x2f6/0xe70
> sound/core/rawmidi.c:1097
> Write of size 3 at addr ffff88803cf1a05a by task kworker/u8:6/13973
> 
> CPU: 3 PID: 13973 Comm: kworker/u8:6 Not tainted 5.18.0 #2
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> 1.13.0-1ubuntu1.1 04/01/2014
> Workqueue: bat_events batadv_nc_worker
> Call Trace:
> <IRQ>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
> print_address_description mm/kasan/report.c:313 [inline]
> print_report.cold+0xe5/0x659 mm/kasan/report.c:429
> kasan_report+0x8a/0x1b0 mm/kasan/report.c:491
> check_region_inline mm/kasan/generic.c:183 [inline]
> kasan_check_range+0x13b/0x190 mm/kasan/generic.c:189
> memcpy+0x39/0x60 mm/kasan/shadow.c:66
> snd_rawmidi_receive+0x2f6/0xe70 sound/core/rawmidi.c:1097
> f_midi_read_data drivers/usb/gadget/function/f_midi.c:253 [inline]
> f_midi_handle_out_data.isra.0+0x1ee/0x290
> drivers/usb/gadget/function/f_midi.c:265
> f_midi_complete+0x3b7/0x480 drivers/usb/gadget/function/f_midi.c:280
> transfer drivers/usb/gadget/udc/dummy_hcd.c:1516 [inline]
> dummy_timer+0x1866/0x33b0 drivers/usb/gadget/udc/dummy_hcd.c:1972
> call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
> expire_timers kernel/time/timer.c:1466 [inline]
> __run_timers kernel/time/timer.c:1737 [inline]
> __run_timers kernel/time/timer.c:1710 [inline]
> run_timer_softirq+0x1084/0x16d0 kernel/time/timer.c:1750
> __do_softirq+0x1d0/0x908 kernel/softirq.c:558
> invoke_softirq kernel/softirq.c:432 [inline]
> __irq_exit_rcu kernel/softirq.c:637 [inline]
> irq_exit_rcu+0xf2/0x130 kernel/softirq.c:649
> sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097
> </IRQ>
> <TASK>
> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:645
> RIP: 0010:lock_release+0x3f0/0x670 kernel/locking/lockdep.c:5649
> Code: 7e 83 f8 01 0f 85 59 01 00 00 9c 58 f6 c4 02 0f 85 44 01 00 00
> 48 f7 04 24 00 02 00 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01
> c5 48 c7 45 00 00 00 00 00 c7 45 08 00 00 00 00 48 8b 84 24
> RSP: 0018:ffffc90008a0fb90 EFLAGS: 00000206
> RAX: dffffc0000000000 RBX: c422640388757846 RCX: 0000000000000000
> RDX: 1ffff11007b1f892 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: 1ffff92001141f74 R08: 0000000000000001 R09: fffffbfff1ce851b
> R10: ffffffff8e7428d7 R11: fffffbfff1ce851a R12: 0000000000000002
> R13: ffff88803d8fc498 R14: 0000000000000003 R15: ffff88803d8fba80
> rcu_lock_release include/linux/rcupdate.h:273 [inline]
> rcu_read_unlock include/linux/rcupdate.h:727 [inline]
> batadv_nc_process_nc_paths.part.0+0x235/0x3c0
> net/batman-adv/network-coding.c:699
> batadv_nc_process_nc_paths net/batman-adv/network-coding.c:679 [inline]
> batadv_nc_worker+0x54f/0x770 net/batman-adv/network-coding.c:728
> process_one_work+0x9cc/0x1650 kernel/workqueue.c:2289
> worker_thread+0x623/0x1070 kernel/workqueue.c:2436
> kthread+0x2e9/0x3a0 kernel/kthread.c:376
> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
> </TASK>
> 
> Allocated by task 17441:
> kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> kasan_set_track mm/kasan/common.c:45 [inline]
> set_alloc_info mm/kasan/common.c:436 [inline]
> ____kasan_kmalloc mm/kasan/common.c:515 [inline]
> ____kasan_kmalloc mm/kasan/common.c:474 [inline]
> __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524
> kasan_kmalloc include/linux/kasan.h:234 [inline]
> __kmalloc_node+0x1fc/0x450 mm/slub.c:4462
> kmalloc_node include/linux/slab.h:604 [inline]
> kvmalloc_node+0x3e/0x190 mm/util.c:580
> kvmalloc include/linux/slab.h:731 [inline]
> kvzalloc include/linux/slab.h:739 [inline]
> snd_rawmidi_runtime_create sound/core/rawmidi.c:162 [inline]
> open_substream+0x340/0x8b0 sound/core/rawmidi.c:306
> rawmidi_open_priv+0x2e8/0x6f0 sound/core/rawmidi.c:352
> snd_rawmidi_kernel_open+0x1b5/0x270 sound/core/rawmidi.c:392
> midisynth_subscribe+0xf2/0x380 sound/core/seq/seq_midi.c:171
> subscribe_port sound/core/seq/seq_ports.c:412 [inline]
> check_and_subscribe_port+0x5be/0x810 sound/core/seq/seq_ports.c:495
> snd_seq_port_connect+0x2e6/0x520 sound/core/seq/seq_ports.c:576
> snd_seq_ioctl_subscribe_port+0x1df/0x310 sound/core/seq/seq_clientmgr.c:1492
> snd_seq_kernel_client_ctl+0x105/0x1b0 sound/core/seq/seq_clientmgr.c:2369
> snd_seq_oss_midi_open+0x3f4/0x670 sound/core/seq/oss/seq_oss_midi.c:368
> snd_seq_oss_synth_reset+0x462/0x890 sound/core/seq/oss/seq_oss_synth.c:407
> snd_seq_oss_reset+0x6f/0x290 sound/core/seq/oss/seq_oss_init.c:435
> snd_seq_oss_release+0x79/0x160 sound/core/seq/oss/seq_oss_init.c:412
> odev_release+0x4f/0x70 sound/core/seq/oss/seq_oss.c:144
> __fput+0x277/0x9d0 fs/file_table.c:317
> task_work_run+0xe0/0x1a0 kernel/task_work.c:164
> resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
> exit_to_user_mode_loop kernel/entry/common.c:169 [inline]
> exit_to_user_mode_prepare+0x253/0x260 kernel/entry/common.c:201
> __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
> syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:294
> do_syscall_64+0x42/0x80 arch/x86/entry/common.c:86
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> 
> Freed by task 17441:
> kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
> kasan_set_track+0x21/0x30 mm/kasan/common.c:45
> kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
> ____kasan_slab_free mm/kasan/common.c:366 [inline]
> ____kasan_slab_free mm/kasan/common.c:328 [inline]
> __kasan_slab_free+0x11d/0x190 mm/kasan/common.c:374
> kasan_slab_free include/linux/kasan.h:200 [inline]
> slab_free_hook mm/slub.c:1728 [inline]
> slab_free_freelist_hook mm/slub.c:1754 [inline]
> slab_free mm/slub.c:3510 [inline]
> kfree+0xec/0x4b0 mm/slub.c:4552
> kvfree+0x42/0x50 mm/util.c:622
> snd_rawmidi_runtime_free sound/core/rawmidi.c:176 [inline]
> close_substream.part.0+0x18e/0x650 sound/core/rawmidi.c:528
> close_substream sound/core/rawmidi.c:507 [inline]
> rawmidi_release_priv+0xd3/0x270 sound/core/rawmidi.c:543
> snd_rawmidi_kernel_release+0x39/0xd0 sound/core/rawmidi.c:564
> midisynth_unsubscribe+0x3b/0x70 sound/core/seq/seq_midi.c:203
> unsubscribe_port sound/core/seq/seq_ports.c:437 [inline]
> __delete_and_unsubscribe_port+0x279/0x4e0 sound/core/seq/seq_ports.c:537
> delete_and_unsubscribe_port+0x59/0x80 sound/core/seq/seq_ports.c:549
> snd_seq_port_disconnect+0x1ee/0x270 sound/core/seq/seq_ports.c:627
> snd_seq_ioctl_unsubscribe_port+0x1df/0x310 sound/core/seq/seq_clientmgr.c:1537
> snd_seq_kernel_client_ctl+0x105/0x1b0 sound/core/seq/seq_clientmgr.c:2369
> snd_seq_oss_midi_close+0x2ff/0x470 sound/core/seq/oss/seq_oss_midi.c:410
> snd_seq_oss_synth_cleanup+0x32c/0x480 sound/core/seq/oss/seq_oss_synth.c:307
> snd_seq_oss_release+0x81/0x160 sound/core/seq/oss/seq_oss_init.c:414
> odev_release+0x4f/0x70 sound/core/seq/oss/seq_oss.c:144
> __fput+0x277/0x9d0 fs/file_table.c:317
> task_work_run+0xe0/0x1a0 kernel/task_work.c:164
> resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
> exit_to_user_mode_loop kernel/entry/common.c:169 [inline]
> exit_to_user_mode_prepare+0x253/0x260 kernel/entry/common.c:201
> __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
> syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:294
> do_syscall_64+0x42/0x80 arch/x86/entry/common.c:86
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> 
> The buggy address belongs to the object at ffff88803cf1a000
> which belongs to the cache kmalloc-4k of size 4096
> The buggy address is located 90 bytes inside of
> 4096-byte region [ffff88803cf1a000, ffff88803cf1b000)
> 
> The buggy address belongs to the physical page:
> page:ffffea0000f3c600 refcount:1 mapcount:0 mapping:0000000000000000
> index:0x0 pfn:0x3cf18
> head:ffffea0000f3c600 order:3 compound_mapcount:0 compound_pincount:0
> flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
> raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011843040
> raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 3, migratetype Unmovable, gfp_mask
> 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL),
> pid 17441, tgid 17441 (syz-executor.0), ts 589072773595, free_ts
> 589014752799
> set_page_owner include/linux/page_owner.h:31 [inline]
> post_alloc_hook mm/page_alloc.c:2434 [inline]
> prep_new_page+0x297/0x330 mm/page_alloc.c:2441
> get_page_from_freelist+0x210e/0x3ab0 mm/page_alloc.c:4182
> __alloc_pages+0x30c/0x6e0 mm/page_alloc.c:5408
> alloc_pages+0x119/0x250 mm/mempolicy.c:2272
> alloc_slab_page mm/slub.c:1799 [inline]
> allocate_slab mm/slub.c:1944 [inline]
> new_slab+0x2a9/0x3f0 mm/slub.c:2004
> ___slab_alloc+0xc62/0x1080 mm/slub.c:3005
> __slab_alloc.isra.0+0x4d/0xa0 mm/slub.c:3092
> slab_alloc_node mm/slub.c:3183 [inline]
> __kmalloc_node+0x340/0x450 mm/slub.c:4458
> kmalloc_node include/linux/slab.h:604 [inline]
> kvmalloc_node+0x3e/0x190 mm/util.c:580
> kvmalloc include/linux/slab.h:731 [inline]
> kvzalloc include/linux/slab.h:739 [inline]
> snd_rawmidi_runtime_create sound/core/rawmidi.c:162 [inline]
> open_substream+0x340/0x8b0 sound/core/rawmidi.c:306
> rawmidi_open_priv+0x592/0x6f0 sound/core/rawmidi.c:357
> snd_rawmidi_kernel_open+0x1b5/0x270 sound/core/rawmidi.c:392
> midisynth_use+0xee/0x270 sound/core/seq/seq_midi.c:215
> subscribe_port sound/core/seq/seq_ports.c:412 [inline]
> check_and_subscribe_port+0x5be/0x810 sound/core/seq/seq_ports.c:495
> snd_seq_port_connect+0x382/0x520 sound/core/seq/seq_ports.c:581
> snd_seq_ioctl_subscribe_port+0x1df/0x310 sound/core/seq/seq_clientmgr.c:1492
> page last free stack trace:
> reset_page_owner include/linux/page_owner.h:24 [inline]
> free_pages_prepare mm/page_alloc.c:1356 [inline]
> free_pcp_prepare+0x51f/0xd00 mm/page_alloc.c:1406
> free_unref_page_prepare mm/page_alloc.c:3328 [inline]
> free_unref_page+0x19/0x5b0 mm/page_alloc.c:3423
> __unfreeze_partials+0x3d2/0x3f0 mm/slub.c:2523
> do_slab_free mm/slub.c:3498 [inline]
> ___cache_free+0x12c/0x140 mm/slub.c:3517
> qlink_free mm/kasan/quarantine.c:157 [inline]
> qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:176
> kasan_quarantine_reduce+0x13d/0x180 mm/kasan/quarantine.c:283
> __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
> kasan_slab_alloc include/linux/kasan.h:224 [inline]
> slab_post_alloc_hook+0x4d/0x4f0 mm/slab.h:749
> slab_alloc_node mm/slub.c:3217 [inline]
> slab_alloc mm/slub.c:3225 [inline]
> __kmem_cache_alloc_lru mm/slub.c:3232 [inline]
> kmem_cache_alloc+0x1be/0x460 mm/slub.c:3242
> getname_flags fs/namei.c:138 [inline]
> getname_flags+0xd2/0x5b0 fs/namei.c:128
> vfs_fstatat+0x73/0xb0 fs/stat.c:254
> __do_sys_newfstatat+0x91/0x110 fs/stat.c:425
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
> 
> Memory state around the buggy address:
> ffff88803cf19f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff88803cf19f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >ffff88803cf1a000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ^
> ffff88803cf1a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff88803cf1a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================
> ----------------
> Code disassembly (best guess):
> 0: 7e 83 jle 0xffffff85
> 2: f8 clc
> 3: 01 0f add %ecx,(%rdi)
> 5: 85 59 01 test %ebx,0x1(%rcx)
> 8: 00 00 add %al,(%rax)
> a: 9c pushfq
> b: 58 pop %rax
> c: f6 c4 02 test $0x2,%ah
> f: 0f 85 44 01 00 00 jne 0x159
> 15: 48 f7 04 24 00 02 00 testq $0x200,(%rsp)
> 1c: 00
> 1d: 74 01 je 0x20
> 1f: fb sti
> 20: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
> 27: fc ff df
> * 2a: 48 01 c5 add %rax,%rbp <-- trapping instruction
> 2d: 48 c7 45 00 00 00 00 movq $0x0,0x0(%rbp)
> 34: 00
> 35: c7 45 08 00 00 00 00 movl $0x0,0x8(%rbp)
> 3c: 48 rex.W
> 3d: 8b .byte 0x8b
> 3e: 84 .byte 0x84
> 3f: 24 .byte 0x24
>