[syzbot] KASAN: use-after-free Read in __snd_rawmidi_transmit_peek
Hello,
syzbot found the following issue on:
HEAD commit: a19944809fe9 Merge tag 'hardening-v5.18-rc3' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16a40ae0f00000 kernel config: https://syzkaller.appspot.com/x/.config?x=eb177500e563582f dashboard link: https://syzkaller.appspot.com/bug?extid=70e777a39907d6d5fd0a compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1590dfa8f00000
IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+70e777a39907d6d5fd0a@syzkaller.appspotmail.com
================================================================== BUG: KASAN: use-after-free in __snd_rawmidi_transmit_peek+0x261/0x360 sound/core/rawmidi.c:1286 Read of size 1 at addr ffff88807eac2072 by task kworker/1:1H/51
CPU: 1 PID: 51 Comm: kworker/1:1H Not tainted 5.18.0-rc2-syzkaller-00050-ga19944809fe9 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_highpri snd_usbmidi_out_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313 print_report mm/kasan/report.c:429 [inline] kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491 __snd_rawmidi_transmit_peek+0x261/0x360 sound/core/rawmidi.c:1286 snd_rawmidi_transmit+0x8d/0xf0 sound/core/rawmidi.c:1411 snd_usbmidi_standard_output+0x264/0xc10 sound/usb/midi.c:650 snd_usbmidi_do_output+0x200/0x510 sound/usb/midi.c:311 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 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 5812: 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 kmalloc_node include/linux/slab.h:604 [inline] kvmalloc_node+0x3e/0x130 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+0x591/0x6f0 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+0x89a/0xb80 sound/core/seq/seq_ports.c:495 snd_seq_port_connect+0x382/0x540 sound/core/seq/seq_ports.c:581 snd_seq_ioctl_subscribe_port+0x1fc/0x400 sound/core/seq/seq_clientmgr.c:1492 snd_seq_kernel_client_ctl+0x102/0x1e0 sound/core/seq/seq_clientmgr.c:2369 snd_seq_oss_midi_open+0x582/0x6e0 sound/core/seq/oss/seq_oss_midi.c:359 snd_seq_oss_synth_setup_midi+0x12d/0x530 sound/core/seq/oss/seq_oss_synth.c:269 snd_seq_oss_open+0x8c3/0xa80 sound/core/seq/oss/seq_oss_init.c:260 odev_open+0x6c/0x90 sound/core/seq/oss/seq_oss.c:128 soundcore_open+0x44e/0x620 sound/sound_core.c:593 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4a1/0x11e0 fs/open.c:824 do_open fs/namei.c:3476 [inline] path_openat+0x1c71/0x2910 fs/namei.c:3609 do_filp_open+0x1aa/0x400 fs/namei.c:3636 do_sys_openat2+0x16d/0x4c0 fs/open.c:1213 do_sys_open fs/open.c:1229 [inline] __do_sys_openat fs/open.c:1245 [inline] __se_sys_openat fs/open.c:1240 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1240 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 5811: 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+0x166/0x1a0 mm/kasan/common.c:328 kasan_slab_free include/linux/kasan.h:200 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754 slab_free mm/slub.c:3510 [inline] kfree+0xd6/0x4d0 mm/slub.c:4552 kvfree+0x42/0x50 mm/util.c:615 snd_rawmidi_runtime_free sound/core/rawmidi.c:176 [inline] close_substream.part.0+0x185/0x720 sound/core/rawmidi.c:528 close_substream sound/core/rawmidi.c:507 [inline] rawmidi_release_priv+0x192/0x270 sound/core/rawmidi.c:547 snd_rawmidi_kernel_release+0x39/0xd0 sound/core/rawmidi.c:564 midisynth_unuse+0x45/0x80 sound/core/seq/seq_midi.c:244 unsubscribe_port sound/core/seq/seq_ports.c:437 [inline] __delete_and_unsubscribe_port+0x270/0x4c0 sound/core/seq/seq_ports.c:537 snd_seq_port_disconnect+0x41c/0x5d0 sound/core/seq/seq_ports.c:616 snd_seq_ioctl_unsubscribe_port+0x1fc/0x400 sound/core/seq/seq_clientmgr.c:1537 snd_seq_kernel_client_ctl+0x102/0x1e0 sound/core/seq/seq_clientmgr.c:2369 snd_seq_oss_midi_close+0x44f/0x4d0 sound/core/seq/oss/seq_oss_midi.c:404 snd_seq_oss_synth_reset+0x422/0x880 sound/core/seq/oss/seq_oss_synth.c:406 snd_seq_oss_reset+0x6f/0x290 sound/core/seq/oss/seq_oss_init.c:435 snd_seq_oss_release+0x78/0x1a0 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+0xdd/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+0x23c/0x250 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+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae
The buggy address belongs to the object at ffff88807eac2000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 114 bytes inside of 4096-byte region [ffff88807eac2000, ffff88807eac3000)
The buggy address belongs to the physical page: page:ffffea0001fab000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7eac0 head:ffffea0001fab000 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea0001d2a000 dead000000000002 ffff888010c42140 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3703, tgid 3703 (syz-executor.4), ts 1615766892626, free_ts 34515408626 prep_new_page mm/page_alloc.c:2441 [inline] get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4182 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5408 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2272 alloc_slab_page mm/slub.c:1799 [inline] allocate_slab+0x26c/0x3c0 mm/slub.c:1944 new_slab mm/slub.c:2004 [inline] ___slab_alloc+0x8df/0xf20 mm/slub.c:3005 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3092 slab_alloc_node mm/slub.c:3183 [inline] slab_alloc mm/slub.c:3225 [inline] kmem_cache_alloc_trace+0x310/0x3f0 mm/slub.c:3256 kmalloc include/linux/slab.h:581 [inline] kzalloc include/linux/slab.h:714 [inline] kobject_uevent_env+0x235/0x1660 lib/kobject_uevent.c:524 device_add+0xb20/0x1e20 drivers/base/core.c:3386 netdev_register_kobject+0x181/0x430 net/core/net-sysfs.c:2008 register_netdevice+0xd9d/0x15b0 net/core/dev.c:9961 __rtnl_newlink+0x1555/0x1760 net/core/rtnetlink.c:3485 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3531 rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5990 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2496 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x543/0x7f0 net/netlink/af_netlink.c:1345 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+0x549/0xd20 mm/page_alloc.c:1406 free_unref_page_prepare mm/page_alloc.c:3328 [inline] free_unref_page+0x19/0x6a0 mm/page_alloc.c:3423 qlink_free mm/kasan/quarantine.c:157 [inline] qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x180/0x200 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 mm/slab.h:749 [inline] slab_alloc_node mm/slub.c:3217 [inline] kmem_cache_alloc_node+0x255/0x3f0 mm/slub.c:3267 __alloc_skb+0x215/0x340 net/core/skbuff.c:414 alloc_skb include/linux/skbuff.h:1300 [inline] alloc_skb_with_frags+0x93/0x730 net/core/skbuff.c:5995 sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2600 unix_dgram_sendmsg+0x414/0x1a90 net/unix/af_unix.c:1896 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:725 __sys_sendto+0x216/0x310 net/socket.c:2040 __do_sys_sendto net/socket.c:2052 [inline] __se_sys_sendto net/socket.c:2048 [inline] __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2048 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae
Memory state around the buggy address: ffff88807eac1f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88807eac1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88807eac2000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^ ffff88807eac2080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807eac2100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================
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On Mon, 18 Apr 2022 12:12:23 +0200, syzbot wrote:
Hello,
syzbot found the following issue on:
HEAD commit: a19944809fe9 Merge tag 'hardening-v5.18-rc3' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16a40ae0f00000 kernel config: https://syzkaller.appspot.com/x/.config?x=eb177500e563582f dashboard link: https://syzkaller.appspot.com/bug?extid=70e777a39907d6d5fd0a compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1590dfa8f00000
IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+70e777a39907d6d5fd0a@syzkaller.appspotmail.com
================================================================== BUG: KASAN: use-after-free in __snd_rawmidi_transmit_peek+0x261/0x360 sound/core/rawmidi.c:1286
Looks like a leftover work. The fix patch is below.
Takashi
-- 8< -- From: Takashi Iwai tiwai@suse.de Subject: [PATCH] ALSA: usb-audio: Fix potential use-after-free at releasing MIDI streams
As recently spotted by syzbot, the USB MIDI code may leave a work that handles the pending output queue even after a stream gets released (either internally via sequencer or via device files), which may lead to use-after-free. We have already a proper drop of pending URBs but this is executed only at the device disconnection.
This patch moves the URB clean-up code into both the code path that is called at releasing, namely, snd_usb_midi_in_endpoint_delete() and snd_usb_midi_out_endpoint_clear() functions, so that the pending URBs and work are cleared properly before releasing the resources.
Reported-by: syzbot+70e777a39907d6d5fd0a@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/00000000000011555605dceaff03@google.com Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/usb/midi.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-)
diff --git a/sound/usb/midi.c b/sound/usb/midi.c index 2c01649c70f6..8e5281f7f1fc 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -1247,6 +1247,10 @@ static void snd_usbmidi_in_endpoint_delete(struct snd_usb_midi_in_endpoint *ep) { unsigned int i;
+ for (i = 0; i < INPUT_URBS; ++i) + if (ep->urbs[i]) + usb_kill_urb(ep->urbs[i]); + for (i = 0; i < INPUT_URBS; ++i) if (ep->urbs[i]) free_urb_and_buffer(ep->umidi, ep->urbs[i], @@ -1327,6 +1331,18 @@ static void snd_usbmidi_out_endpoint_clear(struct snd_usb_midi_out_endpoint *ep) { unsigned int i;
+ cancel_work_sync(&ep->work); + for (i = 0; i < OUTPUT_URBS; ++i) + if (ep->urbs[i].urb) + usb_kill_urb(ep->urbs[i].urb); + if (ep->umidi->usb_protocol_ops->finish_out_endpoint) + ep->umidi->usb_protocol_ops->finish_out_endpoint(ep); + ep->active_urbs = 0; + if (ep->drain_urbs) { + ep->drain_urbs = 0; + wake_up(&ep->drain_wait); + } + for (i = 0; i < OUTPUT_URBS; ++i) if (ep->urbs[i].urb) { free_urb_and_buffer(ep->umidi, ep->urbs[i].urb, @@ -1469,7 +1485,7 @@ static void snd_usbmidi_free(struct snd_usb_midi *umidi) void snd_usbmidi_disconnect(struct list_head *p) { struct snd_usb_midi *umidi; - unsigned int i, j; + unsigned int i;
umidi = list_entry(p, struct snd_usb_midi, list); /* @@ -1487,22 +1503,6 @@ void snd_usbmidi_disconnect(struct list_head *p)
for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) { struct snd_usb_midi_endpoint *ep = &umidi->endpoints[i]; - if (ep->out) - cancel_work_sync(&ep->out->work); - if (ep->out) { - for (j = 0; j < OUTPUT_URBS; ++j) - usb_kill_urb(ep->out->urbs[j].urb); - if (umidi->usb_protocol_ops->finish_out_endpoint) - umidi->usb_protocol_ops->finish_out_endpoint(ep->out); - ep->out->active_urbs = 0; - if (ep->out->drain_urbs) { - ep->out->drain_urbs = 0; - wake_up(&ep->out->drain_wait); - } - } - if (ep->in) - for (j = 0; j < INPUT_URBS; ++j) - usb_kill_urb(ep->in->urbs[j]); /* free endpoints here; later call can result in Oops */ if (ep->out) snd_usbmidi_out_endpoint_clear(ep->out);
On Tue, 19 Apr 2022 11:01:47 +0200, Takashi Iwai wrote:
On Mon, 18 Apr 2022 12:12:23 +0200, syzbot wrote:
Hello,
syzbot found the following issue on:
HEAD commit: a19944809fe9 Merge tag 'hardening-v5.18-rc3' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16a40ae0f00000 kernel config: https://syzkaller.appspot.com/x/.config?x=eb177500e563582f dashboard link: https://syzkaller.appspot.com/bug?extid=70e777a39907d6d5fd0a compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1590dfa8f00000
IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+70e777a39907d6d5fd0a@syzkaller.appspotmail.com
================================================================== BUG: KASAN: use-after-free in __snd_rawmidi_transmit_peek+0x261/0x360 sound/core/rawmidi.c:1286
Looks like a leftover work. The fix patch is below.
On the second thought, this would be rather in a different code path, and the fix should be smaller like below. Let's see.
Takashi
-- 8< -- From: Takashi Iwai tiwai@suse.de Subject: [PATCH] ALSA: usb-audio: Clear MIDI port active flag after draining
When a rawmidi output stream is closed, it calls the drain at first, then does trigger-off only when the drain returns -ERESTARTSYS as a fallback. It implies that each driver should turn off the stream properly after the drain. Meanwhile, USB-audio MIDI interface didn't change the port->active flag after the drain. This may leave the output work picking up the port that is closed right now, which eventually leads to a use-after-free for the already released rawmidi object.
This patch fixes the bug by properly clearing the port->active flag after the output drain.
Reported-by: syzbot+70e777a39907d6d5fd0a@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/00000000000011555605dceaff03@google.com Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/usb/midi.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/sound/usb/midi.c b/sound/usb/midi.c index 2c01649c70f6..7c6ca2b433a5 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -1194,6 +1194,7 @@ static void snd_usbmidi_output_drain(struct snd_rawmidi_substream *substream) } while (drain_urbs && timeout); finish_wait(&ep->drain_wait, &wait); } + port->active = 0; spin_unlock_irq(&ep->buffer_lock); }
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syzbot -
Takashi Iwai