[alsa-devel] KASAN: slab-out-of-bounds Read in build_audio_procunit
Hello,
syzbot found the following crash on:
HEAD commit: 22be26f7 usb-fuzzer: main usb gadget fuzzer driver git tree: https://github.com/google/kasan.git usb-fuzzer console output: https://syzkaller.appspot.com/x/log.txt?x=103893cf600000 kernel config: https://syzkaller.appspot.com/x/.config?x=387eccb7ac68ec5 dashboard link: https://syzkaller.appspot.com/bug?extid=0620f79a1978b1133fd7 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16fd6a40e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1033215f600000
IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+0620f79a1978b1133fd7@syzkaller.appspotmail.com
usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 usb 1-1: Product: syz usb 1-1: Manufacturer: syz usb 1-1: SerialNumber: syz ================================================================== BUG: KASAN: slab-out-of-bounds in uac_processing_unit_iProcessing include/uapi/linux/usb/audio.h:429 [inline] BUG: KASAN: slab-out-of-bounds in build_audio_procunit+0x1306/0x13f0 sound/usb/mixer.c:2436 Read of size 1 at addr ffff8881d537c7b7 by task kworker/0:2/101
CPU: 0 PID: 101 Comm: kworker/0:2 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usb_hub_wq hub_event Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xca/0x13e lib/dump_stack.c:113 print_address_description.constprop.0+0x36/0x50 mm/kasan/report.c:374 __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:506 kasan_report+0xe/0x20 mm/kasan/common.c:634 uac_processing_unit_iProcessing include/uapi/linux/usb/audio.h:429 [inline] build_audio_procunit+0x1306/0x13f0 sound/usb/mixer.c:2436 parse_audio_processing_unit sound/usb/mixer.c:2468 [inline] parse_audio_unit+0x17e9/0x36f0 sound/usb/mixer.c:2757 snd_usb_mixer_controls+0x715/0xb90 sound/usb/mixer.c:3095 snd_usb_create_mixer+0x2b5/0x1890 sound/usb/mixer.c:3445 usb_audio_probe+0xc76/0x2010 sound/usb/card.c:653 usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361 really_probe+0x281/0x6d0 drivers/base/dd.c:548 driver_probe_device+0x104/0x210 drivers/base/dd.c:721 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430 __device_attach+0x217/0x360 drivers/base/dd.c:894 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490 device_add+0xae6/0x16f0 drivers/base/core.c:2201 usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023 generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210 usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266 really_probe+0x281/0x6d0 drivers/base/dd.c:548 driver_probe_device+0x104/0x210 drivers/base/dd.c:721 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430 __device_attach+0x217/0x360 drivers/base/dd.c:894 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490 device_add+0xae6/0x16f0 drivers/base/core.c:2201 usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536 hub_port_connect drivers/usb/core/hub.c:5183 [inline] hub_port_connect_change drivers/usb/core/hub.c:5323 [inline] port_event drivers/usb/core/hub.c:5469 [inline] hub_event+0x1dd0/0x37e0 drivers/usb/core/hub.c:5551 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269 worker_thread+0x96/0xe20 kernel/workqueue.c:2415 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Allocated by task 101: save_stack+0x1b/0x80 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:510 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:483 kmalloc include/linux/slab.h:561 [inline] usb_get_configuration+0x314/0x3050 drivers/usb/core/config.c:857 usb_enumerate_device drivers/usb/core/hub.c:2369 [inline] usb_new_device+0xd3/0x160 drivers/usb/core/hub.c:2505 hub_port_connect drivers/usb/core/hub.c:5183 [inline] hub_port_connect_change drivers/usb/core/hub.c:5323 [inline] port_event drivers/usb/core/hub.c:5469 [inline] hub_event+0x1dd0/0x37e0 drivers/usb/core/hub.c:5551 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269 worker_thread+0x96/0xe20 kernel/workqueue.c:2415 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Freed by task 17: save_stack+0x1b/0x80 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] kasan_set_free_info mm/kasan/common.c:332 [inline] __kasan_slab_free+0x130/0x180 mm/kasan/common.c:471 slab_free_hook mm/slub.c:1424 [inline] slab_free_freelist_hook mm/slub.c:1475 [inline] slab_free mm/slub.c:3018 [inline] kfree+0xe4/0x320 mm/slub.c:3967 urb_destroy drivers/usb/core/urb.c:26 [inline] kref_put include/linux/kref.h:65 [inline] usb_free_urb.part.0+0x7a/0xc0 drivers/usb/core/urb.c:95 usb_free_urb+0x1b/0x30 drivers/usb/core/urb.c:94 usb_start_wait_urb+0x1e5/0x2b0 drivers/usb/core/message.c:79 usb_internal_control_msg drivers/usb/core/message.c:101 [inline] usb_control_msg+0x31c/0x4a0 drivers/usb/core/message.c:152 get_port_status drivers/usb/core/hub.c:569 [inline] hub_ext_port_status+0x125/0x460 drivers/usb/core/hub.c:586 hub_port_status drivers/usb/core/hub.c:608 [inline] hub_activate+0x497/0x1570 drivers/usb/core/hub.c:1111 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269 worker_thread+0x96/0xe20 kernel/workqueue.c:2415 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
The buggy address belongs to the object at ffff8881d537c700 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 183 bytes inside of 192-byte region [ffff8881d537c700, ffff8881d537c7c0) The buggy address belongs to the page: page:ffffea000754df00 refcount:1 mapcount:0 mapping:ffff8881da002a00 index:0x0 flags: 0x200000000000200(slab) raw: 0200000000000200 ffffea000754d680 0000000600000006 ffff8881da002a00 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffff8881d537c680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8881d537c700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881d537c780: 00 00 00 02 fc fc fc fc fc fc fc fc fc fc fc fc
^ ffff8881d537c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d537c880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================
--- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com.
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On Tue, 22 Oct 2019 16:54:07 +0200, syzbot wrote:
Hello,
syzbot found the following crash on:
HEAD commit: 22be26f7 usb-fuzzer: main usb gadget fuzzer driver git tree: https://github.com/google/kasan.git usb-fuzzer console output: https://syzkaller.appspot.com/x/log.txt?x=103893cf600000 kernel config: https://syzkaller.appspot.com/x/.config?x=387eccb7ac68ec5 dashboard link: https://syzkaller.appspot.com/bug?extid=0620f79a1978b1133fd7 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16fd6a40e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1033215f600000
IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+0620f79a1978b1133fd7@syzkaller.appspotmail.com
usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 usb 1-1: Product: syz usb 1-1: Manufacturer: syz usb 1-1: SerialNumber: syz ================================================================== BUG: KASAN: slab-out-of-bounds in uac_processing_unit_iProcessing include/uapi/linux/usb/audio.h:429 [inline] BUG: KASAN: slab-out-of-bounds in build_audio_procunit+0x1306/0x13f0 sound/usb/mixer.c:2436 Read of size 1 at addr ffff8881d537c7b7 by task kworker/0:2/101
CPU: 0 PID: 101 Comm: kworker/0:2 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usb_hub_wq hub_event Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xca/0x13e lib/dump_stack.c:113 print_address_description.constprop.0+0x36/0x50 mm/kasan/report.c:374 __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:506 kasan_report+0xe/0x20 mm/kasan/common.c:634 uac_processing_unit_iProcessing include/uapi/linux/usb/audio.h:429 [inline] build_audio_procunit+0x1306/0x13f0 sound/usb/mixer.c:2436 parse_audio_processing_unit sound/usb/mixer.c:2468 [inline] parse_audio_unit+0x17e9/0x36f0 sound/usb/mixer.c:2757 snd_usb_mixer_controls+0x715/0xb90 sound/usb/mixer.c:3095 snd_usb_create_mixer+0x2b5/0x1890 sound/usb/mixer.c:3445 usb_audio_probe+0xc76/0x2010 sound/usb/card.c:653 usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361 really_probe+0x281/0x6d0 drivers/base/dd.c:548 driver_probe_device+0x104/0x210 drivers/base/dd.c:721 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430 __device_attach+0x217/0x360 drivers/base/dd.c:894 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490 device_add+0xae6/0x16f0 drivers/base/core.c:2201 usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023 generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210 usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266 really_probe+0x281/0x6d0 drivers/base/dd.c:548 driver_probe_device+0x104/0x210 drivers/base/dd.c:721 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430 __device_attach+0x217/0x360 drivers/base/dd.c:894 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490 device_add+0xae6/0x16f0 drivers/base/core.c:2201 usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536 hub_port_connect drivers/usb/core/hub.c:5183 [inline] hub_port_connect_change drivers/usb/core/hub.c:5323 [inline] port_event drivers/usb/core/hub.c:5469 [inline] hub_event+0x1dd0/0x37e0 drivers/usb/core/hub.c:5551 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269 worker_thread+0x96/0xe20 kernel/workqueue.c:2415 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Damn, there was a silly copy&paste error in the validation code. The fix patch is below. I'm going to queue this for the next pull request for 5.4.
thanks,
Takashi
-- 8< -- From: Takashi Iwai tiwai@suse.de Subject: [PATCH] ALSA: usb-audio: Fix copy&paste error in the validator
The recently introduced USB-audio descriptor validator had a stupid copy&paste error that may lead to an unexpected overlook of too short descriptors for processing and extension units. It's likely the cause of the report triggered by syzkaller fuzzer. Let's fix it.
Fixes: 57f8770620e9 ("ALSA: usb-audio: More validations of descriptor units") Reported-by: syzbot+0620f79a1978b1133fd7@syzkaller.appspotmail.com Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/usb/validate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/validate.c b/sound/usb/validate.c index 3c8f73a0eb12..a5e584b60dcd 100644 --- a/sound/usb/validate.c +++ b/sound/usb/validate.c @@ -75,7 +75,7 @@ static bool validate_processing_unit(const void *p,
if (d->bLength < sizeof(*d)) return false; - len = d->bLength < sizeof(*d) + d->bNrInPins; + len = sizeof(*d) + d->bNrInPins; if (d->bLength < len) return false; switch (v->protocol) {
I wish that this could have been detected with static analysis...
On Tue, Oct 22, 2019 at 05:45:14PM +0200, Takashi Iwai wrote:
diff --git a/sound/usb/validate.c b/sound/usb/validate.c index 3c8f73a0eb12..a5e584b60dcd 100644 --- a/sound/usb/validate.c +++ b/sound/usb/validate.c @@ -75,7 +75,7 @@ static bool validate_processing_unit(const void *p,
if (d->bLength < sizeof(*d))
^^^^^^^^^^^^^^^^^^^^^^^ So we know that d->bLength is >= 10.
return false;
- len = d->bLength < sizeof(*d) + d->bNrInPins;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Len is 1 or 0.
- len = sizeof(*d) + d->bNrInPins; if (d->bLength < len)
^^^^^^^^^^^^^^^^
So this condition can't be false.
return false;
But it just makes this return into dead code and we have a lot of dead code paths in the kernel so it doesn't make sense to generate a warning. ... I don't know if I have a solution.
Maybe some day we will have a vim pluggin which will highlight all the dead paths and someone would notice that it that way.
regards, dan carpenter
On Mon, 28 Oct 2019 15:34:06 +0100, Dan Carpenter wrote:
I wish that this could have been detected with static analysis...
On Tue, Oct 22, 2019 at 05:45:14PM +0200, Takashi Iwai wrote:
diff --git a/sound/usb/validate.c b/sound/usb/validate.c index 3c8f73a0eb12..a5e584b60dcd 100644 --- a/sound/usb/validate.c +++ b/sound/usb/validate.c @@ -75,7 +75,7 @@ static bool validate_processing_unit(const void *p,
if (d->bLength < sizeof(*d))
^^^^^^^^^^^^^^^^^^^^^^^So we know that d->bLength is >= 10.
return false;
- len = d->bLength < sizeof(*d) + d->bNrInPins;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^Len is 1 or 0.
- len = sizeof(*d) + d->bNrInPins; if (d->bLength < len)
^^^^^^^^^^^^^^^^So this condition can't be false.
return false;But it just makes this return into dead code and we have a lot of dead code paths in the kernel so it doesn't make sense to generate a warning. ... I don't know if I have a solution.
Maybe some day we will have a vim pluggin which will highlight all the dead paths and someone would notice that it that way.
That'd be awesome :) Of even a simple checker code that can run in the git commit hook should suffice for careless maintainers like me.
thanks,
Takashi
participants (3)
-
Dan Carpenter -
syzbot -
Takashi Iwai