* usb/sounds: slab-out-of-bounds read in snd_usb_create_streams
@ 2017-09-22 12:56 Andrey Konovalov
2017-09-22 13:19 ` Takashi Iwai
0 siblings, 1 reply; 4+ messages in thread
From: Andrey Konovalov @ 2017-09-22 12:56 UTC (permalink / raw)
To: Jaroslav Kysela, Takashi Iwai, Arvind Yadav, alsa-devel, LKML
Cc: Dmitry Vyukov, Kostya Serebryany, syzkaller
Hi!
I've got the following report while fuzzing the kernel with syzkaller.
On commit ebb2c2437d8008d46796902ff390653822af6cc4 (Sep 18).
It seems that there's no check that control_header has enough space
for uac1_ac_header_descriptor in snd_usb_create_streams().
==================================================================
BUG: KASAN: slab-out-of-bounds in usb_audio_probe+0x27b2/0x2ab0
Read of size 1 at addr ffff88006b83a9e8 by task kworker/0:1/24
CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.14.0-rc1-42251-gebb2c2437d80 #224
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:16
dump_stack+0x292/0x395 lib/dump_stack.c:52
print_address_description+0x78/0x280 mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351
kasan_report+0x22f/0x340 mm/kasan/report.c:409
__asan_report_load1_noabort+0x19/0x20 mm/kasan/report.c:427
snd_usb_create_streams sound/usb/card.c:248
usb_audio_probe+0x27b2/0x2ab0 sound/usb/card.c:605
usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361
really_probe drivers/base/dd.c:413
driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
__device_attach_driver+0x230/0x290 drivers/base/dd.c:653
bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
__device_attach+0x26e/0x3d0 drivers/base/dd.c:710
device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
device_add+0xd0b/0x1660 drivers/base/core.c:1835
usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932
generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
really_probe drivers/base/dd.c:413
driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
__device_attach_driver+0x230/0x290 drivers/base/dd.c:653
bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
__device_attach+0x26e/0x3d0 drivers/base/dd.c:710
device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
device_add+0xd0b/0x1660 drivers/base/core.c:1835
usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457
hub_port_connect drivers/usb/core/hub.c:4903
hub_port_connect_change drivers/usb/core/hub.c:5009
port_event drivers/usb/core/hub.c:5115
hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195
process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119
worker_thread+0x221/0x1850 kernel/workqueue.c:2253
kthread+0x3a1/0x470 kernel/kthread.c:231
ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
Allocated by task 24:
save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459
kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
__kmalloc+0x14e/0x310 mm/slub.c:3782
kmalloc ./include/linux/slab.h:498
usb_get_configuration+0x372/0x2a60 drivers/usb/core/config.c:848
usb_enumerate_device drivers/usb/core/hub.c:2290
usb_new_device+0xaae/0x1020 drivers/usb/core/hub.c:2426
hub_port_connect drivers/usb/core/hub.c:4903
hub_port_connect_change drivers/usb/core/hub.c:5009
port_event drivers/usb/core/hub.c:5115
hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195
process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119
worker_thread+0x221/0x1850 kernel/workqueue.c:2253
kthread+0x3a1/0x470 kernel/kthread.c:231
ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
Freed by task 4048:
save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459
kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:524
slab_free_hook mm/slub.c:1390
slab_free_freelist_hook mm/slub.c:1412
slab_free mm/slub.c:2988
kfree+0xf6/0x2f0 mm/slub.c:3919
free_rb_tree_fname+0x8a/0xe0 fs/ext4/dir.c:402
ext4_htree_free_dir_info fs/ext4/dir.c:424
ext4_release_dir+0x49/0x70 fs/ext4/dir.c:622
__fput+0x33e/0x800 fs/file_table.c:210
____fput+0x1a/0x20 fs/file_table.c:244
task_work_run+0x1af/0x280 kernel/task_work.c:112
tracehook_notify_resume ./include/linux/tracehook.h:191
exit_to_usermode_loop+0x1e1/0x220 arch/x86/entry/common.c:162
prepare_exit_to_usermode arch/x86/entry/common.c:197
syscall_return_slowpath+0x414/0x480 arch/x86/entry/common.c:266
entry_SYSCALL_64_fastpath+0xc0/0xc2 arch/x86/entry/entry_64.S:238
The buggy address belongs to the object at ffff88006b83a9c0
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 40 bytes inside of
64-byte region [ffff88006b83a9c0, ffff88006b83aa00)
The buggy address belongs to the page:
page:ffffea0001ae0e80 count:1 mapcount:0 mapping: (null) index:0x0
flags: 0x100000000000100(slab)
raw: 0100000000000100 0000000000000000 0000000000000000 00000001802a002a
raw: 0000000000000000 0000000100000001 ffff88006c403800 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88006b83a880: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
ffff88006b83a900: fb fb fb fb fb fb fb fb fc fc fc fc 00 00 00 00
>ffff88006b83a980: 00 00 fc fc fc fc fc fc 00 00 00 00 07 fc fc fc
^
ffff88006b83aa00: fc fc fc fc 00 00 00 00 00 00 00 00 fc fc fc fc
ffff88006b83aa80: 00 00 00 00 00 00 00 00 fc fc fc fc 00 00 00 00
==================================================================
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: usb/sounds: slab-out-of-bounds read in snd_usb_create_streams 2017-09-22 12:56 usb/sounds: slab-out-of-bounds read in snd_usb_create_streams Andrey Konovalov @ 2017-09-22 13:19 ` Takashi Iwai 2017-09-22 13:55 ` Andrey Konovalov 0 siblings, 1 reply; 4+ messages in thread From: Takashi Iwai @ 2017-09-22 13:19 UTC (permalink / raw) To: Andrey Konovalov Cc: alsa-devel, Arvind Yadav, Jaroslav Kysela, LKML, Dmitry Vyukov, Kostya Serebryany, syzkaller On Fri, 22 Sep 2017 14:56:06 +0200, Andrey Konovalov wrote: > > Hi! > > I've got the following report while fuzzing the kernel with syzkaller. > > On commit ebb2c2437d8008d46796902ff390653822af6cc4 (Sep 18). > > It seems that there's no check that control_header has enough space > for uac1_ac_header_descriptor in snd_usb_create_streams(). Indeed, this might be an issue. Does the patch below fix the problem? Takashi --- diff --git a/sound/usb/card.c b/sound/usb/card.c index 3dc36d913550..fc969efbb37c 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -221,6 +221,7 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) struct usb_interface_descriptor *altsd; void *control_header; int i, protocol; + int rest_bytes; /* find audiocontrol interface */ host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0]; @@ -235,6 +236,13 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) return -EINVAL; } + rest_bytes = (void *)(host_iface->extra + host_iface->extralen) - + control_header; + if (rest_bytes <= 0) { + dev_err(&dev->dev, "invalid control header\n"); + return -EINVAL; + } + switch (protocol) { default: dev_warn(&dev->dev, @@ -245,11 +253,21 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) case UAC_VERSION_1: { struct uac1_ac_header_descriptor *h1 = control_header; + if (rest_bytes < sizeof(*h1)) { + dev_err(&dev->dev, "too short v1 buffer descriptor\n"); + return -EINVAL; + } + if (!h1->bInCollection) { dev_info(&dev->dev, "skipping empty audio interface (v1)\n"); return -EINVAL; } + if (rest_bytes < h1->bLength) { + dev_err(&dev->dev, "invalid buffer length (v1)\n"); + return -EINVAL; + } + if (h1->bLength < sizeof(*h1) + h1->bInCollection) { dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n"); return -EINVAL; ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: usb/sounds: slab-out-of-bounds read in snd_usb_create_streams 2017-09-22 13:19 ` Takashi Iwai @ 2017-09-22 13:55 ` Andrey Konovalov 2017-09-22 14:25 ` Takashi Iwai 0 siblings, 1 reply; 4+ messages in thread From: Andrey Konovalov @ 2017-09-22 13:55 UTC (permalink / raw) To: Takashi Iwai Cc: alsa-devel, Arvind Yadav, Jaroslav Kysela, LKML, Dmitry Vyukov, Kostya Serebryany, syzkaller On Fri, Sep 22, 2017 at 3:19 PM, Takashi Iwai <tiwai@suse.de> wrote: > On Fri, 22 Sep 2017 14:56:06 +0200, > Andrey Konovalov wrote: >> >> Hi! >> >> I've got the following report while fuzzing the kernel with syzkaller. >> >> On commit ebb2c2437d8008d46796902ff390653822af6cc4 (Sep 18). >> >> It seems that there's no check that control_header has enough space >> for uac1_ac_header_descriptor in snd_usb_create_streams(). > > Indeed, this might be an issue. > Does the patch below fix the problem? I believe it does. It does fix the crash with my reproducer. I'm not sure if the (rest_bytes <= 0) check is actually needed though. It seems that if snd_usb_find_csint_desc() returns a non-null value, it'll always be within the buffer. Tested-by: Andrey Konovalov <andreyknvl@google.com> > > > Takashi > > --- > diff --git a/sound/usb/card.c b/sound/usb/card.c > index 3dc36d913550..fc969efbb37c 100644 > --- a/sound/usb/card.c > +++ b/sound/usb/card.c > @@ -221,6 +221,7 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) > struct usb_interface_descriptor *altsd; > void *control_header; > int i, protocol; > + int rest_bytes; > > /* find audiocontrol interface */ > host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0]; > @@ -235,6 +236,13 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) > return -EINVAL; > } > > + rest_bytes = (void *)(host_iface->extra + host_iface->extralen) - > + control_header; > + if (rest_bytes <= 0) { > + dev_err(&dev->dev, "invalid control header\n"); > + return -EINVAL; > + } > + > switch (protocol) { > default: > dev_warn(&dev->dev, > @@ -245,11 +253,21 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) > case UAC_VERSION_1: { > struct uac1_ac_header_descriptor *h1 = control_header; > > + if (rest_bytes < sizeof(*h1)) { > + dev_err(&dev->dev, "too short v1 buffer descriptor\n"); > + return -EINVAL; > + } > + > if (!h1->bInCollection) { > dev_info(&dev->dev, "skipping empty audio interface (v1)\n"); > return -EINVAL; > } > > + if (rest_bytes < h1->bLength) { > + dev_err(&dev->dev, "invalid buffer length (v1)\n"); > + return -EINVAL; > + } > + > if (h1->bLength < sizeof(*h1) + h1->bInCollection) { > dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n"); > return -EINVAL; > > -- > You received this message because you are subscribed to the Google Groups "syzkaller" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller+unsubscribe@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: usb/sounds: slab-out-of-bounds read in snd_usb_create_streams 2017-09-22 13:55 ` Andrey Konovalov @ 2017-09-22 14:25 ` Takashi Iwai 0 siblings, 0 replies; 4+ messages in thread From: Takashi Iwai @ 2017-09-22 14:25 UTC (permalink / raw) To: Andrey Konovalov Cc: alsa-devel, Arvind Yadav, Jaroslav Kysela, LKML, Dmitry Vyukov, Kostya Serebryany, syzkaller On Fri, 22 Sep 2017 15:55:17 +0200, Andrey Konovalov wrote: > > On Fri, Sep 22, 2017 at 3:19 PM, Takashi Iwai <tiwai@suse.de> wrote: > > On Fri, 22 Sep 2017 14:56:06 +0200, > > Andrey Konovalov wrote: > >> > >> Hi! > >> > >> I've got the following report while fuzzing the kernel with syzkaller. > >> > >> On commit ebb2c2437d8008d46796902ff390653822af6cc4 (Sep 18). > >> > >> It seems that there's no check that control_header has enough space > >> for uac1_ac_header_descriptor in snd_usb_create_streams(). > > > > Indeed, this might be an issue. > > Does the patch below fix the problem? > > I believe it does. It does fix the crash with my reproducer. > > I'm not sure if the (rest_bytes <= 0) check is actually needed though. It's superfluous, but safer is safer, and this check is cheap. > It seems that if snd_usb_find_csint_desc() returns a non-null value, > it'll always be within the buffer. > > Tested-by: Andrey Konovalov <andreyknvl@google.com> Thanks, I'm going to queue it. FWIW, below is the official patch. Takashi -- 8< -- From: Takashi Iwai <tiwai@suse.de> Subject: [PATCH] ALSA: usb-audio: Check out-of-bounds access by corrupted buffer descriptor When a USB-audio device receives a maliciously adjusted or corrupted buffer descriptor, the USB-audio driver may access an out-of-bounce value at its parser. This was detected by syzkaller, something like: BUG: KASAN: slab-out-of-bounds in usb_audio_probe+0x27b2/0x2ab0 Read of size 1 at addr ffff88006b83a9e8 by task kworker/0:1/24 CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.14.0-rc1-42251-gebb2c2437d80 #224 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: usb_hub_wq hub_event Call Trace: __dump_stack lib/dump_stack.c:16 dump_stack+0x292/0x395 lib/dump_stack.c:52 print_address_description+0x78/0x280 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 kasan_report+0x22f/0x340 mm/kasan/report.c:409 __asan_report_load1_noabort+0x19/0x20 mm/kasan/report.c:427 snd_usb_create_streams sound/usb/card.c:248 usb_audio_probe+0x27b2/0x2ab0 sound/usb/card.c:605 usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361 really_probe drivers/base/dd.c:413 driver_probe_device+0x610/0xa00 drivers/base/dd.c:557 __device_attach_driver+0x230/0x290 drivers/base/dd.c:653 bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463 __device_attach+0x26e/0x3d0 drivers/base/dd.c:710 device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523 device_add+0xd0b/0x1660 drivers/base/core.c:1835 usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932 generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174 usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266 really_probe drivers/base/dd.c:413 driver_probe_device+0x610/0xa00 drivers/base/dd.c:557 __device_attach_driver+0x230/0x290 drivers/base/dd.c:653 bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463 __device_attach+0x26e/0x3d0 drivers/base/dd.c:710 device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523 device_add+0xd0b/0x1660 drivers/base/core.c:1835 usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457 hub_port_connect drivers/usb/core/hub.c:4903 hub_port_connect_change drivers/usb/core/hub.c:5009 port_event drivers/usb/core/hub.c:5115 hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195 process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119 worker_thread+0x221/0x1850 kernel/workqueue.c:2253 kthread+0x3a1/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 This patch adds the checks of out-of-bounce accesses at appropriate places and bails out when it goes out of the given buffer. Reported-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> --- sound/usb/card.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/sound/usb/card.c b/sound/usb/card.c index 3dc36d913550..23d1d23aefec 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -221,6 +221,7 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) struct usb_interface_descriptor *altsd; void *control_header; int i, protocol; + int rest_bytes; /* find audiocontrol interface */ host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0]; @@ -235,6 +236,15 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) return -EINVAL; } + rest_bytes = (void *)(host_iface->extra + host_iface->extralen) - + control_header; + + /* just to be sure -- this shouldn't hit at all */ + if (rest_bytes <= 0) { + dev_err(&dev->dev, "invalid control header\n"); + return -EINVAL; + } + switch (protocol) { default: dev_warn(&dev->dev, @@ -245,11 +255,21 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) case UAC_VERSION_1: { struct uac1_ac_header_descriptor *h1 = control_header; + if (rest_bytes < sizeof(*h1)) { + dev_err(&dev->dev, "too short v1 buffer descriptor\n"); + return -EINVAL; + } + if (!h1->bInCollection) { dev_info(&dev->dev, "skipping empty audio interface (v1)\n"); return -EINVAL; } + if (rest_bytes < h1->bLength) { + dev_err(&dev->dev, "invalid buffer length (v1)\n"); + return -EINVAL; + } + if (h1->bLength < sizeof(*h1) + h1->bInCollection) { dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n"); return -EINVAL; -- 2.14.1 ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-09-22 14:25 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-09-22 12:56 usb/sounds: slab-out-of-bounds read in snd_usb_create_streams Andrey Konovalov 2017-09-22 13:19 ` Takashi Iwai 2017-09-22 13:55 ` Andrey Konovalov 2017-09-22 14:25 ` Takashi Iwai
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