[alsa-devel] general protection fault in snd_usb_create_mixer
Hello,
syzbot found the following crash on:
HEAD commit: 46178223 usb: gadget: add raw-gadget interface git tree: https://github.com/google/kasan.git usb-fuzzer console output: https://syzkaller.appspot.com/x/log.txt?x=176f9836e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=99c88c44660624e7 dashboard link: https://syzkaller.appspot.com/bug?extid=a36ab65c6653d7ccdd62 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1447d3bae00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17ef3a86e00000
IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a36ab65c6653d7ccdd62@syzkaller.appspotmail.com
usb 1-1: 208:241 : does not exist usb 1-1: 208:242 : does not exist usb 1-1: 208:243 : does not exist usb 1-1: 208:244 : does not exist usb 1-1: 208:245 : does not exist usb 1-1: 208:246 : does not exist usb 1-1: 208:247 : does not exist usb 1-1: 208:248 : does not exist usb 1-1: 208:249 : does not exist usb 1-1: 208:250 : does not exist kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN CPU: 1 PID: 22 Comm: kworker/1:1 Not tainted 5.4.0-rc6+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usb_hub_wq hub_event RIP: 0010:snd_usb_mixer_controls_badd sound/usb/mixer.c:2931 [inline] RIP: 0010:snd_usb_create_mixer+0xbb9/0x1890 sound/usb/mixer.c:3441 Code: ee e8 9b 23 a6 fc 41 39 ee 74 a4 e8 a1 22 a6 fc 48 8b 7c 24 28 89 ee e8 25 59 b4 fe 48 8d 78 10 48 89 c3 48 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 74 08 3c 03 0f 8e 2f 09 00 00 8b 6b 10 bf 01 RSP: 0018:ffff8881d932f0a0 EFLAGS: 00010202 RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff834c5dac RDX: 0000000000000000 RSI: ffffffff834c5e1b RDI: 0000000000000010 RBP: 0000000000000021 R08: ffff8881da24e000 R09: fffffbfff11aadb5 R10: fffffbfff11aadb4 R11: ffffffff88d56da7 R12: 00000000000000da R13: dffffc0000000000 R14: 00000000000000d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000043f100 CR3: 0000000006c21000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: 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:2202 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:2202 usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2537 hub_port_connect drivers/usb/core/hub.c:5184 [inline] hub_port_connect_change drivers/usb/core/hub.c:5324 [inline] port_event drivers/usb/core/hub.c:5470 [inline] hub_event+0x1df8/0x3800 drivers/usb/core/hub.c:5552 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 Modules linked in: ---[ end trace 1d30a29898ec11e8 ]--- RIP: 0010:snd_usb_mixer_controls_badd sound/usb/mixer.c:2931 [inline] RIP: 0010:snd_usb_create_mixer+0xbb9/0x1890 sound/usb/mixer.c:3441 Code: ee e8 9b 23 a6 fc 41 39 ee 74 a4 e8 a1 22 a6 fc 48 8b 7c 24 28 89 ee e8 25 59 b4 fe 48 8d 78 10 48 89 c3 48 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 74 08 3c 03 0f 8e 2f 09 00 00 8b 6b 10 bf 01 RSP: 0018:ffff8881d932f0a0 EFLAGS: 00010202 RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff834c5dac RDX: 0000000000000000 RSI: ffffffff834c5e1b RDI: 0000000000000010 RBP: 0000000000000021 R08: ffff8881da24e000 R09: fffffbfff11aadb5 R10: fffffbfff11aadb4 R11: ffffffff88d56da7 R12: 00000000000000da R13: dffffc0000000000 R14: 00000000000000d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000043f100 CR3: 0000000006c21000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
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On Thu, Nov 21, 2019 at 07:25:09AM -0800, syzbot wrote:
Hello,
syzbot found the following crash on:
HEAD commit: 46178223 usb: gadget: add raw-gadget interface git tree: https://github.com/google/kasan.git usb-fuzzer console output: https://syzkaller.appspot.com/x/log.txt?x=176f9836e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=99c88c44660624e7 dashboard link: https://syzkaller.appspot.com/bug?extid=a36ab65c6653d7ccdd62 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1447d3bae00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17ef3a86e00000
IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a36ab65c6653d7ccdd62@syzkaller.appspotmail.com
usb 1-1: 208:241 : does not exist usb 1-1: 208:242 : does not exist usb 1-1: 208:243 : does not exist usb 1-1: 208:244 : does not exist usb 1-1: 208:245 : does not exist usb 1-1: 208:246 : does not exist usb 1-1: 208:247 : does not exist usb 1-1: 208:248 : does not exist usb 1-1: 208:249 : does not exist usb 1-1: 208:250 : does not exist
These error messages are because:
sound/usb/card.c 128 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface) 129 { 130 struct usb_device *dev = chip->dev; 131 struct usb_host_interface *alts; 132 struct usb_interface_descriptor *altsd; 133 struct usb_interface *iface = usb_ifnum_to_if(dev, interface); 134 135 if (!iface) { 136 dev_err(&dev->dev, "%u:%d : does not exist\n", 137 ctrlif, interface); 138 return -EINVAL; 139 }
"iface" is NULL. The caller ignores the -EINVAL (correctly I think).
Then the NULL dereference happens in snd_usb_mixer_controls_badd()
sound/usb/mixer.c 2903 static int snd_usb_mixer_controls_badd(struct usb_mixer_interface *mixer, 2904 int ctrlif) 2905 { 2906 struct usb_device *dev = mixer->chip->dev; 2907 struct usb_interface_assoc_descriptor *assoc; 2908 int badd_profile = mixer->chip->badd_profile; 2909 struct uac3_badd_profile *f; 2910 const struct usbmix_ctl_map *map; 2911 int p_chmask = 0, c_chmask = 0, st_chmask = 0; 2912 int i; 2913 2914 assoc = usb_ifnum_to_if(dev, ctrlif)->intf_assoc; 2915 2916 /* Detect BADD capture/playback channels from AS EP descriptors */ 2917 for (i = 0; i < assoc->bInterfaceCount; i++) { 2918 int intf = assoc->bFirstInterface + i; 2919 2920 struct usb_interface *iface; 2921 struct usb_host_interface *alts; 2922 struct usb_interface_descriptor *altsd; 2923 unsigned int maxpacksize; 2924 char dir_in; 2925 int chmask, num; 2926 2927 if (intf == ctrlif) 2928 continue; 2929 2930 iface = usb_ifnum_to_if(dev, intf); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ iface is not checked.
Should it be "if (!iface) continue;?"
2931 num = iface->num_altsetting; 2932 2933 if (num < 2) 2934 return -EINVAL; 2935
I'm not sure.
regards, dan carpenter
On Thu, 21 Nov 2019 21:49:56 +0100, Dan Carpenter wrote:
On Thu, Nov 21, 2019 at 07:25:09AM -0800, syzbot wrote:
Hello,
syzbot found the following crash on:
HEAD commit: 46178223 usb: gadget: add raw-gadget interface git tree: https://github.com/google/kasan.git usb-fuzzer console output: https://syzkaller.appspot.com/x/log.txt?x=176f9836e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=99c88c44660624e7 dashboard link: https://syzkaller.appspot.com/bug?extid=a36ab65c6653d7ccdd62 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1447d3bae00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17ef3a86e00000
IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a36ab65c6653d7ccdd62@syzkaller.appspotmail.com
usb 1-1: 208:241 : does not exist usb 1-1: 208:242 : does not exist usb 1-1: 208:243 : does not exist usb 1-1: 208:244 : does not exist usb 1-1: 208:245 : does not exist usb 1-1: 208:246 : does not exist usb 1-1: 208:247 : does not exist usb 1-1: 208:248 : does not exist usb 1-1: 208:249 : does not exist usb 1-1: 208:250 : does not exist
These error messages are because:
sound/usb/card.c 128 static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int interface) 129 { 130 struct usb_device *dev = chip->dev; 131 struct usb_host_interface *alts; 132 struct usb_interface_descriptor *altsd; 133 struct usb_interface *iface = usb_ifnum_to_if(dev, interface); 134 135 if (!iface) { 136 dev_err(&dev->dev, "%u:%d : does not exist\n", 137 ctrlif, interface); 138 return -EINVAL; 139 }
"iface" is NULL. The caller ignores the -EINVAL (correctly I think).
Then the NULL dereference happens in snd_usb_mixer_controls_badd()
sound/usb/mixer.c 2903 static int snd_usb_mixer_controls_badd(struct usb_mixer_interface *mixer, 2904 int ctrlif) 2905 { 2906 struct usb_device *dev = mixer->chip->dev; 2907 struct usb_interface_assoc_descriptor *assoc; 2908 int badd_profile = mixer->chip->badd_profile; 2909 struct uac3_badd_profile *f; 2910 const struct usbmix_ctl_map *map; 2911 int p_chmask = 0, c_chmask = 0, st_chmask = 0; 2912 int i; 2913 2914 assoc = usb_ifnum_to_if(dev, ctrlif)->intf_assoc; 2915 2916 /* Detect BADD capture/playback channels from AS EP descriptors */ 2917 for (i = 0; i < assoc->bInterfaceCount; i++) { 2918 int intf = assoc->bFirstInterface + i; 2919 2920 struct usb_interface *iface; 2921 struct usb_host_interface *alts; 2922 struct usb_interface_descriptor *altsd; 2923 unsigned int maxpacksize; 2924 char dir_in; 2925 int chmask, num; 2926 2927 if (intf == ctrlif) 2928 continue; 2929 2930 iface = usb_ifnum_to_if(dev, intf); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ iface is not checked.
Should it be "if (!iface) continue;?"
Right, that should fix the problem. Although the interface number referred in snd_usb_mixer_controls_badd() can be different from the one checked in snd_usb_create_stream(), the culprit is the missing NULL check there.
thanks,
Takashi
participants (3)
-
Dan Carpenter -
syzbot -
Takashi Iwai