releases/4.13.6/alsa-usb-audio-check-out-of-bounds-access-by-corrupted-buffer-descriptor.patch

   1 From bfc81a8bc18e3c4ba0cbaa7666ff76be2f998991 Mon Sep 17 00:00:00 2001
   2 From: Takashi Iwai <tiwai@suse.de>
   3 Date: Fri, 22 Sep 2017 16:18:53 +0200
   4 Subject: ALSA: usb-audio: Check out-of-bounds access by corrupted buffer descriptor
   5
   6 From: Takashi Iwai <tiwai@suse.de>
   7
   8 commit bfc81a8bc18e3c4ba0cbaa7666ff76be2f998991 upstream.
   9
  10 When a USB-audio device receives a maliciously adjusted or corrupted
  11 buffer descriptor, the USB-audio driver may access an out-of-bounce
  12 value at its parser.  This was detected by syzkaller, something like:
  13
  14   BUG: KASAN: slab-out-of-bounds in usb_audio_probe+0x27b2/0x2ab0
  15   Read of size 1 at addr ffff88006b83a9e8 by task kworker/0:1/24
  16   CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.14.0-rc1-42251-gebb2c2437d80 #224
  17   Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  18   Workqueue: usb_hub_wq hub_event
  19   Call Trace:
  20    __dump_stack lib/dump_stack.c:16
  21    dump_stack+0x292/0x395 lib/dump_stack.c:52
  22    print_address_description+0x78/0x280 mm/kasan/report.c:252
  23    kasan_report_error mm/kasan/report.c:351
  24    kasan_report+0x22f/0x340 mm/kasan/report.c:409
  25    __asan_report_load1_noabort+0x19/0x20 mm/kasan/report.c:427
  26    snd_usb_create_streams sound/usb/card.c:248
  27    usb_audio_probe+0x27b2/0x2ab0 sound/usb/card.c:605
  28    usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361
  29    really_probe drivers/base/dd.c:413
  30    driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
  31    __device_attach_driver+0x230/0x290 drivers/base/dd.c:653
  32    bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
  33    __device_attach+0x26e/0x3d0 drivers/base/dd.c:710
  34    device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
  35    bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
  36    device_add+0xd0b/0x1660 drivers/base/core.c:1835
  37    usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932
  38    generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
  39    usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
  40    really_probe drivers/base/dd.c:413
  41    driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
  42    __device_attach_driver+0x230/0x290 drivers/base/dd.c:653
  43    bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
  44    __device_attach+0x26e/0x3d0 drivers/base/dd.c:710
  45    device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
  46    bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
  47    device_add+0xd0b/0x1660 drivers/base/core.c:1835
  48    usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457
  49    hub_port_connect drivers/usb/core/hub.c:4903
  50    hub_port_connect_change drivers/usb/core/hub.c:5009
  51    port_event drivers/usb/core/hub.c:5115
  52    hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195
  53    process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119
  54    worker_thread+0x221/0x1850 kernel/workqueue.c:2253
  55    kthread+0x3a1/0x470 kernel/kthread.c:231
  56    ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
  57
  58 This patch adds the checks of out-of-bounce accesses at appropriate
  59 places and bails out when it goes out of the given buffer.
  60
  61 Reported-by: Andrey Konovalov <andreyknvl@google.com>
  62 Tested-by: Andrey Konovalov <andreyknvl@google.com>
  63 Signed-off-by: Takashi Iwai <tiwai@suse.de>
  64 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  65
  66 ---
  67  sound/usb/card.c |   20 ++++++++++++++++++++
  68  1 file changed, 20 insertions(+)
  69
  70 --- a/sound/usb/card.c
  71 +++ b/sound/usb/card.c
  72 @@ -221,6 +221,7 @@ static int snd_usb_create_streams(struct
  73         struct usb_interface_descriptor *altsd;
  74         void *control_header;
  75         int i, protocol;
  76 +       int rest_bytes;
  77
  78         /* find audiocontrol interface */
  79         host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
  80 @@ -235,6 +236,15 @@ static int snd_usb_create_streams(struct
  81                 return -EINVAL;
  82         }
  83
  84 +       rest_bytes = (void *)(host_iface->extra + host_iface->extralen) -
  85 +               control_header;
  86 +
  87 +       /* just to be sure -- this shouldn't hit at all */
  88 +       if (rest_bytes <= 0) {
  89 +               dev_err(&dev->dev, "invalid control header\n");
  90 +               return -EINVAL;
  91 +       }
  92 +
  93         switch (protocol) {
  94         default:
  95                 dev_warn(&dev->dev,
  96 @@ -245,11 +255,21 @@ static int snd_usb_create_streams(struct
  97         case UAC_VERSION_1: {
  98                 struct uac1_ac_header_descriptor *h1 = control_header;
  99
 100 +               if (rest_bytes < sizeof(*h1)) {
 101 +                       dev_err(&dev->dev, "too short v1 buffer descriptor\n");
 102 +                       return -EINVAL;
 103 +               }
 104 +
 105                 if (!h1->bInCollection) {
 106                         dev_info(&dev->dev, "skipping empty audio interface (v1)\n");
 107                         return -EINVAL;
 108                 }
 109
 110 +               if (rest_bytes < h1->bLength) {
 111 +                       dev_err(&dev->dev, "invalid buffer length (v1)\n");
 112 +                       return -EINVAL;
 113 +               }
 114 +
 115                 if (h1->bLength < sizeof(*h1) + h1->bInCollection) {
 116                         dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n");
 117                         return -EINVAL;