Date:   Mon, 18 Sep 2017 19:22:24 +0200
From:   Andrey Konovalov <andreyknvl@...gle.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jaejoong Kim <climbbb.kim@...il.com>,
        Jonathan Corbet <corbet@....net>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        USB list <linux-usb@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     syzkaller <syzkaller@...glegroups.com>,
        Kostya Serebryany <kcc@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>
Subject: usb/core: slab-out-of-bounds in usb_set_configuration

Hi!

I've got the following crash while fuzzing the kernel with syzkaller.

On commit ebb2c2437d8008d46796902ff390653822af6cc4 (Sep 18).

It seems there's no proper size check of a
USB_DT_INTERFACE_ASSOCIATION descriptor. It's only checked that the
size is >= 2 in usb_parse_configuration(), so find_iad() might do
out-of-bounds access to intf_assoc->bInterfaceCount.

gadgetfs: bound to dummy_udc driver
usb 1-1: new full-speed USB device number 2 using dummy_hcd
gadgetfs: connected
gadgetfs: disconnected
gadgetfs: connected
usb 1-1: config 1 interface 0 altsetting 0 has an invalid endpoint
with address 0x0, skipping
usb 1-1: New USB device found, idVendor=0020, idProduct=410e
usb 1-1: New USB device strings: Mfr=0, Product=8, SerialNumber=3
usb 1-1: Product: a
usb 1-1: SerialNumber: a
==================================================================
BUG: KASAN: slab-out-of-bounds in usb_set_configuration+0x1859/0x1870
Read of size 1 at addr ffff88006a9d00de by task kworker/0:2/1260

CPU: 0 PID: 1260 Comm: kworker/0:2 Not tainted
4.14.0-rc1-42251-gebb2c2437d80 #169
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
 find_iad drivers/usb/core/message.c:1644
 usb_set_configuration+0x1859/0x1870 drivers/usb/core/message.c:1855
 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 1260:
 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 2870:
 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
 load_elf_binary+0x39c2/0x4fa0 fs/binfmt_elf.c:1087
 search_binary_handler+0x146/0x480 fs/exec.c:1634
 exec_binprm fs/exec.c:1676
 do_execveat_common.isra.31+0x16d2/0x2200 fs/exec.c:1798
 do_execve fs/exec.c:1842
 SYSC_execve fs/exec.c:1923
 SyS_execve+0x3e/0x50 fs/exec.c:1918
 do_syscall_64+0x2c5/0x830 arch/x86/entry/common.c:287
 return_from_SYSCALL_64+0x0/0x7a arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff88006a9d00c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 30 bytes inside of
 32-byte region [ffff88006a9d00c0, ffff88006a9d00e0)
The buggy address belongs to the page:
page:ffffea0001aa7400 count:1 mapcount:0 mapping:          (null)
index:0xffff88006a9d05a0
flags: 0x100000000000100(slab)
raw: 0100000000000100 0000000000000000 ffff88006a9d05a0 0000000180550054
raw: ffffea000193fa00 0000001400000014 ffff88006c403980 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88006a9cff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88006a9d0000: fb fb fb fb fc fc fb fb fb fb fc fc fb fb fb fb
>ffff88006a9d0080: fc fc fb fb fb fb fc fc 00 00 00 05 fc fc fb fb
                                                    ^
 ffff88006a9d0100: fb fb fc fc fb fb fb fb fc fc fb fb fb fb fc fc
 ffff88006a9d0180: 00 00 00 00 fc fc 00 00 00 00 fc fc fb fb fb fb
==================================================================

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