Re: KASAN: slab-out-of-bounds Read in hdpvr_probe

From: syzbot
Date: Mon Jul 01 2019 - 18:30:10 EST

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syzbot has found a reproducer for the following crash on:

HEAD commit: 7829a896 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=17242ab3a00000
kernel config: https://syzkaller.appspot.com/x/.config?x=f6d4561982f71f63
dashboard link: https://syzkaller.appspot.com/bug?extid=79d18aac4bf1770dd050
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14740905a00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=133fd90ba00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+79d18aac4bf1770dd050@xxxxxxxxxxxxxxxxxxxxxxxxx

usb 1-1: config 0 interface 200 altsetting 0 bulk endpoint 0x84 has invalid maxpacket 0
usb 1-1: New USB device found, idVendor=2040, idProduct=4982, bcdDevice=f9.cf
usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 1-1: config 0 descriptor??
==================================================================
BUG: KASAN: slab-out-of-bounds in string_nocheck+0x1d2/0x200 lib/vsprintf.c:605
Read of size 1 at addr ffff8881c65ea220 by task kworker/1:1/22

CPU: 1 PID: 22 Comm: kworker/1:1 Not tainted 5.2.0-rc6+ #13
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+0x67/0x231 mm/kasan/report.c:188
__kasan_report.cold+0x1a/0x32 mm/kasan/report.c:317
kasan_report+0xe/0x20 mm/kasan/common.c:614
string_nocheck+0x1d2/0x200 lib/vsprintf.c:605
string+0xe5/0xf0 lib/vsprintf.c:668
vsnprintf+0x7d3/0x14f0 lib/vsprintf.c:2503
vscnprintf+0x29/0x80 lib/vsprintf.c:2606
vprintk_store+0x40/0x4b0 kernel/printk/printk.c:1907
vprintk_emit+0xc8/0x3e0 kernel/printk/printk.c:1968
vprintk_func+0x75/0x113 kernel/printk/printk_safe.c:386
printk+0xba/0xed kernel/printk/printk.c:2046
device_authorization drivers/media/usb/hdpvr/hdpvr-core.c:140 [inline]
hdpvr_device_init drivers/media/usb/hdpvr/hdpvr-core.c:201 [inline]
hdpvr_probe.cold+0x194/0x1247 drivers/media/usb/hdpvr/hdpvr-core.c:342
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
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+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
usb_new_device.cold+0x8c1/0x1016 drivers/usb/core/hub.c:2534
hub_port_connect drivers/usb/core/hub.c:5089 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
port_event drivers/usb/core/hub.c:5350 [inline]
hub_event+0x1ada/0x3590 drivers/usb/core/hub.c:5432
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 22:
save_stack+0x1b/0x80 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_kmalloc mm/kasan/common.c:489 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:462
kmalloc include/linux/slab.h:547 [inline]
hdpvr_probe+0x1ce/0xac0 drivers/media/usb/hdpvr/hdpvr-core.c:297
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
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+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
usb_new_device.cold+0x8c1/0x1016 drivers/usb/core/hub.c:2534
hub_port_connect drivers/usb/core/hub.c:5089 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
port_event drivers/usb/core/hub.c:5350 [inline]
hub_event+0x1ada/0x3590 drivers/usb/core/hub.c:5432
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8881c65ea1e0
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes to the right of
64-byte region [ffff8881c65ea1e0, ffff8881c65ea220)
The buggy address belongs to the page:
page:ffffea0007197a80 refcount:1 mapcount:0 mapping:ffff8881dac03600 index:0x0
flags: 0x200000000000200(slab)
raw: 0200000000000200 dead000000000100 dead000000000200 ffff8881dac03600
raw: 0000000000000000 00000000802a002a 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881c65ea100: fc fc fc fc fb fb fb fb fb fb fb fb fc fc fc fc
ffff8881c65ea180: fb fb fb fb fb fb fb fb fc fc fc fc 00 00 00 00

ffff8881c65ea200: 00 00 00 00 fc fc fc fc fb fb fb fb fb fb fb fb

^
ffff8881c65ea280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881c65ea300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Next message: Thomas Gleixner: "[BUG] kvm: APIC emulation problem - was Re: [LKP] [x86/hotplug] ..."
Previous message: Olof Johansson: "Re: [PATCH] soc: ti: fix irq-ti-sci link error"
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