syzbot


KASAN: slab-out-of-bounds Read in dlfb_usb_probe

Status: upstream: reported C repro on 2020/03/16 21:47
Reported-by: syzbot+ed94135f896a14d75284@syzkaller.appspotmail.com
First crash: 925d, last: 831d

Cause bisection: introduced by (bisect log) :
commit f2c2e717642c66f7fe7e5dd69b2e8ff5849f4d10
Author: Andrey Konovalov <andreyknvl@google.com>
Date: Mon Feb 24 16:13:03 2020 +0000

  usb: gadget: add raw-gadget interface

Crash: KASAN: slab-out-of-bounds Read in dlfb_usb_probe (log)
Repro: C syz .config

Fix bisection: failed (bisect log)
duplicates (1):
Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
KASAN: slab-out-of-bounds Read in hex_string syz 2 1249d 1248d 0/24 closed as dup on 2020/03/18 15:46
Patch testing requests:
Created Duration User Patch Repo Result
2022/09/20 22:29 16m upstream OK log
2022/09/18 05:29 16m upstream OK log
2022/08/31 22:27 14m https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing error
2022/08/31 21:27 16m https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing error
2022/08/30 18:27 20m upstream OK log

Sample crash report:
usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1: Product: syz
usb 1-1: Manufacturer: syz
usb 1-1: SerialNumber: syz
usb 1-1: config 0 descriptor??
==================================================================
BUG: KASAN: slab-out-of-bounds in hex_string+0x439/0x4c0 lib/vsprintf.c:1137
Read of size 1 at addr ffff8881d11554db by task kworker/0:2/94

CPU: 0 PID: 94 Comm: kworker/0:2 Not tainted 5.7.0-rc1-syzkaller #0
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+0xef/0x16e lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x314 mm/kasan/report.c:382
 __kasan_report.cold+0x37/0x92 mm/kasan/report.c:511
 kasan_report+0x33/0x50 mm/kasan/common.c:625
 hex_string+0x439/0x4c0 lib/vsprintf.c:1137
 pointer+0x45b/0x680 lib/vsprintf.c:2193
 vsnprintf+0x5ac/0x14f0 lib/vsprintf.c:2578
 va_format.isra.0+0x129/0x1b0 lib/vsprintf.c:1652
 pointer+0x4bf/0x680 lib/vsprintf.c:2221
 vsnprintf+0x5ac/0x14f0 lib/vsprintf.c:2578
 vscnprintf+0x29/0x80 lib/vsprintf.c:2677
 vprintk_store+0x40/0x4b0 kernel/printk/printk.c:1942
 vprintk_emit+0xc8/0x3e0 kernel/printk/printk.c:2003
 dev_vprintk_emit+0x4fc/0x541 drivers/base/core.c:3769
 dev_printk_emit+0xba/0xf1 drivers/base/core.c:3780
 __dev_printk+0x1db/0x203 drivers/base/core.c:3792
 _dev_info+0xd7/0x109 drivers/base/core.c:3838
 dlfb_parse_vendor_descriptor drivers/video/fbdev/udlfb.c:1589 [inline]
 dlfb_usb_probe.cold+0x102d/0x1c03 drivers/video/fbdev/udlfb.c:1672
 usb_probe_interface+0x310/0x800 drivers/usb/core/driver.c:374
 really_probe+0x290/0xac0 drivers/base/dd.c:527
 driver_probe_device+0x223/0x350 drivers/base/dd.c:701
 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:808
 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431
 __device_attach+0x21a/0x390 drivers/base/dd.c:874
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
 device_add+0x1367/0x1c20 drivers/base/core.c:2533
 usb_set_configuration+0xed4/0x1850 drivers/usb/core/message.c:2025
 usb_generic_driver_probe+0x9d/0xe0 drivers/usb/core/generic.c:241
 usb_probe_device+0xd9/0x230 drivers/usb/core/driver.c:272
 really_probe+0x290/0xac0 drivers/base/dd.c:527
 driver_probe_device+0x223/0x350 drivers/base/dd.c:701
 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:808
 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431
 __device_attach+0x21a/0x390 drivers/base/dd.c:874
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491
 device_add+0x1367/0x1c20 drivers/base/core.c:2533
 usb_new_device.cold+0x552/0xf6e drivers/usb/core/hub.c:2548
 hub_port_connect drivers/usb/core/hub.c:5195 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5335 [inline]
 port_event drivers/usb/core/hub.c:5481 [inline]
 hub_event+0x226d/0x43c0 drivers/usb/core/hub.c:5563
 process_one_work+0x965/0x1630 kernel/workqueue.c:2268
 worker_thread+0x96/0xe20 kernel/workqueue.c:2414
 kthread+0x326/0x430 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 94:
 save_stack+0x1b/0x40 mm/kasan/common.c:49
 set_track mm/kasan/common.c:57 [inline]
 __kasan_kmalloc mm/kasan/common.c:495 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:468
 kmalloc include/linux/slab.h:560 [inline]
 usb_get_configuration+0x311/0x3a20 drivers/usb/core/config.c:919
 usb_enumerate_device drivers/usb/core/hub.c:2381 [inline]
 usb_new_device+0x42c/0x740 drivers/usb/core/hub.c:2517
 hub_port_connect drivers/usb/core/hub.c:5195 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5335 [inline]
 port_event drivers/usb/core/hub.c:5481 [inline]
 hub_event+0x226d/0x43c0 drivers/usb/core/hub.c:5563
 process_one_work+0x965/0x1630 kernel/workqueue.c:2268
 worker_thread+0x96/0xe20 kernel/workqueue.c:2414
 kthread+0x326/0x430 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 234:
 save_stack+0x1b/0x40 mm/kasan/common.c:49
 set_track mm/kasan/common.c:57 [inline]
 kasan_set_free_info mm/kasan/common.c:317 [inline]
 __kasan_slab_free+0x117/0x160 mm/kasan/common.c:456
 slab_free_hook mm/slub.c:1445 [inline]
 slab_free_freelist_hook mm/slub.c:1478 [inline]
 slab_free mm/slub.c:3035 [inline]
 kfree+0xd5/0x300 mm/slub.c:4003
 single_release+0x8c/0xb0 fs/seq_file.c:584
 __fput+0x33b/0x880 fs/file_table.c:280
 task_work_run+0xf4/0x1b0 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:165
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x4e0/0x5a0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

The buggy address belongs to the object at ffff8881d11554c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 27 bytes inside of
 32-byte region [ffff8881d11554c0, ffff8881d11554e0)
The buggy address belongs to the page:
page:ffffea0007445540 refcount:1 mapcount:0 mapping:0000000039800198 index:0x0
flags: 0x200000000000200(slab)
raw: 0200000000000200 ffffea00071c7040 0000001500000015 ffff8881da003400
raw: 0000000000000000 0000000080400040 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881d1155380: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8881d1155400: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8881d1155480: fb fb fb fb fc fc fc fc 00 00 00 03 fc fc fc fc
                                                    ^
 ffff8881d1155500: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8881d1155580: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================

Crashes (5):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-usb 2020/05/14 23:13 https://github.com/google/kasan.git usb-fuzzer 059e7e0ff26c 2d572622 .config log report syz C
ci2-upstream-usb 2020/03/16 21:22 https://github.com/google/kasan.git usb-fuzzer d6ff8147a51c 749688d2 .config log report syz C
ci-upstream-kasan-gce-selinux-root 2020/05/22 22:50 upstream 051143e1602d 9682898d .config log report syz C
ci-upstream-kasan-gce-root 2020/05/22 19:30 upstream 051143e1602d 9682898d .config log report syz C
ci-qemu-upstream-386 2020/06/19 09:30 upstream 435faf5c218a bc258b50 .config log report syz C
* Struck through repros no longer work on HEAD.