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

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 7f7867ff 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=15e293c8600000
kernel config: https://syzkaller.appspot.com/x/.config?x=792eb47789f57810
dashboard link: https://syzkaller.appspot.com/bug?extid=5a6c4ec678a0c6ee84ba
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+5a6c4e...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in strlen+0x79/0x90 lib/string.c:525
Read of size 1 at addr ffff8881ca981f10 by task syz-executor.4/7644

CPU: 1 PID: 7644 Comm: syz-executor.4 Not tainted 5.3.0-rc2+ #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x6a/0x32c mm/kasan/report.c:351
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
kasan_report+0xe/0x12 mm/kasan/common.c:612
strlen+0x79/0x90 lib/string.c:525
strlen include/linux/string.h:281 [inline]
hidraw_ioctl+0x245/0xae0 drivers/hid/hidraw.c:446
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fed5bb22c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 0000000020000180 RSI: 0000000080404805 RDI: 0000000000000003
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fed5bb236d4
R13: 00000000004c21c6 R14: 00000000004d5528 R15: 00000000ffffffff

Allocated by task 1607:
save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:487 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:460
kmalloc include/linux/slab.h:552 [inline]
syslog_print kernel/printk/printk.c:1346 [inline]
do_syslog kernel/printk/printk.c:1519 [inline]
do_syslog+0x540/0x1380 kernel/printk/printk.c:1493
kmsg_read+0x8a/0xb0 fs/proc/kmsg.c:40
proc_reg_read+0x1c1/0x280 fs/proc/inode.c:223
__vfs_read+0x76/0x100 fs/read_write.c:425
vfs_read+0x1ea/0x430 fs/read_write.c:461
ksys_read+0x127/0x250 fs/read_write.c:587
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 1607:
save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:449
slab_free_hook mm/slub.c:1423 [inline]
slab_free_freelist_hook mm/slub.c:1470 [inline]
slab_free mm/slub.c:3012 [inline]
kfree+0xe4/0x2f0 mm/slub.c:3953
syslog_print kernel/printk/printk.c:1405 [inline]
do_syslog kernel/printk/printk.c:1519 [inline]
do_syslog+0x1098/0x1380 kernel/printk/printk.c:1493
kmsg_read+0x8a/0xb0 fs/proc/kmsg.c:40
proc_reg_read+0x1c1/0x280 fs/proc/inode.c:223
__vfs_read+0x76/0x100 fs/read_write.c:425
vfs_read+0x1ea/0x430 fs/read_write.c:461
ksys_read+0x127/0x250 fs/read_write.c:587
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881ca981b00
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 16 bytes to the right of
1024-byte region [ffff8881ca981b00, ffff8881ca981f00)
The buggy address belongs to the page:
page:ffffea00072a6000 refcount:1 mapcount:0 mapping:ffff8881da002280
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da002280
raw: 0000000000000000 00000000000e000e 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881ca981e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881ca981e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8881ca981f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881ca981f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881ca982000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: e96407b4 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=150426ba600000
kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e

dashboard link: https://syzkaller.appspot.com/bug?extid=5a6c4ec678a0c6ee84ba
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12725c02600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=162163c2600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+5a6c4e...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in strlen+0x79/0x90 lib/string.c:525

Read of size 1 at addr ffff8881d29bdf38 by task syz-executor201/1726

CPU: 1 PID: 1726 Comm: syz-executor201 Not tainted 5.3.0-rc2+ #25

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x6a/0x32c mm/kasan/report.c:351
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
kasan_report+0xe/0x12 mm/kasan/common.c:612
strlen+0x79/0x90 lib/string.c:525
strlen include/linux/string.h:281 [inline]
hidraw_ioctl+0x245/0xae0 drivers/hid/hidraw.c:446
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe

RIP: 0033:0x445679
Code: e8 5c ad 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7

48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff

ff 0f 83 9b cd fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc8514f3a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000445679
RDX: 0000000000000000 RSI: 0000000080404805 RDI: 0000000000000004
RBP: 00000000006d0018 R08: 000000000000000b R09: 00000000004002e0
R10: 000000000000000f R11: 0000000000000246 R12: 00000000004028a0
R13: 0000000000402930 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 0:
(stack is not available)

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8881d29bde60
which belongs to the cache shmem_inode_cache of size 1168
The buggy address is located 216 bytes inside of
1168-byte region [ffff8881d29bde60, ffff8881d29be2f0)

The buggy address belongs to the page:

page:ffffea00074a6f00 refcount:1 mapcount:0 mapping:ffff8881da115180

index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)

raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da115180
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff8881d29bde00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881d29bde80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8881d29bdf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881d29bdf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881d29be000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

[Oliver Neukum]

Am Sonntag, den 11.08.2019, 13:46 -0700 schrieb syzbot:
> syzbot has found a reproducer for the following crash on:
>
> HEAD commit: e96407b4 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=150426ba600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
> dashboard link: https://syzkaller.appspot.com/bug?extid=5a6c4ec678a0c6ee84ba
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12725c02600000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=162163c2600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+5a6c4e...@syzkaller.appspotmail.com

#syz test: https://github.com/google/kasan.git e96407b4

From 700a7cc270f06c6e9881f49e36a7722d16ee37db Mon Sep 17 00:00:00 2001
From: Oliver Neukum <one...@suse.com>
Date: Thu, 8 Aug 2019 15:08:48 +0200
Subject: [PATCH] HID: use strnlen to not walk through kernel memory

If a device sets no phy name we must limit the range
for looking for the end of the string lest we touch
areas of memory we should not touch.

Reported-by: syzbot+5a6c4e...@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <one...@suse.com>
---
drivers/hid/hidraw.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 006bd6f4f653..c7dcff6222b5 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -443,9 +443,7 @@ static long hidraw_ioctl(struct file *file, unsigned int cmd,
}

if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
- int len = strlen(hid->phys) + 1;
- if (len > _IOC_SIZE(cmd))
- len = _IOC_SIZE(cmd);
+ int len = strnlen(hid->phys, _IOC_SIZE(cmd)) + 1;
ret = copy_to_user(user_arg, hid->phys, len) ?
-EFAULT : len;
break;
--
2.16.4

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
KASAN: slab-out-of-bounds Read in hidraw_ioctl

==================================================================
BUG: KASAN: slab-out-of-bounds in strnlen+0x75/0x80 lib/string.c:542
Read of size 1 at addr ffff8881d6a51f38 by task syz-executor.2/2785

CPU: 1 PID: 2785 Comm: syz-executor.2 Not tainted 5.3.0-rc2+ #1

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x6a/0x32c mm/kasan/report.c:351
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
kasan_report+0xe/0x12 mm/kasan/common.c:612

strnlen+0x75/0x80 lib/string.c:542
strnlen include/linux/string.h:292 [inline]
hidraw_ioctl+0x247/0xaa0 drivers/hid/hidraw.c:446

vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe

RIP: 0033:0x459829
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7

48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff

ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc7df1d0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829

RDX: 0000000000000000 RSI: 0000000080404805 RDI: 0000000000000004

RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc7df1d16d4
R13: 00000000004c21de R14: 00000000004d5620 R15: 00000000ffffffff

Allocated by task 2868:

save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:487 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:460

slab_post_alloc_hook mm/slab.h:520 [inline]
slab_alloc_node mm/slub.c:2766 [inline]
__kmalloc_node_track_caller+0xd0/0x230 mm/slub.c:4361
__kmalloc_reserve.isra.0+0x39/0xe0 net/core/skbuff.c:141
__alloc_skb+0xef/0x5a0 net/core/skbuff.c:209
alloc_skb include/linux/skbuff.h:1055 [inline]
alloc_uevent_skb+0x7b/0x210 lib/kobject_uevent.c:289
uevent_net_broadcast_untagged lib/kobject_uevent.c:325 [inline]
kobject_uevent_net_broadcast lib/kobject_uevent.c:408 [inline]
kobject_uevent_env+0x8ee/0x1160 lib/kobject_uevent.c:592
device_add+0xade/0x16f0 drivers/base/core.c:2113
hid_add_device+0x33c/0x990 drivers/hid/hid-core.c:2365
usbhid_probe+0xa81/0xfa0 drivers/hid/usbhid/hid-core.c:1386
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x650 drivers/base/dd.c:548
driver_probe_device+0x101/0x1b0 drivers/base/dd.c:709
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:816
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:882
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2114
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+0x281/0x650 drivers/base/dd.c:548
driver_probe_device+0x101/0x1b0 drivers/base/dd.c:709
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:816
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:882
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2114
usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
hub_port_connect drivers/usb/core/hub.c:5098 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
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

Freed by task 238:

save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:449
slab_free_hook mm/slub.c:1423 [inline]
slab_free_freelist_hook mm/slub.c:1470 [inline]
slab_free mm/slub.c:3012 [inline]
kfree+0xe4/0x2f0 mm/slub.c:3953

skb_free_head+0x8b/0xa0 net/core/skbuff.c:591
skb_release_data+0x41f/0x7c0 net/core/skbuff.c:611
skb_release_all+0x46/0x60 net/core/skbuff.c:665
__kfree_skb net/core/skbuff.c:679 [inline]
consume_skb net/core/skbuff.c:838 [inline]
consume_skb+0xd9/0x320 net/core/skbuff.c:832
skb_free_datagram+0x16/0xf0 net/core/datagram.c:328
netlink_recvmsg+0x65e/0xee0 net/netlink/af_netlink.c:1996
sock_recvmsg_nosec net/socket.c:871 [inline]
sock_recvmsg net/socket.c:889 [inline]
sock_recvmsg+0xca/0x110 net/socket.c:885
___sys_recvmsg+0x271/0x5a0 net/socket.c:2480
__sys_recvmsg+0xe9/0x1b0 net/socket.c:2537
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881d6a51b00
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 56 bytes to the right of
1024-byte region [ffff8881d6a51b00, ffff8881d6a51f00)

The buggy address belongs to the page:

page:ffffea00075a9400 refcount:1 mapcount:0 mapping:ffff8881da002280

index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)

raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da002280
raw: 0000000000000000 00000000000e000e 00000001ffffffff 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff8881d6a51e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d6a51e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8881d6a51f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881d6a51f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d6a52000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit: e96407b4 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git

console output: https://syzkaller.appspot.com/x/log.txt?x=1183deee600000
kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e

compiler: gcc (GCC) 9.0.0 20181231 (experimental)

patch: https://syzkaller.appspot.com/x/patch.diff?x=1603c7c2600000

[Andrey Konovalov]

Trying Alan's fix from another thread here:

#syz test: https://github.com/google/kasan.git usb-fuzzer e96407b4

[syzbot]

want 2 args (repo, branch), got 3


> --
> You received this message because you are subscribed to the Google
> Groups "syzkaller-bugs" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to syzkaller-bug...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/syzkaller-bugs/CAAeHK%2BzeN%2BbLTix2yaWDo-iu_G4D8T1KELjds%3DKVTtywiPpc4g%40mail.gmail.com.

[syzbot]

[Andrey Konovalov]

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
KASAN: slab-out-of-bounds Read in hidraw_ioctl

==================================================================
BUG: KASAN: slab-out-of-bounds in strlen+0x79/0x90 lib/string.c:525

Read of size 1 at addr ffff8881c8035f38 by task syz-executor.4/2833

CPU: 1 PID: 2833 Comm: syz-executor.4 Not tainted 5.3.0-rc2+ #1

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x6a/0x32c mm/kasan/report.c:351
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
kasan_report+0xe/0x12 mm/kasan/common.c:612
strlen+0x79/0x90 lib/string.c:525
strlen include/linux/string.h:281 [inline]
hidraw_ioctl+0x245/0xae0 drivers/hid/hidraw.c:446
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe

RIP: 0033:0x459829
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7

48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff

ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f7a68f6dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829

RDX: 0000000000000000 RSI: 0000000080404805 RDI: 0000000000000004

RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7a68f6e6d4

R13: 00000000004c21de R14: 00000000004d5620 R15: 00000000ffffffff

Allocated by task 0:
(stack is not available)

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8881c8035e60

which belongs to the cache shmem_inode_cache of size 1168
The buggy address is located 216 bytes inside of

1168-byte region [ffff8881c8035e60, ffff8881c80362f0)

The buggy address belongs to the page:

page:ffffea0007200d00 refcount:1 mapcount:0 mapping:ffff8881da115180

index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da115180
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff8881c8035e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881c8035e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8881c8035f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881c8035f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881c8036000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


Tested on:

commit: e96407b4 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git

console output: https://syzkaller.appspot.com/x/log.txt?x=14f14a1e600000
kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e

compiler: gcc (GCC) 9.0.0 20181231 (experimental)

patch: https://syzkaller.appspot.com/x/patch.diff?x=171cd95a600000

[Andrey Konovalov]

On Wed, Aug 21, 2019 at 3:37 PM syzbot
<syzbot+5a6c4e...@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot has tested the proposed patch but the reproducer still triggered
> crash:
> KASAN: slab-out-of-bounds Read in hidraw_ioctl

Same here, a different bug.

[Alan Stern]

Get some debugging info:

#syz test: https://github.com/google/kasan.git e96407b4

Index: usb-devel/drivers/hid/hid-core.c
===================================================================
--- usb-devel.orig/drivers/hid/hid-core.c
+++ usb-devel/drivers/hid/hid-core.c
@@ -1973,6 +1973,8 @@ int hid_hw_start(struct hid_device *hdev
{
int error;

+ dev_info(&hdev->dev, "In hid_hw_start for %p\n", hdev);
+ dump_stack();
error = hdev->ll_driver->start(hdev);
if (error)
return error;
@@ -1998,6 +2000,7 @@ EXPORT_SYMBOL_GPL(hid_hw_start);
*/
void hid_hw_stop(struct hid_device *hdev)
{
+ dev_info(&hdev->dev, "In hid_hw_stop for %p\n", hdev);
hid_disconnect(hdev);
hdev->ll_driver->stop(hdev);
}

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
KASAN: slab-out-of-bounds Read in hidraw_ioctl

==================================================================
BUG: KASAN: slab-out-of-bounds in strlen+0x79/0x90 lib/string.c:525

Read of size 1 at addr ffff8881d619df38 by task syz-executor.5/2984

CPU: 0 PID: 2984 Comm: syz-executor.5 Not tainted 5.3.0-rc2+ #1

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x6a/0x32c mm/kasan/report.c:351
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
kasan_report+0xe/0x12 mm/kasan/common.c:612
strlen+0x79/0x90 lib/string.c:525
strlen include/linux/string.h:281 [inline]
hidraw_ioctl+0x245/0xae0 drivers/hid/hidraw.c:446
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00

RSP: 002b:00007f19881acc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010

RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 0000000080404805 RDI: 0000000000000004

RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f19881ad6d4

R13: 00000000004c21de R14: 00000000004d5620 R15: 00000000ffffffff

Allocated by task 1607:

save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:487 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:460

kmalloc include/linux/slab.h:552 [inline]
syslog_print kernel/printk/printk.c:1346 [inline]
do_syslog kernel/printk/printk.c:1519 [inline]
do_syslog+0x540/0x1380 kernel/printk/printk.c:1493
kmsg_read+0x8a/0xb0 fs/proc/kmsg.c:40
proc_reg_read+0x1c1/0x280 fs/proc/inode.c:223
__vfs_read+0x76/0x100 fs/read_write.c:425
vfs_read+0x1ea/0x430 fs/read_write.c:461
ksys_read+0x127/0x250 fs/read_write.c:587
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 1607:

save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:449
slab_free_hook mm/slub.c:1423 [inline]
slab_free_freelist_hook mm/slub.c:1470 [inline]
slab_free mm/slub.c:3012 [inline]
kfree+0xe4/0x2f0 mm/slub.c:3953

syslog_print kernel/printk/printk.c:1405 [inline]
do_syslog kernel/printk/printk.c:1519 [inline]
do_syslog+0x1098/0x1380 kernel/printk/printk.c:1493
kmsg_read+0x8a/0xb0 fs/proc/kmsg.c:40
proc_reg_read+0x1c1/0x280 fs/proc/inode.c:223
__vfs_read+0x76/0x100 fs/read_write.c:425
vfs_read+0x1ea/0x430 fs/read_write.c:461
ksys_read+0x127/0x250 fs/read_write.c:587
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881d619db00

which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 56 bytes to the right of

1024-byte region [ffff8881d619db00, ffff8881d619df00)

The buggy address belongs to the page:

page:ffffea0007586700 refcount:1 mapcount:0 mapping:ffff8881da002280

index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)

raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da002280
raw: 0000000000000000 00000000000e000e 00000001ffffffff 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff8881d619de00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d619de80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8881d619df00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881d619df80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d619e000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

==================================================================


Tested on:

commit: e96407b4 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git

console output: https://syzkaller.appspot.com/x/log.txt?x=1138542e600000

kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

patch: https://syzkaller.appspot.com/x/patch.diff?x=1197b996600000

[Alan Stern]

On Wed, 21 Aug 2019, syzbot wrote:

Looks like a test is missing in hidraw_ioctl.

Alan Stern

#syz test: https://github.com/google/kasan.git e96407b4

Index: usb-devel/drivers/hid/hidraw.c
===================================================================
--- usb-devel.orig/drivers/hid/hidraw.c
+++ usb-devel/drivers/hid/hidraw.c
@@ -370,7 +370,7 @@ static long hidraw_ioctl(struct file *fi

mutex_lock(&minors_lock);
dev = hidraw_table[minor];
- if (!dev) {
+ if (!dev || !dev->exist) {
ret = -ENODEV;
goto out;
}

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger
crash:

Reported-and-tested-by:
syzbot+5a6c4e...@syzkaller.appspotmail.com

Tested on:

commit: e96407b4 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git

kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

patch: https://syzkaller.appspot.com/x/patch.diff?x=13dca42e600000

Note: testing is done by a robot and is best-effort only.

[Alan Stern]

On Wed, 21 Aug 2019, Andrey Konovalov wrote:

> On Wed, Aug 21, 2019 at 3:37 PM syzbot
> <syzbot+5a6c4e...@syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot has tested the proposed patch but the reproducer still triggered
> > crash:
> > KASAN: slab-out-of-bounds Read in hidraw_ioctl
>
> Same here, a different bug.

It looks like I've got the fix for both these bugs. Testing now...

> > Tested on:
> >
> > commit: e96407b4 usb-fuzzer: main usb gadget fuzzer driver
> > git tree: https://github.com/google/kasan.git
> > console output: https://syzkaller.appspot.com/x/log.txt?x=14f14a1e600000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
> > compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> > patch: https://syzkaller.appspot.com/x/patch.diff?x=171cd95a600000

Why don't these patch-test reports include the dashboard link? It sure
would be handy to have a copy of it here.

Alan Stern

[Andrey Konovalov]

On Wed, Aug 21, 2019 at 6:24 PM Alan Stern <st...@rowland.harvard.edu> wrote:
>
> On Wed, 21 Aug 2019, Andrey Konovalov wrote:
>
> > On Wed, Aug 21, 2019 at 3:37 PM syzbot
> > <syzbot+5a6c4e...@syzkaller.appspotmail.com> wrote:
> > >
> > > Hello,
> > >
> > > syzbot has tested the proposed patch but the reproducer still triggered
> > > crash:
> > > KASAN: slab-out-of-bounds Read in hidraw_ioctl
> >
> > Same here, a different bug.
>
> It looks like I've got the fix for both these bugs. Testing now...

Great! Do you think "BUG: bad usercopy in hidraw_ioctl" can also be
fixed by one of those fixes?

[Andrey Konovalov]

On Wed, Aug 21, 2019 at 6:26 PM Andrey Konovalov <andre...@google.com> wrote:
>
> On Wed, Aug 21, 2019 at 6:24 PM Alan Stern <st...@rowland.harvard.edu> wrote:
> >
> > On Wed, 21 Aug 2019, Andrey Konovalov wrote:
> >
> > > On Wed, Aug 21, 2019 at 3:37 PM syzbot
> > > <syzbot+5a6c4e...@syzkaller.appspotmail.com> wrote:
> > > >
> > > > Hello,
> > > >
> > > > syzbot has tested the proposed patch but the reproducer still triggered
> > > > crash:
> > > > KASAN: slab-out-of-bounds Read in hidraw_ioctl
> > >
> > > Same here, a different bug.
> >
> > It looks like I've got the fix for both these bugs. Testing now...
>
> Great! Do you think "BUG: bad usercopy in hidraw_ioctl" can also be
> fixed by one of those fixes?

We actually have a bunch of other non reproducible bug reports that
come from HID. I think I'll dup them into these two bugs that you've
fixed, and we'll see if syzkaller triggers them again once the fixes
are upstream.

>
> >
> > > > Tested on:
> > > >
> > > > commit: e96407b4 usb-fuzzer: main usb gadget fuzzer driver
> > > > git tree: https://github.com/google/kasan.git
> > > > console output: https://syzkaller.appspot.com/x/log.txt?x=14f14a1e600000
> > > > kernel config: https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
> > > > compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> > > > patch: https://syzkaller.appspot.com/x/patch.diff?x=171cd95a600000
> >
> > Why don't these patch-test reports include the dashboard link? It sure
> > would be handy to have a copy of it here.

Sorry, didn't notice this comment. This should be easy to implement,
I'll look into that, thanks!

[Alan Stern]

The syzbot fuzzer has reported a pair of problems in the
hidraw_ioctl() function: slab-out-of-bounds read and use-after-free
read. An example of the first:

BUG: KASAN: slab-out-of-bounds in strlen+0x79/0x90 lib/string.c:525

Read of size 1 at addr ffff8881c8035f38 by task syz-executor.4/2833

CPU: 1 PID: 2833 Comm: syz-executor.4 Not tainted 5.3.0-rc2+ #1

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x6a/0x32c mm/kasan/report.c:351
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
kasan_report+0xe/0x12 mm/kasan/common.c:612
strlen+0x79/0x90 lib/string.c:525
strlen include/linux/string.h:281 [inline]
hidraw_ioctl+0x245/0xae0 drivers/hid/hidraw.c:446
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00

RSP: 002b:00007f7a68f6dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010

RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 0000000080404805 RDI: 0000000000000004

RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7a68f6e6d4

R13: 00000000004c21de R14: 00000000004d5620 R15: 00000000ffffffff

The two problems have the same cause: hidraw_ioctl() fails to test
whether the device has been removed. This patch adds the missing test.

Reported-and-tested-by: syzbot+5a6c4e...@syzkaller.appspotmail.com
Signed-off-by: Alan Stern <st...@rowland.harvard.edu>
CC: <sta...@vger.kernel.org>

---


[as1910.hidraw-ioctl-fix]


drivers/hid/hidraw.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

[Jiri Kosina]

Thanks a lot Alan for chasing this; I've applied the patch.

--
Jiri Kosina
SUSE Labs