KASAN: slab-out-of-bounds Read in p54u_load_firmware_cb

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 43151d6c 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=12c0112ca00000
kernel config: https://syzkaller.appspot.com/x/.config?x=4183eeef650d1234
dashboard link: https://syzkaller.appspot.com/bug?extid=6d237e74cdc13f036473
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+6d237e...@syzkaller.appspotmail.com

cx231xx 2-1:0.1: New device @ 480 Mbps (2040:b111) with 1 interfaces
cx231xx 2-1:0.1: Not found matching IAD interface
usb 6-1: Direct firmware load for isl3887usb failed with error -2
usb 6-1: Firmware not found.
==================================================================
BUG: KASAN: slab-out-of-bounds in p54u_load_firmware_cb.cold+0x97/0x13a
drivers/net/wireless/intersil/p54/p54usb.c:936
Read of size 8 at addr ffff888099763588 by task kworker/0:1/12

CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.1.0-rc3-319004-g43151d6 #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: events request_firmware_work_func
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xe8/0x16e lib/dump_stack.c:113
print_address_description+0x6c/0x236 mm/kasan/report.c:187
kasan_report.cold+0x1a/0x3c mm/kasan/report.c:317
p54u_load_firmware_cb.cold+0x97/0x13a
drivers/net/wireless/intersil/p54/p54usb.c:936
request_firmware_work_func+0x12d/0x249
drivers/base/firmware_loader/main.c:785
process_one_work+0x90f/0x1580 kernel/workqueue.c:2269
worker_thread+0x9b/0xe20 kernel/workqueue.c:2415
kthread+0x313/0x420 kernel/kthread.c:253
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 7931:
set_track mm/kasan/common.c:87 [inline]
__kasan_kmalloc mm/kasan/common.c:497 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:470
slab_post_alloc_hook mm/slab.h:437 [inline]
slab_alloc_node mm/slub.c:2756 [inline]
__kmalloc_node_track_caller+0xf3/0x320 mm/slub.c:4372
__kmalloc_reserve.isra.0+0x3e/0xf0 net/core/skbuff.c:140
__alloc_skb+0xf4/0x5a0 net/core/skbuff.c:208
alloc_skb include/linux/skbuff.h:1058 [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+0x865/0x13d0 lib/kobject_uevent.c:589
udc_bind_to_driver+0x33e/0x5e0 drivers/usb/gadget/udc/core.c:1357
usb_gadget_probe_driver+0x23f/0x380 drivers/usb/gadget/udc/core.c:1408
fuzzer_ioctl_run drivers/usb/gadget/fuzzer/fuzzer.c:718 [inline]
fuzzer_ioctl+0x15be/0x1d90 drivers/usb/gadget/fuzzer/fuzzer.c:1130
full_proxy_unlocked_ioctl+0x11b/0x180 fs/debugfs/file.c:205
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xced/0x12f0 fs/ioctl.c:696
ksys_ioctl+0xa0/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x74/0xb0 fs/ioctl.c:718
do_syscall_64+0xcf/0x4f0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 805:
set_track mm/kasan/common.c:87 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:459
slab_free_hook mm/slub.c:1429 [inline]
slab_free_freelist_hook+0x5e/0x140 mm/slub.c:1456
slab_free mm/slub.c:3003 [inline]
kfree+0xce/0x290 mm/slub.c:3958
skb_free_head+0x90/0xb0 net/core/skbuff.c:557
skb_release_data+0x543/0x8b0 net/core/skbuff.c:577
skb_release_all+0x4b/0x60 net/core/skbuff.c:631
__kfree_skb net/core/skbuff.c:645 [inline]
consume_skb net/core/skbuff.c:705 [inline]
consume_skb+0xc5/0x2f0 net/core/skbuff.c:699
skb_free_datagram+0x1b/0xf0 net/core/datagram.c:329
netlink_recvmsg+0x663/0xea0 net/netlink/af_netlink.c:2004
sock_recvmsg_nosec net/socket.c:881 [inline]
sock_recvmsg net/socket.c:888 [inline]
sock_recvmsg+0xd1/0x110 net/socket.c:884
___sys_recvmsg+0x278/0x5a0 net/socket.c:2422
__sys_recvmsg+0xee/0x1b0 net/socket.c:2471
do_syscall_64+0xcf/0x4f0 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff888099763180
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 8 bytes to the right of
1024-byte region [ffff888099763180, ffff888099763580)
The buggy address belongs to the page:
page:ffffea000265d800 count:1 mapcount:0 mapping:ffff88812c3f4a00 index:0x0
compound_mapcount: 0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 dead000000000100 dead000000000200 ffff88812c3f4a00
raw: 0000000000000000 00000000000e000e 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff888099763480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888099763500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff888099763580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff888099763600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888099763680: 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.
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[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: 9939f56e 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=135e29faa00000
kernel config: https://syzkaller.appspot.com/x/.config?x=df134eda130bb43a

dashboard link: https://syzkaller.appspot.com/bug?extid=6d237e74cdc13f036473
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=175d946ea00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6d237e...@syzkaller.appspotmail.com

usb 3-1: Direct firmware load for isl3887usb failed with error -2
usb 3-1: Firmware not found.
==================================================================
BUG: KASAN: slab-out-of-bounds in p54u_load_firmware_cb.cold+0x97/0x13d
drivers/net/wireless/intersil/p54/p54usb.c:936
Read of size 8 at addr ffff8881c9cf7588 by task kworker/1:5/2759

CPU: 1 PID: 2759 Comm: kworker/1:5 Not tainted 5.2.0-rc5+ #11

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: events request_firmware_work_func
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
p54u_load_firmware_cb.cold+0x97/0x13d
drivers/net/wireless/intersil/p54/p54usb.c:936
request_firmware_work_func+0x126/0x242
drivers/base/firmware_loader/main.c:785
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 1612:
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]
syslog_print kernel/printk/printk.c:1346 [inline]
do_syslog kernel/printk/printk.c:1519 [inline]
do_syslog+0x4f4/0x12e0 kernel/printk/printk.c:1493
kmsg_read+0x8a/0xb0 fs/proc/kmsg.c:40
proc_reg_read+0x1c1/0x280 fs/proc/inode.c:221
__vfs_read+0x76/0x100 fs/read_write.c:425
vfs_read+0x18e/0x3d0 fs/read_write.c:461
ksys_read+0x127/0x250 fs/read_write.c:587
do_syscall_64+0xb7/0x560 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 1612:
save_stack+0x1b/0x80 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:451
slab_free_hook mm/slub.c:1421 [inline]
slab_free_freelist_hook mm/slub.c:1448 [inline]
slab_free mm/slub.c:2994 [inline]
kfree+0xd7/0x280 mm/slub.c:3949
syslog_print kernel/printk/printk.c:1405 [inline]
do_syslog kernel/printk/printk.c:1519 [inline]
do_syslog+0xff3/0x12e0 kernel/printk/printk.c:1493
kmsg_read+0x8a/0xb0 fs/proc/kmsg.c:40
proc_reg_read+0x1c1/0x280 fs/proc/inode.c:221
__vfs_read+0x76/0x100 fs/read_write.c:425
vfs_read+0x18e/0x3d0 fs/read_write.c:461
ksys_read+0x127/0x250 fs/read_write.c:587
do_syscall_64+0xb7/0x560 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881c9cf7180

which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 8 bytes to the right of

1024-byte region [ffff8881c9cf7180, ffff8881c9cf7580)

The buggy address belongs to the page:

page:ffffea0007273d00 refcount:1 mapcount:0 mapping:ffff8881dac02a00
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 dead000000000100 dead000000000200 ffff8881dac02a00

raw: 0000000000000000 00000000000e000e 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff8881c9cf7480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881c9cf7500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8881c9cf7580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881c9cf7600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881c9cf7680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

[Alan Stern]

Isn't this the same as syzkaller bug 200d4bb11b23d929335f ? Doesn't
the same patch fix it?

Alan Stern

[Christian Lamparter]

I think Kalle hasn't applied it yet? It's still sitting on the patchwork queue:
<https://patchwork.kernel.org/patch/10951527/>

Regards,
Christian

[Andrey Konovalov]

Yes, until this patch is in the tree that is being tested (which is
based on the usb-linus branch; I update it every few weeks), syzbot
considers this bug as open.

>
> Regards,
> Christian
>
>

[Kalle Valo]

I'm hoping to apply this today or tomorrow.

--
Kalle Valo

[Andrey Konovalov]

#syz dup: KASAN: use-after-free Read in p54u_load_firmware_cb