KASAN: global-out-of-bounds Read in load_next_firmware_from_table

[syzbot]

Hello,

syzbot found 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=12fd0e9ba00000
kernel config: https://syzkaller.appspot.com/x/.config?x=f6d4561982f71f63
dashboard link: https://syzkaller.appspot.com/bug?extid=98156c174c5a2cad9f8f
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=125f669ba00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=146b806ba00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+98156c...@syzkaller.appspotmail.com

usb 1-1: Direct firmware load for libertas/usb8388_v5.bin failed with error
-2
usb 1-1: Direct firmware load for libertas/usb8388.bin failed with error -2
usb 1-1: Direct firmware load for usb8388.bin failed with error -2
==================================================================
BUG: KASAN: global-out-of-bounds in
load_next_firmware_from_table+0x267/0x2d0
drivers/net/wireless/marvell/libertas/firmware.c:99
Read of size 8 at addr ffffffff860942b8 by task kworker/1:1/21

CPU: 1 PID: 21 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: 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
load_next_firmware_from_table+0x267/0x2d0
drivers/net/wireless/marvell/libertas/firmware.c:99
helper_firmware_cb+0xdc/0x100
drivers/net/wireless/marvell/libertas/firmware.c:70
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

The buggy address belongs to the variable:
fw_table+0x98/0x5c0

Memory state around the buggy address:
ffffffff86094180: fa fa fa fa 00 04 fa fa fa fa fa fa 00 00 05 fa
ffffffff86094200: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 00
> ffffffff86094280: 00 00 00 00 00 00 fa fa fa fa fa fa 00 00 00 00
^
ffffffff86094300: 00 00 00 01 fa fa fa fa 00 00 00 00 02 fa fa fa
ffffffff86094380: fa fa fa fa 00 03 fa fa fa fa fa fa 00 00 00 00
==================================================================


---
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syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

[syzbot]

Hello,

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

Reported-and-tested-by:
syzbot+98156c...@syzkaller.appspotmail.com

Tested on:

commit: 7829a896 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer

kernel config: https://syzkaller.appspot.com/x/.config?x=f6d4561982f71f63

compiler: gcc (GCC) 9.0.0 20181231 (experimental)

patch: https://syzkaller.appspot.com/x/patch.diff?x=12d39e7ba00000

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

[syzbot]

Hello,

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

Reported-and-tested-by:
syzbot+98156c...@syzkaller.appspotmail.com

Tested on:

commit: 6a3599ce usb-fuzzer: main usb gadget fuzzer driver

git tree: https://github.com/google/kasan.git usb-fuzzer

kernel config: https://syzkaller.appspot.com/x/.config?x=d90745bdf884fc0a

compiler: gcc (GCC) 9.0.0 20181231 (experimental)

patch: https://syzkaller.appspot.com/x/patch.diff?x=14158bcfa00000