Re: KMSAN: kernel-usb-infoleak in hif_usb_send

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    ce8056d1 wip: changed copy_from_user where instrumented
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=13555816900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3afe005fb99591f
dashboard link: https://syzkaller.appspot.com/bug?extid=f83a1df1ed4f67e8d8ad
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11ab61e2900000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17614e6e900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f83a1df1ed4f67e8d8ad@xxxxxxxxxxxxxxxxxxxxxxxxx

usb 1-1: ath9k_htc: Transferred FW: ath9k_htc/htc_9271-1.4.0.fw, size: 51008
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BUG: KMSAN: kernel-usb-infoleak in kmsan_handle_urb+0x28/0x40 mm/kmsan/kmsan_hooks.c:307
CPU: 0 PID: 3219 Comm: kworker/0:2 Not tainted 5.8.0-rc5-syzkaller #0
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+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423
 kmsan_handle_urb+0x28/0x40 mm/kmsan/kmsan_hooks.c:307
 usb_submit_urb+0x861/0x2470 drivers/usb/core/urb.c:406
 hif_usb_send_regout drivers/net/wireless/ath/ath9k/hif_usb.c:127 [inline]
 hif_usb_send+0x633/0x1790 drivers/net/wireless/ath/ath9k/hif_usb.c:470
 htc_issue_send drivers/net/wireless/ath/ath9k/htc_hst.c:34 [inline]
 htc_connect_service+0x14b4/0x19f0 drivers/net/wireless/ath/ath9k/htc_hst.c:275
 ath9k_wmi_connect+0x178/0x2c0 drivers/net/wireless/ath/ath9k/wmi.c:268
 ath9k_init_htc_services+0xf3/0x11f0 drivers/net/wireless/ath/ath9k/htc_drv_init.c:146
 ath9k_htc_probe_device+0x4dc/0x3ed0 drivers/net/wireless/ath/ath9k/htc_drv_init.c:962
 ath9k_htc_hw_init+0xdf/0x190 drivers/net/wireless/ath/ath9k/htc_hst.c:501
 ath9k_hif_usb_firmware_cb+0x42e/0xab0 drivers/net/wireless/ath/ath9k/hif_usb.c:1218
 request_firmware_work_func+0x1aa/0x2d0 drivers/base/firmware_loader/main.c:1001
 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269
 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415
 kthread+0x551/0x590 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2839 [inline]
 __kmalloc_node_track_caller+0xeab/0x12e0 mm/slub.c:4478
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x35f/0xb30 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1083 [inline]
 htc_connect_service+0x1057/0x19f0 drivers/net/wireless/ath/ath9k/htc_hst.c:258
 ath9k_wmi_connect+0x178/0x2c0 drivers/net/wireless/ath/ath9k/wmi.c:268
 ath9k_init_htc_services+0xf3/0x11f0 drivers/net/wireless/ath/ath9k/htc_drv_init.c:146
 ath9k_htc_probe_device+0x4dc/0x3ed0 drivers/net/wireless/ath/ath9k/htc_drv_init.c:962
 ath9k_htc_hw_init+0xdf/0x190 drivers/net/wireless/ath/ath9k/htc_hst.c:501
 ath9k_hif_usb_firmware_cb+0x42e/0xab0 drivers/net/wireless/ath/ath9k/hif_usb.c:1218
 request_firmware_work_func+0x1aa/0x2d0 drivers/base/firmware_loader/main.c:1001
 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269
 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415
 kthread+0x551/0x590 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Bytes 4-7 of 18 are uninitialized
Memory access of size 18 starts at ffff88810755bc00
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