Re: [syzbot] [bluetooth?] KASAN: vmalloc-out-of-bounds Read in hci_devcd_dump

syzbot
2025-04-03T10:30:21Z

syzbot has found a reproducer for the following issue on:

HEAD commit: a1b5bd45d4ee Merge tag 'usb-6.15-rc1' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1709494c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=44bfe55da7676adc
dashboard link: https://syzkaller.appspot.com/bug?extid=ac3c79181f6aecc5120c
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13e60be4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10c5cfb0580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9096ac93f836/disk-a1b5bd45.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/83a88633dd9d/vmlinux-a1b5bd45.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7353859863a8/bzImage-a1b5bd45.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ac3c79181f6aecc5120c@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: vmalloc-out-of-bounds in skb_put_data include/linux/skbuff.h:2752 [inline]
BUG: KASAN: vmalloc-out-of-bounds in hci_devcd_dump+0x142/0x240 net/bluetooth/coredump.c:258
Read of size 140 at addr ffffc90000ace000 by task kworker/u9:1/5151

CPU: 0 UID: 0 PID: 5151 Comm: kworker/u9:1 Not tainted 6.14.0-syzkaller-12886-ga1b5bd45d4ee #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: hci0 hci_devcd_timeout
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:408 [inline]
print_report+0xc3/0x670 mm/kasan/report.c:521
kasan_report+0xe0/0x110 mm/kasan/report.c:634
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
__asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105
skb_put_data include/linux/skbuff.h:2752 [inline]
hci_devcd_dump+0x142/0x240 net/bluetooth/coredump.c:258
hci_devcd_timeout+0xb5/0x2e0 net/bluetooth/coredump.c:413
process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3319 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
kthread+0x3c2/0x780 kernel/kthread.c:464
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>

The buggy address ffffc90000ace000 belongs to a vmalloc virtual mapping
Memory state around the buggy address:
ffffc90000acdf00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90000acdf80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90000ace000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
^
ffffc90000ace080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90000ace100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

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#syz test: git://repo/address.git branch-or-commit-hash
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