Re: BUG: bad usercopy in ld_usb_read (2)

[Johan Hovold]

On Tue, Sep 17, 2019 at 02:20:55PM +0200, Andrey Konovalov wrote:
> On Mon, Sep 16, 2019 at 8:49 PM syzbot
> <syzbot+4cd8c1b2445d0ffe05f6@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit:    f0df5c1b 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=1681c9c1600000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
> > dashboard link: https://syzkaller.appspot.com/bug?extid=4cd8c1b2445d0ffe05f6
> > 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+4cd8c1b2445d0ffe05f6@xxxxxxxxxxxxxxxxxxxxxxxxx
> >
> > ldusb 5-1:0.98: Read buffer overflow, 4466454212372071848 bytes dropped
> > usercopy: Kernel memory exposure attempt detected from process stack
> > (offset 0, size 536871625)!
> > ------------[ cut here ]------------
> > kernel BUG at mm/usercopy.c:98!
> > invalid opcode: 0000 [#1] SMP KASAN
> > CPU: 1 PID: 17170 Comm: syz-executor.4 Not tainted 5.3.0-rc7+ #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> > Google 01/01/2011
> > RIP: 0010:usercopy_abort+0xb9/0xbb mm/usercopy.c:98
> > Code: e8 62 f0 d6 ff 49 89 d9 4d 89 e8 4c 89 e1 41 56 48 89 ee 48 c7 c7 c0
> > f7 cd 85 ff 74 24 08 41 57 48 8b 54 24 20 e8 c6 91 c1 ff <0f> 0b e8 36 f0
> > d6 ff e8 a1 90 fd ff 8b 54 24 04 49 89 d8 4c 89 e1
> > RSP: 0018:ffff8881d308fc40 EFLAGS: 00010282
> > RAX: 0000000000000060 RBX: ffffffff85cdf4e0 RCX: 0000000000000000
> > RDX: 0000000000000000 RSI: ffffffff81288ddd RDI: ffffed103a611f7a
> > RBP: ffffffff85cdf6a0 R08: 0000000000000060 R09: fffffbfff11ad7a3
> > R10: fffffbfff11ad7a2 R11: ffffffff88d6bd17 R12: ffffffff85cdf8c0
> > R13: ffffffff85cdf4e0 R14: 00000000200002c9 R15: ffffffff85cdf4e0
> > FS:  00007fc613f93700(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f983cbbf000 CR3: 00000001cc33e000 CR4: 00000000001406e0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > Call Trace:
> >   __check_object_size mm/usercopy.c:276 [inline]
> >   __check_object_size.cold+0x91/0xbb mm/usercopy.c:250
> >   check_object_size include/linux/thread_info.h:119 [inline]
> >   check_copy_size include/linux/thread_info.h:150 [inline]
> >   copy_to_user include/linux/uaccess.h:151 [inline]
> >   ld_usb_read+0x304/0x780 drivers/usb/misc/ldusb.c:495
> >   __vfs_read+0x76/0x100 fs/read_write.c:425
> >   vfs_read+0x1ea/0x430 fs/read_write.c:461
> >   ksys_read+0x1e8/0x250 fs/read_write.c:587
> >   do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
> >   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> > RIP: 0033:0x4598e9
> > 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:00007fc613f92c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004598e9
> > RDX: 00000000200002c9 RSI: 0000000020000280 RDI: 0000000000000004
> > RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc613f936d4
> > R13: 00000000004c6d1a R14: 00000000004dc0c0 R15: 00000000ffffffff
> > Modules linked in:
> > ---[ end trace b440da0257bb7015 ]---
> > RIP: 0010:usercopy_abort+0xb9/0xbb mm/usercopy.c:98
> > Code: e8 62 f0 d6 ff 49 89 d9 4d 89 e8 4c 89 e1 41 56 48 89 ee 48 c7 c7 c0
> > f7 cd 85 ff 74 24 08 41 57 48 8b 54 24 20 e8 c6 91 c1 ff <0f> 0b e8 36 f0
> > d6 ff e8 a1 90 fd ff 8b 54 24 04 49 89 d8 4c 89 e1
> > RSP: 0018:ffff8881d308fc40 EFLAGS: 00010282
> > RAX: 0000000000000060 RBX: ffffffff85cdf4e0 RCX: 0000000000000000
> > RDX: 0000000000000000 RSI: ffffffff81288ddd RDI: ffffed103a611f7a
> > RBP: ffffffff85cdf6a0 R08: 0000000000000060 R09: fffffbfff11ad7a3
> > R10: fffffbfff11ad7a2 R11: ffffffff88d6bd17 R12: ffffffff85cdf8c0
> > R13: ffffffff85cdf4e0 R14: 00000000200002c9 R15: ffffffff85cdf4e0
> > FS:  00007fc613f93700(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f983cbbf000 CR3: 00000001cc33e000 CR4: 00000000001406e0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> >
> >
> > ---
> > 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 syzkaller@xxxxxxxxxxxxxxxxx
> >
> > syzbot will keep track of this bug report. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> 
> Need to wait until all HID fixes are upstream, before we can actually
> tell if this is a new issue or not. Duping to the Logitech bug for
> now.
> 
> #syz dup: general protection fault in __pm_runtime_resume

Different bug (and driver). 

#syz dup: KASAN: slab-out-of-bounds Read in ld_usb_read (3)