Re: general protection fault in qp_release_pages

[Dmitry Vyukov]

On Mon, Oct 12, 2020 at 10:01 AM Arnd Bergmann <arnd@xxxxxxxx> wrote:
>
> On Mon, Oct 12, 2020 at 8:11 AM syzbot
> <syzbot+f58fe4bb535845237057@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    3dd0130f Merge branch 'akpm' (patches from Andrew)
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=1219a8e8500000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=c06bcf3cc963d91c
> > dashboard link: https://syzkaller.appspot.com/bug?extid=f58fe4bb535845237057
> > compiler:       gcc (GCC) 10.1.0-syz 20200507
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=113937fb900000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1049031b900000
> >
> > Bisection is inconclusive: the issue happens on the oldest tested release.
> >
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12d57007900000
> > final oops:     https://syzkaller.appspot.com/x/report.txt?x=11d57007900000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=16d57007900000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+f58fe4bb535845237057@xxxxxxxxxxxxxxxxxxxxxxxxx
> >
>
> I looked at this for a bit, and I think there is a missing range check
> for one of the
> members of 'struct vmci_qp_alloc_info' somewhere in the ioctl path.
>
> https://syzkaller.appspot.com/x/repro.c?x=1049031b900000 shows what
> arguments get passed, and while all the members are small, my guess is
> that something is wrong with the sizes in qp_host_alloc_queue() allocating
> an array based on produce_size/consume_size, while
> qp_host_register_user_memory() bases the size on the larger
> ppn_va/num_ppns.
>
> Adding everyone from the git history that did meaningful changes in the past
> for this driver, as there is no specific maintainer file entry for
> them to further
> investigate.

Hi Arnd,

There is already a recorded fix for this on the dashboard:
https://syzkaller.appspot.com/bug?extid=f58fe4bb535845237057
VMCI: check return value of get_user_pages_fast() for errors


> > general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
> > KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
> > CPU: 1 PID: 6894 Comm: syz-executor291 Not tainted 5.9.0-rc8-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > RIP: 0010:compound_head include/linux/page-flags.h:182 [inline]
> > RIP: 0010:put_page include/linux/mm.h:1172 [inline]
> > RIP: 0010:qp_release_pages+0x5a/0x310 drivers/misc/vmw_vmci/vmci_queue_pair.c:635
> > Code: 5c ad d1 fc 4d 85 f6 c7 44 24 04 00 00 00 00 0f 85 0f 01 00 00 e9 27 02 00 00 e8 c1 b0 d1 fc 48 8d 7d 08 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 62 02 00 00 48 8b 45 08 31 ff 49 89 c4 48 89
> > RSP: 0018:ffffc900014e7948 EFLAGS: 00010202
> > RAX: 0000000000000001 RBX: ffff8880a06990d0 RCX: ffffffff84a48f81
> > RDX: ffff88808e3ec300 RSI: ffffffff84a48e4f RDI: 0000000000000008
> > RBP: 0000000000000000 R08: 0000000000000001 R09: ffff8880960634ff
> > R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffffd
> > R13: dffffc0000000000 R14: fffffffffffffff2 R15: 0000000000000000
> > FS:  0000000001e5e880(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 0000000020000040 CR3: 00000000a1e74000 CR4: 00000000001506e0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > Call Trace:
> >  qp_host_get_user_memory+0x249/0x3e0 drivers/misc/vmw_vmci/vmci_queue_pair.c:660
> >  qp_host_register_user_memory drivers/misc/vmw_vmci/vmci_queue_pair.c:704 [inline]
> >  qp_broker_create drivers/misc/vmw_vmci/vmci_queue_pair.c:1383 [inline]
> >  qp_broker_alloc+0x10f9/0x1bf0 drivers/misc/vmw_vmci/vmci_queue_pair.c:1737
> >  vmci_qp_broker_alloc+0x48/0x60 drivers/misc/vmw_vmci/vmci_queue_pair.c:1930
> >  vmci_host_do_alloc_queuepair.constprop.0+0x1b4/0x400 drivers/misc/vmw_vmci/vmci_host.c:488
> >  vmci_host_unlocked_ioctl+0x13cc/0x1e60 drivers/misc/vmw_vmci/vmci_host.c:927
> >  vfs_ioctl fs/ioctl.c:48 [inline]
> >  __do_sys_ioctl fs/ioctl.c:753 [inline]
> >  __se_sys_ioctl fs/ioctl.c:739 [inline]
> >  __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
> >  do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> >  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > RIP: 0033:0x4402f9
> > Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
> > RSP: 002b:00007ffd6af99eb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> > RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004402f9
> > RDX: 0000000020000100 RSI: 00000000000007a8 RDI: 0000000000000003
> > RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
> > R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000401b00
> > R13: 0000000000401b90 R14: 0000000000000000 R15: 0000000000000000
> > Modules linked in:
> > ---[ end trace 5d73c037702bf45c ]---
> > RIP: 0010:compound_head include/linux/page-flags.h:182 [inline]
> > RIP: 0010:put_page include/linux/mm.h:1172 [inline]
> > RIP: 0010:qp_release_pages+0x5a/0x310 drivers/misc/vmw_vmci/vmci_queue_pair.c:635
> > Code: 5c ad d1 fc 4d 85 f6 c7 44 24 04 00 00 00 00 0f 85 0f 01 00 00 e9 27 02 00 00 e8 c1 b0 d1 fc 48 8d 7d 08 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 62 02 00 00 48 8b 45 08 31 ff 49 89 c4 48 89
> > RSP: 0018:ffffc900014e7948 EFLAGS: 00010202
> > RAX: 0000000000000001 RBX: ffff8880a06990d0 RCX: ffffffff84a48f81
> > RDX: ffff88808e3ec300 RSI: ffffffff84a48e4f RDI: 0000000000000008
> > RBP: 0000000000000000 R08: 0000000000000001 R09: ffff8880960634ff
> > R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffffd
> > R13: dffffc0000000000 R14: fffffffffffffff2 R15: 0000000000000000
> > FS:  0000000001e5e880(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 0000000020000040 CR3: 00000000a1e74000 CR4: 00000000001506e0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> >
> >
> > ---
> > This report 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@xxxxxxxxxxxxxxxx.
> >
> > syzbot will keep track of this issue. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> > syzbot can test patches for this issue, for details see:
> > https://goo.gl/tpsmEJ#testing-patches
>
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