Re: Out-of-bounds access in nfnetlink_bind

[Andrey Ryabinin]

2014-12-02 10:53 GMT+03:00 Dmitry Vyukov <dvyukov@xxxxxxxxxx>:
> Hi,
>
> I am working on Kernel AddressSanitizer, a fast memory error detector
> for kernel:
> https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel
>
> Here is an error report that I got while running trinity:
>
> ==================================================================
> BUG: AddressSanitizer: out of bounds access in
> nfnetlink_bind+0xbf/0xe0 at addr ffffffff82eef710
> Read of size 4 by task trinity-main/2533
> Out-of-bounds access to the global variable 'nfnl_group2type'
> [ffffffff82eef6e0-ffffffff82eef704) defined at
> net/netfilter/nfnetlink.c:43:18
> CPU: 0 PID: 2533 Comm: trinity-main Not tainted 3.18.0-rc1+ #44
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>  ffffffff835173e8 ffff8800b989fd18 ffffffff82a3d66f 0000000000000007
>  ffff8800b989fdc0 ffff8800b989fda8 ffffffff813a3826 0000000000000012
>  0000000000000000 0000000100000018 0000000000000296 ffff8800b989fd88
> Call Trace:
>  [<ffffffff813a39c1>] __asan_report_load4_noabort+0x41/0x50
> mm/kasan/report.c:236
>  [<ffffffff824769cf>] nfnetlink_bind+0xbf/0xe0 net/netfilter/nfnetlink.c:467
>  [<ffffffff82469b71>] netlink_bind+0x221/0x7e0 net/netlink/af_netlink.c:1472
>  [<ffffffff8238bf77>] SYSC_bind+0x117/0x170 net/socket.c:1541
>  [<ffffffff8238dc29>] SyS_bind+0x9/0x10 net/socket.c:1527
>  [<ffffffff82a522a9>] system_call_fastpath+0x12/0x17
> arch/x86/kernel/entry_64.S:422
> Memory state around the buggy address:
>  ffffffff82eef480: 00 00 00 00 00 00 00 00 00 00 00 00 00 f8 f8 f8
>  ffffffff82eef500: f8 f8 f8 f8 00 00 00 00 f8 f8 f8 f8 00 00 00 01
>  ffffffff82eef580: f8 f8 f8 f8 00 00 00 00 05 f8 f8 f8 f8 f8 f8 f8
>  ffffffff82eef600: 00 00 04 f8 f8 f8 f8 f8 00 00 f8 f8 f8 f8 f8 f8
>  ffffffff82eef680: 00 00 00 00 07 f8 f8 f8 f8 f8 f8 f8 00 00 00 00
>>ffffffff82eef700: 04 f8 f8 f8 f8 f8 f8 f8 00 06 f8 f8 f8 f8 f8 f8
>                          ^
>  ffffffff82eef780: 00 00 00 05 f8 f8 f8 f8 00 00 00 00 00 f8 f8 f8
>  ffffffff82eef800: f8 f8 f8 f8 00 00 00 00 02 f8 f8 f8 f8 f8 f8 f8
>  ffffffff82eef880: 00 00 00 00 06 f8 f8 f8 f8 f8 f8 f8 00 00 00 04
>  ffffffff82eef900: f8 f8 f8 f8 00 00 00 00 00 04 f8 f8 f8 f8 f8 f8
>  ffffffff82eef980: 00 00 00 07 f8 f8 f8 f8 00 00 00 06 f8 f8 f8 f8
> ==================================================================
>
> My source is on revision f114040e3ea6e07372334ade75d1ee0
>
> As far as I see netlink_bind just calls nfnetlink_bind with whatever
> groups user has requested; nfnetlink_bind in turn do not do any checks
> before indexing the global nfnl_group2type array with the group.

I've reported this few weeks ago: https://lkml.org/lkml/2014/11/13/65
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