Re: BUG: KASAN: stack-out-of-bounds in ipv6_addr_equal include/net/ipv6.h

On Fri, Jun 15, 2018 at 8:33 AM, air icy [off-list ref] wrote:

Hi,
I found a kernel bug with enchanced syzkaller in the newest linux kernel v4.17.
The output is as follows:

==================================================================
BUG: KASAN: stack-out-of-bounds in ipv6_addr_equal include/net/ipv6.h:508 [inline]
BUG: KASAN: stack-out-of-bounds in __xfrm6_state_addr_check include/net/xfrm.h:1358 [inline]
BUG: KASAN: stack-out-of-bounds in xfrm_state_addr_check include/net/xfrm.h:1375 [inline]
BUG: KASAN: stack-out-of-bounds in xfrm_state_find+0x2693/0x2740 net/xfrm/xfrm_state.c:959
Read of size 4 at addr ffff880065d77b70 by task syz-executor1/10036

This may be related to "KMSAN: uninit-value in xfrm_state_find":
https://groups.google.com/d/msg/syzkaller-bugs/myqLUHNGRRc/Zb3SlyJZBwAJ

CPU: 0 PID: 10036 Comm: syz-executor1 Not tainted 4.17.0 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
Call Trace:

The buggy address belongs to the page:
page:ffffea0001975dc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x100000000000000()
raw: 0100000000000000 0000000000000000 ffffea0001975dc8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff880065d77a00: 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f4 f4 f4 f2
 ffff880065d77a80: f2 f2 f2 00 00 00 00 f2 f2 f2 f2 00 00 00 00 00

quoted

ffff880065d77b00: f4 f4 f4 f2 f2 f2 f2 00 00 00 00 00 00 00 f4 f2

                                                             ^
 ffff880065d77b80: f2 f2 f2 00 00 00 00 00 00 00 00 00 f4 f4 f4 f3
 ffff880065d77c00: f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 10036 Comm: syz-executor1 Tainted: G    B             4.17.0 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
Call Trace:
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

bugzilla url: https://bugzilla.kernel.org/show_bug.cgi?id=200065
config file is attached in this email

thanks
Xuwen Tu

 log2

 report2

 .config

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