netdev - Re: net/sctp: BUG: KASAN: stack-out-of-bounds in memcmp

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Message-ID: <cd16b62f-228a-e3de-f68e-6db39e97da0b@gmail.com>
Date:   Sat, 15 Oct 2016 16:28:44 +0800
From:   Baozeng Ding <sploving1@...il.com>
To:     Xin Long <lucien.xin@...il.com>
Cc:     Vladislav Yasevich <vyasevich@...il.com>,
        Neil Horman <nhorman@...driver.com>,
        David Miller <davem@...emloft.net>, linux-sctp@...r.kernel.org,
        network dev <netdev@...r.kernel.org>
Subject: Re: net/sctp: BUG: KASAN: stack-out-of-bounds in memcmp

Hello Xin Long,

On 2016/10/14 19:13, Xin Long wrote:
> On Sat, Aug 20, 2016 at 3:51 PM, Baozeng Ding <sploving1@...il.com> wrote:
>> Hello all,
>> The following program triggers  stack-out-of-bounds in memcmp. The kernel version is 4.8.0-rc1+ (on Aug 13 commit 118253a593bd1c57de2d1193df1ccffe1abe745b). Thanks.
> ...
>>
>> #define _GNU_SOURCE
>> #include <unistd.h>
>> #include <stdint.h>
>> #include <sys/socket.h>
>> #include <sys/mman.h>
>> #include <linux/in.h>
>> #include <fcntl.h>
>> #include <string.h>
>> #include <stdio.h>
>>
>> int main()
>> {
>>         int fd;
>>         mmap((void *)0x20000000ul, 0xff2000ul, 0x3ul, 0x32ul, -1, 0x0ul);
>>         fd = socket(AF_INET6, SOCK_STREAM, IPPROTO_SCTP);
>>         memcpy((void*)0x20f82f80, "\x0a\x00\xab\x12\x72\xd4\x19\x9a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x85\xda\x00\xa0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 128);
>>         bind(fd, (struct sockaddr*)0x20f82f80ul, 0x80ul);
>>         *(uint64_t*)0x202e1fc8 = (uint64_t)0x20f77f80;
>>         *(uint32_t*)0x202e1fd0 = (uint32_t)0x80;
>>         *(uint64_t*)0x202e1fd8 = (uint64_t)0x20f7dfe0;
>>         *(uint64_t*)0x202e1fe0 = (uint64_t)0x2;
>>         *(uint64_t*)0x202e1fe8 = (uint64_t)0x20f77000;
>>         *(uint64_t*)0x202e1ff0 = (uint64_t)0x3;
>>         *(uint32_t*)0x202e1ff8 = (uint32_t)0x80;
>>         memcpy((void*)0x20f77f80, "\x0a\x00\xab\x12\xb0\xb3\x20\x7b\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\xc2\xc2\x0b\xb2\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 128);
>>         *(uint64_t*)0x20f7dfe0 = (uint64_t)0x20f77fc5;
>>         *(uint64_t*)0x20f7dfe8 = (uint64_t)0x3b;
>>         *(uint64_t*)0x20f7dff0 = (uint64_t)0x20f77fac;
>>         *(uint64_t*)0x20f7dff8 = (uint64_t)0x54;
>>         memcpy((void*)0x20f77fc5, "\xa5\x7d\xf3\xc4\xfe\xd3\xfd\x44\x63\x00\x8c\x1e\x4c\x2e\x8d\x8d\x9a\x9c\x9c\x9d\x5b\x7c\xe1\x06\xf7\x15\x16\xed\x68\xd1\xfc\xf4\xa4\x3a\xe4\x69\x51\x16\x74\xf4\x1a\xcf\x0e\x99\xc3\xa3\x87\xe7\x81\x6c\x10\x78\x75\x17\x69\x9d\x11\x0c\xc7", 59);
>>         memcpy((void*)0x20f77fac, "\x86\x08\x89\x3c\xf3\x58\xea\xe7\x64\x6a\xfb\xb5\xe8\xdd\x5f\x69\xa5\xd4\xdc\xd9\xe7\x71\x95\x07\x78\x7b\x21\xda\x43\x9c\x62\x4d\xca\x64\xb5\x6e\x96\x55\xe9\x58\x76\x66\x1d\xb9\x7b\xe6\x20\xc1\xa9\xed\x70\xc1\x2b\x7c\x86\x8c\xba\x28\xb3\x2c\xb9\x64\xb7\x84\x65\x0d\x7f\xa6\x98\x6f\x49\xcb\x35\xad\x5a\xdf\x13\x75\x99\x57\x7e\xbb\x38\x89", 84);
>>         *(uint64_t*)0x20f77000 = (uint64_t)0x15;
>>         *(uint32_t*)0x20f77008 = (uint32_t)0x1;
>>         *(uint32_t*)0x20f7700c = (uint32_t)0xfffffffffffffffe;
>>         *(uint8_t*)0x20f77010 = (uint8_t)0xbb;
>>         *(uint8_t*)0x20f77011 = (uint8_t)0x2;
>>         *(uint8_t*)0x20f77012 = (uint8_t)0x5;
>>         *(uint8_t*)0x20f77013 = (uint8_t)0x2;
>>         *(uint8_t*)0x20f77014 = (uint8_t)0x80000000;
>>         *(uint64_t*)0x20f77015 = (uint64_t)0x10;
>>         *(uint32_t*)0x20f7701d = (uint32_t)0xffff;
>>         *(uint32_t*)0x20f77021 = (uint32_t)0x1;
>>         *(uint64_t*)0x20f77025 = (uint64_t)0x13;
>>         *(uint32_t*)0x20f7702d = (uint32_t)0x6;
>>         *(uint32_t*)0x20f77031 = (uint32_t)0xfffffffffffffe00;
>>         *(uint8_t*)0x20f77035 = (uint8_t)0x80000000;
>>         *(uint8_t*)0x20f77036 = (uint8_t)0xfffffffffffffff8;
>>         sendmmsg(fd, (struct mmsghdr *)0x202e1fc8ul, 0x1ul, 0x1ul);
>>         return 0;
>> }
>>
> Hi, Baozeng, I couldn't reproduce this issue with this script,
> even in 118253a593bd1c57de2d1193df1ccffe1abe745b
> do I need to do some extra config for this ?
> 
You need config KASAN.
CONFIG_HAVE_ARCH_KASAN=y
CONFIG_KASAN=y
CONFIG_KASAN_INLINE=y
CONFIG_KASAN_SHADOW_OFFSET=0xdffffc0000000000

I justed tested with b67be92feb486f800d80d72c67fd87b47b79b18e(Octor 12),
it sitll exits. If you still cannot reproduce it, i will send the .config to you privately. Thanks.