use-after-free in ip6_setup_cork
From: Dmitry Vyukov
Date: Sat Nov 28 2015 - 06:01:43 EST
Hello,
The following program triggers use-after-free in ip6_setup_cork:
// autogenerated by syzkaller (http://github.com/google/syzkaller)
#include <syscall.h>
#include <string.h>
#include <stdint.h>
#include <pthread.h>
int r1, r3, r4;
void *thr0(void *arg)
{
*(uint64_t*)0x20000d90 = 0x20000fd3;
*(uint64_t*)0x20000d98 = 0x2d;
*(uint64_t*)0x20000da0 = 0x20000fa4;
*(uint64_t*)0x20000da8 = 0x5c;
*(uint64_t*)0x20000db0 = 0x20000fac;
*(uint64_t*)0x20000db8 = 0x71;
*(uint64_t*)0x20000dc0 = 0x20000fb6;
*(uint64_t*)0x20000dc8 = 0xec;
*(uint64_t*)0x20000dd0 = 0x20000fae;
*(uint64_t*)0x20000dd8 = 0x70;
syscall(SYS_vmsplice, r4, 0x20000d90ul, 0x5ul, 0x2ul, 0, 0);
return 0;
}
void *thr1(void *arg)
{
memcpy((void*)0x200025e5, "\xbb\xef\x44\xd6\x33\x93", 6);
syscall(SYS_setsockopt, r1, 0x29ul, 0x6ul, 0x200025e5ul, 0x6ul, 0);
return 0;
}
void *thr2(void *arg)
{
syscall(SYS_splice, r3, 0x0ul, r1, 0x0ul, 0xaful, 0x3ul);
return 0;
}
int main()
{
syscall(SYS_mmap, 0x20000000ul, 0x10000ul, 0x3ul, 0x32ul,
0xfffffffffffffffful, 0x0ul);
r1 = syscall(SYS_socket, 0xaul, 0x80002ul, 0x0ul, 0, 0, 0);
syscall(SYS_pipe2, 0x20001000ul, 0x800ul, 0, 0, 0, 0);
r3 = *(uint32_t*)0x20001000;
r4 = *(uint32_t*)0x20001004;
memcpy((void*)0x20003000,
"\x0a\x00\x33\xe2\x61\x44\xfe\x90\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x5b\x11\x6d\x22",
28);
long r6 = syscall(SYS_connect, r1, 0x20003000ul, 0x1cul, 0, 0, 0);
pthread_t th[4];
pthread_create(&th[0], 0, thr0, 0);
pthread_create(&th[1], 0, thr1, 0);
pthread_create(&th[2], 0, thr2, 0);
pthread_create(&th[3], 0, thr1, 0);
pthread_join(th[0], 0);
pthread_join(th[1], 0);
pthread_join(th[2], 0);
pthread_join(th[3], 0);
return 0;
}
==================================================================
BUG: KASAN: use-after-free in ip6_setup_cork+0xeb8/0x11a0 at addr
ffff88006d36da08
Read of size 4 by task executor/23958
=============================================================================
BUG kmalloc-64 (Not tainted): kasan: bad access detected
-----------------------------------------------------------------------------
Disabling lock debugging due to kernel taint
INFO: Allocated in sock_kmalloc+0x7f/0xc0 age=9 cpu=3 pid=23946
[< none >] ___slab_alloc+0x41c/0x460 mm/slub.c:2438
[< none >] __slab_alloc+0x1b/0x30 mm/slub.c:2467
[< inline >] slab_alloc_node mm/slub.c:2530
[< inline >] slab_alloc mm/slub.c:2572
[< none >] __kmalloc+0x156/0x1b0 mm/slub.c:3532
[< inline >] kmalloc include/linux/slab.h:463
[< none >] sock_kmalloc+0x7f/0xc0 net/core/sock.c:1774
[< none >] do_ipv6_setsockopt.isra.8+0x779/0x2a60
net/ipv6/ipv6_sockglue.c:483
[< none >] ipv6_setsockopt+0x9b/0x140 net/ipv6/ipv6_sockglue.c:885
[< none >] udpv6_setsockopt+0x45/0x80 net/ipv6/udp.c:1425
[< none >] sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2645
[< inline >] SYSC_setsockopt net/socket.c:1757
[< none >] SyS_setsockopt+0x158/0x240 net/socket.c:1736
[< none >] entry_SYSCALL_64_fastpath+0x12/0x71
arch/x86/entry/entry_64.S:185
INFO: Freed in sock_kfree_s+0x29/0x70 age=11 cpu=2 pid=23957
[< none >] __slab_free+0x1fb/0x300 mm/slub.c:2648
[< inline >] slab_free mm/slub.c:2803
[< none >] kfree+0x13b/0x160 mm/slub.c:3632
[< inline >] __sock_kfree_s net/core/sock.c:1795
[< none >] sock_kfree_s+0x29/0x70 net/core/sock.c:1801
[< none >] do_ipv6_setsockopt.isra.8+0x815/0x2a60
net/ipv6/ipv6_sockglue.c:506
[< none >] ipv6_setsockopt+0x9b/0x140 net/ipv6/ipv6_sockglue.c:885
[< none >] udpv6_setsockopt+0x45/0x80 net/ipv6/udp.c:1425
[< none >] sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2645
[< inline >] SYSC_setsockopt net/socket.c:1757
[< none >] SyS_setsockopt+0x158/0x240 net/socket.c:1736
[< none >] entry_SYSCALL_64_fastpath+0x12/0x71
arch/x86/entry/entry_64.S:185
INFO: Slab 0xffffea0001b4db00 objects=20 used=8 fp=0xffff88006d36da08
flags=0x500000000004080
INFO: Object 0xffff88006d36da08 @offset=6664 fp=0xffff88006d36d3e8
CPU: 3 PID: 23958 Comm: executor Tainted: G B 4.4.0-rc2+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
00000000ffffffff ffff88003c32f348 ffffffff81a2bdb0 ffff88003e807840
ffff88006d36da08 ffff88006d36c000 ffff88003c32f378 ffffffff814541d4
ffff88003e807840 ffffea0001b4db00 ffff88006d36da08 ffff88006d126000
Call Trace:
[<ffffffff8145b9ae>] __asan_report_load4_noabort+0x3e/0x40
mm/kasan/report.c:279
[<ffffffff829de1e8>] ip6_setup_cork+0xeb8/0x11a0 net/ipv6/ip6_output.c:1200
[<ffffffff829e9e2a>] ip6_make_skb+0x19a/0x3b0 net/ipv6/ip6_output.c:1769
[<ffffffff82a3c3e6>] udpv6_sendmsg+0x11c6/0x2120 net/ipv6/udp.c:1314
[<ffffffff829038cc>] inet_sendmsg+0x23c/0x340 net/ipv4/af_inet.c:733
[< inline >] sock_sendmsg_nosec net/socket.c:610
[<ffffffff826adc2a>] sock_sendmsg+0xca/0x110 net/socket.c:620
[<ffffffff826ae057>] kernel_sendmsg+0x47/0x60 net/socket.c:628
[<ffffffff826b564a>] sock_no_sendpage+0xfa/0x130 net/core/sock.c:2270
[<ffffffff826ac6d0>] kernel_sendpage+0x90/0xe0 net/socket.c:3278
[<ffffffff826ac7c5>] sock_sendpage+0xa5/0xd0 net/socket.c:765
[<ffffffff814feca4>] pipe_to_sendpage+0x264/0x320 fs/splice.c:720
[< inline >] splice_from_pipe_feed fs/splice.c:772
[<ffffffff81501435>] __splice_from_pipe+0x235/0x6d0 fs/splice.c:897
[<ffffffff81504677>] splice_from_pipe+0xf7/0x140 fs/splice.c:932
[<ffffffff81504700>] generic_splice_sendpage+0x40/0x50 fs/splice.c:1105
[< inline >] do_splice_from fs/splice.c:1124
[< inline >] do_splice fs/splice.c:1400
[< inline >] SYSC_splice fs/splice.c:1703
[<ffffffff815052f8>] SyS_splice+0x7c8/0x15c0 fs/splice.c:1686
[<ffffffff82ddc0ae>] entry_SYSCALL_64_fastpath+0x12/0x71
arch/x86/entry/entry_64.S:185
==================================================================
On commit 78c4a49a69e910a162b05e4e8727b9bdbf948f13 (Nov 25).
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