From mboxrd@z Thu Jan 1 00:00:00 1970 From: syzbot Subject: KASAN: use-after-free Read in _decode_session6 Date: Thu, 06 Sep 2018 09:41:03 -0700 Message-ID: <0000000000008d5a360575368e31@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes To: davem@davemloft.net, herbert@gondor.apana.org.au, kuznet@ms2.inr.ac.ru, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, steffen.klassert@secunet.com, syzkaller-bugs@googlegroups.com, yoshfuji@linux-ipv6.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: b36fdc6853a3 Merge tag 'gpio-v4.19-2' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1556a396400000 kernel config: https://syzkaller.appspot.com/x/.config?x=4c7e83258d6e0156 dashboard link: https://syzkaller.appspot.com/bug?extid=e8c1d30881266e47eb33 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14d42021400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13d09f1e400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+e8c1d30881266e47eb33@syzkaller.appspotmail.com audit: type=1400 audit(1536202560.246:9): avc: denied { prog_run } for pid=4752 comm="syz-executor726" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=bpf permissive=1 ================================================================== BUG: KASAN: use-after-free in _decode_session6+0x1331/0x14e0 net/ipv6/xfrm6_policy.c:161 Read of size 1 at addr ffff8801bb87e97f by task syz-executor726/4752 CPU: 0 PID: 4752 Comm: syz-executor726 Not tainted 4.19.0-rc2+ #2 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 _decode_session6+0x1331/0x14e0 net/ipv6/xfrm6_policy.c:161 __xfrm_decode_session+0x71/0x140 net/xfrm/xfrm_policy.c:2299 xfrm_decode_session include/net/xfrm.h:1232 [inline] vti6_tnl_xmit+0x3fc/0x1bb1 net/ipv6/ip6_vti.c:542 __netdev_start_xmit include/linux/netdevice.h:4287 [inline] netdev_start_xmit include/linux/netdevice.h:4296 [inline] xmit_one net/core/dev.c:3216 [inline] dev_hard_start_xmit+0x272/0xc10 net/core/dev.c:3232 __dev_queue_xmit+0x2ab2/0x3870 net/core/dev.c:3802 dev_queue_xmit+0x17/0x20 net/core/dev.c:3835 __bpf_tx_skb net/core/filter.c:2012 [inline] __bpf_redirect_common net/core/filter.c:2050 [inline] __bpf_redirect+0x5b7/0xae0 net/core/filter.c:2057 ____bpf_clone_redirect net/core/filter.c:2090 [inline] bpf_clone_redirect+0x2f6/0x490 net/core/filter.c:2062 bpf_prog_c39d1ba309a769f7+0xd1e/0x1000 Allocated by task 4752: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 __do_kmalloc_node mm/slab.c:3682 [inline] __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3696 __kmalloc_reserve.isra.41+0x3a/0xe0 net/core/skbuff.c:137 pskb_expand_head+0x230/0x10e0 net/core/skbuff.c:1463 skb_ensure_writable+0x3dd/0x640 net/core/skbuff.c:5129 __bpf_try_make_writable net/core/filter.c:1633 [inline] bpf_try_make_writable net/core/filter.c:1639 [inline] bpf_try_make_head_writable net/core/filter.c:1647 [inline] ____bpf_clone_redirect net/core/filter.c:2084 [inline] bpf_clone_redirect+0x14a/0x490 net/core/filter.c:2062 bpf_prog_c39d1ba309a769f7+0xd1e/0x1000 Freed by task 4752: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x210 mm/slab.c:3813 skb_free_head+0x99/0xc0 net/core/skbuff.c:550 skb_release_data+0x6a4/0x880 net/core/skbuff.c:570 skb_release_all+0x4a/0x60 net/core/skbuff.c:627 __kfree_skb net/core/skbuff.c:641 [inline] kfree_skb+0x19d/0x4e0 net/core/skbuff.c:659 vti6_tnl_xmit+0x387/0x1bb1 net/ipv6/ip6_vti.c:561 __netdev_start_xmit include/linux/netdevice.h:4287 [inline] netdev_start_xmit include/linux/netdevice.h:4296 [inline] xmit_one net/core/dev.c:3216 [inline] dev_hard_start_xmit+0x272/0xc10 net/core/dev.c:3232 __dev_queue_xmit+0x2ab2/0x3870 net/core/dev.c:3802 dev_queue_xmit+0x17/0x20 net/core/dev.c:3835 __bpf_tx_skb net/core/filter.c:2012 [inline] __bpf_redirect_common net/core/filter.c:2050 [inline] __bpf_redirect+0x5b7/0xae0 net/core/filter.c:2057 ____bpf_clone_redirect net/core/filter.c:2090 [inline] bpf_clone_redirect+0x2f6/0x490 net/core/filter.c:2062 bpf_prog_c39d1ba309a769f7+0xd1e/0x1000 The buggy address belongs to the object at ffff8801bb87e780 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 511 bytes inside of 512-byte region [ffff8801bb87e780, ffff8801bb87e980) The buggy address belongs to the page: page:ffffea0006ee1f80 count:1 mapcount:0 mapping:ffff8801dac00940 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0006eefd48 ffffea00073f5f08 ffff8801dac00940 raw: 0000000000000000 ffff8801bb87e000 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801bb87e800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801bb87e880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801bb87e900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801bb87e980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801bb87ea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This bug is generated by a bot. 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