From: B K Karthik <bkkarthik@pesu.pes.edu>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: syzbot <syzbot+72ff2fa98097767b5a27@syzkaller.appspotmail.com>,
Anant Thazhemadam <anant.thazhemadam@gmail.com>,
David Miller <davem@davemloft.net>,
Herbert Xu <herbert@gondor.apana.org.au>,
Jakub Kicinski <kuba@kernel.org>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
LKML <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
Steffen Klassert <steffen.klassert@secunet.com>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Subject: Re: KASAN: use-after-free Read in __xfrm6_tunnel_spi_lookup
Date: Thu, 10 Sep 2020 13:37:49 +0530 [thread overview]
Message-ID: <CAAhDqq0qcnMKdaoRnaGM6G8H1U7SAmTvX=hgEoor1=_eJff-Vw@mail.gmail.com> (raw)
In-Reply-To: <CACT4Y+bUK4icp1TMfhWOj=vEXULbiUQ84RXYaKnB=3J_N3wZCQ@mail.gmail.com>
On Thu, Sep 10, 2020 at 1:32 PM Dmitry Vyukov <dvyukov@google.com> wrote:
>
> On Thu, Sep 10, 2020 at 9:20 AM Anant Thazhemadam
> <anant.thazhemadam@gmail.com> wrote:
> > Looks like this bug is no longer valid. I'm not sure which commit seems to have fixed it. Can this be marked as invalid or closed yet?
>
> You can see on the dashboard (or in mailing list archives) that B K
> Karthik tested a patch for this bug in July:
> https://syzkaller.appspot.com/bug?extid=72ff2fa98097767b5a27
>
> So perhaps that patch fixes it? Karthik, did you send it? Was it
> merged? Did the commit include the syzbot Reported-by tag?
>
I did send it. I was taking a u32 spi value and casting it to a
pointer to an IP address. Steffen Klassert
<steffen.klassert@secunet.com> pointed out to me that the approach i
was looking at was completely wrong.
https://lkml.org/lkml/2020/7/27/361 is the conversation. hope this
helps.
thanks,
karthik
>
>
> On Thu, Jul 16, 2020 at 4:05 AM syzbot
> <syzbot+72ff2fa98097767b5a27@syzkaller.appspotmail.com> wrote:
> >
> > syzbot has found a reproducer for the following issue on:
> >
> > HEAD commit: ca0e494a Add linux-next specific files for 20200715
> > git tree: linux-next
> > console output: https://syzkaller.appspot.com/x/log.txt?x=175099bf100000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=2c76d72659687242
> > dashboard link: https://syzkaller.appspot.com/bug?extid=72ff2fa98097767b5a27
> > compiler: gcc (GCC) 10.1.0-syz 20200507
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=112e8dbf100000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=109429bf100000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+72ff2fa98097767b5a27@syzkaller.appspotmail.com
> >
> > netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
> > netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
> > netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
> > ==================================================================
> > BUG: KASAN: use-after-free in __xfrm6_tunnel_spi_lookup+0x3a9/0x3b0 net/ipv6/xfrm6_tunnel.c:79
> > Read of size 8 at addr ffff8880934578a8 by task syz-executor437/6811
> > CPU: 0 PID: 6811 Comm: syz-executor437 Not tainted 5.8.0-rc5-next-20200715-syzkaller #0
> > 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+0x18f/0x20d lib/dump_stack.c:118
> > print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
> > __kasan_report mm/kasan/report.c:513 [inline]
> > kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
> > __xfrm6_tunnel_spi_lookup+0x3a9/0x3b0 net/ipv6/xfrm6_tunnel.c:79
> > xfrm6_tunnel_spi_lookup+0x8a/0x1d0 net/ipv6/xfrm6_tunnel.c:95
> > xfrmi6_rcv_tunnel+0xb9/0x100 net/xfrm/xfrm_interface.c:824
> > tunnel6_rcv+0xef/0x2b0 net/ipv6/tunnel6.c:148
> > ip6_protocol_deliver_rcu+0x2e8/0x1670 net/ipv6/ip6_input.c:433
> > ip6_input_finish+0x7f/0x160 net/ipv6/ip6_input.c:474
> > NF_HOOK include/linux/netfilter.h:307 [inline]
> > NF_HOOK include/linux/netfilter.h:301 [inline]
> > ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:483
> > dst_input include/net/dst.h:449 [inline]
> > ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
> > NF_HOOK include/linux/netfilter.h:307 [inline]
> > NF_HOOK include/linux/netfilter.h:301 [inline]
> > ipv6_rcv+0x28e/0x3c0 net/ipv6/ip6_input.c:307
> > __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5287
> > __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5401
> > netif_receive_skb_internal net/core/dev.c:5503 [inline]
> > netif_receive_skb+0x159/0x990 net/core/dev.c:5562
> > tun_rx_batched.isra.0+0x460/0x720 drivers/net/tun.c:1518
> > tun_get_user+0x23b2/0x35b0 drivers/net/tun.c:1972
> > tun_chr_write_iter+0xba/0x151 drivers/net/tun.c:2001
> > call_write_iter include/linux/fs.h:1879 [inline]
> > new_sync_write+0x422/0x650 fs/read_write.c:515
> > vfs_write+0x59d/0x6b0 fs/read_write.c:595
> > ksys_write+0x12d/0x250 fs/read_write.c:648
> > do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
> > entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > RIP: 0033:0x403d50
> > Code: Bad RIP value.
> > RSP: 002b:00007ffe8fe93368 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000403d50
> > RDX: 000000000000005e RSI: 00000000200007c0 RDI: 00000000000000f0
> > RBP: 00007ffe8fe93390 R08: 0000000000000000 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe8fe93380
> > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> > Allocated by task 6811:
> > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
> > kasan_set_track mm/kasan/common.c:56 [inline]
> > __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
> > __do_kmalloc mm/slab.c:3655 [inline]
> > __kmalloc+0x1a8/0x320 mm/slab.c:3664
> > kmalloc include/linux/slab.h:559 [inline]
> > kzalloc include/linux/slab.h:666 [inline]
> > tomoyo_init_log+0x1335/0x1e50 security/tomoyo/audit.c:275
> > tomoyo_supervisor+0x32f/0xeb0 security/tomoyo/common.c:2097
> > tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline]
> > tomoyo_path_number_perm+0x3ed/0x4d0 security/tomoyo/file.c:734
> > security_file_ioctl+0x50/0xb0 security/security.c:1489
> > ksys_ioctl+0x50/0x180 fs/ioctl.c:747
> > __do_sys_ioctl fs/ioctl.c:762 [inline]
> > __se_sys_ioctl fs/ioctl.c:760 [inline]
> > __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760
> > do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
> > entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > Freed by task 6811:
> > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
> > kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
> > kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
> > __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
> > __cache_free mm/slab.c:3418 [inline]
> > kfree+0x103/0x2c0 mm/slab.c:3756
> > tomoyo_supervisor+0x350/0xeb0 security/tomoyo/common.c:2149
> > tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline]
> > tomoyo_path_number_perm+0x3ed/0x4d0 security/tomoyo/file.c:734
> > security_file_ioctl+0x50/0xb0 security/security.c:1489
> > ksys_ioctl+0x50/0x180 fs/ioctl.c:747
> > __do_sys_ioctl fs/ioctl.c:762 [inline]
> > __se_sys_ioctl fs/ioctl.c:760 [inline]
> > __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760
> > do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
> > entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > The buggy address belongs to the object at ffff888093457800
> > which belongs to the cache kmalloc-512 of size 512
> > The buggy address is located 168 bytes inside of
> > 512-byte region [ffff888093457800, ffff888093457a00)
> > The buggy address belongs to the page:
> > page:000000005c2b5911 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x93457
> > flags: 0xfffe0000000200(slab)
> > raw: 00fffe0000000200 ffffea00028d4308 ffffea0002834c88 ffff8880aa000600
> > raw: 0000000000000000 ffff888093457000 0000000100000004 0000000000000000
> > page dumped because: kasan: bad access detected
> > Memory state around the buggy address:
> > ffff888093457780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > ffff888093457800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > >ffff888093457880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ^
> > ffff888093457900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ffff888093457980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ==================================================================
next prev parent reply other threads:[~2020-09-10 8:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-15 19:02 KASAN: use-after-free Read in __xfrm6_tunnel_spi_lookup syzbot
2020-07-16 2:05 ` syzbot
2020-09-10 8:02 ` Dmitry Vyukov
2020-09-10 8:07 ` B K Karthik [this message]
2020-09-10 8:09 ` Dmitry Vyukov
2020-09-11 8:06 ` Steffen Klassert
2020-09-11 8:18 ` Dmitry Vyukov
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