From: Sasha Levin <sasha.levin@oracle.com>
To: linux-fsdevel <linux-fsdevel@vger.kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>, Jan Kara <jack@suse.cz>,
Dave Jones <davej@redhat.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: fs: use after free in /proc/pid/mountinfo
Date: Wed, 02 Jul 2014 23:15:04 -0400 [thread overview]
Message-ID: <53B4CAB8.5070407@oracle.com> (raw)
In-Reply-To: <53B3F331.7090204@oracle.com>
On 07/02/2014 07:55 AM, Sasha Levin wrote:
> Hi all,
>
> While fuzzing with trinity inside a KVM tools guest running the latest -next
> kernel I've stumbled on the following spew:
>
> [ 3569.869749] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
> [ 3569.869769] Dumping ftrace buffer:
> [ 3569.869879] (ftrace buffer empty)
> [ 3569.869894] Modules linked in:
> [ 3569.869900] CPU: 7 PID: 10239 Comm: trinity-c86 Tainted: G W 3.16.0-rc3-next-20140701-sasha-00023-g4eb2544-dirty #759
> [ 3569.869906] task: ffff88039e873000 ti: ffff880393f8c000 task.ti: ffff880393f8c000
> [ 3569.869932] RIP: show_mountinfo (fs/proc_namespace.c:127)
> [ 3569.869938] RSP: 0018:ffff880393f8fd08 EFLAGS: 00010282
> [ 3569.869943] RAX: ffff880200c6d208 RBX: 6b6b6b6b6b6b6b03 RCX: 0000000000000074
> [ 3569.869946] RDX: 0000000000000000 RSI: 6b6b6b6b6b6b6b03 RDI: ffff880200c6d208
> [ 3569.869953] RBP: ffff880393f8fd58 R08: 0000000000000001 R09: ffff88039e873d38
> [ 3569.869957] R10: 0000000000000001 R11: 0000000000000000 R12: ffff880200c6d208
> [ 3569.869962] R13: 6b6b6b6b6b6b6b6b R14: ffff880393f8ff50 R15: ffff880200c6d208
> [ 3569.869966] FS: 00007f6f20db9700(0000) GS:ffff8801ece00000(0000) knlGS:0000000000000000
> [ 3569.869969] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 3569.869974] CR2: 00007f6f20bee000 CR3: 00000003a0775000 CR4: 00000000000006a0
> [ 3569.869992] Stack:
> [ 3569.870011] ffff880393f8ff50 ffff880200c6d208 ffff880393f8fd48 ffffffff984e10ea
> [ 3569.870025] ffffffff9532c7fe ffff8802069a3b80 0000000000000065 6b6b6b6b6b6b6b6b
> [ 3569.870036] ffff880393f8ff50 ffff880200c6d208 ffff880393f8fd68 ffffffff9532c756
> [ 3569.870038] Call Trace:
> [ 3569.870051] ? down_read (kernel/locking/rwsem.c:45 (discriminator 2))
> [ 3569.870059] ? m_start (kernel/module.c:3634)
> [ 3569.870069] m_show (kernel/module.c:3649)
> [ 3569.870076] seq_read (fs/seq_file.c:235)
> [ 3569.870081] ? single_open_size (fs/seq_file.c:166)
> [ 3569.870092] do_loop_readv_writev (fs/read_write.c:708)
> [ 3569.870098] ? single_open_size (fs/seq_file.c:166)
> [ 3569.870098] do_readv_writev (fs/read_write.c:840)
> [ 3569.870098] ? get_parent_ip (kernel/sched/core.c:2550)
> [ 3569.870098] ? mutex_lock_nested (./arch/x86/include/asm/preempt.h:98 kernel/locking/mutex.c:570 kernel/locking/mutex.c:587)
> [ 3569.870098] ? __fdget_pos (fs/file.c:714)
> [ 3569.870098] ? __fdget_pos (fs/file.c:714)
> [ 3569.870098] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2557 kernel/locking/lockdep.c:2599)
> [ 3569.870098] ? __fget_light (fs/file.c:685)
> [ 3569.870098] vfs_readv (fs/read_write.c:866)
> [ 3569.870098] SyS_readv (fs/read_write.c:892 fs/read_write.c:884)
> [ 3569.870098] tracesys (arch/x86/kernel/entry_64.S:542)
> [ 3569.870098] Code: 00 00 00 00 66 66 66 66 90 55 48 89 e5 48 83 ec 50 48 89 5d d8 48 89 f3 4c 89 65 e0 49 89 fc 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 <48> 8b 06 48 89 75 b0 4c 8b 76 08 8b 96 ec 00 00 00 48 89 45 b8
> All code
> ========
> 0: 00 00 add %al,(%rax)
> 2: 00 00 add %al,(%rax)
> 4: 66 66 66 66 90 data32 data32 data32 xchg %ax,%ax
> 9: 55 push %rbp
> a: 48 89 e5 mov %rsp,%rbp
> d: 48 83 ec 50 sub $0x50,%rsp
> 11: 48 89 5d d8 mov %rbx,-0x28(%rbp)
> 15: 48 89 f3 mov %rsi,%rbx
> 18: 4c 89 65 e0 mov %r12,-0x20(%rbp)
> 1c: 49 89 fc mov %rdi,%r12
> 1f: 4c 89 6d e8 mov %r13,-0x18(%rbp)
> 23: 4c 89 75 f0 mov %r14,-0x10(%rbp)
> 27: 4c 89 7d f8 mov %r15,-0x8(%rbp)
> 2b:* 48 8b 06 mov (%rsi),%rax <-- trapping instruction
> 2e: 48 89 75 b0 mov %rsi,-0x50(%rbp)
> 32: 4c 8b 76 08 mov 0x8(%rsi),%r14
> 36: 8b 96 ec 00 00 00 mov 0xec(%rsi),%edx
> 3c: 48 89 45 b8 mov %rax,-0x48(%rbp)
> ...
>
> Code starting with the faulting instruction
> ===========================================
> 0: 48 8b 06 mov (%rsi),%rax
> 3: 48 89 75 b0 mov %rsi,-0x50(%rbp)
> 7: 4c 8b 76 08 mov 0x8(%rsi),%r14
> b: 8b 96 ec 00 00 00 mov 0xec(%rsi),%edx
> 11: 48 89 45 b8 mov %rax,-0x48(%rbp)
> ...
> [ 3569.870098] RIP show_mountinfo (fs/proc_namespace.c:127)
> [ 3569.870098] RSP <ffff880393f8fd08>
>
>
> Thanks,
> Sasha
>
This one seems related:
[ 4292.460172] kernel tried to execute NX-protected page - exploit attempt? (uid: 84)
[ 4292.462109] BUG: unable to handle kernel paging request at ffff8804650c3ec8
[ 4292.464167] IP: 0xffff8804650c3ec8 (??:?)
[ 4292.465775] PGD 24b7d067 PUD 703f42067 PMD 703e19067 PTE 80000004650c3163
[ 4292.467882] Oops: 0011 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 4292.469606] Dumping ftrace buffer:
[ 4292.470032] (ftrace buffer empty)
[ 4292.470032] Modules linked in:
[ 4292.470032] CPU: 9 PID: 16397 Comm: trinity-c103 Tainted: G W 3.16.0-rc3-next-20140702-sasha-00023-ga35ffce-dirty #760
[ 4292.470032] task: ffff8801b479b000 ti: ffff8804650c0000 task.ti: ffff8804650c0000
[ 4292.470032] RIP: 0xffff8804650c3ec8 (??:?)
[ 4292.470032] RSP: 0000:ffff8804650c3e60 EFLAGS: 00010293
[ 4292.470032] RAX: ffff8803d5e586a0 RBX: ffff88007bf85b00 RCX: ffff8800a5ab69a8
[ 4292.470032] RDX: 0000000000000000 RSI: ffffffffa31352f8 RDI: ffff8803d5e5b6a8
[ 4292.470032] RBP: ffff8804650c3e58 R08: ffff8803d5e5b6a8 R09: 0000000000000009
[ 4292.470032] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 4292.490142] R13: ffff8803d5e5b6a8 R14: ffff8804650c3f50 R15: ffff88008082e900
[ 4292.490142] FS: 00007ff380e2e700(0000) GS:ffff88025ce00000(0000) knlGS:0000000000000000
[ 4292.490142] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4292.490142] CR2: ffff8804650c3ec8 CR3: 000000017f20e000 CR4: 00000000000006a0
[ 4292.490142] Stack:
[ 4292.490142] ffffffff9d332972 0000000000000009 0000000081000000 ffff88008082e940
[ 4292.490142] 0000000000000e5f 0000000000000000 0000000000000001 ffff8804650c3ec8
[ 4292.490142] ffff8803d69b1ff0 ffff88007bf85b00 0000000081000000 ffff8804650c3f50
[ 4292.490142] Call Trace:
[ 4292.490142] seq_read (fs/seq_file.c:265)
[ 4292.490142] ? proc_reg_read (fs/proc/inode.c:211)
[ 4292.508936] ? vfs_read (fs/read_write.c:430)
[ 4292.508936] ? SyS_read (fs/read_write.c:568 fs/read_write.c:560)
[ 4292.508936] ? ia32_do_call (arch/x86/ia32/ia32entry.S:430)
[ 4292.508936] Code: 88 ff ff f0 1f 9b d6 03 88 ff ff 00 5b f8 7b 00 88 ff ff 00 00 00 81 00 00 00 00 50 3f 0c 65 04 88 ff ff 03 00 00 00 00 00 00 00 <f8> 3e 0c 65 04 88 ff ff 42 ae 37 9d ff ff ff ff 08 3f 0c 65 04
All code
========
0: 88 ff mov %bh,%bh
2: ff f0 push %rax
4: 1f (bad)
5: 9b fwait
6: d6 (bad)
7: 03 88 ff ff 00 5b add 0x5b00ffff(%rax),%ecx
d: f8 clc
e: 7b 00 jnp 0x10
10: 88 ff mov %bh,%bh
12: ff 00 incl (%rax)
14: 00 00 add %al,(%rax)
16: 81 00 00 00 00 50 addl $0x50000000,(%rax)
1c: 3f (bad)
1d: 0c 65 or $0x65,%al
1f: 04 88 add $0x88,%al
21: ff (bad)
22: ff 03 incl (%rbx)
24: 00 00 add %al,(%rax)
26: 00 00 add %al,(%rax)
28: 00 00 add %al,(%rax)
2a:* 00 f8 add %bh,%al <-- trapping instruction
2c: 3e ds
2d: 0c 65 or $0x65,%al
2f: 04 88 add $0x88,%al
31: ff (bad)
32: ff 42 ae incl -0x52(%rdx)
35: 37 (bad)
36: 9d popfq
37: ff (bad)
38: ff (bad)
39: ff (bad)
3a: ff 08 decl (%rax)
3c: 3f (bad)
3d: 0c 65 or $0x65,%al
3f: 04 00 add $0x0,%al
Code starting with the faulting instruction
===========================================
0: f8 clc
1: 3e ds
2: 0c 65 or $0x65,%al
4: 04 88 add $0x88,%al
6: ff (bad)
7: ff 42 ae incl -0x52(%rdx)
a: 37 (bad)
b: 9d popfq
c: ff (bad)
d: ff (bad)
e: ff (bad)
f: ff 08 decl (%rax)
11: 3f (bad)
12: 0c 65 or $0x65,%al
14: 04 00 add $0x0,%al
[ 4292.508936] RIP 0xffff8804650c3ec8 (??:?)
[ 4292.508936] RSP <ffff8804650c3e60>
[ 4292.508936] CR2: ffff8804650c3ec8
Thanks,
Sasha
next prev parent reply other threads:[~2014-07-03 3:15 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-02 11:55 fs: use after free in /proc/pid/mountinfo Sasha Levin
2014-07-03 3:15 ` Sasha Levin [this message]
2014-07-03 21:37 ` David Rientjes
2014-07-04 14:55 ` Sasha Levin
2014-07-04 22:35 ` please do not merge 058504edd026 (was Re: fs: use after free in /proc/pid/mountinfo) David Rientjes
2014-07-04 22:35 ` [stable] " David Rientjes
2014-07-07 23:05 ` Greg KH
2014-07-07 23:05 ` [stable] " Greg KH
2014-07-07 23:06 ` Andrew Morton
2014-07-07 23:19 ` Greg KH
2014-07-07 23:19 ` [stable] " Greg KH
2014-07-06 10:04 ` fs: use after free in /proc/pid/mountinfo Heiko Carstens
2014-07-09 14:24 ` Heiko Carstens
2014-07-09 20:31 ` Andrew Morton
2014-07-09 22:10 ` Sasha Levin
2014-07-09 22:59 ` Andrew Morton
2014-07-15 13:52 ` Sasha Levin
2014-07-15 23:01 ` David Rientjes
2014-07-23 20:57 ` Andrew Morton
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