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Message-ID: <20151012120249.GB16370@unicorn.suse.cz>
Date: Mon, 12 Oct 2015 14:02:49 +0200
From: Michal Kubecek <mkubecek@...e.cz>
To: Dmitry Vyukov <dvyukov@...gle.com>
Cc: Al Viro <viro@...iv.linux.org.uk>,
"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
David Miller <davem@...emloft.net>,
Hannes Frederic Sowa <hannes@...essinduktion.org>,
dhowells@...hat.com, paul@...l-moore.com, salyzyn@...roid.com,
sds@...ho.nsa.gov, ying.xue@...driver.com, netdev@...r.kernel.org,
syzkaller@...glegroups.com, Kostya Serebryany <kcc@...gle.com>,
Alexander Potapenko <glider@...gle.com>,
Andrey Konovalov <andreyknvl@...gle.com>,
Sasha Levin <sasha.levin@...cle.com>,
Julien Tinnes <jln@...gle.com>,
Kees Cook <keescook@...gle.com>,
Mathias Krause <minipli@...glemail.com>,
Jason Baron <jbaron@...mai.com>,
Rainer Weikusat <rweikusat@...ileactivedefense.com>
Subject: Re: Use-after-free in ep_remove_wait_queue
On Mon, Oct 12, 2015 at 01:07:55PM +0200, Dmitry Vyukov wrote:
> Hello,
>
> The following program causes use-after-in kernel:
>
...
> long r0 = syscall(SYS_mmap, 0x20001000ul, 0x1000ul, 0x3ul,
> 0x32ul, 0xfffffffffffffffful, 0x0ul);
> long r1 = syscall(SYS_mmap, 0x20000000ul, 0x1000ul, 0x3ul,
> 0x32ul, 0xfffffffffffffffful, 0x0ul);
> long r2 = syscall(SYS_socketpair, 0x1ul, 0x3ul, 0x1ul, 0x20000ffcul);
> long r3 = -1;
> if (r2 != -1)
> r3 = *(uint32_t*)0x20000ffc;
> long r4 = -1;
> if (r2 != -1)
> r4 = *(uint32_t*)0x20001000;
> long r5 = syscall(SYS_epoll_create, 0x1ul);
> long r6 = syscall(SYS_mmap, 0x20003000ul, 0x1000ul, 0x3ul,
> 0x32ul, 0xfffffffffffffffful, 0x0ul);
> long r7 = syscall(SYS_dup3, r4, r3, 0x80000ul);
> *(uint32_t*)0x20003000 = 0x6;
> *(uint32_t*)0x20003004 = 0x2;
> *(uint64_t*)0x20003008 = 0x6;
> long r11 = syscall(SYS_epoll_ctl, r5, 0x1ul, r3, 0x20003000ul);
> long r12 = syscall(SYS_mmap, 0x20002000ul, 0x1000ul, 0x3ul,
> 0x32ul, 0xfffffffffffffffful, 0x0ul);
> memcpy((void*)0x20002000, "\x00", 1);
> long r14 = syscall(SYS_write, r7, 0x20002000ul, 0x1ul);
> *(uint64_t*)0x20001a4d = 0x5;
> long r16 = syscall(SYS_epoll_pwait, r5, 0x20004000ul, 0x1ul,
> 0x1ul, 0x20001a4dul, 0x8ul);
> return 0;
...
> Call Trace:
> [< inline >] __list_del include/linux/list.h:89
> [< inline >] list_del include/linux/list.h:107
> [< inline >] __remove_wait_queue include/linux/wait.h:145
> [<ffffffff811bfbab>] remove_wait_queue+0xfb/0x120 kernel/sched/wait.c:50
> [< inline >] ep_remove_wait_queue fs/eventpoll.c:524
> [<ffffffff8154094b>] ep_unregister_pollwait.isra.7+0x10b/0x1c0
> fs/eventpoll.c:542
> [<ffffffff81541417>] ep_free+0x97/0x190 fs/eventpoll.c:759 (discriminator 3)
> [<ffffffff81541554>] ep_eventpoll_release+0x44/0x60 fs/eventpoll.c:791
> [<ffffffff814772ad>] __fput+0x21d/0x6e0 fs/file_table.c:208
> [<ffffffff814777f5>] ____fput+0x15/0x20 fs/file_table.c:244
> [<ffffffff81150094>] task_work_run+0x164/0x1f0 kernel/task_work.c:115
> (discriminator 1)
> [< inline >] exit_task_work include/linux/task_work.h:21
> [<ffffffff810fe7ae>] do_exit+0xa4e/0x2d40 kernel/exit.c:746
> [<ffffffff81104426>] do_group_exit+0xf6/0x340 kernel/exit.c:874
> [< inline >] SYSC_exit_group kernel/exit.c:885
> [<ffffffff8110468d>] SyS_exit_group+0x1d/0x20 kernel/exit.c:883
> [<ffffffff82e424d1>] entry_SYSCALL_64_fastpath+0x31/0x95
> arch/x86/entry/entry_64.S:187
>
> INFO: Allocated in sk_prot_alloc+0x69/0x340 age=6 cpu=1 pid=10568
> [< none >] __slab_alloc+0x426/0x470 mm/slub.c:2402
> [< inline >] slab_alloc_node mm/slub.c:2470
> [< inline >] slab_alloc mm/slub.c:2512
> [< none >] kmem_cache_alloc+0x10d/0x140 mm/slub.c:2517
> [< none >] sk_prot_alloc+0x69/0x340 net/core/sock.c:1329
> [< none >] sk_alloc+0x33/0x280 net/core/sock.c:1404
> [< none >] unix_create1+0x5e/0x3d0 net/unix/af_unix.c:648
> [< none >] unix_create+0x14d/0x1f0 net/unix/af_unix.c:707
> [< none >] __sock_create+0x1f1/0x4c0 net/socket.c:1169
> [< inline >] sock_create net/socket.c:1209
> [< inline >] SYSC_socketpair net/socket.c:1281
> [< none >] SyS_socketpair+0x10f/0x4d0 net/socket.c:1260
> [< none >] entry_SYSCALL_64_fastpath+0x31/0x95
> arch/x86/entry/entry_64.S:187
>
> INFO: Freed in sk_destruct+0x2e9/0x400 age=9 cpu=1 pid=10568
> [< none >] __slab_free+0x12d/0x280 mm/slub.c:2587 (discriminator 1)
> [< inline >] slab_free mm/slub.c:2736
> [< none >] kmem_cache_free+0x161/0x180 mm/slub.c:2745
> [< inline >] sk_prot_free net/core/sock.c:1374
> [< none >] sk_destruct+0x2e9/0x400 net/core/sock.c:1452
> [< none >] __sk_free+0x57/0x200 net/core/sock.c:1460
> [< none >] sk_free+0x30/0x40 net/core/sock.c:1471
> [< inline >] sock_put include/net/sock.h:1593
> [< none >] unix_dgram_sendmsg+0xeaf/0x1100 net/unix/af_unix.c:1571
> [< inline >] sock_sendmsg_nosec net/socket.c:610
> [< none >] sock_sendmsg+0xca/0x110 net/socket.c:620
> [< none >] sock_write_iter+0x216/0x3a0 net/socket.c:819
> [< inline >] new_sync_write fs/read_write.c:478
> [< none >] __vfs_write+0x2ed/0x3d0 fs/read_write.c:491
> [< none >] vfs_write+0x173/0x4a0 fs/read_write.c:538
> [< inline >] SYSC_write fs/read_write.c:585
> [< none >] SyS_write+0x108/0x220 fs/read_write.c:577
> [< none >] entry_SYSCALL_64_fastpath+0x31/0x95
> arch/x86/entry/entry_64.S:187
Probably the issue discussed in
http://thread.gmane.org/gmane.linux.kernel/2057497/
and previous related threads.
Michal Kubecek
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