linux-stable.git/net, branch v3.4.111 Linux kernel stable tree af_unix: Guard against other == sk in unix_dgram_sendmsg 2016-03-21T01:17:57+00:00 Rainer Weikusat rweikusat@mobileactivedefense.com 2016-02-11T19:37:27+00:00 78578995555b40356a7c4a64d772fe169bb42767 commit a5527dda344fff0514b7989ef7a755729769daa1 upstream. The unix_dgram_sendmsg routine use the following test if (unlikely(unix_peer(other) != sk && unix_recvq_full(other))) { to determine if sk and other are in an n:1 association (either established via connect or by using sendto to send messages to an unrelated socket identified by address). This isn't correct as the specified address could have been bound to the sending socket itself or because this socket could have been connected to itself by the time of the unix_peer_get but disconnected before the unix_state_lock(other). In both cases, the if-block would be entered despite other == sk which might either block the sender unintentionally or lead to trying to unlock the same spin lock twice for a non-blocking send. Add a other != sk check to guard against this. Fixes: 7d267278a9ec ("unix: avoid use-after-free in ep_remove_wait_queue") Reported-By: Philipp Hahn <pmhahn@pmhahn.de> Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com> Tested-by: Philipp Hahn <pmhahn@pmhahn.de> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Zefan Li <lizefan@huawei.com> 
commit a5527dda344fff0514b7989ef7a755729769daa1 upstream.

The unix_dgram_sendmsg routine use the following test

if (unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {

to determine if sk and other are in an n:1 association (either
established via connect or by using sendto to send messages to an
unrelated socket identified by address). This isn't correct as the
specified address could have been bound to the sending socket itself or
because this socket could have been connected to itself by the time of
the unix_peer_get but disconnected before the unix_state_lock(other). In
both cases, the if-block would be entered despite other == sk which
might either block the sender unintentionally or lead to trying to unlock
the same spin lock twice for a non-blocking send. Add a other != sk
check to guard against this.

Fixes: 7d267278a9ec ("unix: avoid use-after-free in ep_remove_wait_queue")
Reported-By: Philipp Hahn <pmhahn@pmhahn.de>
Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Tested-by: Philipp Hahn <pmhahn@pmhahn.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zefan Li <lizefan@huawei.com>
ipv6: prevent fib6_run_gc() contention 2016-03-21T01:17:57+00:00 Michal Kubeček mkubecek@suse.cz 2013-08-01T08:04:14+00:00 5317d9af12a59e83a6f173eac3808cc21f6e9d2b commit 2ac3ac8f86f2fe065d746d9a9abaca867adec577 upstream. On a high-traffic router with many processors and many IPv6 dst entries, soft lockup in fib6_run_gc() can occur when number of entries reaches gc_thresh. This happens because fib6_run_gc() uses fib6_gc_lock to allow only one thread to run the garbage collector but ip6_dst_gc() doesn't update net->ipv6.ip6_rt_last_gc until fib6_run_gc() returns. On a system with many entries, this can take some time so that in the meantime, other threads pass the tests in ip6_dst_gc() (ip6_rt_last_gc is still not updated) and wait for the lock. They then have to run the garbage collector one after another which blocks them for quite long. Resolve this by replacing special value ~0UL of expire parameter to fib6_run_gc() by explicit "force" parameter to choose between spin_lock_bh() and spin_trylock_bh() and call fib6_run_gc() with force=false if gc_thresh is reached but not max_size. Signed-off-by: Michal Kubecek <mkubecek@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net> [lizf: Backported to 3.4: adjust context] Signed-off-by: Zefan Li <lizefan@huawei.com> 
commit 2ac3ac8f86f2fe065d746d9a9abaca867adec577 upstream.

On a high-traffic router with many processors and many IPv6 dst
entries, soft lockup in fib6_run_gc() can occur when number of
entries reaches gc_thresh.

This happens because fib6_run_gc() uses fib6_gc_lock to allow
only one thread to run the garbage collector but ip6_dst_gc()
doesn't update net->ipv6.ip6_rt_last_gc until fib6_run_gc()
returns. On a system with many entries, this can take some time
so that in the meantime, other threads pass the tests in
ip6_dst_gc() (ip6_rt_last_gc is still not updated) and wait for
the lock. They then have to run the garbage collector one after
another which blocks them for quite long.

Resolve this by replacing special value ~0UL of expire parameter
to fib6_run_gc() by explicit "force" parameter to choose between
spin_lock_bh() and spin_trylock_bh() and call fib6_run_gc() with
force=false if gc_thresh is reached but not max_size.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
SUNRPC: never enqueue a ->rq_cong request on ->sending 2016-03-21T01:17:56+00:00 Neil Brown neilb@suse.de 2015-06-15T05:55:30+00:00 31469735a1e6618754230266fb842c3f7510cd28 commit 298073181112a6ab6c30fe7971b99de968daf81e upstream. If the sending queue has a task without ->rq_cong set at the front, and then a number of tasks with ->rq_cong set such that they use the entire congestion window, then the queue deadlocks. The first entry cannot be processed until later entries complete. This scenario has been seen with a client using UDP to access a server, and the network connection breaking for a period of time - it doesn't recover. It never really makes sense for an ->rq_cong request to be on the ->sending queue, but it can happen when a request is being retried, and finds the transport if locked (XPRT_LOCKED). In this case we simple call __xprt_put_cong() and the deadlock goes away. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Zefan Li <lizefan@huawei.com> 
commit 298073181112a6ab6c30fe7971b99de968daf81e upstream.

If the sending queue has a task without ->rq_cong set at the front,
and then a number of tasks with ->rq_cong set such that they use
the entire congestion window, then the queue deadlocks.  The first
entry cannot be processed until later entries complete.

This scenario has been seen with a client using UDP to access a server,
and the network connection breaking for a period of time - it doesn't
recover.

It never really makes sense for an ->rq_cong request to be on the ->sending
queue, but it can happen when a request is being retried, and finds
the transport if locked (XPRT_LOCKED).  In this case we simple call
__xprt_put_cong() and the deadlock goes away.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Zefan Li <lizefan@huawei.com>
atm: deal with setting entry before mkip was called 2016-03-21T01:17:56+00:00 Sasha Levin sasha.levin@oracle.com 2015-09-16T19:30:21+00:00 faf7b6b0d45be29f6586784f56159592c9e5f3fc commit 34f5b0066435ffb793049b84fafd29fa195bcf90 upstream. If we didn't call ATMARP_MKIP before ATMARP_ENCAP the VCC descriptor is non-existant and we'll end up dereferencing a NULL ptr: [1033173.491930] kasan: GPF could be caused by NULL-ptr deref or user memory accessirq event stamp: 123386 [1033173.493678] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN [1033173.493689] Modules linked in: [1033173.493697] CPU: 9 PID: 23815 Comm: trinity-c64 Not tainted 4.2.0-next-20150911-sasha-00043-g353d875-dirty #2545 [1033173.493706] task: ffff8800630c4000 ti: ffff880063110000 task.ti: ffff880063110000 [1033173.493823] RIP: clip_ioctl (net/atm/clip.c:320 net/atm/clip.c:689) [1033173.493826] RSP: 0018:ffff880063117a88 EFLAGS: 00010203 [1033173.493828] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 000000000000000c [1033173.493830] RDX: 0000000000000002 RSI: ffffffffb3f10720 RDI: 0000000000000014 [1033173.493832] RBP: ffff880063117b80 R08: ffff88047574d9a4 R09: 0000000000000000 [1033173.493834] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1000c622f53 [1033173.493836] R13: ffff8800cb905500 R14: ffff8808d6da2000 R15: 00000000fffffdfd [1033173.493840] FS: 00007fa56b92d700(0000) GS:ffff880478000000(0000) knlGS:0000000000000000 [1033173.493843] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [1033173.493845] CR2: 0000000000000000 CR3: 00000000630e8000 CR4: 00000000000006a0 [1033173.493855] Stack: [1033173.493862] ffffffffb0b60444 000000000000eaea 0000000041b58ab3 ffffffffb3c3ce32 [1033173.493867] ffffffffb0b6f3e0 ffffffffb0b60444 ffffffffb5ea2e50 1ffff1000c622f5e [1033173.493873] ffff8800630c4cd8 00000000000ee09a ffffffffb3ec4888 ffffffffb5ea2de8 [1033173.493874] Call Trace: [1033173.494108] do_vcc_ioctl (net/atm/ioctl.c:170) [1033173.494113] vcc_ioctl (net/atm/ioctl.c:189) [1033173.494116] svc_ioctl (net/atm/svc.c:605) [1033173.494200] sock_do_ioctl (net/socket.c:874) [1033173.494204] sock_ioctl (net/socket.c:958) [1033173.494244] do_vfs_ioctl (fs/ioctl.c:43 fs/ioctl.c:607) [1033173.494290] SyS_ioctl (fs/ioctl.c:622 fs/ioctl.c:613) [1033173.494295] entry_SYSCALL_64_fastpath (arch/x86/entry/entry_64.S:186) [1033173.494362] Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 50 09 00 00 49 8b 9e 60 06 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 14 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 14 09 00 All code ======== 0: fa cli 1: 48 c1 ea 03 shr $0x3,%rdx 5: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 9: 0f 85 50 09 00 00 jne 0x95f f: 49 8b 9e 60 06 00 00 mov 0x660(%r14),%rbx 16: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1d: fc ff df 20: 48 8d 7b 14 lea 0x14(%rbx),%rdi 24: 48 89 fa mov %rdi,%rdx 27: 48 c1 ea 03 shr $0x3,%rdx 2b:* 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction 2f: 48 89 fa mov %rdi,%rdx 32: 83 e2 07 and $0x7,%edx 35: 38 d0 cmp %dl,%al 37: 7f 08 jg 0x41 39: 84 c0 test %al,%al 3b: 0f 85 14 09 00 00 jne 0x955 Code starting with the faulting instruction =========================================== 0: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax 4: 48 89 fa mov %rdi,%rdx 7: 83 e2 07 and $0x7,%edx a: 38 d0 cmp %dl,%al c: 7f 08 jg 0x16 e: 84 c0 test %al,%al 10: 0f 85 14 09 00 00 jne 0x92a [1033173.494366] RIP clip_ioctl (net/atm/clip.c:320 net/atm/clip.c:689) [1033173.494368] RSP <ffff880063117a88> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Zefan Li <lizefan@huawei.com> 
commit 34f5b0066435ffb793049b84fafd29fa195bcf90 upstream.

If we didn't call ATMARP_MKIP before ATMARP_ENCAP the VCC descriptor is
non-existant and we'll end up dereferencing a NULL ptr:

[1033173.491930] kasan: GPF could be caused by NULL-ptr deref or user memory accessirq event stamp: 123386
[1033173.493678] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN
[1033173.493689] Modules linked in:
[1033173.493697] CPU: 9 PID: 23815 Comm: trinity-c64 Not tainted 4.2.0-next-20150911-sasha-00043-g353d875-dirty #2545
[1033173.493706] task: ffff8800630c4000 ti: ffff880063110000 task.ti: ffff880063110000
[1033173.493823] RIP: clip_ioctl (net/atm/clip.c:320 net/atm/clip.c:689)
[1033173.493826] RSP: 0018:ffff880063117a88  EFLAGS: 00010203
[1033173.493828] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 000000000000000c
[1033173.493830] RDX: 0000000000000002 RSI: ffffffffb3f10720 RDI: 0000000000000014
[1033173.493832] RBP: ffff880063117b80 R08: ffff88047574d9a4 R09: 0000000000000000
[1033173.493834] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1000c622f53
[1033173.493836] R13: ffff8800cb905500 R14: ffff8808d6da2000 R15: 00000000fffffdfd
[1033173.493840] FS:  00007fa56b92d700(0000) GS:ffff880478000000(0000) knlGS:0000000000000000
[1033173.493843] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[1033173.493845] CR2: 0000000000000000 CR3: 00000000630e8000 CR4: 00000000000006a0
[1033173.493855] Stack:
[1033173.493862]  ffffffffb0b60444 000000000000eaea 0000000041b58ab3 ffffffffb3c3ce32
[1033173.493867]  ffffffffb0b6f3e0 ffffffffb0b60444 ffffffffb5ea2e50 1ffff1000c622f5e
[1033173.493873]  ffff8800630c4cd8 00000000000ee09a ffffffffb3ec4888 ffffffffb5ea2de8
[1033173.493874] Call Trace:
[1033173.494108] do_vcc_ioctl (net/atm/ioctl.c:170)
[1033173.494113] vcc_ioctl (net/atm/ioctl.c:189)
[1033173.494116] svc_ioctl (net/atm/svc.c:605)
[1033173.494200] sock_do_ioctl (net/socket.c:874)
[1033173.494204] sock_ioctl (net/socket.c:958)
[1033173.494244] do_vfs_ioctl (fs/ioctl.c:43 fs/ioctl.c:607)
[1033173.494290] SyS_ioctl (fs/ioctl.c:622 fs/ioctl.c:613)
[1033173.494295] entry_SYSCALL_64_fastpath (arch/x86/entry/entry_64.S:186)
[1033173.494362] Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 50 09 00 00 49 8b 9e 60 06 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 14 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 14 09 00
All code

========
   0:   fa                      cli
   1:   48 c1 ea 03             shr    $0x3,%rdx
   5:   80 3c 02 00             cmpb   $0x0,(%rdx,%rax,1)
   9:   0f 85 50 09 00 00       jne    0x95f
   f:   49 8b 9e 60 06 00 00    mov    0x660(%r14),%rbx
  16:   48 b8 00 00 00 00 00    movabs $0xdffffc0000000000,%rax
  1d:   fc ff df
  20:   48 8d 7b 14             lea    0x14(%rbx),%rdi
  24:   48 89 fa                mov    %rdi,%rdx
  27:   48 c1 ea 03             shr    $0x3,%rdx
  2b:*  0f b6 04 02             movzbl (%rdx,%rax,1),%eax               <-- trapping instruction
  2f:   48 89 fa                mov    %rdi,%rdx
  32:   83 e2 07                and    $0x7,%edx
  35:   38 d0                   cmp    %dl,%al
  37:   7f 08                   jg     0x41
  39:   84 c0                   test   %al,%al
  3b:   0f 85 14 09 00 00       jne    0x955

Code starting with the faulting instruction
===========================================
   0:   0f b6 04 02             movzbl (%rdx,%rax,1),%eax
   4:   48 89 fa                mov    %rdi,%rdx
   7:   83 e2 07                and    $0x7,%edx
   a:   38 d0                   cmp    %dl,%al
   c:   7f 08                   jg     0x16
   e:   84 c0                   test   %al,%al
  10:   0f 85 14 09 00 00       jne    0x92a
[1033173.494366] RIP clip_ioctl (net/atm/clip.c:320 net/atm/clip.c:689)
[1033173.494368]  RSP <ffff880063117a88>

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zefan Li <lizefan@huawei.com>
netfilter: nf_conntrack: fix RCU race in nf_conntrack_find_get 2016-03-21T01:17:56+00:00 Andrey Vagin avagin@openvz.org 2014-01-29T18:34:14+00:00 9b3dd23a4533ee0a288e4c6c77276c6791426a1a commit c6825c0976fa7893692e0e43b09740b419b23c09 upstream. Lets look at destroy_conntrack: hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); ... nf_conntrack_free(ct) kmem_cache_free(net->ct.nf_conntrack_cachep, ct); net->ct.nf_conntrack_cachep is created with SLAB_DESTROY_BY_RCU. The hash is protected by rcu, so readers look up conntracks without locks. A conntrack is removed from the hash, but in this moment a few readers still can use the conntrack. Then this conntrack is released and another thread creates conntrack with the same address and the equal tuple. After this a reader starts to validate the conntrack: * It's not dying, because a new conntrack was created * nf_ct_tuple_equal() returns true. But this conntrack is not initialized yet, so it can not be used by two threads concurrently. In this case BUG_ON may be triggered from nf_nat_setup_info(). Florian Westphal suggested to check the confirm bit too. I think it's right. task 1 task 2 task 3 nf_conntrack_find_get ____nf_conntrack_find destroy_conntrack hlist_nulls_del_rcu nf_conntrack_free kmem_cache_free __nf_conntrack_alloc kmem_cache_alloc memset(&ct->tuplehash[IP_CT_DIR_MAX], if (nf_ct_is_dying(ct)) if (!nf_ct_tuple_equal() I'm not sure, that I have ever seen this race condition in a real life. Currently we are investigating a bug, which is reproduced on a few nodes. In our case one conntrack is initialized from a few tasks concurrently, we don't have any other explanation for this. <2>[46267.083061] kernel BUG at net/ipv4/netfilter/nf_nat_core.c:322! ... <4>[46267.083951] RIP: 0010:[<ffffffffa01e00a4>] [<ffffffffa01e00a4>] nf_nat_setup_info+0x564/0x590 [nf_nat] ... <4>[46267.085549] Call Trace: <4>[46267.085622] [<ffffffffa023421b>] alloc_null_binding+0x5b/0xa0 [iptable_nat] <4>[46267.085697] [<ffffffffa02342bc>] nf_nat_rule_find+0x5c/0x80 [iptable_nat] <4>[46267.085770] [<ffffffffa0234521>] nf_nat_fn+0x111/0x260 [iptable_nat] <4>[46267.085843] [<ffffffffa0234798>] nf_nat_out+0x48/0xd0 [iptable_nat] <4>[46267.085919] [<ffffffff814841b9>] nf_iterate+0x69/0xb0 <4>[46267.085991] [<ffffffff81494e70>] ? ip_finish_output+0x0/0x2f0 <4>[46267.086063] [<ffffffff81484374>] nf_hook_slow+0x74/0x110 <4>[46267.086133] [<ffffffff81494e70>] ? ip_finish_output+0x0/0x2f0 <4>[46267.086207] [<ffffffff814b5890>] ? dst_output+0x0/0x20 <4>[46267.086277] [<ffffffff81495204>] ip_output+0xa4/0xc0 <4>[46267.086346] [<ffffffff814b65a4>] raw_sendmsg+0x8b4/0x910 <4>[46267.086419] [<ffffffff814c10fa>] inet_sendmsg+0x4a/0xb0 <4>[46267.086491] [<ffffffff814459aa>] ? sock_update_classid+0x3a/0x50 <4>[46267.086562] [<ffffffff81444d67>] sock_sendmsg+0x117/0x140 <4>[46267.086638] [<ffffffff8151997b>] ? _spin_unlock_bh+0x1b/0x20 <4>[46267.086712] [<ffffffff8109d370>] ? autoremove_wake_function+0x0/0x40 <4>[46267.086785] [<ffffffff81495e80>] ? do_ip_setsockopt+0x90/0xd80 <4>[46267.086858] [<ffffffff8100be0e>] ? call_function_interrupt+0xe/0x20 <4>[46267.086936] [<ffffffff8118cb10>] ? ub_slab_ptr+0x20/0x90 <4>[46267.087006] [<ffffffff8118cb10>] ? ub_slab_ptr+0x20/0x90 <4>[46267.087081] [<ffffffff8118f2e8>] ? kmem_cache_alloc+0xd8/0x1e0 <4>[46267.087151] [<ffffffff81445599>] sys_sendto+0x139/0x190 <4>[46267.087229] [<ffffffff81448c0d>] ? sock_setsockopt+0x16d/0x6f0 <4>[46267.087303] [<ffffffff810efa47>] ? audit_syscall_entry+0x1d7/0x200 <4>[46267.087378] [<ffffffff810ef795>] ? __audit_syscall_exit+0x265/0x290 <4>[46267.087454] [<ffffffff81474885>] ? compat_sys_setsockopt+0x75/0x210 <4>[46267.087531] [<ffffffff81474b5f>] compat_sys_socketcall+0x13f/0x210 <4>[46267.087607] [<ffffffff8104dea3>] ia32_sysret+0x0/0x5 <4>[46267.087676] Code: 91 20 e2 01 75 29 48 89 de 4c 89 f7 e8 56 fa ff ff 85 c0 0f 84 68 fc ff ff 0f b6 4d c6 41 8b 45 00 e9 4d fb ff ff e8 7c 19 e9 e0 <0f> 0b eb fe f6 05 17 91 20 e2 80 74 ce 80 3d 5f 2e 00 00 00 74 <1>[46267.088023] RIP [<ffffffffa01e00a4>] nf_nat_setup_info+0x564/0x590 Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Florian Westphal <fw@strlen.de> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> Cc: "David S. Miller" <davem@davemloft.net> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Signed-off-by: Andrey Vagin <avagin@openvz.org> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Zefan Li <lizefan@huawei.com> 
commit c6825c0976fa7893692e0e43b09740b419b23c09 upstream.

Lets look at destroy_conntrack:

hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
...
nf_conntrack_free(ct)
	kmem_cache_free(net->ct.nf_conntrack_cachep, ct);

net->ct.nf_conntrack_cachep is created with SLAB_DESTROY_BY_RCU.

The hash is protected by rcu, so readers look up conntracks without
locks.
A conntrack is removed from the hash, but in this moment a few readers
still can use the conntrack. Then this conntrack is released and another
thread creates conntrack with the same address and the equal tuple.
After this a reader starts to validate the conntrack:
* It's not dying, because a new conntrack was created
* nf_ct_tuple_equal() returns true.

But this conntrack is not initialized yet, so it can not be used by two
threads concurrently. In this case BUG_ON may be triggered from
nf_nat_setup_info().

Florian Westphal suggested to check the confirm bit too. I think it's
right.

task 1			task 2			task 3
			nf_conntrack_find_get
			 ____nf_conntrack_find
destroy_conntrack
 hlist_nulls_del_rcu
 nf_conntrack_free
 kmem_cache_free
						__nf_conntrack_alloc
						 kmem_cache_alloc
						 memset(&ct->tuplehash[IP_CT_DIR_MAX],
			 if (nf_ct_is_dying(ct))
			 if (!nf_ct_tuple_equal()

I'm not sure, that I have ever seen this race condition in a real life.
Currently we are investigating a bug, which is reproduced on a few nodes.
In our case one conntrack is initialized from a few tasks concurrently,
we don't have any other explanation for this.

<2>[46267.083061] kernel BUG at net/ipv4/netfilter/nf_nat_core.c:322!
...
<4>[46267.083951] RIP: 0010:[<ffffffffa01e00a4>]  [<ffffffffa01e00a4>] nf_nat_setup_info+0x564/0x590 [nf_nat]
...
<4>[46267.085549] Call Trace:
<4>[46267.085622]  [<ffffffffa023421b>] alloc_null_binding+0x5b/0xa0 [iptable_nat]
<4>[46267.085697]  [<ffffffffa02342bc>] nf_nat_rule_find+0x5c/0x80 [iptable_nat]
<4>[46267.085770]  [<ffffffffa0234521>] nf_nat_fn+0x111/0x260 [iptable_nat]
<4>[46267.085843]  [<ffffffffa0234798>] nf_nat_out+0x48/0xd0 [iptable_nat]
<4>[46267.085919]  [<ffffffff814841b9>] nf_iterate+0x69/0xb0
<4>[46267.085991]  [<ffffffff81494e70>] ? ip_finish_output+0x0/0x2f0
<4>[46267.086063]  [<ffffffff81484374>] nf_hook_slow+0x74/0x110
<4>[46267.086133]  [<ffffffff81494e70>] ? ip_finish_output+0x0/0x2f0
<4>[46267.086207]  [<ffffffff814b5890>] ? dst_output+0x0/0x20
<4>[46267.086277]  [<ffffffff81495204>] ip_output+0xa4/0xc0
<4>[46267.086346]  [<ffffffff814b65a4>] raw_sendmsg+0x8b4/0x910
<4>[46267.086419]  [<ffffffff814c10fa>] inet_sendmsg+0x4a/0xb0
<4>[46267.086491]  [<ffffffff814459aa>] ? sock_update_classid+0x3a/0x50
<4>[46267.086562]  [<ffffffff81444d67>] sock_sendmsg+0x117/0x140
<4>[46267.086638]  [<ffffffff8151997b>] ? _spin_unlock_bh+0x1b/0x20
<4>[46267.086712]  [<ffffffff8109d370>] ? autoremove_wake_function+0x0/0x40
<4>[46267.086785]  [<ffffffff81495e80>] ? do_ip_setsockopt+0x90/0xd80
<4>[46267.086858]  [<ffffffff8100be0e>] ? call_function_interrupt+0xe/0x20
<4>[46267.086936]  [<ffffffff8118cb10>] ? ub_slab_ptr+0x20/0x90
<4>[46267.087006]  [<ffffffff8118cb10>] ? ub_slab_ptr+0x20/0x90
<4>[46267.087081]  [<ffffffff8118f2e8>] ? kmem_cache_alloc+0xd8/0x1e0
<4>[46267.087151]  [<ffffffff81445599>] sys_sendto+0x139/0x190
<4>[46267.087229]  [<ffffffff81448c0d>] ? sock_setsockopt+0x16d/0x6f0
<4>[46267.087303]  [<ffffffff810efa47>] ? audit_syscall_entry+0x1d7/0x200
<4>[46267.087378]  [<ffffffff810ef795>] ? __audit_syscall_exit+0x265/0x290
<4>[46267.087454]  [<ffffffff81474885>] ? compat_sys_setsockopt+0x75/0x210
<4>[46267.087531]  [<ffffffff81474b5f>] compat_sys_socketcall+0x13f/0x210
<4>[46267.087607]  [<ffffffff8104dea3>] ia32_sysret+0x0/0x5
<4>[46267.087676] Code: 91 20 e2 01 75 29 48 89 de 4c 89 f7 e8 56 fa ff ff 85 c0 0f 84 68 fc ff ff 0f b6 4d c6 41 8b 45 00 e9 4d fb ff ff e8 7c 19 e9 e0 <0f> 0b eb fe f6 05 17 91 20 e2 80 74 ce 80 3d 5f 2e 00 00 00 74
<1>[46267.088023] RIP  [<ffffffffa01e00a4>] nf_nat_setup_info+0x564/0x590

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Zefan Li <lizefan@huawei.com>
ipv6: probe routes asynchronous in rt6_probe 2016-03-21T01:17:56+00:00 Hannes Frederic Sowa hannes@stressinduktion.org 2013-10-21T04:17:15+00:00 bea46f475c5c07022e69b61db190c470bf862f1f commit c2f17e827b419918c856131f592df9521e1a38e3 upstream. Routes need to be probed asynchronous otherwise the call stack gets exhausted when the kernel attemps to deliver another skb inline, like e.g. xt_TEE does, and we probe at the same time. We update neigh->updated still at once, otherwise we would send to many probes. Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net> [lizf: Backported to 3.4: adjust context] Signed-off-by: Zefan Li <lizefan@huawei.com> 
commit c2f17e827b419918c856131f592df9521e1a38e3 upstream.

Routes need to be probed asynchronous otherwise the call stack gets
exhausted when the kernel attemps to deliver another skb inline, like
e.g. xt_TEE does, and we probe at the same time.

We update neigh->updated still at once, otherwise we would send to
many probes.

Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
net: avoid to hang up on sending due to sysctl configuration overflow. 2016-03-21T01:17:56+00:00 bingtian.ly@taobao.com bingtian.ly@taobao.com 2013-01-23T20:35:28+00:00 d865a115933e9edbd86aa36dbfe8d42e2fc5f2a5 commit cdda88912d62f9603d27433338a18be83ef23ac1 upstream. I found if we write a larger than 4GB value to some sysctl variables, the sending syscall will hang up forever, because these variables are 32 bits, such large values make them overflow to 0 or negative. This patch try to fix overflow or prevent from zero value setup of below sysctl variables: net.core.wmem_default net.core.rmem_default net.core.rmem_max net.core.wmem_max net.ipv4.udp_rmem_min net.ipv4.udp_wmem_min net.ipv4.tcp_wmem net.ipv4.tcp_rmem Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Li Yu <raise.sail@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> [lizf: Backported to 3.4: adjust context] Signed-off-by: Zefan Li <lizefan@huawei.com> 
commit cdda88912d62f9603d27433338a18be83ef23ac1 upstream.

    I found if we write a larger than 4GB value to some sysctl
variables, the sending syscall will hang up forever, because these
variables are 32 bits, such large values make them overflow to 0 or
negative.

    This patch try to fix overflow or prevent from zero value setup
of below sysctl variables:

net.core.wmem_default
net.core.rmem_default

net.core.rmem_max
net.core.wmem_max

net.ipv4.udp_rmem_min
net.ipv4.udp_wmem_min

net.ipv4.tcp_wmem
net.ipv4.tcp_rmem

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Li Yu <raise.sail@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
ipv6: addrconf: validate new MTU before applying it 2016-03-21T01:17:55+00:00 Marcelo Leitner mleitner@redhat.com 2015-02-23T14:17:13+00:00 59c8392ffcf3d6e39dcdd558e0354afc545f4c91 commit 77751427a1ff25b27d47a4c36b12c3c8667855ac upstream. Currently we don't check if the new MTU is valid or not and this allows one to configure a smaller than minimum allowed by RFCs or even bigger than interface own MTU, which is a problem as it may lead to packet drops. If you have a daemon like NetworkManager running, this may be exploited by remote attackers by forging RA packets with an invalid MTU, possibly leading to a DoS. (NetworkManager currently only validates for values too small, but not for too big ones.) The fix is just to make sure the new value is valid. That is, between IPV6_MIN_MTU and interface's MTU. Note that similar check is already performed at ndisc_router_discovery(), for when kernel itself parses the RA. Signed-off-by: Marcelo Ricardo Leitner <mleitner@redhat.com> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Zefan Li <lizefan@huawei.com> 
commit 77751427a1ff25b27d47a4c36b12c3c8667855ac upstream.

Currently we don't check if the new MTU is valid or not and this allows
one to configure a smaller than minimum allowed by RFCs or even bigger
than interface own MTU, which is a problem as it may lead to packet
drops.

If you have a daemon like NetworkManager running, this may be exploited
by remote attackers by forging RA packets with an invalid MTU, possibly
leading to a DoS. (NetworkManager currently only validates for values
too small, but not for too big ones.)

The fix is just to make sure the new value is valid. That is, between
IPV6_MIN_MTU and interface's MTU.

Note that similar check is already performed at
ndisc_router_discovery(), for when kernel itself parses the RA.

Signed-off-by: Marcelo Ricardo Leitner <mleitner@redhat.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zefan Li <lizefan@huawei.com>
RDS: fix race condition when sending a message on unbound socket 2016-03-21T01:17:54+00:00 Quentin Casasnovas quentin.casasnovas@oracle.com 2015-11-24T22:13:21+00:00 4ee85dafc1710f14f0c498076505add6aae52742 commit 8c7188b23474cca017b3ef354c4a58456f68303a upstream. Sasha's found a NULL pointer dereference in the RDS connection code when sending a message to an apparently unbound socket. The problem is caused by the code checking if the socket is bound in rds_sendmsg(), which checks the rs_bound_addr field without taking a lock on the socket. This opens a race where rs_bound_addr is temporarily set but where the transport is not in rds_bind(), leading to a NULL pointer dereference when trying to dereference 'trans' in __rds_conn_create(). Vegard wrote a reproducer for this issue, so kindly ask him to share if you're interested. I cannot reproduce the NULL pointer dereference using Vegard's reproducer with this patch, whereas I could without. Complete earlier incomplete fix to CVE-2015-6937: 74e98eb08588 ("RDS: verify the underlying transport exists before creating a connection") Cc: David S. Miller <davem@davemloft.net> Reviewed-by: Vegard Nossum <vegard.nossum@oracle.com> Reviewed-by: Sasha Levin <sasha.levin@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Zefan Li <lizefan@huawei.com> 
commit 8c7188b23474cca017b3ef354c4a58456f68303a upstream.

Sasha's found a NULL pointer dereference in the RDS connection code when
sending a message to an apparently unbound socket.  The problem is caused
by the code checking if the socket is bound in rds_sendmsg(), which checks
the rs_bound_addr field without taking a lock on the socket.  This opens a
race where rs_bound_addr is temporarily set but where the transport is not
in rds_bind(), leading to a NULL pointer dereference when trying to
dereference 'trans' in __rds_conn_create().

Vegard wrote a reproducer for this issue, so kindly ask him to share if
you're interested.

I cannot reproduce the NULL pointer dereference using Vegard's reproducer
with this patch, whereas I could without.

Complete earlier incomplete fix to CVE-2015-6937:

  74e98eb08588 ("RDS: verify the underlying transport exists before creating a connection")

Cc: David S. Miller <davem@davemloft.net>

Reviewed-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zefan Li <lizefan@huawei.com>
RDS: verify the underlying transport exists before creating a connection 2016-03-21T01:17:53+00:00 Sasha Levin sasha.levin@oracle.com 2015-09-08T14:53:40+00:00 473d720744271e4803c86d528917286cff75373e commit 74e98eb085889b0d2d4908f59f6e00026063014f upstream. There was no verification that an underlying transport exists when creating a connection, this would cause dereferencing a NULL ptr. It might happen on sockets that weren't properly bound before attempting to send a message, which will cause a NULL ptr deref: [135546.047719] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN [135546.051270] Modules linked in: [135546.051781] CPU: 4 PID: 15650 Comm: trinity-c4 Not tainted 4.2.0-next-20150902-sasha-00041-gbaa1222-dirty #2527 [135546.053217] task: ffff8800835bc000 ti: ffff8800bc708000 task.ti: ffff8800bc708000 [135546.054291] RIP: __rds_conn_create (net/rds/connection.c:194) [135546.055666] RSP: 0018:ffff8800bc70fab0 EFLAGS: 00010202 [135546.056457] RAX: dffffc0000000000 RBX: 0000000000000f2c RCX: ffff8800835bc000 [135546.057494] RDX: 0000000000000007 RSI: ffff8800835bccd8 RDI: 0000000000000038 [135546.058530] RBP: ffff8800bc70fb18 R08: 0000000000000001 R09: 0000000000000000 [135546.059556] R10: ffffed014d7a3a23 R11: ffffed014d7a3a21 R12: 0000000000000000 [135546.060614] R13: 0000000000000001 R14: ffff8801ec3d0000 R15: 0000000000000000 [135546.061668] FS: 00007faad4ffb700(0000) GS:ffff880252000000(0000) knlGS:0000000000000000 [135546.062836] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [135546.063682] CR2: 000000000000846a CR3: 000000009d137000 CR4: 00000000000006a0 [135546.064723] Stack: [135546.065048] ffffffffafe2055c ffffffffafe23fc1 ffffed00493097bf ffff8801ec3d0008 [135546.066247] 0000000000000000 00000000000000d0 0000000000000000 ac194a24c0586342 [135546.067438] 1ffff100178e1f78 ffff880320581b00 ffff8800bc70fdd0 ffff880320581b00 [135546.068629] Call Trace: [135546.069028] ? __rds_conn_create (include/linux/rcupdate.h:856 net/rds/connection.c:134) [135546.069989] ? rds_message_copy_from_user (net/rds/message.c:298) [135546.071021] rds_conn_create_outgoing (net/rds/connection.c:278) [135546.071981] rds_sendmsg (net/rds/send.c:1058) [135546.072858] ? perf_trace_lock (include/trace/events/lock.h:38) [135546.073744] ? lockdep_init (kernel/locking/lockdep.c:3298) [135546.074577] ? rds_send_drop_to (net/rds/send.c:976) [135546.075508] ? __might_fault (./arch/x86/include/asm/current.h:14 mm/memory.c:3795) [135546.076349] ? __might_fault (mm/memory.c:3795) [135546.077179] ? rds_send_drop_to (net/rds/send.c:976) [135546.078114] sock_sendmsg (net/socket.c:611 net/socket.c:620) [135546.078856] SYSC_sendto (net/socket.c:1657) [135546.079596] ? SYSC_connect (net/socket.c:1628) [135546.080510] ? trace_dump_stack (kernel/trace/trace.c:1926) [135546.081397] ? ring_buffer_unlock_commit (kernel/trace/ring_buffer.c:2479 kernel/trace/ring_buffer.c:2558 kernel/trace/ring_buffer.c:2674) [135546.082390] ? trace_buffer_unlock_commit (kernel/trace/trace.c:1749) [135546.083410] ? trace_event_raw_event_sys_enter (include/trace/events/syscalls.h:16) [135546.084481] ? do_audit_syscall_entry (include/trace/events/syscalls.h:16) [135546.085438] ? trace_buffer_unlock_commit (kernel/trace/trace.c:1749) [135546.085515] rds_ib_laddr_check(): addr 36.74.25.172 ret -99 node type -1 Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Zefan Li <lizefan@huawei.com> 
commit 74e98eb085889b0d2d4908f59f6e00026063014f upstream.

There was no verification that an underlying transport exists when creating
a connection, this would cause dereferencing a NULL ptr.

It might happen on sockets that weren't properly bound before attempting to
send a message, which will cause a NULL ptr deref:

[135546.047719] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN
[135546.051270] Modules linked in:
[135546.051781] CPU: 4 PID: 15650 Comm: trinity-c4 Not tainted 4.2.0-next-20150902-sasha-00041-gbaa1222-dirty #2527
[135546.053217] task: ffff8800835bc000 ti: ffff8800bc708000 task.ti: ffff8800bc708000
[135546.054291] RIP: __rds_conn_create (net/rds/connection.c:194)
[135546.055666] RSP: 0018:ffff8800bc70fab0  EFLAGS: 00010202
[135546.056457] RAX: dffffc0000000000 RBX: 0000000000000f2c RCX: ffff8800835bc000
[135546.057494] RDX: 0000000000000007 RSI: ffff8800835bccd8 RDI: 0000000000000038
[135546.058530] RBP: ffff8800bc70fb18 R08: 0000000000000001 R09: 0000000000000000
[135546.059556] R10: ffffed014d7a3a23 R11: ffffed014d7a3a21 R12: 0000000000000000
[135546.060614] R13: 0000000000000001 R14: ffff8801ec3d0000 R15: 0000000000000000
[135546.061668] FS:  00007faad4ffb700(0000) GS:ffff880252000000(0000) knlGS:0000000000000000
[135546.062836] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[135546.063682] CR2: 000000000000846a CR3: 000000009d137000 CR4: 00000000000006a0
[135546.064723] Stack:
[135546.065048]  ffffffffafe2055c ffffffffafe23fc1 ffffed00493097bf ffff8801ec3d0008
[135546.066247]  0000000000000000 00000000000000d0 0000000000000000 ac194a24c0586342
[135546.067438]  1ffff100178e1f78 ffff880320581b00 ffff8800bc70fdd0 ffff880320581b00
[135546.068629] Call Trace:
[135546.069028] ? __rds_conn_create (include/linux/rcupdate.h:856 net/rds/connection.c:134)
[135546.069989] ? rds_message_copy_from_user (net/rds/message.c:298)
[135546.071021] rds_conn_create_outgoing (net/rds/connection.c:278)
[135546.071981] rds_sendmsg (net/rds/send.c:1058)
[135546.072858] ? perf_trace_lock (include/trace/events/lock.h:38)
[135546.073744] ? lockdep_init (kernel/locking/lockdep.c:3298)
[135546.074577] ? rds_send_drop_to (net/rds/send.c:976)
[135546.075508] ? __might_fault (./arch/x86/include/asm/current.h:14 mm/memory.c:3795)
[135546.076349] ? __might_fault (mm/memory.c:3795)
[135546.077179] ? rds_send_drop_to (net/rds/send.c:976)
[135546.078114] sock_sendmsg (net/socket.c:611 net/socket.c:620)
[135546.078856] SYSC_sendto (net/socket.c:1657)
[135546.079596] ? SYSC_connect (net/socket.c:1628)
[135546.080510] ? trace_dump_stack (kernel/trace/trace.c:1926)
[135546.081397] ? ring_buffer_unlock_commit (kernel/trace/ring_buffer.c:2479 kernel/trace/ring_buffer.c:2558 kernel/trace/ring_buffer.c:2674)
[135546.082390] ? trace_buffer_unlock_commit (kernel/trace/trace.c:1749)
[135546.083410] ? trace_event_raw_event_sys_enter (include/trace/events/syscalls.h:16)
[135546.084481] ? do_audit_syscall_entry (include/trace/events/syscalls.h:16)
[135546.085438] ? trace_buffer_unlock_commit (kernel/trace/trace.c:1749)
[135546.085515] rds_ib_laddr_check(): addr 36.74.25.172 ret -99 node type -1

Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Zefan Li <lizefan@huawei.com>