linux-stable.git/net/sctp, branch v3.5

sctp: Fix list corruption resulting from freeing an association on a list

2012-07-17T05:32:26+00:00

A few days ago Dave Jones reported this oops:

[22766.294255] general protection fault: 0000 [#1] PREEMPT SMP
[22766.295376] CPU 0
[22766.295384] Modules linked in:
[22766.387137]  ffffffffa169f292 6b6b6b6b6b6b6b6b ffff880147c03a90
ffff880147c03a74
[22766.387135] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 00000000000
[22766.387136] Process trinity-watchdo (pid: 10896, threadinfo ffff88013e7d2000,
[22766.387137] Stack:
[22766.387140]  ffff880147c03a10
[22766.387140]  ffffffffa169f2b6
[22766.387140]  ffff88013ed95728
[22766.387143]  0000000000000002
[22766.387143]  0000000000000000
[22766.387143]  ffff880003fad062
[22766.387144]  ffff88013c120000
[22766.387144]
[22766.387145] Call Trace:
[22766.387145]  
[22766.387150]  [] ? __sctp_lookup_association+0x62/0xd0
[sctp]
[22766.387154]  [] __sctp_lookup_association+0x86/0xd0 [sctp]
[22766.387157]  [] sctp_rcv+0x207/0xbb0 [sctp]
[22766.387161]  [] ? trace_hardirqs_off_caller+0x28/0xd0
[22766.387163]  [] ? nf_hook_slow+0x133/0x210
[22766.387166]  [] ? ip_local_deliver_finish+0x4c/0x4c0
[22766.387168]  [] ip_local_deliver_finish+0x18d/0x4c0
[22766.387169]  [] ? ip_local_deliver_finish+0x4c/0x4c0
[22766.387171]  [] ip_local_deliver+0x47/0x80
[22766.387172]  [] ip_rcv_finish+0x150/0x680
[22766.387174]  [] ip_rcv+0x214/0x320
[22766.387176]  [] __netif_receive_skb+0x7b7/0x910
[22766.387178]  [] ? __netif_receive_skb+0x11c/0x910
[22766.387180]  [] ? put_lock_stats.isra.25+0xe/0x40
[22766.387182]  [] netif_receive_skb+0x23/0x1f0
[22766.387183]  [] ? dev_gro_receive+0x139/0x440
[22766.387185]  [] napi_skb_finish+0x70/0xa0
[22766.387187]  [] napi_gro_receive+0xf5/0x130
[22766.387218]  [] e1000_receive_skb+0x59/0x70 [e1000e]
[22766.387242]  [] e1000_clean_rx_irq+0x28b/0x460 [e1000e]
[22766.387266]  [] e1000e_poll+0x78/0x430 [e1000e]
[22766.387268]  [] net_rx_action+0x1aa/0x3d0
[22766.387270]  [] ? account_system_vtime+0x10f/0x130
[22766.387273]  [] __do_softirq+0xe0/0x420
[22766.387275]  [] call_softirq+0x1c/0x30
[22766.387278]  [] do_softirq+0xd5/0x110
[22766.387279]  [] irq_exit+0xd5/0xe0
[22766.387281]  [] do_IRQ+0x63/0xd0
[22766.387283]  [] common_interrupt+0x6f/0x6f
[22766.387283]  
[22766.387284]
[22766.387285]  [] ? retint_swapgs+0x13/0x1b
[22766.387285] Code: c0 90 5d c3 66 0f 1f 44 00 00 4c 89 c8 5d c3 0f 1f 00 55 48
89 e5 48 83
ec 20 48 89 5d e8 4c 89 65 f0 4c 89 6d f8 66 66 66 66 90 <0f> b7 87 98 00 00 00
48 89 fb
49 89 f5 66 c1 c0 08 66 39 46 02
[22766.387307]
[22766.387307] RIP
[22766.387311]  [] sctp_assoc_is_match+0x19/0x90 [sctp]
[22766.387311]  RSP 
[22766.387142]  ffffffffa16ab120
[22766.599537] ---[ end trace 3f6dae82e37b17f5 ]---
[22766.601221] Kernel panic - not syncing: Fatal exception in interrupt

It appears from his analysis and some staring at the code that this is likely
occuring because an association is getting freed while still on the
sctp_assoc_hashtable.  As a result, we get a gpf when traversing the hashtable
while a freed node corrupts part of the list.

Nominally I would think that an mibalanced refcount was responsible for this,
but I can't seem to find any obvious imbalance.  What I did note however was
that the two places where we create an association using
sctp_primitive_ASSOCIATE (__sctp_connect and sctp_sendmsg), have failure paths
which free a newly created association after calling sctp_primitive_ASSOCIATE.
sctp_primitive_ASSOCIATE brings us into the sctp_sf_do_prm_asoc path, which
issues a SCTP_CMD_NEW_ASOC side effect, which in turn adds a new association to
the aforementioned hash table.  the sctp command interpreter that process side
effects has not way to unwind previously processed commands, so freeing the
association from the __sctp_connect or sctp_sendmsg error path would lead to a
freed association remaining on this hash table.

I've fixed this but modifying sctp_[un]hash_established to use hlist_del_init,
which allows us to proerly use hlist_unhashed to check if the node is on a
hashlist safely during a delete.  That in turn alows us to safely call
sctp_unhash_established in the __sctp_connect and sctp_sendmsg error paths
before freeing them, regardles of what the associations state is on the hash
list.

I noted, while I was doing this, that the __sctp_unhash_endpoint was using
hlist_unhsashed in a simmilar fashion, but never nullified any removed nodes
pointers to make that function work properly, so I fixed that up in a simmilar
fashion.

I attempted to test this using a virtual guest running the SCTP_RR test from
netperf in a loop while running the trinity fuzzer, both in a loop.  I wasn't
able to recreate the problem prior to this fix, nor was I able to trigger the
failure after (neither of which I suppose is suprising).  Given the trace above
however, I think its likely that this is what we hit.

Signed-off-by: Neil Horman 
Reported-by: davej@redhat.com
CC: davej@redhat.com
CC: "David S. Miller" 
CC: Vlad Yasevich 
CC: Sridhar Samudrala 
CC: linux-sctp@vger.kernel.org
Signed-off-by: David S. Miller

sctp: be more restrictive in transport selection on bundled sacks

2012-07-01T05:44:35+00:00

It was noticed recently that when we send data on a transport, its possible that
we might bundle a sack that arrived on a different transport.  While this isn't
a major problem, it does go against the SHOULD requirement in section 6.4 of RFC
2960:

 An endpoint SHOULD transmit reply chunks (e.g., SACK, HEARTBEAT ACK,
   etc.) to the same destination transport address from which it
   received the DATA or control chunk to which it is replying.  This
   rule should also be followed if the endpoint is bundling DATA chunks
   together with the reply chunk.

This patch seeks to correct that.  It restricts the bundling of sack operations
to only those transports which have moved the ctsn of the association forward
since the last sack.  By doing this we guarantee that we only bundle outbound
saks on a transport that has received a chunk since the last sack.  This brings
us into stricter compliance with the RFC.

Vlad had initially suggested that we strictly allow only sack bundling on the
transport that last moved the ctsn forward.  While this makes sense, I was
concerned that doing so prevented us from bundling in the case where we had
received chunks that moved the ctsn on multiple transports.  In those cases, the
RFC allows us to select any of the transports having received chunks to bundle
the sack on.  so I've modified the approach to allow for that, by adding a state
variable to each transport that tracks weather it has moved the ctsn since the
last sack.  This I think keeps our behavior (and performance), close enough to
our current profile that I think we can do this without a sysctl knob to
enable/disable it.

Signed-off-by: Neil Horman 
CC: Vlad Yaseivch 
CC: David S. Miller 
CC: linux-sctp@vger.kernel.org
Reported-by: Michele Baldessari 
Reported-by: sorin serban 
Acked-by: Vlad Yasevich 
Signed-off-by: David S. Miller

sctp: fix warning when compiling without IPv6

2012-06-19T07:26:26+00:00

net/sctp/protocol.c: In function ‘sctp_addr_wq_timeout_handler’:
net/sctp/protocol.c:676: warning: label ‘free_next’ defined but not used

Signed-off-by: Daniel Halperin 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2012-05-17T02:17:37+00:00

net: Convert net_ratelimit uses to net__ratelimited

2012-05-15T17:45:03+00:00

Standardize the net core ratelimited logging functions.

Coalesce formats, align arguments.
Change a printk then vprintk sequence to use printf extension %pV.

Signed-off-by: Joe Perches 
Signed-off-by: David S. Miller

sctp: check cached dst before using it

2012-05-11T03:15:47+00:00

dst_check() will take care of SA (and obsolete field), hence
IPsec rekeying scenario is taken into account.

Signed-off-by: Nicolas Dichtel 
Acked-by: Vlad Yaseivch 
Signed-off-by: David S. Miller

net: add a limit parameter to sk_add_backlog()

2012-04-24T02:28:28+00:00

sk_add_backlog() & sk_rcvqueues_full() hard coded sk_rcvbuf as the
memory limit. We need to make this limit a parameter for TCP use.

No functional change expected in this patch, all callers still using the
old sk_rcvbuf limit.

Signed-off-by: Eric Dumazet 
Cc: Neal Cardwell 
Cc: Tom Herbert 
Cc: Maciej Żenczykowski 
Cc: Yuchung Cheng 
Cc: Ilpo Järvinen 
Cc: Rick Jones 
Signed-off-by: David S. Miller

net: Convert all sysctl registrations to register_net_sysctl

2012-04-21T01:22:30+00:00

This results in code with less boiler plate that is a bit easier
to read.

Additionally stops us from using compatibility code in the sysctl
core, hastening the day when the compatibility code can be removed.

Signed-off-by: Eric W. Biederman 
Acked-by: Pavel Emelyanov 
Signed-off-by: David S. Miller

net: Move all of the network sysctls without a namespace into init_net.

2012-04-21T01:21:17+00:00

This makes it clearer which sysctls are relative to your current network
namespace.

This makes it a little less error prone by not exposing sysctls for the
initial network namespace in other namespaces.

This is the same way we handle all of our other network interfaces to
userspace and I can't honestly remember why we didn't do this for
sysctls right from the start.

Signed-off-by: Eric W. Biederman 
Acked-by: Pavel Emelyanov 
Signed-off-by: David S. Miller

net: cleanup unsigned to unsigned int

2012-04-15T16:44:40+00:00

Use of "unsigned int" is preferred to bare "unsigned" in net tree.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller