[v2.6.34-stable 61/77] sctp: malloc enough room for asconf-ack chunk

Paul Gortmaker
2013-01-08T23:39:48Z

From: Wei Yongjun <yjwei@cn.fujitsu.com>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------

commit 2cab86bee8e7f353e6ac8c15b3eb906643497644 upstream.

Sometime the ASCONF_ACK parameters can equal to the fourfold of
ASCONF parameters, this only happend in some special case:

ASCONF parameter is :
Unrecognized Parameter (4 bytes)
ASCONF_ACK parameter should be:
Error Cause Indication parameter (8 bytes header)
+ Error Cause (4 bytes header)
+ Unrecognized Parameter (4bytes)

Four 4bytes Unrecognized Parameters in ASCONF chunk will cause panic.

Pid: 0, comm: swapper Not tainted 2.6.38-next+ #22 Bochs Bochs
EIP: 0060:[<c0717eae>] EFLAGS: 00010246 CPU: 0
EIP is at skb_put+0x60/0x70
EAX: 00000077 EBX: c09060e2 ECX: dec1dc30 EDX: c09469c0
ESI: 00000000 EDI: de3c8d40 EBP: dec1dc58 ESP: dec1dc2c
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Process swapper (pid: 0, ti=dec1c000 task=c09aef20 task.ti=c0980000)
Stack:
c09469c0 e1894fa4 00000044 00000004 de3c8d00 de3c8d00 de3c8d44 de3c8d40
c09060e2 de25dd80 de3c8d40 dec1dc7c e1894fa4 dec1dcb0 00000040 00000004
00000000 00000800 00000004 00000004 dec1dce0 e1895a2b dec1dcb4 de25d960
Call Trace:
[<e1894fa4>] ? sctp_addto_chunk+0x4e/0x89 [sctp]
[<e1894fa4>] sctp_addto_chunk+0x4e/0x89 [sctp]
[<e1895a2b>] sctp_process_asconf+0x32f/0x3d1 [sctp]
[<e188d554>] sctp_sf_do_asconf+0xf8/0x173 [sctp]
[<e1890b02>] sctp_do_sm+0xb8/0x159 [sctp]
[<e18a2248>] ? sctp_cname+0x0/0x52 [sctp]
[<e189392d>] sctp_assoc_bh_rcv+0xac/0xe3 [sctp]
[<e1897d76>] sctp_inq_push+0x2d/0x30 [sctp]
[<e18a21b2>] sctp_rcv+0x7a7/0x83d [sctp]
[<c077a95c>] ? ipv4_confirm+0x118/0x125
[<c073a970>] ? nf_iterate+0x34/0x62
[<c074789d>] ? ip_local_deliver_finish+0x0/0x194
[<c074789d>] ? ip_local_deliver_finish+0x0/0x194
[<c0747992>] ip_local_deliver_finish+0xf5/0x194
[<c074789d>] ? ip_local_deliver_finish+0x0/0x194
[<c0747a6e>] NF_HOOK.clone.1+0x3d/0x44
[<c0747ab3>] ip_local_deliver+0x3e/0x44
[<c074789d>] ? ip_local_deliver_finish+0x0/0x194
[<c074775c>] ip_rcv_finish+0x29f/0x2c7
[<c07474bd>] ? ip_rcv_finish+0x0/0x2c7
[<c0747a6e>] NF_HOOK.clone.1+0x3d/0x44
[<c0747cae>] ip_rcv+0x1f5/0x233
[<c07474bd>] ? ip_rcv_finish+0x0/0x2c7
[<c071dce3>] __netif_receive_skb+0x310/0x336
[<c07221f3>] netif_receive_skb+0x4b/0x51
[<e0a4ed3d>] cp_rx_poll+0x1e7/0x29c [8139cp]
[<c072275e>] net_rx_action+0x65/0x13a
[<c0445a54>] __do_softirq+0xa1/0x149
[<c04459b3>] ? __do_softirq+0x0/0x149
<IRQ>
[<c0445891>] ? irq_exit+0x37/0x72
[<c040a7e9>] ? do_IRQ+0x81/0x95
[<c07b3670>] ? common_interrupt+0x30/0x38
[<c0428058>] ? native_safe_halt+0xa/0xc
[<c040f5d7>] ? default_idle+0x58/0x92
[<c0408fb0>] ? cpu_idle+0x96/0xb2
[<c0797989>] ? rest_init+0x5d/0x5f
[<c09fd90c>] ? start_kernel+0x34b/0x350
[<c09fd0cb>] ? i386_start_kernel+0xba/0xc1

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
net/sctp/sm_make_chunk.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 70d6c10..ad633d9 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -3110,10 +3110,10 @@ struct sctp_chunk *sctp_process_asconf(struct sctp_association *asoc,

/* create an ASCONF_ACK chunk.
* Based on the definitions of parameters, we know that the size of
- * ASCONF_ACK parameters are less than or equal to the twice of ASCONF
+ * ASCONF_ACK parameters are less than or equal to the fourfold of ASCONF
* parameters.
*/
- asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 2);
+ asconf_ack = sctp_make_asconf_ack(asoc, serial, chunk_len * 4);
if (!asconf_ack)
goto done;

--
1.7.12.1