kernel.git/net/sctp, branch linux-3.11.y

net: sctp: do not trigger BUG_ON in sctp_cmd_delete_tcb

2013-11-20T20:31:37Z

[ Upstream commit 7926c1d5be0b7cbe5b8d5c788d7d39237e7b212c ] Introduced in f9e42b853523 ("net: sctp: sideeffect: throw BUG if primary_path is NULL"), we intended to find a buggy assoc that's part of the assoc hash table with a primary_path that is NULL. However, we better remove the BUG_ON for now and find a more suitable place to assert for these things as Mark reports that this also triggers the bug when duplication cookie processing happens, and the assoc is not part of the hash table (so all good in this case). Such a situation can for example easily be reproduced by: tc qdisc add dev eth0 root handle 1: prio bands 2 priomap 1 1 1 1 1 1 tc qdisc add dev eth0 parent 1:2 handle 20: netem loss 20% tc filter add dev eth0 protocol ip parent 1: prio 2 u32 match ip \ protocol 132 0xff match u8 0x0b 0xff at 32 flowid 1:2 This drops 20% of COOKIE-ACK packets. After some follow-up discussion with Vlad we came to the conclusion that for now we should still better remove this BUG_ON() assertion, and come up with two follow-ups later on, that is, i) find a more suitable place for this assertion, and possibly ii) have a special allocator/initializer for such kind of temporary assocs. Reported-by: Mark Thomas Signed-off-by: Vlad Yasevich Signed-off-by: Daniel Borkmann Acked-by: Neil Horman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

sctp: Perform software checksum if packet has to be fragmented.

2013-11-04T12:35:17Z

[ Upstream commit d2dbbba77e95dff4b4f901fee236fef6d9552072 ] IP/IPv6 fragmentation knows how to compute only TCP/UDP checksum. This causes problems if SCTP packets has to be fragmented and ipsummed has been set to PARTIAL due to checksum offload support. This condition can happen when retransmitting after MTU discover, or when INIT or other control chunks are larger then MTU. Check for the rare fragmentation condition in SCTP and use software checksum calculation in this case. CC: Fan Du Signed-off-by: Vlad Yasevich Acked-by: Neil Horman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

sctp: Use software crc32 checksum when xfrm transform will happen.

2013-11-04T12:35:16Z

[ Upstream commit 27127a82561a2a3ed955ce207048e1b066a80a2a ] igb/ixgbe have hardware sctp checksum support, when this feature is enabled and also IPsec is armed to protect sctp traffic, ugly things happened as xfrm_output checks CHECKSUM_PARTIAL to do checksum operation(sum every thing up and pack the 16bits result in the checksum field). The result is fail establishment of sctp communication. Signed-off-by: Fan Du Cc: Neil Horman Cc: Steffen Klassert Signed-off-by: Vlad Yasevich Acked-by: Neil Horman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sctp: rfc4443: do not report ICMP redirects to user space

2013-10-14T01:14:25Z

[ Upstream commit 3f96a532113131d5a65ac9e00fc83cfa31b0295f ] Adapt the same behaviour for SCTP as present in TCP for ICMP redirect messages. For IPv6, RFC4443, section 2.4. says: ... (e) An ICMPv6 error message MUST NOT be originated as a result of receiving the following: ... (e.2) An ICMPv6 redirect message [IPv6-DISC]. ... Therefore, do not report an error to user space, just invoke dst's redirect callback and leave, same for IPv4 as done in TCP as well. The implication w/o having this patch could be that the reception of such packets would generate a poll notification and in worst case it could even tear down the whole connection. Therefore, stop updating sk_err on redirects. Reported-by: Duan Jiong Reported-by: Hannes Frederic Sowa Suggested-by: Vlad Yasevich Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sctp: fix ipv6 ipsec encryption bug in sctp_v6_xmit

2013-10-14T01:14:25Z

[ Upstream commit 95ee62083cb6453e056562d91f597552021e6ae7 ] Alan Chester reported an issue with IPv6 on SCTP that IPsec traffic is not being encrypted, whereas on IPv4 it is. Setting up an AH + ESP transport does not seem to have the desired effect: SCTP + IPv4: 22:14:20.809645 IP (tos 0x2,ECT(0), ttl 64, id 0, offset 0, flags [DF], proto AH (51), length 116) 192.168.0.2 > 192.168.0.5: AH(spi=0x00000042,sumlen=16,seq=0x1): ESP(spi=0x00000044,seq=0x1), length 72 22:14:20.813270 IP (tos 0x2,ECT(0), ttl 64, id 0, offset 0, flags [DF], proto AH (51), length 340) 192.168.0.5 > 192.168.0.2: AH(spi=0x00000043,sumlen=16,seq=0x1): SCTP + IPv6: 22:31:19.215029 IP6 (class 0x02, hlim 64, next-header SCTP (132) payload length: 364) fe80::222:15ff:fe87:7fc.3333 > fe80::92e6:baff:fe0d:5a54.36767: sctp 1) [INIT ACK] [init tag: 747759530] [rwnd: 62464] [OS: 10] [MIS: 10] Moreover, Alan says: This problem was seen with both Racoon and Racoon2. Other people have seen this with OpenSwan. When IPsec is configured to encrypt all upper layer protocols the SCTP connection does not initialize. After using Wireshark to follow packets, this is because the SCTP packet leaves Box A unencrypted and Box B believes all upper layer protocols are to be encrypted so it drops this packet, causing the SCTP connection to fail to initialize. When IPsec is configured to encrypt just SCTP, the SCTP packets are observed unencrypted. In fact, using `socat sctp6-listen:3333 -` on one end and transferring "plaintext" string on the other end, results in cleartext on the wire where SCTP eventually does not report any errors, thus in the latter case that Alan reports, the non-paranoid user might think he's communicating over an encrypted transport on SCTP although he's not (tcpdump ... -X): ... 0x0030: 5d70 8e1a 0003 001a 177d eb6c 0000 0000 ]p.......}.l.... 0x0040: 0000 0000 706c 6169 6e74 6578 740a 0000 ....plaintext... Only in /proc/net/xfrm_stat we can see XfrmInTmplMismatch increasing on the receiver side. Initial follow-up analysis from Alan's bug report was done by Alexey Dobriyan. Also thanks to Vlad Yasevich for feedback on this. SCTP has its own implementation of sctp_v6_xmit() not calling inet6_csk_xmit(). This has the implication that it probably never really got updated along with changes in inet6_csk_xmit() and therefore does not seem to invoke xfrm handlers. SCTP's IPv4 xmit however, properly calls ip_queue_xmit() to do the work. Since a call to inet6_csk_xmit() would solve this problem, but result in unecessary route lookups, let us just use the cached flowi6 instead that we got through sctp_v6_get_dst(). Since all SCTP packets are being sent through sctp_packet_transmit(), we do the route lookup / flow caching in sctp_transport_route(), hold it in tp->dst and skb_dst_set() right after that. If we would alter fl6->daddr in sctp_v6_xmit() to np->opt->srcrt, we possibly could run into the same effect of not having xfrm layer pick it up, hence, use fl6_update_dst() in sctp_v6_get_dst() instead to get the correct source routed dst entry, which we assign to the skb. Also source address routing example from 625034113 ("sctp: fix sctp to work with ipv6 source address routing") still works with this patch! Nevertheless, in RFC5095 it is actually 'recommended' to not use that anyway due to traffic amplification [1]. So it seems we're not supposed to do that anyway in sctp_v6_xmit(). Moreover, if we overwrite the flow destination here, the lower IPv6 layer will be unable to put the correct destination address into IP header, as routing header is added in ipv6_push_nfrag_opts() but then probably with wrong final destination. Things aside, result of this patch is that we do not have any XfrmInTmplMismatch increase plus on the wire with this patch it now looks like: SCTP + IPv6: 08:17:47.074080 IP6 2620:52:0:102f:7a2b:cbff:fe27:1b0a > 2620:52:0:102f:213:72ff:fe32:7eba: AH(spi=0x00005fb4,seq=0x1): ESP(spi=0x00005fb5,seq=0x1), length 72 08:17:47.074264 IP6 2620:52:0:102f:213:72ff:fe32:7eba > 2620:52:0:102f:7a2b:cbff:fe27:1b0a: AH(spi=0x00003d54,seq=0x1): ESP(spi=0x00003d55,seq=0x1), length 296 This fixes Kernel Bugzilla 24412. This security issue seems to be present since 2.6.18 kernels. Lets just hope some big passive adversary in the wild didn't have its fun with that. lksctp-tools IPv6 regression test suite passes as well with this patch. [1] http://www.secdev.org/conf/IPv6_RH_security-csw07.pdf Reported-by: Alan Chester Reported-by: Alexey Dobriyan Signed-off-by: Daniel Borkmann Cc: Steffen Klassert Cc: Hannes Frederic Sowa Acked-by: Vlad Yasevich Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sctp: fix smatch warning in sctp_send_asconf_del_ip

2013-10-14T01:14:24Z

[ Upstream commit 88362ad8f9a6cea787420b57cc27ccacef000dbe ] This was originally reported in [1] and posted by Neil Horman [2], he said: Fix up a missed null pointer check in the asconf code. If we don't find a local address, but we pass in an address length of more than 1, we may dereference a NULL laddr pointer. Currently this can't happen, as the only users of the function pass in the value 1 as the addrcnt parameter, but its not hot path, and it doesn't hurt to check for NULL should that ever be the case. The callpath from sctp_asconf_mgmt() looks okay. But this could be triggered from sctp_setsockopt_bindx() call with SCTP_BINDX_REM_ADDR and addrcnt > 1 while passing all possible addresses from the bind list to SCTP_BINDX_REM_ADDR so that we do *not* find a single address in the association's bind address list that is not in the packed array of addresses. If this happens when we have an established association with ASCONF-capable peers, then we could get a NULL pointer dereference as we only check for laddr == NULL && addrcnt == 1 and call later sctp_make_asconf_update_ip() with NULL laddr. BUT: this actually won't happen as sctp_bindx_rem() will catch such a case and return with an error earlier. As this is incredably unintuitive and error prone, add a check to catch at least future bugs here. As Neil says, its not hot path. Introduced by 8a07eb0a5 ("sctp: Add ASCONF operation on the single-homed host"). [1] http://www.spinics.net/lists/linux-sctp/msg02132.html [2] http://www.spinics.net/lists/linux-sctp/msg02133.html Reported-by: Dan Carpenter Signed-off-by: Neil Horman Signed-off-by: Daniel Borkmann Cc: Michio Honda Acked-By: Neil Horman Acked-by: Vlad Yasevich Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sctp: fix bug in sctp_poll for SOCK_SELECT_ERR_QUEUE

2013-10-14T01:14:24Z

[ Upstream commit a0fb05d1aef0f5df936f80b726d1b3bfd4275f95 ] If we do not add braces around ... mask |= POLLERR | sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? POLLPRI : 0; ... then this condition always evaluates to true as POLLERR is defined as 8 and binary or'd with whatever result comes out of sock_flag(). Hence instead of (X | Y) ? A : B, transform it into X | (Y ? A : B). Unfortunatelty, commit 8facd5fb73 ("net: fix smatch warnings inside datagram_poll") forgot about SCTP. :-( Introduced by 7d4c04fc170 ("net: add option to enable error queue packets waking select"). Signed-off-by: Daniel Borkmann Cc: Jacob Keller Acked-by: Neil Horman Acked-by: Vlad Yasevich Acked-by: Jacob Keller Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sctp: sctp_transport_destroy{, _rcu}: fix potential pointer corruption

2013-08-13T05:13:47Z

Probably this one is quite unlikely to be triggered, but it's more safe to do the call_rcu() at the end after we have dropped the reference on the asoc and freed sctp packet chunks. The reason why is because in sctp_transport_destroy_rcu() the transport is being kfree()'d, and if we're unlucky enough we could run into corrupted pointers. Probably that's more of theoretical nature, but it's safer to have this simple fix. Introduced by commit 8c98653f ("sctp: sctp_close: fix release of bindings for deferred call_rcu's"). I also did the 8c98653f regression test and it's fine that way. Signed-off-by: Daniel Borkmann Acked-by: Vlad Yasevich Signed-off-by: David S. Miller

net: sctp: sctp_assoc_control_transport: fix MTU size in SCTP_PF state

2013-08-13T05:12:20Z

The SCTP Quick failover draft [1] section 5.1, point 5 says that the cwnd should be 1 MTU. So, instead of 1, set it to 1 MTU. [1] https://tools.ietf.org/html/draft-nishida-tsvwg-sctp-failover-05 Reported-by: Karl Heiss Signed-off-by: Daniel Borkmann Cc: Neil Horman Acked-by: Vlad Yasevich Acked-by: Neil Horman Signed-off-by: David S. Miller

net: sctp: confirm route during forward progress

2013-07-09T19:49:56Z

This fix has been proposed originally by Vlad Yasevich. He says: When SCTP makes forward progress (receives a SACK that acks new chunks, renegs, or answeres 0-window probes) or when HB-ACK arrives, mark the route as confirmed so we don't unnecessarily send NUD probes. Having a simple SCTP client/server that exchange data chunks every 1sec, without this patch ARP requests are sent periodically every 40-60sec. With this fix applied, an ARP request is only done once right at the "session" beginning. Also, when clearing the related ARP cache entry manually during the session, a new request is correctly done. I have only "backported" this to net-next and tested that it works, so full credit goes to Vlad. Signed-off-by: Vlad Yasevich Signed-off-by: Daniel Borkmann Acked-by: Neil Horman Signed-off-by: David S. Miller