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path: root/net/sctp/sm_statefuns.c
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2016-10-29sctp: validate chunk len before actually using itMarcelo Ricardo Leitner
Andrey Konovalov reported that KASAN detected that SCTP was using a slab beyond the boundaries. It was caused because when handling out of the blue packets in function sctp_sf_ootb() it was checking the chunk len only after already processing the first chunk, validating only for the 2nd and subsequent ones. The fix is to just move the check upwards so it's also validated for the 1st chunk. Reported-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-22sctp: rename WORD_TRUNC/ROUND macrosMarcelo Ricardo Leitner
To something more meaningful these days, specially because this is working on packet headers or lengths and which are not tied to any CPU arch but to the protocol itself. So, WORD_TRUNC becomes SCTP_TRUNC4 and WORD_ROUND becomes SCTP_PAD4. Reported-by: David Laight <David.Laight@ACULAB.COM> Reported-by: David Miller <davem@davemloft.net> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-13sctp: only check for ECN if peer is using itMarcelo Ricardo Leitner
Currently only read-only checks are performed up to the point on where we check if peer is ECN capable, checks which we can avoid otherwise. The flag ecn_ce_done is only used to perform this check once per incoming packet, and nothing more. Thus this patch moves the peer check up. Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-13sctp: avoid identifying address family many times for a chunkMarcelo Ricardo Leitner
Identifying address family operations during rx path is not something expensive but it's ugly to the eye to have it done multiple times, specially when we already validated it during initial rx processing. This patch takes advantage of the now shared sctp_input_cb and make the pointer to the operations readily available. Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-13sctp: allow GSO frags to access the chunk tooMarcelo Ricardo Leitner
SCTP will try to access original IP headers on sctp_recvmsg in order to copy the addresses used. There are also other places that do similar access to IP or even SCTP headers. But after 90017accff61 ("sctp: Add GSO support") they aren't always there because they are only present in the header skb. SCTP handles the queueing of incoming data by cloning the incoming skb and limiting to only the relevant payload. This clone has its cb updated to something different and it's then queued on socket rx queue. Thus we need to fix this in two moments. For rx path, not related to socket queue yet, this patch uses a partially copied sctp_input_cb to such GSO frags. This restores the ability to access the headers for this part of the code. Regarding the socket rx queue, it removes iif member from sctp_event and also add a chunk pointer on it. With these changes we're always able to reach the headers again. The biggest change here is that now the sctp_chunk struct and the original skb are only freed after the application consumed the buffer. Note however that the original payload was already like this due to the skb cloning. For iif, SCTP's IPv4 code doesn't use it, so no change is necessary. IPv6 now can fetch it directly from original's IPv6 CB as the original skb is still accessible. In the future we probably can simplify sctp_v*_skb_iif() stuff, as sctp_v4_skb_iif() was called but it's return value not used, and now it's not even called, but such cleanup is out of scope for this change. Fixes: 90017accff61 ("sctp: Add GSO support") Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-01-11sctp: fix use-after-free in pr_debug statementMarcelo Ricardo Leitner
Dmitry Vyukov reported a use-after-free in the code expanded by the macro debug_post_sfx, which is caused by the use of the asoc pointer after it was freed within sctp_side_effect() scope. This patch fixes it by allowing sctp_side_effect to clear that asoc pointer when the TCB is freed. As Vlad explained, we also have to cover the SCTP_DISPOSITION_ABORT case because it will trigger DELETE_TCB too on that same loop. Also, there were places issuing SCTP_CMD_INIT_FAILED and ASSOC_FAILED but returning SCTP_DISPOSITION_CONSUME, which would fool the scheme above. Fix it by returning SCTP_DISPOSITION_ABORT instead. The macro is already prepared to handle such NULL pointer. Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-30sctp: sctp should release assoc when sctp_make_abort_user return NULL in ↵Xin Long
sctp_close In sctp_close, sctp_make_abort_user may return NULL because of memory allocation failure. If this happens, it will bypass any state change and never free the assoc. The assoc has no chance to be freed and it will be kept in memory with the state it had even after the socket is closed by sctp_close(). So if sctp_make_abort_user fails to allocate memory, we should abort the asoc via sctp_primitive_ABORT as well. Just like the annotation in sctp_sf_cookie_wait_prm_abort and sctp_sf_do_9_1_prm_abort said, "Even if we can't send the ABORT due to low memory delete the TCB. This is a departure from our typical NOMEM handling". But then the chunk is NULL (low memory) and the SCTP_CMD_REPLY cmd would dereference the chunk pointer, and system crash. So we should add SCTP_CMD_REPLY cmd only when the chunk is not NULL, just like other places where it adds SCTP_CMD_REPLY cmd. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-06sctp: start t5 timer only when peer rwnd is 0 and local state is ↵lucien
SHUTDOWN_PENDING when A sends a data to B, then A close() and enter into SHUTDOWN_PENDING state, if B neither claim his rwnd is 0 nor send SACK for this data, A will keep retransmitting this data until t5 timeout, Max.Retrans times can't work anymore, which is bad. if B's rwnd is not 0, it should send abort after Max.Retrans times, only when B's rwnd == 0 and A's retransmitting beyonds Max.Retrans times, A will start t5 timer, which is also commit f8d960524328 ("sctp: Enforce retransmission limit during shutdown") means, but it lacks the condition peer rwnd == 0. so fix it by adding a bit (zero_window_announced) in peer to record if the last rwnd is 0. If it was, zero_window_announced will be set. and use this bit to decide if start t5 timer when local.state is SHUTDOWN_PENDING. Fixes: commit f8d960524328 ("sctp: Enforce retransmission limit during shutdown") Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-05net: sctp: avoid incorrect time_t useArnd Bergmann
We want to avoid using time_t in the kernel because of the y2038 overflow problem. The use in sctp is not for storing seconds at all, but instead uses microseconds and is passed as 32-bit on all machines. This patch changes the type to u32, which better fits the use. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Vlad Yasevich <vyasevich@gmail.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: linux-sctp@vger.kernel.org Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-21sctp: fix cut and paste issue in commentMarcelo Ricardo Leitner
Cookie ACK is always received by the association initiator, so fix the comment to avoid confusion. Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-14net: sctp: fix remote memory pressure from excessive queueingDaniel Borkmann
This scenario is not limited to ASCONF, just taken as one example triggering the issue. When receiving ASCONF probes in the form of ... -------------- INIT[ASCONF; ASCONF_ACK] -------------> <----------- INIT-ACK[ASCONF; ASCONF_ACK] ------------ -------------------- COOKIE-ECHO --------------------> <-------------------- COOKIE-ACK --------------------- ---- ASCONF_a; [ASCONF_b; ...; ASCONF_n;] JUNK ------> [...] ---- ASCONF_m; [ASCONF_o; ...; ASCONF_z;] JUNK ------> ... where ASCONF_a, ASCONF_b, ..., ASCONF_z are good-formed ASCONFs and have increasing serial numbers, we process such ASCONF chunk(s) marked with !end_of_packet and !singleton, since we have not yet reached the SCTP packet end. SCTP does only do verification on a chunk by chunk basis, as an SCTP packet is nothing more than just a container of a stream of chunks which it eats up one by one. We could run into the case that we receive a packet with a malformed tail, above marked as trailing JUNK. All previous chunks are here goodformed, so the stack will eat up all previous chunks up to this point. In case JUNK does not fit into a chunk header and there are no more other chunks in the input queue, or in case JUNK contains a garbage chunk header, but the encoded chunk length would exceed the skb tail, or we came here from an entirely different scenario and the chunk has pdiscard=1 mark (without having had a flush point), it will happen, that we will excessively queue up the association's output queue (a correct final chunk may then turn it into a response flood when flushing the queue ;)): I ran a simple script with incremental ASCONF serial numbers and could see the server side consuming excessive amount of RAM [before/after: up to 2GB and more]. The issue at heart is that the chunk train basically ends with !end_of_packet and !singleton markers and since commit 2e3216cd54b1 ("sctp: Follow security requirement of responding with 1 packet") therefore preventing an output queue flush point in sctp_do_sm() -> sctp_cmd_interpreter() on the input chunk (chunk = event_arg) even though local_cork is set, but its precedence has changed since then. In the normal case, the last chunk with end_of_packet=1 would trigger the queue flush to accommodate possible outgoing bundling. In the input queue, sctp_inq_pop() seems to do the right thing in terms of discarding invalid chunks. So, above JUNK will not enter the state machine and instead be released and exit the sctp_assoc_bh_rcv() chunk processing loop. It's simply the flush point being missing at loop exit. Adding a try-flush approach on the output queue might not work as the underlying infrastructure might be long gone at this point due to the side-effect interpreter run. One possibility, albeit a bit of a kludge, would be to defer invalid chunk freeing into the state machine in order to possibly trigger packet discards and thus indirectly a queue flush on error. It would surely be better to discard chunks as in the current, perhaps better controlled environment, but going back and forth, it's simply architecturally not possible. I tried various trailing JUNK attack cases and it seems to look good now. Joint work with Vlad Yasevich. Fixes: 2e3216cd54b1 ("sctp: Follow security requirement of responding with 1 packet") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-14net: sctp: fix skb_over_panic when receiving malformed ASCONF chunksDaniel Borkmann
Commit 6f4c618ddb0 ("SCTP : Add paramters validity check for ASCONF chunk") added basic verification of ASCONF chunks, however, it is still possible to remotely crash a server by sending a special crafted ASCONF chunk, even up to pre 2.6.12 kernels: skb_over_panic: text:ffffffffa01ea1c3 len:31056 put:30768 head:ffff88011bd81800 data:ffff88011bd81800 tail:0x7950 end:0x440 dev:<NULL> ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:129! [...] Call Trace: <IRQ> [<ffffffff8144fb1c>] skb_put+0x5c/0x70 [<ffffffffa01ea1c3>] sctp_addto_chunk+0x63/0xd0 [sctp] [<ffffffffa01eadaf>] sctp_process_asconf+0x1af/0x540 [sctp] [<ffffffff8152d025>] ? _read_unlock_bh+0x15/0x20 [<ffffffffa01e0038>] sctp_sf_do_asconf+0x168/0x240 [sctp] [<ffffffffa01e3751>] sctp_do_sm+0x71/0x1210 [sctp] [<ffffffff8147645d>] ? fib_rules_lookup+0xad/0xf0 [<ffffffffa01e6b22>] ? sctp_cmp_addr_exact+0x32/0x40 [sctp] [<ffffffffa01e8393>] sctp_assoc_bh_rcv+0xd3/0x180 [sctp] [<ffffffffa01ee986>] sctp_inq_push+0x56/0x80 [sctp] [<ffffffffa01fcc42>] sctp_rcv+0x982/0xa10 [sctp] [<ffffffffa01d5123>] ? ipt_local_in_hook+0x23/0x28 [iptable_filter] [<ffffffff8148bdc9>] ? nf_iterate+0x69/0xb0 [<ffffffff81496d10>] ? ip_local_deliver_finish+0x0/0x2d0 [<ffffffff8148bf86>] ? nf_hook_slow+0x76/0x120 [<ffffffff81496d10>] ? ip_local_deliver_finish+0x0/0x2d0 [<ffffffff81496ded>] ip_local_deliver_finish+0xdd/0x2d0 [<ffffffff81497078>] ip_local_deliver+0x98/0xa0 [<ffffffff8149653d>] ip_rcv_finish+0x12d/0x440 [<ffffffff81496ac5>] ip_rcv+0x275/0x350 [<ffffffff8145c88b>] __netif_receive_skb+0x4ab/0x750 [<ffffffff81460588>] netif_receive_skb+0x58/0x60 This can be triggered e.g., through a simple scripted nmap connection scan injecting the chunk after the handshake, for example, ... -------------- INIT[ASCONF; ASCONF_ACK] -------------> <----------- INIT-ACK[ASCONF; ASCONF_ACK] ------------ -------------------- COOKIE-ECHO --------------------> <-------------------- COOKIE-ACK --------------------- ------------------ ASCONF; UNKNOWN ------------------> ... where ASCONF chunk of length 280 contains 2 parameters ... 1) Add IP address parameter (param length: 16) 2) Add/del IP address parameter (param length: 255) ... followed by an UNKNOWN chunk of e.g. 4 bytes. Here, the Address Parameter in the ASCONF chunk is even missing, too. This is just an example and similarly-crafted ASCONF chunks could be used just as well. The ASCONF chunk passes through sctp_verify_asconf() as all parameters passed sanity checks, and after walking, we ended up successfully at the chunk end boundary, and thus may invoke sctp_process_asconf(). Parameter walking is done with WORD_ROUND() to take padding into account. In sctp_process_asconf()'s TLV processing, we may fail in sctp_process_asconf_param() e.g., due to removal of the IP address that is also the source address of the packet containing the ASCONF chunk, and thus we need to add all TLVs after the failure to our ASCONF response to remote via helper function sctp_add_asconf_response(), which basically invokes a sctp_addto_chunk() adding the error parameters to the given skb. When walking to the next parameter this time, we proceed with ... length = ntohs(asconf_param->param_hdr.length); asconf_param = (void *)asconf_param + length; ... instead of the WORD_ROUND()'ed length, thus resulting here in an off-by-one that leads to reading the follow-up garbage parameter length of 12336, and thus throwing an skb_over_panic for the reply when trying to sctp_addto_chunk() next time, which implicitly calls the skb_put() with that length. Fix it by using sctp_walk_params() [ which is also used in INIT parameter processing ] macro in the verification *and* in ASCONF processing: it will make sure we don't spill over, that we walk parameters WORD_ROUND()'ed. Moreover, we're being more defensive and guard against unknown parameter types and missized addresses. Joint work with Vlad Yasevich. Fixes: b896b82be4ae ("[SCTP] ADDIP: Support for processing incoming ASCONF_ACK chunks.") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Vlad Yasevich <vyasevich@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-06sctp: handle association restarts when the socket is closed.Vlad Yasevich
Currently association restarts do not take into consideration the state of the socket. When a restart happens, the current assocation simply transitions into established state. This creates a condition where a remote system, through a the restart procedure, may create a local association that is no way reachable by user. The conditions to trigger this are as follows: 1) Remote does not acknoledge some data causing data to remain outstanding. 2) Local application calls close() on the socket. Since data is still outstanding, the association is placed in SHUTDOWN_PENDING state. However, the socket is closed. 3) The remote tries to create a new association, triggering a restart on the local system. The association moves from SHUTDOWN_PENDING to ESTABLISHED. At this point, it is no longer reachable by any socket on the local system. This patch addresses the above situation by moving the newly ESTABLISHED association into SHUTDOWN-SENT state and bundling a SHUTDOWN after the COOKIE-ACK chunk. This way, the restarted associate immidiately enters the shutdown procedure and forces the termination of the unreachable association. Reported-by: David Laight <David.Laight@aculab.com> Signed-off-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-15net: sctp: remove unnecessary break after return/gotoFabian Frederick
Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-18net: sctp: cache auth_enable per endpointVlad Yasevich
Currently, it is possible to create an SCTP socket, then switch auth_enable via sysctl setting to 1 and crash the system on connect: Oops[#1]: CPU: 0 PID: 0 Comm: swapper Not tainted 3.14.1-mipsgit-20140415 #1 task: ffffffff8056ce80 ti: ffffffff8055c000 task.ti: ffffffff8055c000 [...] Call Trace: [<ffffffff8043c4e8>] sctp_auth_asoc_set_default_hmac+0x68/0x80 [<ffffffff8042b300>] sctp_process_init+0x5e0/0x8a4 [<ffffffff8042188c>] sctp_sf_do_5_1B_init+0x234/0x34c [<ffffffff804228c8>] sctp_do_sm+0xb4/0x1e8 [<ffffffff80425a08>] sctp_endpoint_bh_rcv+0x1c4/0x214 [<ffffffff8043af68>] sctp_rcv+0x588/0x630 [<ffffffff8043e8e8>] sctp6_rcv+0x10/0x24 [<ffffffff803acb50>] ip6_input+0x2c0/0x440 [<ffffffff8030fc00>] __netif_receive_skb_core+0x4a8/0x564 [<ffffffff80310650>] process_backlog+0xb4/0x18c [<ffffffff80313cbc>] net_rx_action+0x12c/0x210 [<ffffffff80034254>] __do_softirq+0x17c/0x2ac [<ffffffff800345e0>] irq_exit+0x54/0xb0 [<ffffffff800075a4>] ret_from_irq+0x0/0x4 [<ffffffff800090ec>] rm7k_wait_irqoff+0x24/0x48 [<ffffffff8005e388>] cpu_startup_entry+0xc0/0x148 [<ffffffff805a88b0>] start_kernel+0x37c/0x398 Code: dd0900b8 000330f8 0126302d <dcc60000> 50c0fff1 0047182a a48306a0 03e00008 00000000 ---[ end trace b530b0551467f2fd ]--- Kernel panic - not syncing: Fatal exception in interrupt What happens while auth_enable=0 in that case is, that ep->auth_hmacs is initialized to NULL in sctp_auth_init_hmacs() when endpoint is being created. After that point, if an admin switches over to auth_enable=1, the machine can crash due to NULL pointer dereference during reception of an INIT chunk. When we enter sctp_process_init() via sctp_sf_do_5_1B_init() in order to respond to an INIT chunk, the INIT verification succeeds and while we walk and process all INIT params via sctp_process_param() we find that net->sctp.auth_enable is set, therefore do not fall through, but invoke sctp_auth_asoc_set_default_hmac() instead, and thus, dereference what we have set to NULL during endpoint initialization phase. The fix is to make auth_enable immutable by caching its value during endpoint initialization, so that its original value is being carried along until destruction. The bug seems to originate from the very first days. Fix in joint work with Daniel Borkmann. Reported-by: Joshua Kinard <kumba@gentoo.org> Signed-off-by: Vlad Yasevich <vyasevic@redhat.com> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Tested-by: Joshua Kinard <kumba@gentoo.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-14Revert "net: sctp: Fix a_rwnd/rwnd management to reflect real state of the ↵Daniel Borkmann
receiver's buffer" This reverts commit ef2820a735f7 ("net: sctp: Fix a_rwnd/rwnd management to reflect real state of the receiver's buffer") as it introduced a serious performance regression on SCTP over IPv4 and IPv6, though a not as dramatic on the latter. Measurements are on 10Gbit/s with ixgbe NICs. Current state: [root@Lab200slot2 ~]# iperf3 --sctp -4 -c 192.168.241.3 -V -l 1452 -t 60 iperf version 3.0.1 (10 January 2014) Linux Lab200slot2 3.14.0 #1 SMP Thu Apr 3 23:18:29 EDT 2014 x86_64 Time: Fri, 11 Apr 2014 17:56:21 GMT Connecting to host 192.168.241.3, port 5201 Cookie: Lab200slot2.1397238981.812898.548918 [ 4] local 192.168.241.2 port 38616 connected to 192.168.241.3 port 5201 Starting Test: protocol: SCTP, 1 streams, 1452 byte blocks, omitting 0 seconds, 60 second test [ ID] Interval Transfer Bandwidth [ 4] 0.00-1.09 sec 20.8 MBytes 161 Mbits/sec [ 4] 1.09-2.13 sec 10.8 MBytes 86.8 Mbits/sec [ 4] 2.13-3.15 sec 3.57 MBytes 29.5 Mbits/sec [ 4] 3.15-4.16 sec 4.33 MBytes 35.7 Mbits/sec [ 4] 4.16-6.21 sec 10.4 MBytes 42.7 Mbits/sec [ 4] 6.21-6.21 sec 0.00 Bytes 0.00 bits/sec [ 4] 6.21-7.35 sec 34.6 MBytes 253 Mbits/sec [ 4] 7.35-11.45 sec 22.0 MBytes 45.0 Mbits/sec [ 4] 11.45-11.45 sec 0.00 Bytes 0.00 bits/sec [ 4] 11.45-11.45 sec 0.00 Bytes 0.00 bits/sec [ 4] 11.45-11.45 sec 0.00 Bytes 0.00 bits/sec [ 4] 11.45-12.51 sec 16.0 MBytes 126 Mbits/sec [ 4] 12.51-13.59 sec 20.3 MBytes 158 Mbits/sec [ 4] 13.59-14.65 sec 13.4 MBytes 107 Mbits/sec [ 4] 14.65-16.79 sec 33.3 MBytes 130 Mbits/sec [ 4] 16.79-16.79 sec 0.00 Bytes 0.00 bits/sec [ 4] 16.79-17.82 sec 5.94 MBytes 48.7 Mbits/sec (etc) [root@Lab200slot2 ~]# iperf3 --sctp -6 -c 2001:db8:0:f101::1 -V -l 1400 -t 60 iperf version 3.0.1 (10 January 2014) Linux Lab200slot2 3.14.0 #1 SMP Thu Apr 3 23:18:29 EDT 2014 x86_64 Time: Fri, 11 Apr 2014 19:08:41 GMT Connecting to host 2001:db8:0:f101::1, port 5201 Cookie: Lab200slot2.1397243321.714295.2b3f7c [ 4] local 2001:db8:0:f101::2 port 55804 connected to 2001:db8:0:f101::1 port 5201 Starting Test: protocol: SCTP, 1 streams, 1400 byte blocks, omitting 0 seconds, 60 second test [ ID] Interval Transfer Bandwidth [ 4] 0.00-1.00 sec 169 MBytes 1.42 Gbits/sec [ 4] 1.00-2.00 sec 201 MBytes 1.69 Gbits/sec [ 4] 2.00-3.00 sec 188 MBytes 1.58 Gbits/sec [ 4] 3.00-4.00 sec 174 MBytes 1.46 Gbits/sec [ 4] 4.00-5.00 sec 165 MBytes 1.39 Gbits/sec [ 4] 5.00-6.00 sec 199 MBytes 1.67 Gbits/sec [ 4] 6.00-7.00 sec 163 MBytes 1.36 Gbits/sec [ 4] 7.00-8.00 sec 174 MBytes 1.46 Gbits/sec [ 4] 8.00-9.00 sec 193 MBytes 1.62 Gbits/sec [ 4] 9.00-10.00 sec 196 MBytes 1.65 Gbits/sec [ 4] 10.00-11.00 sec 157 MBytes 1.31 Gbits/sec [ 4] 11.00-12.00 sec 175 MBytes 1.47 Gbits/sec [ 4] 12.00-13.00 sec 192 MBytes 1.61 Gbits/sec [ 4] 13.00-14.00 sec 199 MBytes 1.67 Gbits/sec (etc) After patch: [root@Lab200slot2 ~]# iperf3 --sctp -4 -c 192.168.240.3 -V -l 1452 -t 60 iperf version 3.0.1 (10 January 2014) Linux Lab200slot2 3.14.0+ #1 SMP Mon Apr 14 12:06:40 EDT 2014 x86_64 Time: Mon, 14 Apr 2014 16:40:48 GMT Connecting to host 192.168.240.3, port 5201 Cookie: Lab200slot2.1397493648.413274.65e131 [ 4] local 192.168.240.2 port 50548 connected to 192.168.240.3 port 5201 Starting Test: protocol: SCTP, 1 streams, 1452 byte blocks, omitting 0 seconds, 60 second test [ ID] Interval Transfer Bandwidth [ 4] 0.00-1.00 sec 240 MBytes 2.02 Gbits/sec [ 4] 1.00-2.00 sec 239 MBytes 2.01 Gbits/sec [ 4] 2.00-3.00 sec 240 MBytes 2.01 Gbits/sec [ 4] 3.00-4.00 sec 239 MBytes 2.00 Gbits/sec [ 4] 4.00-5.00 sec 245 MBytes 2.05 Gbits/sec [ 4] 5.00-6.00 sec 240 MBytes 2.01 Gbits/sec [ 4] 6.00-7.00 sec 240 MBytes 2.02 Gbits/sec [ 4] 7.00-8.00 sec 239 MBytes 2.01 Gbits/sec With the reverted patch applied, the SCTP/IPv4 performance is back to normal on latest upstream for IPv4 and IPv6 and has same throughput as 3.4.2 test kernel, steady and interval reports are smooth again. Fixes: ef2820a735f7 ("net: sctp: Fix a_rwnd/rwnd management to reflect real state of the receiver's buffer") Reported-by: Peter Butler <pbutler@sonusnet.com> Reported-by: Dongsheng Song <dongsheng.song@gmail.com> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Tested-by: Peter Butler <pbutler@sonusnet.com> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nsn.com> Cc: Alexander Sverdlin <alexander.sverdlin@nsn.com> Cc: Vlad Yasevich <vyasevich@gmail.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-05net: sctp: fix skb leakage in COOKIE ECHO path of chunk->auth_chunkDaniel Borkmann
While working on ec0223ec48a9 ("net: sctp: fix sctp_sf_do_5_1D_ce to verify if we/peer is AUTH capable"), we noticed that there's a skb memory leakage in the error path. Running the same reproducer as in ec0223ec48a9 and by unconditionally jumping to the error label (to simulate an error condition) in sctp_sf_do_5_1D_ce() receive path lets kmemleak detector bark about the unfreed chunk->auth_chunk skb clone: Unreferenced object 0xffff8800b8f3a000 (size 256): comm "softirq", pid 0, jiffies 4294769856 (age 110.757s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 89 ab 75 5e d4 01 58 13 00 00 00 00 00 00 00 00 ..u^..X......... backtrace: [<ffffffff816660be>] kmemleak_alloc+0x4e/0xb0 [<ffffffff8119f328>] kmem_cache_alloc+0xc8/0x210 [<ffffffff81566929>] skb_clone+0x49/0xb0 [<ffffffffa0467459>] sctp_endpoint_bh_rcv+0x1d9/0x230 [sctp] [<ffffffffa046fdbc>] sctp_inq_push+0x4c/0x70 [sctp] [<ffffffffa047e8de>] sctp_rcv+0x82e/0x9a0 [sctp] [<ffffffff815abd38>] ip_local_deliver_finish+0xa8/0x210 [<ffffffff815a64af>] nf_reinject+0xbf/0x180 [<ffffffffa04b4762>] nfqnl_recv_verdict+0x1d2/0x2b0 [nfnetlink_queue] [<ffffffffa04aa40b>] nfnetlink_rcv_msg+0x14b/0x250 [nfnetlink] [<ffffffff815a3269>] netlink_rcv_skb+0xa9/0xc0 [<ffffffffa04aa7cf>] nfnetlink_rcv+0x23f/0x408 [nfnetlink] [<ffffffff815a2bd8>] netlink_unicast+0x168/0x250 [<ffffffff815a2fa1>] netlink_sendmsg+0x2e1/0x3f0 [<ffffffff8155cc6b>] sock_sendmsg+0x8b/0xc0 [<ffffffff8155d449>] ___sys_sendmsg+0x369/0x380 What happens is that commit bbd0d59809f9 clones the skb containing the AUTH chunk in sctp_endpoint_bh_rcv() when having the edge case that an endpoint requires COOKIE-ECHO chunks to be authenticated: ---------- INIT[RANDOM; CHUNKS; HMAC-ALGO] ----------> <------- INIT-ACK[RANDOM; CHUNKS; HMAC-ALGO] --------- ------------------ AUTH; COOKIE-ECHO ----------------> <-------------------- COOKIE-ACK --------------------- When we enter sctp_sf_do_5_1D_ce() and before we actually get to the point where we process (and subsequently free) a non-NULL chunk->auth_chunk, we could hit the "goto nomem_init" path from an error condition and thus leave the cloned skb around w/o freeing it. The fix is to centrally free such clones in sctp_chunk_destroy() handler that is invoked from sctp_chunk_free() after all refs have dropped; and also move both kfree_skb(chunk->auth_chunk) there, so that chunk->auth_chunk is either NULL (since sctp_chunkify() allocs new chunks through kmem_cache_zalloc()) or non-NULL with a valid skb pointer. chunk->skb and chunk->auth_chunk are the only skbs in the sctp_chunk structure that need to be handeled. While at it, we should use consume_skb() for both. It is the same as dev_kfree_skb() but more appropriately named as we are not a device but a protocol. Also, this effectively replaces the kfree_skb() from both invocations into consume_skb(). Functions are the same only that kfree_skb() assumes that the frame was being dropped after a failure (e.g. for tools like drop monitor), usage of consume_skb() seems more appropriate in function sctp_chunk_destroy() though. Fixes: bbd0d59809f9 ("[SCTP]: Implement the receive and verification of AUTH chunk") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Vlad Yasevich <yasevich@gmail.com> Cc: Neil Horman <nhorman@tuxdriver.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-03net: sctp: fix sctp_sf_do_5_1D_ce to verify if we/peer is AUTH capableDaniel Borkmann
RFC4895 introduced AUTH chunks for SCTP; during the SCTP handshake RANDOM; CHUNKS; HMAC-ALGO are negotiated (CHUNKS being optional though): ---------- INIT[RANDOM; CHUNKS; HMAC-ALGO] ----------> <------- INIT-ACK[RANDOM; CHUNKS; HMAC-ALGO] --------- -------------------- COOKIE-ECHO --------------------> <-------------------- COOKIE-ACK --------------------- A special case is when an endpoint requires COOKIE-ECHO chunks to be authenticated: ---------- INIT[RANDOM; CHUNKS; HMAC-ALGO] ----------> <------- INIT-ACK[RANDOM; CHUNKS; HMAC-ALGO] --------- ------------------ AUTH; COOKIE-ECHO ----------------> <-------------------- COOKIE-ACK --------------------- RFC4895, section 6.3. Receiving Authenticated Chunks says: The receiver MUST use the HMAC algorithm indicated in the HMAC Identifier field. If this algorithm was not specified by the receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk during association setup, the AUTH chunk and all the chunks after it MUST be discarded and an ERROR chunk SHOULD be sent with the error cause defined in Section 4.1. [...] If no endpoint pair shared key has been configured for that Shared Key Identifier, all authenticated chunks MUST be silently discarded. [...] When an endpoint requires COOKIE-ECHO chunks to be authenticated, some special procedures have to be followed because the reception of a COOKIE-ECHO chunk might result in the creation of an SCTP association. If a packet arrives containing an AUTH chunk as a first chunk, a COOKIE-ECHO chunk as the second chunk, and possibly more chunks after them, and the receiver does not have an STCB for that packet, then authentication is based on the contents of the COOKIE-ECHO chunk. In this situation, the receiver MUST authenticate the chunks in the packet by using the RANDOM parameters, CHUNKS parameters and HMAC_ALGO parameters obtained from the COOKIE-ECHO chunk, and possibly a local shared secret as inputs to the authentication procedure specified in Section 6.3. If authentication fails, then the packet is discarded. If the authentication is successful, the COOKIE-ECHO and all the chunks after the COOKIE-ECHO MUST be processed. If the receiver has an STCB, it MUST process the AUTH chunk as described above using the STCB from the existing association to authenticate the COOKIE-ECHO chunk and all the chunks after it. [...] Commit bbd0d59809f9 introduced the possibility to receive and verification of AUTH chunk, including the edge case for authenticated COOKIE-ECHO. On reception of COOKIE-ECHO, the function sctp_sf_do_5_1D_ce() handles processing, unpacks and creates a new association if it passed sanity checks and also tests for authentication chunks being present. After a new association has been processed, it invokes sctp_process_init() on the new association and walks through the parameter list it received from the INIT chunk. It checks SCTP_PARAM_RANDOM, SCTP_PARAM_HMAC_ALGO and SCTP_PARAM_CHUNKS, and copies them into asoc->peer meta data (peer_random, peer_hmacs, peer_chunks) in case sysctl -w net.sctp.auth_enable=1 is set. If in INIT's SCTP_PARAM_SUPPORTED_EXT parameter SCTP_CID_AUTH is set, peer_random != NULL and peer_hmacs != NULL the peer is to be assumed asoc->peer.auth_capable=1, in any other case asoc->peer.auth_capable=0. Now, if in sctp_sf_do_5_1D_ce() chunk->auth_chunk is available, we set up a fake auth chunk and pass that on to sctp_sf_authenticate(), which at latest in sctp_auth_calculate_hmac() reliably dereferences a NULL pointer at position 0..0008 when setting up the crypto key in crypto_hash_setkey() by using asoc->asoc_shared_key that is NULL as condition key_id == asoc->active_key_id is true if the AUTH chunk was injected correctly from remote. This happens no matter what net.sctp.auth_enable sysctl says. The fix is to check for net->sctp.auth_enable and for asoc->peer.auth_capable before doing any operations like sctp_sf_authenticate() as no key is activated in sctp_auth_asoc_init_active_key() for each case. Now as RFC4895 section 6.3 states that if the used HMAC-ALGO passed from the INIT chunk was not used in the AUTH chunk, we SHOULD send an error; however in this case it would be better to just silently discard such a maliciously prepared handshake as we didn't even receive a parameter at all. Also, as our endpoint has no shared key configured, section 6.3 says that MUST silently discard, which we are doing from now onwards. Before calling sctp_sf_pdiscard(), we need not only to free the association, but also the chunk->auth_chunk skb, as commit bbd0d59809f9 created a skb clone in that case. I have tested this locally by using netfilter's nfqueue and re-injecting packets into the local stack after maliciously modifying the INIT chunk (removing RANDOM; HMAC-ALGO param) and the SCTP packet containing the COOKIE_ECHO (injecting AUTH chunk before COOKIE_ECHO). Fixed with this patch applied. Fixes: bbd0d59809f9 ("[SCTP]: Implement the receive and verification of AUTH chunk") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Vlad Yasevich <yasevich@gmail.com> Cc: Neil Horman <nhorman@tuxdriver.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-17net: sctp: Fix a_rwnd/rwnd management to reflect real state of the ↵Matija Glavinic Pecotic
receiver's buffer Implementation of (a)rwnd calculation might lead to severe performance issues and associations completely stalling. These problems are described and solution is proposed which improves lksctp's robustness in congestion state. 1) Sudden drop of a_rwnd and incomplete window recovery afterwards Data accounted in sctp_assoc_rwnd_decrease takes only payload size (sctp data), but size of sk_buff, which is blamed against receiver buffer, is not accounted in rwnd. Theoretically, this should not be the problem as actual size of buffer is double the amount requested on the socket (SO_RECVBUF). Problem here is that this will have bad scaling for data which is less then sizeof sk_buff. E.g. in 4G (LTE) networks, link interfacing radio side will have a large portion of traffic of this size (less then 100B). An example of sudden drop and incomplete window recovery is given below. Node B exhibits problematic behavior. Node A initiates association and B is configured to advertise rwnd of 10000. A sends messages of size 43B (size of typical sctp message in 4G (LTE) network). On B data is left in buffer by not reading socket in userspace. Lets examine when we will hit pressure state and declare rwnd to be 0 for scenario with above stated parameters (rwnd == 10000, chunk size == 43, each chunk is sent in separate sctp packet) Logic is implemented in sctp_assoc_rwnd_decrease: socket_buffer (see below) is maximum size which can be held in socket buffer (sk_rcvbuf). current_alloced is amount of data currently allocated (rx_count) A simple expression is given for which it will be examined after how many packets for above stated parameters we enter pressure state: We start by condition which has to be met in order to enter pressure state: socket_buffer < currently_alloced; currently_alloced is represented as size of sctp packets received so far and not yet delivered to userspace. x is the number of chunks/packets (since there is no bundling, and each chunk is delivered in separate packet, we can observe each chunk also as sctp packet, and what is important here, having its own sk_buff): socket_buffer < x*each_sctp_packet; each_sctp_packet is sctp chunk size + sizeof(struct sk_buff). socket_buffer is twice the amount of initially requested size of socket buffer, which is in case of sctp, twice the a_rwnd requested: 2*rwnd < x*(payload+sizeof(struc sk_buff)); sizeof(struct sk_buff) is 190 (3.13.0-rc4+). Above is stated that rwnd is 10000 and each payload size is 43 20000 < x(43+190); x > 20000/233; x ~> 84; After ~84 messages, pressure state is entered and 0 rwnd is advertised while received 84*43B ~= 3612B sctp data. This is why external observer notices sudden drop from 6474 to 0, as it will be now shown in example: IP A.34340 > B.12345: sctp (1) [INIT] [init tag: 1875509148] [rwnd: 81920] [OS: 10] [MIS: 65535] [init TSN: 1096057017] IP B.12345 > A.34340: sctp (1) [INIT ACK] [init tag: 3198966556] [rwnd: 10000] [OS: 10] [MIS: 10] [init TSN: 902132839] IP A.34340 > B.12345: sctp (1) [COOKIE ECHO] IP B.12345 > A.34340: sctp (1) [COOKIE ACK] IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057017] [SID: 0] [SSEQ 0] [PPID 0x18] IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057017] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0] IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057018] [SID: 0] [SSEQ 1] [PPID 0x18] IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057018] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0] IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057019] [SID: 0] [SSEQ 2] [PPID 0x18] IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057019] [a_rwnd 9914] [#gap acks 0] [#dup tsns 0] <...> IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057098] [SID: 0] [SSEQ 81] [PPID 0x18] IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057098] [a_rwnd 6517] [#gap acks 0] [#dup tsns 0] IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057099] [SID: 0] [SSEQ 82] [PPID 0x18] IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057099] [a_rwnd 6474] [#gap acks 0] [#dup tsns 0] IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057100] [SID: 0] [SSEQ 83] [PPID 0x18] --> Sudden drop IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 0] [#gap acks 0] [#dup tsns 0] At this point, rwnd_press stores current rwnd value so it can be later restored in sctp_assoc_rwnd_increase. This however doesn't happen as condition to start slowly increasing rwnd until rwnd_press is returned to rwnd is never met. This condition is not met since rwnd, after it hit 0, must first reach rwnd_press by adding amount which is read from userspace. Let us observe values in above example. Initial a_rwnd is 10000, pressure was hit when rwnd was ~6500 and the amount of actual sctp data currently waiting to be delivered to userspace is ~3500. When userspace starts to read, sctp_assoc_rwnd_increase will be blamed only for sctp data, which is ~3500. Condition is never met, and when userspace reads all data, rwnd stays on 3569. IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 1505] [#gap acks 0] [#dup tsns 0] IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057100] [a_rwnd 3010] [#gap acks 0] [#dup tsns 0] IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057101] [SID: 0] [SSEQ 84] [PPID 0x18] IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057101] [a_rwnd 3569] [#gap acks 0] [#dup tsns 0] --> At this point userspace read everything, rwnd recovered only to 3569 IP A.34340 > B.12345: sctp (1) [DATA] (B)(E) [TSN: 1096057102] [SID: 0] [SSEQ 85] [PPID 0x18] IP B.12345 > A.34340: sctp (1) [SACK] [cum ack 1096057102] [a_rwnd 3569] [#gap acks 0] [#dup tsns 0] Reproduction is straight forward, it is enough for sender to send packets of size less then sizeof(struct sk_buff) and receiver keeping them in its buffers. 2) Minute size window for associations sharing the same socket buffer In case multiple associations share the same socket, and same socket buffer (sctp.rcvbuf_policy == 0), different scenarios exist in which congestion on one of the associations can permanently drop rwnd of other association(s). Situation will be typically observed as one association suddenly having rwnd dropped to size of last packet received and never recovering beyond that point. Different scenarios will lead to it, but all have in common that one of the associations (let it be association from 1)) nearly depleted socket buffer, and the other association blames socket buffer just for the amount enough to start the pressure. This association will enter pressure state, set rwnd_press and announce 0 rwnd. When data is read by userspace, similar situation as in 1) will occur, rwnd will increase just for the size read by userspace but rwnd_press will be high enough so that association doesn't have enough credit to reach rwnd_press and restore to previous state. This case is special case of 1), being worse as there is, in the worst case, only one packet in buffer for which size rwnd will be increased. Consequence is association which has very low maximum rwnd ('minute size', in our case down to 43B - size of packet which caused pressure) and as such unusable. Scenario happened in the field and labs frequently after congestion state (link breaks, different probabilities of packet drop, packet reordering) and with scenario 1) preceding. Here is given a deterministic scenario for reproduction: >From node A establish two associations on the same socket, with rcvbuf_policy being set to share one common buffer (sctp.rcvbuf_policy == 0). On association 1 repeat scenario from 1), that is, bring it down to 0 and restore up. Observe scenario 1). Use small payload size (here we use 43). Once rwnd is 'recovered', bring it down close to 0, as in just one more packet would close it. This has as a consequence that association number 2 is able to receive (at least) one more packet which will bring it in pressure state. E.g. if association 2 had rwnd of 10000, packet received was 43, and we enter at this point into pressure, rwnd_press will have 9957. Once payload is delivered to userspace, rwnd will increase for 43, but conditions to restore rwnd to original state, just as in 1), will never be satisfied. --> Association 1, between A.y and B.12345 IP A.55915 > B.12345: sctp (1) [INIT] [init tag: 836880897] [rwnd: 10000] [OS: 10] [MIS: 65535] [init TSN: 4032536569] IP B.12345 > A.55915: sctp (1) [INIT ACK] [init tag: 2873310749] [rwnd: 81920] [OS: 10] [MIS: 10] [init TSN: 3799315613] IP A.55915 > B.12345: sctp (1) [COOKIE ECHO] IP B.12345 > A.55915: sctp (1) [COOKIE ACK] --> Association 2, between A.z and B.12346 IP A.55915 > B.12346: sctp (1) [INIT] [init tag: 534798321] [rwnd: 10000] [OS: 10] [MIS: 65535] [init TSN: 2099285173] IP B.12346 > A.55915: sctp (1) [INIT ACK] [init tag: 516668823] [rwnd: 81920] [OS: 10] [MIS: 10] [init TSN: 3676403240] IP A.55915 > B.12346: sctp (1) [COOKIE ECHO] IP B.12346 > A.55915: sctp (1) [COOKIE ACK] --> Deplete socket buffer by sending messages of size 43B over association 1 IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315613] [SID: 0] [SSEQ 0] [PPID 0x18] IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315613] [a_rwnd 9957] [#gap acks 0] [#dup tsns 0] <...> IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315696] [a_rwnd 6388] [#gap acks 0] [#dup tsns 0] IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315697] [SID: 0] [SSEQ 84] [PPID 0x18] IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315697] [a_rwnd 6345] [#gap acks 0] [#dup tsns 0] --> Sudden drop on 1 IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315698] [SID: 0] [SSEQ 85] [PPID 0x18] IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315698] [a_rwnd 0] [#gap acks 0] [#dup tsns 0] --> Here userspace read, rwnd 'recovered' to 3698, now deplete again using association 1 so there is place in buffer for only one more packet IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315799] [SID: 0] [SSEQ 186] [PPID 0x18] IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315799] [a_rwnd 86] [#gap acks 0] [#dup tsns 0] IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315800] [SID: 0] [SSEQ 187] [PPID 0x18] IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 43] [#gap acks 0] [#dup tsns 0] --> Socket buffer is almost depleted, but there is space for one more packet, send them over association 2, size 43B IP B.12346 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3676403240] [SID: 0] [SSEQ 0] [PPID 0x18] IP A.55915 > B.12346: sctp (1) [SACK] [cum ack 3676403240] [a_rwnd 0] [#gap acks 0] [#dup tsns 0] --> Immediate drop IP A.60995 > B.12346: sctp (1) [SACK] [cum ack 387491510] [a_rwnd 0] [#gap acks 0] [#dup tsns 0] --> Read everything from the socket, both association recover up to maximum rwnd they are capable of reaching, note that association 1 recovered up to 3698, and association 2 recovered only to 43 IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 1548] [#gap acks 0] [#dup tsns 0] IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315800] [a_rwnd 3053] [#gap acks 0] [#dup tsns 0] IP B.12345 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3799315801] [SID: 0] [SSEQ 188] [PPID 0x18] IP A.55915 > B.12345: sctp (1) [SACK] [cum ack 3799315801] [a_rwnd 3698] [#gap acks 0] [#dup tsns 0] IP B.12346 > A.55915: sctp (1) [DATA] (B)(E) [TSN: 3676403241] [SID: 0] [SSEQ 1] [PPID 0x18] IP A.55915 > B.12346: sctp (1) [SACK] [cum ack 3676403241] [a_rwnd 43] [#gap acks 0] [#dup tsns 0] A careful reader might wonder why it is necessary to reproduce 1) prior reproduction of 2). It is simply easier to observe when to send packet over association 2 which will push association into the pressure state. Proposed solution: Both problems share the same root cause, and that is improper scaling of socket buffer with rwnd. Solution in which sizeof(sk_buff) is taken into concern while calculating rwnd is not possible due to fact that there is no linear relationship between amount of data blamed in increase/decrease with IP packet in which payload arrived. Even in case such solution would be followed, complexity of the code would increase. Due to nature of current rwnd handling, slow increase (in sctp_assoc_rwnd_increase) of rwnd after pressure state is entered is rationale, but it gives false representation to the sender of current buffer space. Furthermore, it implements additional congestion control mechanism which is defined on implementation, and not on standard basis. Proposed solution simplifies whole algorithm having on mind definition from rfc: o Receiver Window (rwnd): This gives the sender an indication of the space available in the receiver's inbound buffer. Core of the proposed solution is given with these lines: sctp_assoc_rwnd_update: if ((asoc->base.sk->sk_rcvbuf - rx_count) > 0) asoc->rwnd = (asoc->base.sk->sk_rcvbuf - rx_count) >> 1; else asoc->rwnd = 0; We advertise to sender (half of) actual space we have. Half is in the braces depending whether you would like to observe size of socket buffer as SO_RECVBUF or twice the amount, i.e. size is the one visible from userspace, that is, from kernelspace. In this way sender is given with good approximation of our buffer space, regardless of the buffer policy - we always advertise what we have. Proposed solution fixes described problems and removes necessity for rwnd restoration algorithm. Finally, as proposed solution is simplification, some lines of code, along with some bytes in struct sctp_association are saved. Version 2 of the patch addressed comments from Vlad. Name of the function is set to be more descriptive, and two parts of code are changed, in one removing the superfluous call to sctp_assoc_rwnd_update since call would not result in update of rwnd, and the other being reordering of the code in a way that call to sctp_assoc_rwnd_update updates rwnd. Version 3 corrected change introduced in v2 in a way that existing function is not reordered/copied in line, but it is correctly called. Thanks Vlad for suggesting. Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nsn.com> Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nsn.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-26sctp: fix checkpatch errors with indentwangweidong
fix checkpatch errors below: ERROR: switch and case should be at the same inden ERROR: code indent should use tabs where possible Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-26sctp: fix checkpatch errors with (foo*)|foo * bar|foo* barwangweidong
fix checkpatch errors below: ERROR: "(foo*)" should be "(foo *)" ERROR: "foo * bar" should be "foo *bar" ERROR: "foo* bar" should be "foo *bar" Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-26sctp: fix checkpatch errors with space required or prohibitedwangweidong
fix checkpatch errors while the space is required or prohibited to the "=,()++..." Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/ethernet/intel/i40e/i40e_main.c drivers/net/macvtap.c Both minor merge hassles, simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-10sctp: properly latch and use autoclose value from sock to associationNeil Horman
Currently, sctp associations latch a sockets autoclose value to an association at association init time, subject to capping constraints from the max_autoclose sysctl value. This leads to an odd situation where an application may set a socket level autoclose timeout, but sliently sctp will limit the autoclose timeout to something less than that. Fix this by modifying the autoclose setsockopt function to check the limit, cap it and warn the user via syslog that the timeout is capped. This will allow getsockopt to return valid autoclose timeout values that reflect what subsequent associations actually use. While were at it, also elimintate the assoc->autoclose variable, it duplicates whats in the timeout array, which leads to multiple sources for the same information, that may differ (as the former isn't subject to any capping). This gives us the timeout information in a canonical place and saves some space in the association structure as well. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> CC: Wang Weidong <wangweidong1@huawei.com> CC: David Miller <davem@davemloft.net> CC: Vlad Yasevich <vyasevich@gmail.com> CC: netdev@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06sctp: Fix FSF address in file headersJeff Kirsher
Several files refer to an old address for the Free Software Foundation in the file header comment. Resolve by replacing the address with the URL <http://www.gnu.org/licenses/> so that we do not have to keep updating the header comments anytime the address changes. CC: Vlad Yasevich <vyasevich@gmail.com> CC: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-09net: sctp: trivial: update bug report in header commentDaniel Borkmann
With the restructuring of the lksctp.org site, we only allow bug reports through the SCTP mailing list linux-sctp@vger.kernel.org, not via SF, as SF is only used for web hosting and nothing more. While at it, also remove the obvious statement that bugs will be fixed and incooperated into the kernel. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-24net: sctp: trivial: update mailing list addressDaniel Borkmann
The SCTP mailing list address to send patches or questions to is linux-sctp@vger.kernel.org and not lksctp-developers@lists.sourceforge.net anymore. Therefore, update all occurences. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-01net: sctp: rework debugging framework to use pr_debug and friendsDaniel Borkmann
We should get rid of all own SCTP debug printk macros and use the ones that the kernel offers anyway instead. This makes the code more readable and conform to the kernel code, and offers all the features of dynamic debbuging that pr_debug() et al has, such as only turning on/off portions of debug messages at runtime through debugfs. The runtime cost of having CONFIG_DYNAMIC_DEBUG enabled, but none of the debug statements printing, is negligible [1]. If kernel debugging is completly turned off, then these statements will also compile into "empty" functions. While we're at it, we also need to change the Kconfig option as it /now/ only refers to the ifdef'ed code portions in outqueue.c that enable further debugging/tracing of SCTP transaction fields. Also, since SCTP_ASSERT code was enabled with this Kconfig option and has now been removed, we transform those code parts into WARNs resp. where appropriate BUG_ONs so that those bugs can be more easily detected as probably not many people have SCTP debugging permanently turned on. To turn on all SCTP debugging, the following steps are needed: # mount -t debugfs none /sys/kernel/debug # echo -n 'module sctp +p' > /sys/kernel/debug/dynamic_debug/control This can be done more fine-grained on a per file, per line basis and others as described in [2]. [1] https://www.kernel.org/doc/ols/2009/ols2009-pages-39-46.pdf [2] Documentation/dynamic-debug-howto.txt Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-06-14net: sctp: sctp_sf_do_prm_asoc: do SCTP_CMD_INIT_CHOOSE_TRANSPORT firstDaniel Borkmann
While this currently cannot trigger any NULL pointer dereference in sctp_seq_dump_local_addrs(), better change the order of commands to prevent a future bug to happen. Although we first add SCTP_CMD_NEW_ASOC and then set the SCTP_CMD_INIT_CHOOSE_TRANSPORT, it is okay for now, since this primitive is only called by sctp_connect() or sctp_sendmsg() with sctp_assoc_add_peer() set first. However, lets do this precaution and first set the transport and then add it to the association hashlist to prevent in future something to possibly triggering this. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-13sctp: Use correct sideffect command in duplicate cookie handlingVlad Yasevich
When SCTP is done processing a duplicate cookie chunk, it tries to delete a newly created association. For that, it has to set the right association for the side-effect processing to work. However, when it uses the SCTP_CMD_NEW_ASOC command, that performs more work then really needed (like hashing the associationa and assigning it an id) and there is no point to do that only to delete the association as a next step. In fact, it also creates an impossible condition where an association may be found by the getsockopt() call, and that association is empty. This causes a crash in some sctp getsockopts. The solution is rather simple. We simply use SCTP_CMD_SET_ASOC command that doesn't have all the overhead and does exactly what we need. Reported-by: Karl Heiss <kheiss@gmail.com> Tested-by: Karl Heiss <kheiss@gmail.com> CC: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Vlad Yasevich <vyasevich@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-01-27sctp: set association state to established in dupcook_a handlerXufeng Zhang
While sctp handling a duplicate COOKIE-ECHO and the action is 'Association restart', sctp_sf_do_dupcook_a() will processing the unexpected COOKIE-ECHO for peer restart, but it does not set the association state to SCTP_STATE_ESTABLISHED, so the association could stuck in SCTP_STATE_SHUTDOWN_PENDING state forever. This violates the sctp specification: RFC 4960 5.2.4. Handle a COOKIE ECHO when a TCB Exists Action A) In this case, the peer may have restarted. ..... After this, the endpoint shall enter the ESTABLISHED state. To resolve this problem, adding a SCTP_CMD_NEW_STATE cmd to the command list before SCTP_CMD_REPLY cmd, this will set the restart association to SCTP_STATE_ESTABLISHED state properly and also avoid I-bit being set in the DATA chunk header when COOKIE_ACK is bundled with DATA chunks. Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-12-13Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial branch from Jiri Kosina: "Usual stuff -- comment/printk typo fixes, documentation updates, dead code elimination." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits) HOWTO: fix double words typo x86 mtrr: fix comment typo in mtrr_bp_init propagate name change to comments in kernel source doc: Update the name of profiling based on sysfs treewide: Fix typos in various drivers treewide: Fix typos in various Kconfig wireless: mwifiex: Fix typo in wireless/mwifiex driver messages: i2o: Fix typo in messages/i2o scripts/kernel-doc: check that non-void fcts describe their return value Kernel-doc: Convention: Use a "Return" section to describe return values radeon: Fix typo and copy/paste error in comments doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c various: Fix spelling of "asynchronous" in comments. Fix misspellings of "whether" in comments. eisa: Fix spelling of "asynchronous". various: Fix spelling of "registered" in comments. doc: fix quite a few typos within Documentation target: iscsi: fix comment typos in target/iscsi drivers treewide: fix typo of "suport" in various comments and Kconfig treewide: fix typo of "suppport" in various comments ...
2012-12-03sctp: Add support to per-association statistics via a new ↵Michele Baldessari
SCTP_GET_ASSOC_STATS call The current SCTP stack is lacking a mechanism to have per association statistics. This is an implementation modeled after OpenSolaris' SCTP_GET_ASSOC_STATS. Userspace part will follow on lksctp if/when there is a general ACK on this. V4: - Move ipackets++ before q->immediate.func() for consistency reasons - Move sctp_max_rto() at the end of sctp_transport_update_rto() to avoid returning bogus RTO values - return asoc->rto_min when max_obs_rto value has not changed V3: - Increase ictrlchunks in sctp_assoc_bh_rcv() as well - Move ipackets++ to sctp_inq_push() - return 0 when no rto updates took place since the last call V2: - Implement partial retrieval of stat struct to cope for future expansion - Kill the rtxpackets counter as it cannot be precise anyway - Rename outseqtsns to outofseqtsns to make it clearer that these are out of sequence unexpected TSNs - Move asoc->ipackets++ under a lock to avoid potential miscounts - Fold asoc->opackets++ into the already existing asoc check - Kill unneeded (q->asoc) test when increasing rtxchunks - Do not count octrlchunks if sending failed (SCTP_XMIT_OK != 0) - Don't count SHUTDOWNs as SACKs - Move SCTP_GET_ASSOC_STATS to the private space API - Adjust the len check in sctp_getsockopt_assoc_stats() to allow for future struct growth - Move association statistics in their own struct - Update idupchunks when we send a SACK with dup TSNs - return min_rto in max_rto when RTO has not changed. Also return the transport when max_rto last changed. Signed-off: Michele Baldessari <michele@acksyn.org> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-30sctp: verify length provided in heartbeat information parameterThomas Graf
If the variable parameter length provided in the mandatory heartbeat information parameter exceeds the calculated payload length the packet has been corrupted. Reply with a parameter length protocol violation message. Signed-off-by: Thomas Graf <tgraf@suug.ch> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-19treewide: fix typo of "suport" in various comments and KconfigMasanari Iida
Signed-off-by: Masanari Iida <standby24x7@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-10-04sctp: check src addr when processing SACK to update transport stateNicolas Dichtel
Suppose we have an SCTP connection with two paths. After connection is established, path1 is not available, thus this path is marked as inactive. Then traffic goes through path2, but for some reasons packets are delayed (after rto.max). Because packets are delayed, the retransmit mechanism will switch again to path1. At this time, we receive a delayed SACK from path2. When we update the state of the path in sctp_check_transmitted(), we do not take into account the source address of the SACK, hence we update the wrong path. Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-14sctp: Make sysctl tunables per netEric W. Biederman
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-14sctp: Push struct net down into sctp_verify_ext_paramEric W. Biederman
Add struct net as a parameter to sctp_verify_param so it can be passed to sctp_verify_ext_param where struct net will be needed when the sctp tunables become per net tunables. Add struct net as a parameter to sctp_verify_init so struct net can be passed to sctp_verify_param. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-14sctp: Push struct net down into all of the state machine functionsEric W. Biederman
There are a handle of state machine functions primarily those dealing with processing INIT packets where there is neither a valid endpoint nor a valid assoication from which to derive a struct net. Therefore add struct net * to the parameter list of sctp_state_fn_t and update all of the state machine functions. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-14sctp: Push struct net down into sctp_transport_initEric W. Biederman
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-14sctp: Make the mib per network namespaceEric W. Biederman
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-14sctp: Make the ctl_sock per network namespaceEric W. Biederman
- Kill sctp_get_ctl_sock, it is useless now. - Pass struct net where needed so net->sctp.ctl_sock is accessible. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-15net: Convert net_ratelimit uses to net_<level>_ratelimitedJoe Perches
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 <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-15net: cleanup unsigned to unsigned intEric Dumazet
Use of "unsigned int" is preferred to bare "unsigned" in net tree. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-09-22Merge branch 'master' of github.com:davem330/netDavid S. Miller
Conflicts: MAINTAINERS drivers/net/Kconfig drivers/net/ethernet/broadcom/bnx2x/bnx2x_link.c drivers/net/ethernet/broadcom/tg3.c drivers/net/wireless/iwlwifi/iwl-pci.c drivers/net/wireless/iwlwifi/iwl-trans-tx-pcie.c drivers/net/wireless/rt2x00/rt2800usb.c drivers/net/wireless/wl12xx/main.c
2011-09-16sctp: deal with multiple COOKIE_ECHO chunksMax Matveev
Attempt to reduce the number of IP packets emitted in response to single SCTP packet (2e3216cd) introduced a complication - if a packet contains two COOKIE_ECHO chunks and nothing else then SCTP state machine corks the socket while processing first COOKIE_ECHO and then loses the association and forgets to uncork the socket. To deal with the issue add new SCTP command which can be used to set association explictly. Use this new command when processing second COOKIE_ECHO chunk to restore the context for SCTP state machine. Signed-off-by: Max Matveev <makc@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-08-24sctp: Bundle HEAERTBEAT into ASCONF_ACKMichio Honda
With this patch a HEARTBEAT chunk is bundled into the ASCONF-ACK for ADD IP ADDRESS, confirming the new destination as quickly as possible. Signed-off-by: Michio Honda <micchie@sfc.wide.ad.jp> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-07-14Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: net/bluetooth/l2cap_core.c
2011-07-07sctp: Enforce retransmission limit during shutdownThomas Graf
When initiating a graceful shutdown while having data chunks on the retransmission queue with a peer which is in zero window mode the shutdown is never completed because the retransmission error count is reset periodically by the following two rules: - Do not timeout association while doing zero window probe. - Reset overall error count when a heartbeat request has been acknowledged. The graceful shutdown will wait for all outstanding TSN to be acknowledged before sending the SHUTDOWN request. This never happens due to the peer's zero window not acknowledging the continuously retransmitted data chunks. Although the error counter is incremented for each failed retransmission, the receiving of the SACK announcing the zero window clears the error count again immediately. Also heartbeat requests continue to be sent periodically. The peer acknowledges these requests causing the error counter to be reset as well. This patch changes behaviour to only reset the overall error counter for the above rules while not in shutdown. After reaching the maximum number of retransmission attempts, the T5 shutdown guard timer is scheduled to give the receiver some additional time to recover. The timer is stopped as soon as the receiver acknowledges any data. The issue can be easily reproduced by establishing a sctp association over the loopback device, constantly queueing data at the sender while not reading any at the receiver. Wait for the window to reach zero, then initiate a shutdown by killing both processes simultaneously. The association will never be freed and the chunks on the retransmission queue will be retransmitted indefinitely. Signed-off-by: Thomas Graf <tgraf@infradead.org> Acked-by: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-07-01sctp: Reduce switch/case indentJoe Perches
Make the case labels the same indent as the switch. git diff -w shows useless break;s removed after returns and a comment added to an unnecessary default: break; because of a dubious gcc warning. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>