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2014-07-23net: sctp: inherit auth_capable on INIT collisionsDaniel Borkmann1-0/+1
Jason reported an oops caused by SCTP on his ARM machine with SCTP authentication enabled: Internal error: Oops: 17 [#1] ARM CPU: 0 PID: 104 Comm: sctp-test Not tainted 3.13.0-68744-g3632f30c9b20-dirty #1 task: c6eefa40 ti: c6f52000 task.ti: c6f52000 PC is at sctp_auth_calculate_hmac+0xc4/0x10c LR is at sg_init_table+0x20/0x38 pc : [<c024bb80>] lr : [<c00f32dc>] psr: 40000013 sp : c6f538e8 ip : 00000000 fp : c6f53924 r10: c6f50d80 r9 : 00000000 r8 : 00010000 r7 : 00000000 r6 : c7be4000 r5 : 00000000 r4 : c6f56254 r3 : c00c8170 r2 : 00000001 r1 : 00000008 r0 : c6f1e660 Flags: nZcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 0005397f Table: 06f28000 DAC: 00000015 Process sctp-test (pid: 104, stack limit = 0xc6f521c0) Stack: (0xc6f538e8 to 0xc6f54000) [...] Backtrace: [<c024babc>] (sctp_auth_calculate_hmac+0x0/0x10c) from [<c0249af8>] (sctp_packet_transmit+0x33c/0x5c8) [<c02497bc>] (sctp_packet_transmit+0x0/0x5c8) from [<c023e96c>] (sctp_outq_flush+0x7fc/0x844) [<c023e170>] (sctp_outq_flush+0x0/0x844) from [<c023ef78>] (sctp_outq_uncork+0x24/0x28) [<c023ef54>] (sctp_outq_uncork+0x0/0x28) from [<c0234364>] (sctp_side_effects+0x1134/0x1220) [<c0233230>] (sctp_side_effects+0x0/0x1220) from [<c02330b0>] (sctp_do_sm+0xac/0xd4) [<c0233004>] (sctp_do_sm+0x0/0xd4) from [<c023675c>] (sctp_assoc_bh_rcv+0x118/0x160) [<c0236644>] (sctp_assoc_bh_rcv+0x0/0x160) from [<c023d5bc>] (sctp_inq_push+0x6c/0x74) [<c023d550>] (sctp_inq_push+0x0/0x74) from [<c024a6b0>] (sctp_rcv+0x7d8/0x888) While we already had various kind of bugs in that area ec0223ec48a9 ("net: sctp: fix sctp_sf_do_5_1D_ce to verify if we/peer is AUTH capable") and b14878ccb7fa ("net: sctp: cache auth_enable per endpoint"), this one is a bit of a different kind. Giving a bit more background on why SCTP authentication is needed can be found in RFC4895: SCTP uses 32-bit verification tags to protect itself against blind attackers. These values are not changed during the lifetime of an SCTP association. Looking at new SCTP extensions, there is the need to have a method of proving that an SCTP chunk(s) was really sent by the original peer that started the association and not by a malicious attacker. To cause this bug, we're triggering an INIT collision between peers; normal SCTP handshake where both sides intent to authenticate packets contains RANDOM; CHUNKS; HMAC-ALGO parameters that are being negotiated among peers: ---------- INIT[RANDOM; CHUNKS; HMAC-ALGO] ----------> <------- INIT-ACK[RANDOM; CHUNKS; HMAC-ALGO] --------- -------------------- COOKIE-ECHO --------------------> <-------------------- COOKIE-ACK --------------------- RFC4895 says that each endpoint therefore knows its own random number and the peer's random number *after* the association has been established. The local and peer's random number along with the shared key are then part of the secret used for calculating the HMAC in the AUTH chunk. Now, in our scenario, we have 2 threads with 1 non-blocking SEQ_PACKET socket each, setting up common shared SCTP_AUTH_KEY and SCTP_AUTH_ACTIVE_KEY properly, and each of them calling sctp_bindx(3), listen(2) and connect(2) against each other, thus the handshake looks similar to this, e.g.: ---------- INIT[RANDOM; CHUNKS; HMAC-ALGO] ----------> <------- INIT-ACK[RANDOM; CHUNKS; HMAC-ALGO] --------- <--------- INIT[RANDOM; CHUNKS; HMAC-ALGO] ----------- -------- INIT-ACK[RANDOM; CHUNKS; HMAC-ALGO] --------> ... Since such collisions can also happen with verification tags, the RFC4895 for AUTH rather vaguely says under section 6.1: In case of INIT collision, the rules governing the handling of this Random Number follow the same pattern as those for the Verification Tag, as explained in Section 5.2.4 of RFC 2960 [5]. Therefore, each endpoint knows its own Random Number and the peer's Random Number after the association has been established. In RFC2960, section 5.2.4, we're eventually hitting Action B: B) In this case, both sides may be attempting to start an association at about the same time but the peer endpoint started its INIT after responding to the local endpoint's INIT. Thus it may have picked a new Verification Tag not being aware of the previous Tag it had sent this endpoint. The endpoint should stay in or enter the ESTABLISHED state but it MUST update its peer's Verification Tag from the State Cookie, stop any init or cookie timers that may running and send a COOKIE ACK. In other words, the handling of the Random parameter is the same as behavior for the Verification Tag as described in Action B of section 5.2.4. Looking at the code, we exactly hit the sctp_sf_do_dupcook_b() case which triggers an SCTP_CMD_UPDATE_ASSOC command to the side effect interpreter, and in fact it properly copies over peer_{random, hmacs, chunks} parameters from the newly created association to update the existing one. Also, the old asoc_shared_key is being released and based on the new params, sctp_auth_asoc_init_active_key() updated. However, the issue observed in this case is that the previous asoc->peer.auth_capable was 0, and has *not* been updated, so that instead of creating a new secret, we're doing an early return from the function sctp_auth_asoc_init_active_key() leaving asoc->asoc_shared_key as NULL. However, we now have to authenticate chunks from the updated chunk list (e.g. COOKIE-ACK). That in fact causes the server side when responding with ... <------------------ AUTH; COOKIE-ACK ----------------- ... to trigger a NULL pointer dereference, since in sctp_packet_transmit(), it discovers that an AUTH chunk is being queued for xmit, and thus it calls sctp_auth_calculate_hmac(). Since the asoc->active_key_id is still inherited from the endpoint, and the same as encoded into the chunk, it uses asoc->asoc_shared_key, which is still NULL, as an asoc_key and dereferences it in ... crypto_hash_setkey(desc.tfm, &asoc_key->data[0], asoc_key->len) ... causing an oops. All this happens because sctp_make_cookie_ack() called with the *new* association has the peer.auth_capable=1 and therefore marks the chunk with auth=1 after checking sctp_auth_send_cid(), but it is *actually* sent later on over the then *updated* association's transport that didn't initialize its shared key due to peer.auth_capable=0. Since control chunks in that case are not sent by the temporary association which are scheduled for deletion, they are issued for xmit via SCTP_CMD_REPLY in the interpreter with the context of the *updated* association. peer.auth_capable was 0 in the updated association (which went from COOKIE_WAIT into ESTABLISHED state), since all previous processing that performed sctp_process_init() was being done on temporary associations, that we eventually throw away each time. The correct fix is to update to the new peer.auth_capable value as well in the collision case via sctp_assoc_update(), so that in case the collision migrated from 0 -> 1, sctp_auth_asoc_init_active_key() can properly recalculate the secret. This therefore fixes the observed server panic. Fixes: 730fc3d05cd4 ("[SCTP]: Implete SCTP-AUTH parameter processing") Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Tested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Cc: Vlad Yasevich <vyasevich@gmail.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-15net: sctp: fix information leaks in ulpevent layerDaniel Borkmann1-107/+15
While working on some other SCTP code, I noticed that some structures shared with user space are leaking uninitialized stack or heap buffer. In particular, struct sctp_sndrcvinfo has a 2 bytes hole between .sinfo_flags and .sinfo_ppid that remains unfilled by us in sctp_ulpevent_read_sndrcvinfo() when putting this into cmsg. But also struct sctp_remote_error contains a 2 bytes hole that we don't fill but place into a skb through skb_copy_expand() via sctp_ulpevent_make_remote_error(). Both structures are defined by the IETF in RFC6458: * Section 5.3.2. SCTP Header Information Structure: The sctp_sndrcvinfo structure is defined below: struct sctp_sndrcvinfo { uint16_t sinfo_stream; uint16_t sinfo_ssn; uint16_t sinfo_flags; <-- 2 bytes hole --> uint32_t sinfo_ppid; uint32_t sinfo_context; uint32_t sinfo_timetolive; uint32_t sinfo_tsn; uint32_t sinfo_cumtsn; sctp_assoc_t sinfo_assoc_id; }; * 6.1.3. SCTP_REMOTE_ERROR: A remote peer may send an Operation Error message to its peer. This message indicates a variety of error conditions on an association. The entire ERROR chunk as it appears on the wire is included in an SCTP_REMOTE_ERROR event. Please refer to the SCTP specification [RFC4960] and any extensions for a list of possible error formats. An SCTP error notification has the following format: struct sctp_remote_error { uint16_t sre_type; uint16_t sre_flags; uint32_t sre_length; uint16_t sre_error; <-- 2 bytes hole --> sctp_assoc_t sre_assoc_id; uint8_t sre_data[]; }; Fix this by setting both to 0 before filling them out. We also have other structures shared between user and kernel space in SCTP that contains holes (e.g. struct sctp_paddrthlds), but we copy that buffer over from user space first and thus don't need to care about it in that cases. While at it, we can also remove lengthy comments copied from the draft, instead, we update the comment with the correct RFC number where one can look it up. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-20net: sctp: check proc_dointvec result in proc_sctp_do_authDaniel Borkmann1-2/+1
When writing to the sysctl field net.sctp.auth_enable, it can well be that the user buffer we handed over to proc_dointvec() via proc_sctp_do_auth() handler contains something other than integers. In that case, we would set an uninitialized 4-byte value from the stack to net->sctp.auth_enable that can be leaked back when reading the sysctl variable, and it can unintentionally turn auth_enable on/off based on the stack content since auth_enable is interpreted as a boolean. Fix it up by making sure proc_dointvec() returned sucessfully. Fixes: b14878ccb7fa ("net: sctp: cache auth_enable per endpoint") Reported-by: Florian Westphal <fwestpha@redhat.com> 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>
2014-06-19net: sctp: propagate sysctl errors from proc_do* properlyDaniel Borkmann1-20/+23
sysctl handler proc_sctp_do_hmac_alg(), proc_sctp_do_rto_min() and proc_sctp_do_rto_max() do not properly reflect some error cases when writing values via sysctl from internal proc functions such as proc_dointvec() and proc_dostring(). In all these cases we pass the test for write != 0 and partially do additional work just to notice that additional sanity checks fail and we return with hard-coded -EINVAL while proc_do* functions might also return different errors. So fix this up by simply testing a successful return of proc_do* right after calling it. This also allows to propagate its return value onwards to the user. While touching this, also fix up some minor style issues. Fixes: 4f3fdf3bc59c ("sctp: add check rto_min and rto_max in sysctl") Fixes: 3c68198e7511 ("sctp: Make hmac algorithm selection for cookie generation dynamic") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-15net: sctp: fix permissions for rto_alpha and rto_beta knobsDaniel Borkmann1-4/+28
Commit 3fd091e73b81 ("[SCTP]: Remove multiple levels of msecs to jiffies conversions.") has silently changed permissions for rto_alpha and rto_beta knobs from 0644 to 0444. The purpose of this was to discourage users from tweaking rto_alpha and rto_beta knobs in production environments since they are key to correctly compute rtt/srtt. RFC4960 under section 6.3.1. RTO Calculation says regarding rto_alpha and rto_beta under rule C3 and C4: [...] C3) When a new RTT measurement R' is made, set RTTVAR <- (1 - RTO.Beta) * RTTVAR + RTO.Beta * |SRTT - R'| and SRTT <- (1 - RTO.Alpha) * SRTT + RTO.Alpha * R' Note: The value of SRTT used in the update to RTTVAR is its value before updating SRTT itself using the second assignment. After the computation, update RTO <- SRTT + 4 * RTTVAR. C4) When data is in flight and when allowed by rule C5 below, a new RTT measurement MUST be made each round trip. Furthermore, new RTT measurements SHOULD be made no more than once per round trip for a given destination transport address. There are two reasons for this recommendation: First, it appears that measuring more frequently often does not in practice yield any significant benefit [ALLMAN99]; second, if measurements are made more often, then the values of RTO.Alpha and RTO.Beta in rule C3 above should be adjusted so that SRTT and RTTVAR still adjust to changes at roughly the same rate (in terms of how many round trips it takes them to reflect new values) as they would if making only one measurement per round-trip and using RTO.Alpha and RTO.Beta as given in rule C3. However, the exact nature of these adjustments remains a research issue. [...] While it is discouraged to adjust rto_alpha and rto_beta and not further specified how to adjust them, the RFC also doesn't explicitly forbid it, but rather gives a RECOMMENDED default value (rto_alpha=3, rto_beta=2). We have a couple of users relying on the old permissions before they got changed. That said, if someone really has the urge to adjust them, we could allow it with a warning in the log. Fixes: 3fd091e73b81 ("[SCTP]: Remove multiple levels of msecs to jiffies conversions.") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-12sctp: Fix sk_ack_backlog wrap-around problemXufeng Zhang1-1/+1
Consider the scenario: For a TCP-style socket, while processing the COOKIE_ECHO chunk in sctp_sf_do_5_1D_ce(), after it has passed a series of sanity check, a new association would be created in sctp_unpack_cookie(), but afterwards, some processing maybe failed, and sctp_association_free() will be called to free the previously allocated association, in sctp_association_free(), sk_ack_backlog value is decremented for this socket, since the initial value for sk_ack_backlog is 0, after the decrement, it will be 65535, a wrap-around problem happens, and if we want to establish new associations afterward in the same socket, ABORT would be triggered since sctp deem the accept queue as full. Fix this issue by only decrementing sk_ack_backlog for associations in the endpoint's list. Fix-suggested-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-11net: sctp: fix incorrect type in gfp initializerDaniel Borkmann1-1/+1
This fixes the following sparse warning: net/sctp/associola.c:1556:29: warning: incorrect type in initializer (different base types) net/sctp/associola.c:1556:29: expected bool [unsigned] [usertype] preload net/sctp/associola.c:1556:29: got restricted gfp_t Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-11net: sctp: improve sctp_select_active_and_retran_path selectionDaniel Borkmann1-5/+45
In function sctp_select_active_and_retran_path(), we walk the transport list in order to look for the two most recently used ACTIVE transports (trans_pri, trans_sec). In case we didn't find anything ACTIVE, we currently just camp on a possibly PF or INACTIVE transport that is primary path; this behavior actually dates back to linux-history tree of the very early days of lksctp, and can yield a behavior that chooses suboptimal transport paths. Instead, be a bit more clever by reusing and extending the recently introduced sctp_trans_elect_best() handler. In case both transports are evaluated to have the same score resulting from their states, break the tie by looking at: 1) transport patch error count 2) last_time_heard value from each transport. This is analogous to Nishida's Quick Failover draft [1], section 5.1, 3: The sender SHOULD avoid data transmission to PF destinations. When all destinations are in either PF or Inactive state, the sender MAY either move the destination from PF to active state (and transmit data to the active destination) or the sender MAY transmit data to a PF destination. In the former scenario, (i) the sender MUST NOT notify the ULP about the state transition, and (ii) MUST NOT clear the destination's error counter. It is recommended that the sender picks the PF destination with least error count (fewest consecutive timeouts) for data transmission. In case of a tie (multiple PF destinations with same error count), the sender MAY choose the last active destination. Thus for sctp_select_active_and_retran_path(), we keep track of the best, if any, transport that is in PF state and in case no ACTIVE transport has been found (hence trans_{pri,sec} is NULL), we select the best out of the three: current primary_path and retran_path as well as a possible PF transport. The secondary may still camp on the original primary_path as before. The change in sctp_trans_elect_best() with a more fine grained tie selection also improves at the same time path selection for sctp_assoc_update_retran_path() in case of non-ACTIVE states. [1] http://tools.ietf.org/html/draft-nishida-tsvwg-sctp-failover-05 Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-11net: sctp: migrate most recently used transport to ktimeDaniel Borkmann3-5/+7
Be more precise in transport path selection and use ktime helpers instead of jiffies to compare and pick the better primary and secondary recently used transports. This also avoids any side-effects during a possible roll-over, and could lead to better path decision-making. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-11net: sctp: refactor active path selectionDaniel Borkmann1-59/+61
This patch just refactors and moves the code for the active path selection into its own helper function outside of sctp_assoc_control_transport() which is already big enough. No functional changes here. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-11ktime: add ktime_after and ktime_before helperDaniel Borkmann1-1/+1
Add two minimal helper functions analogous to time_before() and time_after() that will later on both be needed by SCTP code. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-24net: Split sk_no_check into sk_no_check_{rx,tx}Tom Herbert1-1/+2
Define separate fields in the sock structure for configuring disabling checksums in both TX and RX-- sk_no_check_tx and sk_no_check_rx. The SO_NO_CHECK socket option only affects sk_no_check_tx. Also, removed UDP_CSUM_* defines since they are no longer necessary. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-24net: Eliminate no_check from protoswTom Herbert2-4/+0
It doesn't seem like an protocols are setting anything other than the default, and allowing to arbitrarily disable checksums for a whole protocol seems dangerous. This can be done on a per socket basis. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-14snmp: fix some left over of snmp statsWANG Cong1-1/+1
Fengguang reported the following sparse warning: >> net/ipv6/proc.c:198:41: sparse: incorrect type in argument 1 (different address spaces) net/ipv6/proc.c:198:41: expected void [noderef] <asn:3>*mib net/ipv6/proc.c:198:41: got void [noderef] <asn:3>**pcpumib Fixes: commit 698365fa1874aa7635d51667a3 (net: clean up snmp stats code) Reported-by: Fengguang Wu <fengguang.wu@intel.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-14ipv4: make ip_local_reserved_ports per netnsWANG Cong1-2/+3
ip_local_port_range is already per netns, so should ip_local_reserved_ports be. And since it is none by default we don't actually need it when we don't enable CONFIG_SYSCTL. By the way, rename inet_is_reserved_local_port() to inet_is_local_reserved_port() Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-12net: rename local_df to ignore_dfWANG Cong2-2/+2
As suggested by several people, rename local_df to ignore_df, since it means "ignore df bit if it is set". Cc: Maciej Żenczykowski <maze@google.com> Cc: Florian Westphal <fw@strlen.de> Cc: David S. Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-12Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2-5/+9
Conflicts: drivers/net/ethernet/altera/altera_sgdma.c net/netlink/af_netlink.c net/sched/cls_api.c net/sched/sch_api.c The netlink conflict dealt with moving to netlink_capable() and netlink_ns_capable() in the 'net' tree vs. supporting 'tc' operations in non-init namespaces. These were simple transformations from netlink_capable to netlink_ns_capable. The Altera driver conflict was simply code removal overlapping some void pointer cast cleanups in net-next. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-10sctp: add a checking for sctp_sysctl_net_registerwangweidong1-0/+4
When register_net_sysctl failed, we should free the sysctl_table. Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-10Revert "sctp: optimize the sctp_sysctl_net_register"wangweidong1-10/+7
This revert commit efb842c45("sctp: optimize the sctp_sysctl_net_register"), Since it doesn't kmemdup a sysctl_table for init_net, so the init_net->sctp.sysctl_header->ctl_table_arg points to sctp_net_table which is a static array pointer. So when doing sctp_sysctl_net_unregister, it will free sctp_net_table, then we will get a NULL pointer dereference like that: [ 262.948220] BUG: unable to handle kernel NULL pointer dereference at 000000000000006c [ 262.948232] IP: [<ffffffff81144b70>] kfree+0x80/0x420 [ 262.948260] PGD db80a067 PUD dae12067 PMD 0 [ 262.948268] Oops: 0000 [#1] SMP [ 262.948273] Modules linked in: sctp(-) crc32c_generic libcrc32c ... [ 262.948338] task: ffff8800db830190 ti: ffff8800dad00000 task.ti: ffff8800dad00000 [ 262.948344] RIP: 0010:[<ffffffff81144b70>] [<ffffffff81144b70>] kfree+0x80/0x420 [ 262.948353] RSP: 0018:ffff8800dad01d88 EFLAGS: 00010046 [ 262.948358] RAX: 0100000000000000 RBX: ffffffffa0227940 RCX: ffffea0000707888 [ 262.948363] RDX: ffffea0000707888 RSI: 0000000000000001 RDI: ffffffffa0227940 [ 262.948369] RBP: ffff8800dad01de8 R08: 0000000000000000 R09: ffff8800d9e983a9 [ 262.948374] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffa0227940 [ 262.948380] R13: ffffffff8187cfc0 R14: 0000000000000000 R15: ffffffff8187da10 [ 262.948386] FS: 00007fa2a2658700(0000) GS:ffff880112800000(0000) knlGS:0000000000000000 [ 262.948394] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 262.948400] CR2: 000000000000006c CR3: 00000000cddc0000 CR4: 00000000000006e0 [ 262.948410] Stack: [ 262.948413] ffff8800dad01da8 0000000000000286 0000000020227940 ffffffffa0227940 [ 262.948422] ffff8800dad01dd8 ffffffff811b7fa1 ffffffffa0227940 ffffffffa0227940 [ 262.948431] ffffffff8187d960 ffffffff8187cfc0 ffffffff8187d960 ffffffff8187da10 [ 262.948440] Call Trace: [ 262.948457] [<ffffffff811b7fa1>] ? unregister_sysctl_table+0x51/0xa0 [ 262.948476] [<ffffffffa020d1a1>] sctp_sysctl_net_unregister+0x21/0x30 [sctp] [ 262.948490] [<ffffffffa020ef6d>] sctp_net_exit+0x12d/0x150 [sctp] [ 262.948512] [<ffffffff81394f49>] ops_exit_list+0x39/0x60 [ 262.948522] [<ffffffff813951ed>] unregister_pernet_operations+0x3d/0x70 [ 262.948530] [<ffffffff81395292>] unregister_pernet_subsys+0x22/0x40 [ 262.948544] [<ffffffffa020efcc>] sctp_exit+0x3c/0x12d [sctp] [ 262.948562] [<ffffffff810c5e04>] SyS_delete_module+0x194/0x210 [ 262.948577] [<ffffffff81240fde>] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 262.948587] [<ffffffff815217a2>] system_call_fastpath+0x16/0x1b With this revert, it won't occur the Oops. Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-08net: clean up snmp stats codeWANG Cong1-4/+5
commit 8f0ea0fe3a036a47767f9c80e (snmp: reduce percpu needs by 50%) reduced snmp array size to 1, so technically it doesn't have to be an array any more. What's more, after the following commit: commit 933393f58fef9963eac61db8093689544e29a600 Date: Thu Dec 22 11:58:51 2011 -0600 percpu: Remove irqsafe_cpu_xxx variants We simply say that regular this_cpu use must be safe regardless of preemption and interrupt state. That has no material change for x86 and s390 implementations of this_cpu operations. However, arches that do not provide their own implementation for this_cpu operations will now get code generated that disables interrupts instead of preemption. probably no arch wants to have SNMP_ARRAY_SZ == 2. At least after almost 3 years, no one complains. So, just convert the array to a single pointer and remove snmp_mib_init() and snmp_mib_free() as well. Cc: Christoph Lameter <cl@linux.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-28net: sctp: Don't transition to PF state when transport has exhausted ↵Karl Heiss1-4/+3
'Path.Max.Retrans'. Don't transition to the PF state on every strike after 'Path.Max.Retrans'. Per draft-ietf-tsvwg-sctp-failover-03 Section 5.1.6: Additional (PMR - PFMR) consecutive timeouts on a PF destination confirm the path failure, upon which the destination transitions to the Inactive state. As described in [RFC4960], the sender (i) SHOULD notify ULP about this state transition, and (ii) transmit heartbeats to the Inactive destination at a lower frequency as described in Section 8.3 of [RFC4960]. This also prevents sending SCTP_ADDR_UNREACHABLE to the user as the state bounces between SCTP_INACTIVE and SCTP_PF for each subsequent strike. Signed-off-by: Karl Heiss <kheiss@gmail.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-28sctp: reset flowi4_oif parameter on route lookupXufeng Zhang1-1/+6
commit 813b3b5db83 (ipv4: Use caller's on-stack flowi as-is in output route lookups.) introduces another regression which is very similar to the problem of commit e6b45241c (ipv4: reset flowi parameters on route connect) wants to fix: Before we call ip_route_output_key() in sctp_v4_get_dst() to get a dst that matches a bind address as the source address, we have already called this function previously and the flowi parameters have been initialized including flowi4_oif, so when we call this function again, the process in __ip_route_output_key() will be different because of the setting of flowi4_oif, and we'll get a networking device which corresponds to the inputted flowi4_oif as the output device, this is wrong because we'll never hit this place if the previously returned source address of dst match one of the bound addresses. To reproduce this problem, a vlan setting is enough: # ifconfig eth0 up # route del default # vconfig add eth0 2 # vconfig add eth0 3 # ifconfig eth0.2 10.0.1.14 netmask 255.255.255.0 # route add default gw 10.0.1.254 dev eth0.2 # ifconfig eth0.3 10.0.0.14 netmask 255.255.255.0 # ip rule add from 10.0.0.14 table 4 # ip route add table 4 default via 10.0.0.254 src 10.0.0.14 dev eth0.3 # sctp_darn -H 10.0.0.14 -P 36422 -h 10.1.4.134 -p 36422 -s -I You'll detect that all the flow are routed to eth0.2(10.0.1.254). Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com> Signed-off-by: Julian Anastasov <ja@ssi.bg> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-21sctp: add support for busy polling to sctp protocolNeil Horman2-0/+9
The busy polling socket option adds support for sockets to busy wait on data arriving on the napi queue from which they have most recently received a frame. Currently only tcp and udp support this feature, but theres no reason sctp can't do so as well. Add it in so appliations can take advantage of it Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Vlad Yasevich <vyasevich@gmail.com> CC: "David S. Miller" <davem@davemloft.net> CC: Daniel Borkmann <dborkman@redhat.com> CC: netdev@vger.kernel.org Acked-by: Vlad Yasevich <vyasevich@gmail.com> Acked-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-19net: sctp: cache auth_enable per endpointVlad Yasevich6-59/+89
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>
2014-04-15ipv4: add a sock pointer to ip_queue_xmit()Eric Dumazet1-1/+1
ip_queue_xmit() assumes the skb it has to transmit is attached to an inet socket. Commit 31c70d5956fc ("l2tp: keep original skb ownership") changed l2tp to not change skb ownership and thus broke this assumption. One fix is to add a new 'struct sock *sk' parameter to ip_queue_xmit(), so that we do not assume skb->sk points to the socket used by l2tp tunnel. Fixes: 31c70d5956fc ("l2tp: keep original skb ownership") Reported-by: Zhan Jianyu <nasa4836@gmail.com> Tested-by: Zhan Jianyu <nasa4836@gmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-15Revert "net: sctp: Fix a_rwnd/rwnd management to reflect real state of the ↵Daniel Borkmann4-24/+74
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>
2014-04-12net: Fix use after free by removing length arg from sk_data_ready callbacks.David S. Miller2-3/+3
Several spots in the kernel perform a sequence like: skb_queue_tail(&sk->s_receive_queue, skb); sk->sk_data_ready(sk, skb->len); But at the moment we place the SKB onto the socket receive queue it can be consumed and freed up. So this skb->len access is potentially to freed up memory. Furthermore, the skb->len can be modified by the consumer so it is possible that the value isn't accurate. And finally, no actual implementation of this callback actually uses the length argument. And since nobody actually cared about it's value, lots of call sites pass arbitrary values in such as '0' and even '1'. So just remove the length argument from the callback, that way there is no confusion whatsoever and all of these use-after-free cases get fixed as a side effect. Based upon a patch by Eric Dumazet and his suggestion to audit this issue tree-wide. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-09net: sctp: test if association is dead in sctp_wake_up_waitersDaniel Borkmann1-0/+6
In function sctp_wake_up_waiters(), we need to involve a test if the association is declared dead. If so, we don't have any reference to a possible sibling association anymore and need to invoke sctp_write_space() instead, and normally walk the socket's associations and notify them of new wmem space. The reason for special casing is that otherwise, we could run into the following issue when a sctp_primitive_SEND() call from sctp_sendmsg() fails, and tries to flush an association's outq, i.e. in the following way: sctp_association_free() `-> list_del(&asoc->asocs) <-- poisons list pointer asoc->base.dead = true sctp_outq_free(&asoc->outqueue) `-> __sctp_outq_teardown() `-> sctp_chunk_free() `-> consume_skb() `-> sctp_wfree() `-> sctp_wake_up_waiters() <-- dereferences poisoned pointers if asoc->ep->sndbuf_policy=0 Therefore, only walk the list in an 'optimized' way if we find that the current association is still active. We could also use list_del_init() in addition when we call sctp_association_free(), but as Vlad suggests, we want to trap such bugs and thus leave it poisoned as is. Why is it safe to resolve the issue by testing for asoc->base.dead? Parallel calls to sctp_sendmsg() are protected under socket lock, that is lock_sock()/release_sock(). Only within that path under lock held, we're setting skb/chunk owner via sctp_set_owner_w(). Eventually, chunks are freed directly by an association still under that lock. So when traversing association list on destruction time from sctp_wake_up_waiters() via sctp_wfree(), a different CPU can't be running sctp_wfree() while another one calls sctp_association_free() as both happens under the same lock. Therefore, this can also not race with setting/testing against asoc->base.dead as we are guaranteed for this to happen in order, under lock. Further, Vlad says: the times we check asoc->base.dead is when we've cached an association pointer for later processing. In between cache and processing, the association may have been freed and is simply still around due to reference counts. We check asoc->base.dead under a lock, so it should always be safe to check and not race against sctp_association_free(). Stress-testing seems fine now, too. Fixes: cd253f9f357d ("net: sctp: wake up all assocs if sndbuf policy is per socket") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Vlad Yasevich <vyasevic@redhat.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Vlad Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-08net: sctp: wake up all assocs if sndbuf policy is per socketDaniel Borkmann1-1/+35
SCTP charges chunks for wmem accounting via skb->truesize in sctp_set_owner_w(), and sctp_wfree() respectively as the reverse operation. If a sender runs out of wmem, it needs to wait via sctp_wait_for_sndbuf(), and gets woken up by a call to __sctp_write_space() mostly via sctp_wfree(). __sctp_write_space() is being called per association. Although we assign sk->sk_write_space() to sctp_write_space(), which is then being done per socket, it is only used if send space is increased per socket option (SO_SNDBUF), as SOCK_USE_WRITE_QUEUE is set and therefore not invoked in sock_wfree(). Commit 4c3a5bdae293 ("sctp: Don't charge for data in sndbuf again when transmitting packet") fixed an issue where in case sctp_packet_transmit() manages to queue up more than sndbuf bytes, sctp_wait_for_sndbuf() will never be woken up again unless it is interrupted by a signal. However, a still remaining issue is that if net.sctp.sndbuf_policy=0, that is accounting per socket, and one-to-many sockets are in use, the reclaimed write space from sctp_wfree() is 'unfairly' handed back on the server to the association that is the lucky one to be woken up again via __sctp_write_space(), while the remaining associations are never be woken up again (unless by a signal). The effect disappears with net.sctp.sndbuf_policy=1, that is wmem accounting per association, as it guarantees a fair share of wmem among associations. Therefore, if we have reclaimed memory in case of per socket accounting, wake all related associations to a socket in a fair manner, that is, traverse the socket association list starting from the current neighbour of the association and issue a __sctp_write_space() to everyone until we end up waking ourselves. This guarantees that no association is preferred over another and even if more associations are taken into the one-to-many session, all receivers will get messages from the server and are not stalled forever on high load. This setting still leaves the advantage of per socket accounting in touch as an association can still use up global limits if unused by others. Fixes: 4eb701dfc618 ("[SCTP] Fix SCTP sendbuffer accouting.") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Thomas Graf <tgraf@suug.ch> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Vlad Yasevich <vyasevic@redhat.com> Acked-by: Vlad Yasevich <vyasevic@redhat.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2-7/+2
Conflicts: drivers/net/usb/r8152.c drivers/net/xen-netback/netback.c Both the r8152 and netback conflicts were simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-13net: sctp: remove NULL check in sctp_assoc_update_retran_pathDaniel Borkmann1-2/+1
This is basically just to let Coverity et al shut up. Remove an unneeded NULL check in sctp_assoc_update_retran_path(). It is safe to remove it, because in sctp_assoc_update_retran_path() we iterate over the list of transports, our own transport which is asoc->peer.retran_path included. In the iteration, we skip the list head element and transports in state SCTP_UNCONFIRMED. Such transports came from peer addresses received in INIT/INIT-ACK address parameters. They are not yet confirmed by a heartbeat and not available for data transfers. We know however that in the list of transports, even if it contains such elements, it at least contains our asoc->peer.retran_path as well, so even if next to that element, we only encounter SCTP_UNCONFIRMED transports, we are always going to fall back to asoc->peer.retran_path through sctp_trans_elect_best(), as that is for sure not SCTP_UNCONFIRMED as per fbdf501c9374 ("sctp: Do no select unconfirmed transports for retransmissions"). Whenever we call sctp_trans_elect_best() it will give us a non-NULL element back, and therefore when we break out of the loop, we are guaranteed to have a non-NULL transport pointer, and can remove the NULL check. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-06net: sctp: fix skb leakage in COOKIE ECHO path of chunk->auth_chunkDaniel Borkmann2-7/+2
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>
2014-03-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller3-53/+90
Conflicts: drivers/net/wireless/ath/ath9k/recv.c drivers/net/wireless/mwifiex/pcie.c net/ipv6/sit.c The SIT driver conflict consists of a bug fix being done by hand in 'net' (missing u64_stats_init()) whilst in 'net-next' a helper was created (netdev_alloc_pcpu_stats()) which takes care of this. The two wireless conflicts were overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-04net: sctp: fix sctp_sf_do_5_1D_ce to verify if we/peer is AUTH capableDaniel Borkmann1-0/+7
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>
2014-02-22net: sctp: rework multihoming retransmission path selection to rfc4960Daniel Borkmann1-50/+79
Problem statement: 1) both paths (primary path1 and alternate path2) are up after the association has been established i.e., HB packets are normally exchanged, 2) path2 gets inactive after path_max_retrans * max_rto timed out (i.e. path2 is down completely), 3) now, if a transmission times out on the only surviving/active path1 (any ~1sec network service impact could cause this like a channel bonding failover), then the retransmitted packets are sent over the inactive path2; this happens with partial failover and without it. Besides not being optimal in the above scenario, a small failure or timeout in the only existing path has the potential to cause long delays in the retransmission (depending on RTO_MAX) until the still active path is reselected. Further, when the T3-timeout occurs, we have active_patch == retrans_path, and even though the timeout occurred on the initial transmission of data, not a retransmit, we end up updating retransmit path. RFC4960, section 6.4. "Multi-Homed SCTP Endpoints" states under 6.4.1. "Failover from an Inactive Destination Address" the following: Some of the transport addresses of a multi-homed SCTP endpoint may become inactive due to either the occurrence of certain error conditions (see Section 8.2) or adjustments from the SCTP user. When there is outbound data to send and the primary path becomes inactive (e.g., due to failures), or where the SCTP user explicitly requests to send data to an inactive destination transport address, before reporting an error to its ULP, the SCTP endpoint should try to send the data to an alternate __active__ destination transport address if one exists. When retransmitting data that timed out, if the endpoint is multihomed, it should consider each source-destination address pair in its retransmission selection policy. When retransmitting timed-out data, the endpoint should attempt to pick the most divergent source-destination pair from the original source-destination pair to which the packet was transmitted. Note: Rules for picking the most divergent source-destination pair are an implementation decision and are not specified within this document. So, we should first reconsider to take the current active retransmission transport if we cannot find an alternative active one. If all of that fails, we can still round robin through unkown, partial failover, and inactive ones in the hope to find something still suitable. Commit 4141ddc02a92 ("sctp: retran_path update bug fix") broke that behaviour by selecting the next inactive transport when no other active transport was found besides the current assoc's peer.retran_path. Before commit 4141ddc02a92, we would have traversed through the list until we reach our peer.retran_path again, and in case that is still in state SCTP_ACTIVE, we would take it and return. Only if that is not the case either, we take the next inactive transport. Besides all that, another issue is that transports in state SCTP_UNKNOWN could be preferred over transports in state SCTP_ACTIVE in case a SCTP_ACTIVE transport appears after SCTP_UNKNOWN in the transport list yielding a weaker transport state to be used in retransmission. This patch mostly reverts 4141ddc02a92, but also rewrites this function to introduce more clarity and strictness into the code. A strict priority of transport states is enforced in this patch, hence selection is active > unkown > partial failover > inactive. Fixes: 4141ddc02a92 ("sctp: retran_path update bug fix") Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Acked-by: Vlad Yasevich <yasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-20net: sctp: Potentially-Failed state should not be reached from unconfirmed stateMatija Glavinic Pecotic1-3/+4
In current implementation it is possible to reach PF state from unconfirmed. We can interpret sctp-failover-02 in a way that PF state is meant to be reached only from active state, in the end, this is when entering PF state makes sense. Here are few quotes from sctp-failover-02, but regardless of these, same understanding can be reached from whole section 5: Section 5.1, quickfailover guide: "The PF state is an intermediate state between Active and Failed states." "Each time the T3-rtx timer expires on an active or idle destination, the error counter of that destination address will be incremented. When the value in the error counter exceeds PFMR, the endpoint should mark the destination transport address as PF." There are several concrete reasons for such interpretation. For start, rfc4960 does not take into concern quickfailover algorithm. Therefore, quickfailover must comply to 4960. Point where this compliance can be argued is following behavior: When PF is entered, association overall error counter is incremented for each missed HB. This is contradictory to rfc4960, as address, while in unconfirmed state, is subjected to probing, and while it is probed, it should not increment association overall error counter. This has as a consequence that we might end up in situation in which we drop association due path failure on unconfirmed address, in case we have wrong configuration in a way: Association.Max.Retrans == Path.Max.Retrans. Another reason is that entering PF from unconfirmed will cause a loss of address confirmed event when address is once (if) confirmed. This is fine from failover guide point of view, but it is not consistent with behavior preceding failover implementation and recommendation from 4960: 5.4. Path Verification Whenever a path is confirmed, an indication MAY be given to the upper layer. Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nsn.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-19Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller5-90/+67
Conflicts: drivers/net/bonding/bond_3ad.h drivers/net/bonding/bond_main.c Two minor conflicts in bonding, both of which were overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-19net: sctp: fix sctp_connectx abi for ia32 emulation/compat modeDaniel Borkmann1-9/+32
SCTP's sctp_connectx() abi breaks for 64bit kernels compiled with 32bit emulation (e.g. ia32 emulation or x86_x32). Due to internal usage of 'struct sctp_getaddrs_old' which includes a struct sockaddr pointer, sizeof(param) check will always fail in kernel as the structure in 64bit kernel space is 4bytes larger than for user binaries compiled in 32bit mode. Thus, applications making use of sctp_connectx() won't be able to run under such circumstances. Introduce a compat interface in the kernel to deal with such situations by using a 'struct compat_sctp_getaddrs_old' structure where user data is copied into it, and then sucessively transformed into a 'struct sctp_getaddrs_old' structure with the help of compat_ptr(). That fixes sctp_connectx() abi without any changes needed in user space, and lets the SCTP test suite pass when compiled in 32bit and run on 64bit kernels. Fixes: f9c67811ebc0 ("sctp: Fix regression introduced by new sctp_connectx api") 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>
2014-02-17net: sctp: Fix a_rwnd/rwnd management to reflect real state of the ↵Matija Glavinic Pecotic4-74/+24
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>
2014-02-14net: remove unnecessary return'sstephen hemminger1-1/+0
One of my pet coding style peeves is the practice of adding extra return; at the end of function. Kill several instances of this in network code. I suppose some coccinelle wizardy could do this automatically. Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-14sctp: optimize the sctp_sysctl_net_registerwangweidong1-7/+10
Here, when the net is init_net, we needn't to kmemdup the ctl_table again. So add a check for net. Also we can save some memory. Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-14sctp: fix a missed .data initializationwangweidong1-0/+1
As commit 3c68198e75111a90("sctp: Make hmac algorithm selection for cookie generation dynamic"), we miss the .data initialization. If we don't use the net_namespace, the problem that parts of the sysctl configuration won't be isolation and won't occur. In sctp_sysctl_net_register(), we register the sysctl for each net, in the for(), we use the 'table[i].data' as check condition, so when the 'i' is the index of sctp_hmac_alg, the data is NULL, then break. So add the .data initialization. Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-07net: sctp: fix initialization of local source address on accepted ipv6 socketsMatija Glavinic Pecotic1-0/+2
commit efe4208f47f907b86f528788da711e8ab9dea44d: 'ipv6: make lookups simpler and faster' broke initialization of local source address on accepted ipv6 sockets. Before the mentioned commit receive address was copied along with the contents of ipv6_pinfo in sctp_v6_create_accept_sk. Now when it is moved, it has to be copied separately. This also fixes lksctp's ipv6 regression in a sense that test_getname_v6, TC5 - 'getsockname on a connected server socket' now passes. Signed-off-by: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nsn.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-22sctp: remove macros sctp_bh_[un]lock_sockwangweidong4-21/+21
Redefined bh_[un]lock_sock to sctp_bh[un]lock_sock for user space friendly code which we haven't use in years, so removing them. Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-22sctp: remove macros sctp_{lock|release}_sockwangweidong1-31/+31
Redefined {lock|release}_sock to sctp_{lock|release}_sock for user space friendly code which we haven't use in years, so removing them. Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-22sctp: remove macros sctp_write_[un]_lockwangweidong1-8/+8
Redefined write_[un]lock to sctp_write_[un]lock for user space friendly code which we haven't use in years, so removing them. Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-22sctp: remove macros sctp_spin_[un]lockwangweidong1-8/+8
Redefined spin_[un]lock to sctp_spin_[un]lock for user space friendly code which we haven't use in years, so removing them. Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-22sctp: remove macros sctp_local_bh_{disable|enable}wangweidong4-26/+26
Redefined local_bh_{disable|enable} to sctp_local_bh_{disable|enable} for user space friendly code which we haven't use in years, so removing them. Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-17sctp: remove the unnecessary assignmentwangweidong1-1/+0
When go the right path, the status is 0, no need to assign it again. So just remove the assignment. Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-16sctp: create helper function to enable|disable sackdelaywangweidong1-18/+19
add sctp_spp_sackdelay_{enable|disable} helper function for avoiding code duplication. Signed-off-by: Wang Weidong <wangweidong1@huawei.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>