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2015-04-19tcp: Fix crash in TCP Fast OpenBen Hutchings
Commit 355a901e6cf1 ("tcp: make connect() mem charging friendly") changed tcp_send_syn_data() to perform an open-coded copy of the 'syn' skb rather than using skb_copy_expand(). The open-coded copy does not cover the skb_shared_info::gso_segs field, so in the new skb it is left set to 0. When this commit was backported into stable branches between 3.10.y and 3.16.7-ckty inclusive, it triggered the BUG() in tcp_transmit_skb(). Since Linux 3.18 the GSO segment count is kept in the tcp_skb_cb::tcp_gso_segs field and tcp_send_syn_data() does copy the tcp_skb_cb structure to the new skb, so mainline and newer stable branches are not affected. Set skb_shared_info::gso_segs to the correct value of 1. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-26tcp: make connect() mem charging friendlyEric Dumazet
[ Upstream commit 355a901e6cf1b2b763ec85caa2a9f04fbcc4ab4a ] While working on sk_forward_alloc problems reported by Denys Fedoryshchenko, we found that tcp connect() (and fastopen) do not call sk_wmem_schedule() for SYN packet (and/or SYN/DATA packet), so sk_forward_alloc is negative while connect is in progress. We can fix this by calling regular sk_stream_alloc_skb() both for the SYN packet (in tcp_connect()) and the syn_data packet in tcp_send_syn_data() Then, tcp_send_syn_data() can avoid copying syn_data as we simply can manipulate syn_data->cb[] to remove SYN flag (and increment seq) Instead of open coding memcpy_fromiovecend(), simply use this helper. This leaves in socket write queue clean fast clone skbs. This was tested against our fastopen packetdrill tests. Reported-by: Denys Fedoryshchenko <nuclearcat@nuclearcat.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-26tcp: fix tcp fin memory accountingJosh Hunt
[ Upstream commit d22e1537181188e5dc8cbc51451832625035bdc2 ] tcp_send_fin() does not account for the memory it allocates properly, so sk_forward_alloc can be negative in cases where we've sent a FIN: ss example output (ss -amn | grep -B1 f4294): tcp FIN-WAIT-1 0 1 192.168.0.1:45520 192.0.2.1:8080 skmem:(r0,rb87380,t0,tb87380,f4294966016,w1280,o0,bl0) Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-26inet_diag: fix possible overflow in inet_diag_dump_one_icsk()Eric Dumazet
[ Upstream commit c8e2c80d7ec00d020320f905822bf49c5ad85250 ] inet_diag_dump_one_icsk() allocates too small skb. Add inet_sk_attr_size() helper right before inet_sk_diag_fill() so that it can be updated if/when new attributes are added. iproute2/ss currently does not use this dump_one() interface, this might explain nobody noticed this problem yet. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-18udp: only allow UFO for packets from SOCK_DGRAM socketsMichal Kubeček
[ Upstream commit acf8dd0a9d0b9e4cdb597c2f74802f79c699e802 ] If an over-MTU UDP datagram is sent through a SOCK_RAW socket to a UFO-capable device, ip_ufo_append_data() sets skb->ip_summed to CHECKSUM_PARTIAL unconditionally as all GSO code assumes transport layer checksum is to be computed on segmentation. However, in this case, skb->csum_start and skb->csum_offset are never set as raw socket transmit path bypasses udp_send_skb() where they are usually set. As a result, driver may access invalid memory when trying to calculate the checksum and store the result (as observed in virtio_net driver). Moreover, the very idea of modifying the userspace provided UDP header is IMHO against raw socket semantics (I wasn't able to find a document clearly stating this or the opposite, though). And while allowing CHECKSUM_NONE in the UFO case would be more efficient, it would be a bit too intrusive change just to handle a corner case like this. Therefore disallowing UFO for packets from SOCK_DGRAM seems to be the best option. Signed-off-by: Michal Kubecek <mkubecek@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-18ipv4: ip_check_defrag should not assume that skb_network_offset is zeroAlexander Drozdov
[ Upstream commit 3e32e733d1bbb3f227259dc782ef01d5706bdae0 ] ip_check_defrag() may be used by af_packet to defragment outgoing packets. skb_network_offset() of af_packet's outgoing packets is not zero. Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-18ipv4: ip_check_defrag should correctly check return value of skb_copy_bitsAlexander Drozdov
[ Upstream commit fba04a9e0c869498889b6445fd06cbe7da9bb834 ] skb_copy_bits() returns zero on success and negative value on error, so it is needed to invert the condition in ip_check_defrag(). Fixes: 1bf3751ec90c ("ipv4: ip_check_defrag must not modify skb before unsharing") Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-26ipv4: tcp: get rid of ugly unicast_sockEric Dumazet
[ Upstream commit bdbbb8527b6f6a358dbcb70dac247034d665b8e4 ] In commit be9f4a44e7d41 ("ipv4: tcp: remove per net tcp_sock") I tried to address contention on a socket lock, but the solution I chose was horrible : commit 3a7c384ffd57e ("ipv4: tcp: unicast_sock should not land outside of TCP stack") addressed a selinux regression. commit 0980e56e506b ("ipv4: tcp: set unicast_sock uc_ttl to -1") took care of another regression. commit b5ec8eeac46 ("ipv4: fix ip_send_skb()") fixed another regression. commit 811230cd85 ("tcp: ipv4: initialize unicast_sock sk_pacing_rate") was another shot in the dark. Really, just use a proper socket per cpu, and remove the skb_orphan() call, to re-enable flow control. This solves a serious problem with FQ packet scheduler when used in hostile environments, as we do not want to allocate a flow structure for every RST packet sent in response to a spoofed packet. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-26tcp: ipv4: initialize unicast_sock sk_pacing_rateEric Dumazet
[ Upstream commit 811230cd853d62f09ed0addd0ce9a1b9b0e13fb5 ] When I added sk_pacing_rate field, I forgot to initialize its value in the per cpu unicast_sock used in ip_send_unicast_reply() This means that for sch_fq users, RST packets, or ACK packets sent on behalf of TIME_WAIT sockets might be sent to slowly or even dropped once we reach the per flow limit. Signed-off-by: Eric Dumazet <edumazet@google.com> Fixes: 95bd09eb2750 ("tcp: TSO packets automatic sizing") Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-26ping: Fix race in free in receive pathsubashab@codeaurora.org
[ Upstream commit fc752f1f43c1c038a2c6ae58cc739ebb5953ccb0 ] An exception is seen in ICMP ping receive path where the skb destructor sock_rfree() tries to access a freed socket. This happens because ping_rcv() releases socket reference with sock_put() and this internally frees up the socket. Later icmp_rcv() will try to free the skb and as part of this, skb destructor is called and which leads to a kernel panic as the socket is freed already in ping_rcv(). -->|exception -007|sk_mem_uncharge -007|sock_rfree -008|skb_release_head_state -009|skb_release_all -009|__kfree_skb -010|kfree_skb -011|icmp_rcv -012|ip_local_deliver_finish Fix this incorrect free by cloning this skb and processing this cloned skb instead. This patch was suggested by Eric Dumazet Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-26udp_diag: Fix socket skipping within chainHerbert Xu
[ Upstream commit 86f3cddbc3037882414c7308973530167906b7e9 ] While working on rhashtable walking I noticed that the UDP diag dumping code is buggy. In particular, the socket skipping within a chain never happens, even though we record the number of sockets that should be skipped. As this code was supposedly copied from TCP, this patch does what TCP does and resets num before we walk a chain. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-26ipv4: try to cache dst_entries which would cause a redirectHannes Frederic Sowa
[ Upstream commit df4d92549f23e1c037e83323aff58a21b3de7fe0 ] Not caching dst_entries which cause redirects could be exploited by hosts on the same subnet, causing a severe DoS attack. This effect aggravated since commit f88649721268999 ("ipv4: fix dst race in sk_dst_get()"). Lookups causing redirects will be allocated with DST_NOCACHE set which will force dst_release to free them via RCU. Unfortunately waiting for RCU grace period just takes too long, we can end up with >1M dst_entries waiting to be released and the system will run OOM. rcuos threads cannot catch up under high softirq load. Attaching the flag to emit a redirect later on to the specific skb allows us to cache those dst_entries thus reducing the pressure on allocation and deallocation. This issue was discovered by Marcelo Leitner. Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: Marcelo Leitner <mleitner@redhat.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-26ip: zero sockaddr returned on error queueWillem de Bruijn
[ Upstream commit f812116b174e59a350acc8e4856213a166a91222 ] The sockaddr is returned in IP(V6)_RECVERR as part of errhdr. That structure is defined and allocated on the stack as struct { struct sock_extended_err ee; struct sockaddr_in(6) offender; } errhdr; The second part is only initialized for certain SO_EE_ORIGIN values. Always initialize it completely. An MTU exceeded error on a SOCK_RAW/IPPROTO_RAW is one example that would return uninitialized bytes. Signed-off-by: Willem de Bruijn <willemb@google.com> ---- Also verified that there is no padding between errhdr.ee and errhdr.offender that could leak additional kernel data. Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-01-27tcp: Do not apply TSO segment limit to non-TSO packetsHerbert Xu
[ Upstream commit 843925f33fcc293d80acf2c5c8a78adf3344d49b ] Thomas Jarosch reported IPsec TCP stalls when a PMTU event occurs. In fact the problem was completely unrelated to IPsec. The bug is also reproducible if you just disable TSO/GSO. The problem is that when the MSS goes down, existing queued packet on the TX queue that have not been transmitted yet all look like TSO packets and get treated as such. This then triggers a bug where tcp_mss_split_point tells us to generate a zero-sized packet on the TX queue. Once that happens we're screwed because the zero-sized packet can never be removed by ACKs. Fixes: 1485348d242 ("tcp: Apply device TSO segment limit earlier") Reported-by: Thomas Jarosch <thomas.jarosch@intra2net.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cheers, Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-12-06ipv4: Fix incorrect error code when adding an unreachable routePanu Matilainen
[ Upstream commit 49dd18ba4615eaa72f15c9087dea1c2ab4744cf5 ] Trying to add an unreachable route incorrectly returns -ESRCH if if custom FIB rules are present: [root@localhost ~]# ip route add 74.125.31.199 dev eth0 via 1.2.3.4 RTNETLINK answers: Network is unreachable [root@localhost ~]# ip rule add to 55.66.77.88 table 200 [root@localhost ~]# ip route add 74.125.31.199 dev eth0 via 1.2.3.4 RTNETLINK answers: No such process [root@localhost ~]# Commit 83886b6b636173b206f475929e58fac75c6f2446 ("[NET]: Change "not found" return value for rule lookup") changed fib_rules_lookup() to use -ESRCH as a "not found" code internally, but for user space it should be translated into -ENETUNREACH. Handle the translation centrally in ipv4-specific fib_lookup(), leaving the DECnet case alone. On a related note, commit b7a71b51ee37d919e4098cd961d59a883fd272d8 ("ipv4: removed redundant conditional") removed a similar translation from ip_route_input_slow() prematurely AIUI. Fixes: b7a71b51ee37 ("ipv4: removed redundant conditional") Signed-off-by: Panu Matilainen <pmatilai@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-14ipv4: dst_entry leak in ip_send_unicast_reply()Vasily Averin
[ Upstream commit 4062090e3e5caaf55bed4523a69f26c3265cc1d2 ] ip_setup_cork() called inside ip_append_data() steals dst entry from rt to cork and in case errors in __ip_append_data() nobody frees stolen dst entry Fixes: 2e77d89b2fa8 ("net: avoid a pair of dst_hold()/dst_release() in ip_append_data()") Signed-off-by: Vasily Averin <vvs@parallels.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-14ipv4: fix nexthop attlen check in fib_nh_matchJiri Pirko
[ Upstream commit f76936d07c4eeb36d8dbb64ebd30ab46ff85d9f7 ] fib_nh_match does not match nexthops correctly. Example: ip route add 172.16.10/24 nexthop via 192.168.122.12 dev eth0 \ nexthop via 192.168.122.13 dev eth0 ip route del 172.16.10/24 nexthop via 192.168.122.14 dev eth0 \ nexthop via 192.168.122.15 dev eth0 Del command is successful and route is removed. After this patch applied, the route is correctly matched and result is: RTNETLINK answers: No such process Please consider this for stable trees as well. Fixes: 4e902c57417c4 ("[IPv4]: FIB configuration using struct fib_config") Signed-off-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-10-15tcp: fixing TLP's FIN recoveryPer Hurtig
[ Upstream commit bef1909ee3ed1ca39231b260a8d3b4544ecd0c8f ] Fix to a problem observed when losing a FIN segment that does not contain data. In such situations, TLP is unable to recover from *any* tail loss and instead adds at least PTO ms to the retransmission process, i.e., RTO = RTO + PTO. Signed-off-by: Per Hurtig <per.hurtig@kau.se> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Nandita Dukkipati <nanditad@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-10-15tcp: fix tcp_release_cb() to dispatch via address family for mtu_reduced()Neal Cardwell
[ Upstream commit 4fab9071950c2021d846e18351e0f46a1cffd67b ] Make sure we use the correct address-family-specific function for handling MTU reductions from within tcp_release_cb(). Previously AF_INET6 sockets were incorrectly always using the IPv6 code path when sometimes they were handling IPv4 traffic and thus had an IPv4 dst. Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Diagnosed-by: Willem de Bruijn <willemb@google.com> Fixes: 563d34d057862 ("tcp: dont drop MTU reduction indications") Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-08-14tcp: Fix integer-overflow in TCP vegasChristoph Paasch
[ Upstream commit 1f74e613ded11517db90b2bd57e9464d9e0fb161 ] In vegas we do a multiplication of the cwnd and the rtt. This may overflow and thus their result is stored in a u64. However, we first need to cast the cwnd so that actually 64-bit arithmetic is done. Then, we need to do do_div to allow this to be used on 32-bit arches. Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Doug Leith <doug.leith@nuim.ie> Fixes: 8d3a564da34e (tcp: tcp_vegas cong avoid fix) Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-08-14tcp: Fix integer-overflows in TCP venoChristoph Paasch
[ Upstream commit 45a07695bc64b3ab5d6d2215f9677e5b8c05a7d0 ] In veno we do a multiplication of the cwnd and the rtt. This may overflow and thus their result is stored in a u64. However, we first need to cast the cwnd so that actually 64-bit arithmetic is done. A first attempt at fixing 76f1017757aa0 ([TCP]: TCP Veno congestion control) was made by 159131149c2 (tcp: Overflow bug in Vegas), but it failed to add the required cast in tcp_veno_cong_avoid(). Fixes: 76f1017757aa0 ([TCP]: TCP Veno congestion control) Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-08-14ip: make IP identifiers less predictableEric Dumazet
[ Upstream commit 04ca6973f7c1a0d8537f2d9906a0cf8e69886d75 ] In "Counting Packets Sent Between Arbitrary Internet Hosts", Jeffrey and Jedidiah describe ways exploiting linux IP identifier generation to infer whether two machines are exchanging packets. With commit 73f156a6e8c1 ("inetpeer: get rid of ip_id_count"), we changed IP id generation, but this does not really prevent this side-channel technique. This patch adds a random amount of perturbation so that IP identifiers for a given destination [1] are no longer monotonically increasing after an idle period. Note that prandom_u32_max(1) returns 0, so if generator is used at most once per jiffy, this patch inserts no hole in the ID suite and do not increase collision probability. This is jiffies based, so in the worst case (HZ=1000), the id can rollover after ~65 seconds of idle time, which should be fine. We also change the hash used in __ip_select_ident() to not only hash on daddr, but also saddr and protocol, so that ICMP probes can not be used to infer information for other protocols. For IPv6, adds saddr into the hash as well, but not nexthdr. If I ping the patched target, we can see ID are now hard to predict. 21:57:11.008086 IP (...) A > target: ICMP echo request, seq 1, length 64 21:57:11.010752 IP (... id 2081 ...) target > A: ICMP echo reply, seq 1, length 64 21:57:12.013133 IP (...) A > target: ICMP echo request, seq 2, length 64 21:57:12.015737 IP (... id 3039 ...) target > A: ICMP echo reply, seq 2, length 64 21:57:13.016580 IP (...) A > target: ICMP echo request, seq 3, length 64 21:57:13.019251 IP (... id 3437 ...) target > A: ICMP echo reply, seq 3, length 64 [1] TCP sessions uses a per flow ID generator not changed by this patch. Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Jeffrey Knockel <jeffk@cs.unm.edu> Reported-by: Jedidiah R. Crandall <crandall@cs.unm.edu> Cc: Willy Tarreau <w@1wt.eu> Cc: Hannes Frederic Sowa <hannes@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-08-14inetpeer: get rid of ip_id_countEric Dumazet
[ Upstream commit 73f156a6e8c1074ac6327e0abd1169e95eb66463 ] Ideally, we would need to generate IP ID using a per destination IP generator. linux kernels used inet_peer cache for this purpose, but this had a huge cost on servers disabling MTU discovery. 1) each inet_peer struct consumes 192 bytes 2) inetpeer cache uses a binary tree of inet_peer structs, with a nominal size of ~66000 elements under load. 3) lookups in this tree are hitting a lot of cache lines, as tree depth is about 20. 4) If server deals with many tcp flows, we have a high probability of not finding the inet_peer, allocating a fresh one, inserting it in the tree with same initial ip_id_count, (cf secure_ip_id()) 5) We garbage collect inet_peer aggressively. IP ID generation do not have to be 'perfect' Goal is trying to avoid duplicates in a short period of time, so that reassembly units have a chance to complete reassembly of fragments belonging to one message before receiving other fragments with a recycled ID. We simply use an array of generators, and a Jenkin hash using the dst IP as a key. ipv6_select_ident() is put back into net/ipv6/ip6_output.c where it belongs (it is only used from this file) secure_ip_id() and secure_ipv6_id() no longer are needed. Rename ip_select_ident_more() to ip_select_ident_segs() to avoid unnecessary decrement/increment of the number of segments. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-28ipv4: fix buffer overflow in ip_options_compile()Eric Dumazet
[ Upstream commit 10ec9472f05b45c94db3c854d22581a20b97db41 ] There is a benign buffer overflow in ip_options_compile spotted by AddressSanitizer[1] : Its benign because we always can access one extra byte in skb->head (because header is followed by struct skb_shared_info), and in this case this byte is not even used. [28504.910798] ================================================================== [28504.912046] AddressSanitizer: heap-buffer-overflow in ip_options_compile [28504.913170] Read of size 1 by thread T15843: [28504.914026] [<ffffffff81802f91>] ip_options_compile+0x121/0x9c0 [28504.915394] [<ffffffff81804a0d>] ip_options_get_from_user+0xad/0x120 [28504.916843] [<ffffffff8180dedf>] do_ip_setsockopt.isra.15+0x8df/0x1630 [28504.918175] [<ffffffff8180ec60>] ip_setsockopt+0x30/0xa0 [28504.919490] [<ffffffff8181e59b>] tcp_setsockopt+0x5b/0x90 [28504.920835] [<ffffffff8177462f>] sock_common_setsockopt+0x5f/0x70 [28504.922208] [<ffffffff817729c2>] SyS_setsockopt+0xa2/0x140 [28504.923459] [<ffffffff818cfb69>] system_call_fastpath+0x16/0x1b [28504.924722] [28504.925106] Allocated by thread T15843: [28504.925815] [<ffffffff81804995>] ip_options_get_from_user+0x35/0x120 [28504.926884] [<ffffffff8180dedf>] do_ip_setsockopt.isra.15+0x8df/0x1630 [28504.927975] [<ffffffff8180ec60>] ip_setsockopt+0x30/0xa0 [28504.929175] [<ffffffff8181e59b>] tcp_setsockopt+0x5b/0x90 [28504.930400] [<ffffffff8177462f>] sock_common_setsockopt+0x5f/0x70 [28504.931677] [<ffffffff817729c2>] SyS_setsockopt+0xa2/0x140 [28504.932851] [<ffffffff818cfb69>] system_call_fastpath+0x16/0x1b [28504.934018] [28504.934377] The buggy address ffff880026382828 is located 0 bytes to the right [28504.934377] of 40-byte region [ffff880026382800, ffff880026382828) [28504.937144] [28504.937474] Memory state around the buggy address: [28504.938430] ffff880026382300: ........ rrrrrrrr rrrrrrrr rrrrrrrr [28504.939884] ffff880026382400: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr [28504.941294] ffff880026382500: .....rrr rrrrrrrr rrrrrrrr rrrrrrrr [28504.942504] ffff880026382600: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr [28504.943483] ffff880026382700: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr [28504.944511] >ffff880026382800: .....rrr rrrrrrrr rrrrrrrr rrrrrrrr [28504.945573] ^ [28504.946277] ffff880026382900: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr [28505.094949] ffff880026382a00: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr [28505.096114] ffff880026382b00: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr [28505.097116] ffff880026382c00: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr [28505.098472] ffff880026382d00: ffffffff rrrrrrrr rrrrrrrr rrrrrrrr [28505.099804] Legend: [28505.100269] f - 8 freed bytes [28505.100884] r - 8 redzone bytes [28505.101649] . - 8 allocated bytes [28505.102406] x=1..7 - x allocated bytes + (8-x) redzone bytes [28505.103637] ================================================================== [1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-28tcp: fix false undo corner casesYuchung Cheng
[ Upstream commit 6e08d5e3c8236e7484229e46fdf92006e1dd4c49 ] The undo code assumes that, upon entering loss recovery, TCP 1) always retransmit something 2) the retransmission never fails locally (e.g., qdisc drop) so undo_marker is set in tcp_enter_recovery() and undo_retrans is incremented only when tcp_retransmit_skb() is successful. When the assumption is broken because TCP's cwnd is too small to retransmit or the retransmit fails locally. The next (DUP)ACK would incorrectly revert the cwnd and the congestion state in tcp_try_undo_dsack() or tcp_may_undo(). Subsequent (DUP)ACKs may enter the recovery state. The sender repeatedly enter and (incorrectly) exit recovery states if the retransmits continue to fail locally while receiving (DUP)ACKs. The fix is to initialize undo_retrans to -1 and start counting on the first retransmission. Always increment undo_retrans even if the retransmissions fail locally because they couldn't cause DSACKs to undo the cwnd reduction. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-28igmp: fix the problem when mc leave groupdingtianhong
[ Upstream commit 52ad353a5344f1f700c5b777175bdfa41d3cd65a ] The problem was triggered by these steps: 1) create socket, bind and then setsockopt for add mc group. mreq.imr_multiaddr.s_addr = inet_addr("255.0.0.37"); mreq.imr_interface.s_addr = inet_addr("192.168.1.2"); setsockopt(sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)); 2) drop the mc group for this socket. mreq.imr_multiaddr.s_addr = inet_addr("255.0.0.37"); mreq.imr_interface.s_addr = inet_addr("0.0.0.0"); setsockopt(sockfd, IPPROTO_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq)); 3) and then drop the socket, I found the mc group was still used by the dev: netstat -g Interface RefCnt Group --------------- ------ --------------------- eth2 1 255.0.0.37 Normally even though the IP_DROP_MEMBERSHIP return error, the mc group still need to be released for the netdev when drop the socket, but this process was broken when route default is NULL, the reason is that: The ip_mc_leave_group() will choose the in_dev by the imr_interface.s_addr, if input addr is NULL, the default route dev will be chosen, then the ifindex is got from the dev, then polling the inet->mc_list and return -ENODEV, but if the default route dev is NULL, the in_dev and ifIndex is both NULL, when polling the inet->mc_list, the mc group will be released from the mc_list, but the dev didn't dec the refcnt for this mc group, so when dropping the socket, the mc_list is NULL and the dev still keep this group. v1->v2: According Hideaki's suggestion, we should align with IPv6 (RFC3493) and BSDs, so I add the checking for the in_dev before polling the mc_list, make sure when we remove the mc group, dec the refcnt to the real dev which was using the mc address. The problem would never happened again. Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-28ipv4: icmp: Fix pMTU handling for rare caseEdward Allcutt
[ Upstream commit 68b7107b62983f2cff0948292429d5f5999df096 ] Some older router implementations still send Fragmentation Needed errors with the Next-Hop MTU field set to zero. This is explicitly described as an eventuality that hosts must deal with by the standard (RFC 1191) since older standards specified that those bits must be zero. Linux had a generic (for all of IPv4) implementation of the algorithm described in the RFC for searching a list of MTU plateaus for a good value. Commit 46517008e116 ("ipv4: Kill ip_rt_frag_needed().") removed this as part of the changes to remove the routing cache. Subsequently any Fragmentation Needed packet with a zero Next-Hop MTU has been discarded without being passed to the per-protocol handlers or notifying userspace for raw sockets. When there is a router which does not implement RFC 1191 on an MTU limited path then this results in stalled connections since large packets are discarded and the local protocols are not notified so they never attempt to lower the pMTU. One example I have seen is an OpenBSD router terminating IPSec tunnels. It's worth pointing out that this case is distinct from the BSD 4.2 bug which incorrectly calculated the Next-Hop MTU since the commit in question dismissed that as a valid concern. All of the per-protocols handlers implement the simple approach from RFC 1191 of immediately falling back to the minimum value. Although this is sub-optimal it is vastly preferable to connections hanging indefinitely. Remove the Next-Hop MTU != 0 check and allow such packets to follow the normal path. Fixes: 46517008e116 ("ipv4: Kill ip_rt_frag_needed().") Signed-off-by: Edward Allcutt <edward.allcutt@openmarket.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-28tcp: Fix divide by zero when pushing during tcp-repairChristoph Paasch
[ Upstream commit 5924f17a8a30c2ae18d034a86ee7581b34accef6 ] When in repair-mode and TCP_RECV_QUEUE is set, we end up calling tcp_push with mss_now being 0. If data is in the send-queue and tcp_set_skb_tso_segs gets called, we crash because it will divide by mss_now: [ 347.151939] divide error: 0000 [#1] SMP [ 347.152907] Modules linked in: [ 347.152907] CPU: 1 PID: 1123 Comm: packetdrill Not tainted 3.16.0-rc2 #4 [ 347.152907] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 347.152907] task: f5b88540 ti: f3c82000 task.ti: f3c82000 [ 347.152907] EIP: 0060:[<c1601359>] EFLAGS: 00210246 CPU: 1 [ 347.152907] EIP is at tcp_set_skb_tso_segs+0x49/0xa0 [ 347.152907] EAX: 00000b67 EBX: f5acd080 ECX: 00000000 EDX: 00000000 [ 347.152907] ESI: f5a28f40 EDI: f3c88f00 EBP: f3c83d10 ESP: f3c83d00 [ 347.152907] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 [ 347.152907] CR0: 80050033 CR2: 083158b0 CR3: 35146000 CR4: 000006b0 [ 347.152907] Stack: [ 347.152907] c167f9d9 f5acd080 000005b4 00000002 f3c83d20 c16013e6 f3c88f00 f5acd080 [ 347.152907] f3c83da0 c1603b5a f3c83d38 c10a0188 00000000 00000000 f3c83d84 c10acc85 [ 347.152907] c1ad5ec0 00000000 00000000 c1ad679c 010003e0 00000000 00000000 f3c88fc8 [ 347.152907] Call Trace: [ 347.152907] [<c167f9d9>] ? apic_timer_interrupt+0x2d/0x34 [ 347.152907] [<c16013e6>] tcp_init_tso_segs+0x36/0x50 [ 347.152907] [<c1603b5a>] tcp_write_xmit+0x7a/0xbf0 [ 347.152907] [<c10a0188>] ? up+0x28/0x40 [ 347.152907] [<c10acc85>] ? console_unlock+0x295/0x480 [ 347.152907] [<c10ad24f>] ? vprintk_emit+0x1ef/0x4b0 [ 347.152907] [<c1605716>] __tcp_push_pending_frames+0x36/0xd0 [ 347.152907] [<c15f4860>] tcp_push+0xf0/0x120 [ 347.152907] [<c15f7641>] tcp_sendmsg+0xf1/0xbf0 [ 347.152907] [<c116d920>] ? kmem_cache_free+0xf0/0x120 [ 347.152907] [<c106a682>] ? __sigqueue_free+0x32/0x40 [ 347.152907] [<c106a682>] ? __sigqueue_free+0x32/0x40 [ 347.152907] [<c114f0f0>] ? do_wp_page+0x3e0/0x850 [ 347.152907] [<c161c36a>] inet_sendmsg+0x4a/0xb0 [ 347.152907] [<c1150269>] ? handle_mm_fault+0x709/0xfb0 [ 347.152907] [<c15a006b>] sock_aio_write+0xbb/0xd0 [ 347.152907] [<c1180b79>] do_sync_write+0x69/0xa0 [ 347.152907] [<c1181023>] vfs_write+0x123/0x160 [ 347.152907] [<c1181d55>] SyS_write+0x55/0xb0 [ 347.152907] [<c167f0d8>] sysenter_do_call+0x12/0x28 This can easily be reproduced with the following packetdrill-script (the "magic" with netem, sk_pacing and limit_output_bytes is done to prevent the kernel from pushing all segments, because hitting the limit without doing this is not so easy with packetdrill): 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 +0 < S 0:0(0) win 32792 <mss 1460> +0 > S. 0:0(0) ack 1 <mss 1460> +0.1 < . 1:1(0) ack 1 win 65000 +0 accept(3, ..., ...) = 4 // This forces that not all segments of the snd-queue will be pushed +0 `tc qdisc add dev tun0 root netem delay 10ms` +0 `sysctl -w net.ipv4.tcp_limit_output_bytes=2` +0 setsockopt(4, SOL_SOCKET, 47, [2], 4) = 0 +0 write(4,...,10000) = 10000 +0 write(4,...,10000) = 10000 // Set tcp-repair stuff, particularly TCP_RECV_QUEUE +0 setsockopt(4, SOL_TCP, 19, [1], 4) = 0 +0 setsockopt(4, SOL_TCP, 20, [1], 4) = 0 // This now will make the write push the remaining segments +0 setsockopt(4, SOL_SOCKET, 47, [20000], 4) = 0 +0 `sysctl -w net.ipv4.tcp_limit_output_bytes=130000` // Now we will crash +0 write(4,...,1000) = 1000 This happens since ec3423257508 (tcp: fix retransmission in repair mode). Prior to that, the call to tcp_push was prevented by a check for tp->repair. The patch fixes it, by adding the new goto-label out_nopush. When exiting tcp_sendmsg and a push is not required, which is the case for tp->repair, we go to this label. When repairing and calling send() with TCP_RECV_QUEUE, the data is actually put in the receive-queue. So, no push is required because no data has been added to the send-queue. Cc: Andrew Vagin <avagin@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Fixes: ec3423257508 (tcp: fix retransmission in repair mode) Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be> Acked-by: Andrew Vagin <avagin@openvz.org> Acked-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-28ipv4: irq safe sk_dst_[re]set() and ipv4_sk_update_pmtu() fixEric Dumazet
[ Upstream commit 7f502361531e9eecb396cf99bdc9e9a59f7ebd7f ] We have two different ways to handle changes to sk->sk_dst First way (used by TCP) assumes socket lock is owned by caller, and use no extra lock : __sk_dst_set() & __sk_dst_reset() Another way (used by UDP) uses sk_dst_lock because socket lock is not always taken. Note that sk_dst_lock is not softirq safe. These ways are not inter changeable for a given socket type. ipv4_sk_update_pmtu(), added in linux-3.8, added a race, as it used the socket lock as synchronization, but users might be UDP sockets. Instead of converting sk_dst_lock to a softirq safe version, use xchg() as we did for sk_rx_dst in commit e47eb5dfb296b ("udp: ipv4: do not use sk_dst_lock from softirq context") In a follow up patch, we probably can remove sk_dst_lock, as it is only used in IPv6. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Steffen Klassert <steffen.klassert@secunet.com> Fixes: 9cb3a50c5f63e ("ipv4: Invalidate the socket cached route on pmtu events if possible") Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-28tcp: fix tcp_match_skb_to_sack() for unaligned SACK at end of an skbNeal Cardwell
[ Upstream commit 2cd0d743b05e87445c54ca124a9916f22f16742e ] If there is an MSS change (or misbehaving receiver) that causes a SACK to arrive that covers the end of an skb but is less than one MSS, then tcp_match_skb_to_sack() was rounding up pkt_len to the full length of the skb ("Round if necessary..."), then chopping all bytes off the skb and creating a zero-byte skb in the write queue. This was visible now because the recently simplified TLP logic in bef1909ee3ed1c ("tcp: fixing TLP's FIN recovery") could find that 0-byte skb at the end of the write queue, and now that we do not check that skb's length we could send it as a TLP probe. Consider the following example scenario: mss: 1000 skb: seq: 0 end_seq: 4000 len: 4000 SACK: start_seq: 3999 end_seq: 4000 The tcp_match_skb_to_sack() code will compute: in_sack = false pkt_len = start_seq - TCP_SKB_CB(skb)->seq = 3999 - 0 = 3999 new_len = (pkt_len / mss) * mss = (3999/1000)*1000 = 3000 new_len += mss = 4000 Previously we would find the new_len > skb->len check failing, so we would fall through and set pkt_len = new_len = 4000 and chop off pkt_len of 4000 from the 4000-byte skb, leaving a 0-byte segment afterward in the write queue. With this new commit, we notice that the new new_len >= skb->len check succeeds, so that we return without trying to fragment. Fixes: adb92db857ee ("tcp: Make SACK code to split only at mss boundaries") Reported-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Ilpo Jarvinen <ilpo.jarvinen@helsinki.fi> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-28ip_tunnel: fix ip_tunnel_lookupDmitry Popov
[ Upstream commit e0056593b61253f1a8a9941dacda22e73b963cdc ] This patch fixes 3 similar bugs where incoming packets might be routed into wrong non-wildcard tunnels: 1) Consider the following setup: ip address add 1.1.1.1/24 dev eth0 ip address add 1.1.1.2/24 dev eth0 ip tunnel add ipip1 remote 2.2.2.2 local 1.1.1.1 mode ipip dev eth0 ip link set ipip1 up Incoming ipip packets from 2.2.2.2 were routed into ipip1 even if it has dst = 1.1.1.2. Moreover even if there was wildcard tunnel like ip tunnel add ipip0 remote 2.2.2.2 local any mode ipip dev eth0 but it was created before explicit one (with local 1.1.1.1), incoming ipip packets with src = 2.2.2.2 and dst = 1.1.1.2 were still routed into ipip1. Same issue existed with all tunnels that use ip_tunnel_lookup (gre, vti) 2) ip address add 1.1.1.1/24 dev eth0 ip tunnel add ipip1 remote 2.2.146.85 local 1.1.1.1 mode ipip dev eth0 ip link set ipip1 up Incoming ipip packets with dst = 1.1.1.1 were routed into ipip1, no matter what src address is. Any remote ip address which has ip_tunnel_hash = 0 raised this issue, 2.2.146.85 is just an example, there are more than 4 million of them. And again, wildcard tunnel like ip tunnel add ipip0 remote any local 1.1.1.1 mode ipip dev eth0 wouldn't be ever matched if it was created before explicit tunnel like above. Gre & vti tunnels had the same issue. 3) ip address add 1.1.1.1/24 dev eth0 ip tunnel add gre1 remote 2.2.146.84 local 1.1.1.1 key 1 mode gre dev eth0 ip link set gre1 up Any incoming gre packet with key = 1 were routed into gre1, no matter what src/dst addresses are. Any remote ip address which has ip_tunnel_hash = 0 raised the issue, 2.2.146.84 is just an example, there are more than 4 million of them. Wildcard tunnel like ip tunnel add gre2 remote any local any key 1 mode gre dev eth0 wouldn't be ever matched if it was created before explicit tunnel like above. All this stuff happened because while looking for a wildcard tunnel we didn't check that matched tunnel is a wildcard one. Fixed. Signed-off-by: Dmitry Popov <ixaphire@qrator.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-06netfilter: ipt_ULOG: fix info leaksMathias Krause
commit 278f2b3e2af5f32ea1afe34fa12a2518153e6e49 upstream. The ulog messages leak heap bytes by the means of padding bytes and incompletely filled string arrays. Fix those by memset(0)'ing the whole struct before filling it. Signed-off-by: Mathias Krause <minipli@googlemail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Jan Tore Morken <jantore@morken.priv.no> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-06-26ipv4: fix a race in ip4_datagram_release_cb()Eric Dumazet
[ Upstream commit 9709674e68646cee5a24e3000b3558d25412203a ] Alexey gave a AddressSanitizer[1] report that finally gave a good hint at where was the origin of various problems already reported by Dormando in the past [2] Problem comes from the fact that UDP can have a lockless TX path, and concurrent threads can manipulate sk_dst_cache, while another thread, is holding socket lock and calls __sk_dst_set() in ip4_datagram_release_cb() (this was added in linux-3.8) It seems that all we need to do is to use sk_dst_check() and sk_dst_set() so that all the writers hold same spinlock (sk->sk_dst_lock) to prevent corruptions. TCP stack do not need this protection, as all sk_dst_cache writers hold the socket lock. [1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel AddressSanitizer: heap-use-after-free in ipv4_dst_check Read of size 2 by thread T15453: [<ffffffff817daa3a>] ipv4_dst_check+0x1a/0x90 ./net/ipv4/route.c:1116 [<ffffffff8175b789>] __sk_dst_check+0x89/0xe0 ./net/core/sock.c:531 [<ffffffff81830a36>] ip4_datagram_release_cb+0x46/0x390 ??:0 [<ffffffff8175eaea>] release_sock+0x17a/0x230 ./net/core/sock.c:2413 [<ffffffff81830882>] ip4_datagram_connect+0x462/0x5d0 ??:0 [<ffffffff81846d06>] inet_dgram_connect+0x76/0xd0 ./net/ipv4/af_inet.c:534 [<ffffffff817580ac>] SYSC_connect+0x15c/0x1c0 ./net/socket.c:1701 [<ffffffff817596ce>] SyS_connect+0xe/0x10 ./net/socket.c:1682 [<ffffffff818b0a29>] system_call_fastpath+0x16/0x1b ./arch/x86/kernel/entry_64.S:629 Freed by thread T15455: [<ffffffff8178d9b8>] dst_destroy+0xa8/0x160 ./net/core/dst.c:251 [<ffffffff8178de25>] dst_release+0x45/0x80 ./net/core/dst.c:280 [<ffffffff818304c1>] ip4_datagram_connect+0xa1/0x5d0 ??:0 [<ffffffff81846d06>] inet_dgram_connect+0x76/0xd0 ./net/ipv4/af_inet.c:534 [<ffffffff817580ac>] SYSC_connect+0x15c/0x1c0 ./net/socket.c:1701 [<ffffffff817596ce>] SyS_connect+0xe/0x10 ./net/socket.c:1682 [<ffffffff818b0a29>] system_call_fastpath+0x16/0x1b ./arch/x86/kernel/entry_64.S:629 Allocated by thread T15453: [<ffffffff8178d291>] dst_alloc+0x81/0x2b0 ./net/core/dst.c:171 [<ffffffff817db3b7>] rt_dst_alloc+0x47/0x50 ./net/ipv4/route.c:1406 [< inlined >] __ip_route_output_key+0x3e8/0xf70 __mkroute_output ./net/ipv4/route.c:1939 [<ffffffff817dde08>] __ip_route_output_key+0x3e8/0xf70 ./net/ipv4/route.c:2161 [<ffffffff817deb34>] ip_route_output_flow+0x14/0x30 ./net/ipv4/route.c:2249 [<ffffffff81830737>] ip4_datagram_connect+0x317/0x5d0 ??:0 [<ffffffff81846d06>] inet_dgram_connect+0x76/0xd0 ./net/ipv4/af_inet.c:534 [<ffffffff817580ac>] SYSC_connect+0x15c/0x1c0 ./net/socket.c:1701 [<ffffffff817596ce>] SyS_connect+0xe/0x10 ./net/socket.c:1682 [<ffffffff818b0a29>] system_call_fastpath+0x16/0x1b ./arch/x86/kernel/entry_64.S:629 [2] <4>[196727.311203] general protection fault: 0000 [#1] SMP <4>[196727.311224] Modules linked in: xt_TEE xt_dscp xt_DSCP macvlan bridge coretemp crc32_pclmul ghash_clmulni_intel gpio_ich microcode ipmi_watchdog ipmi_devintf sb_edac edac_core lpc_ich mfd_core tpm_tis tpm tpm_bios ipmi_si ipmi_msghandler isci igb libsas i2c_algo_bit ixgbe ptp pps_core mdio <4>[196727.311333] CPU: 17 PID: 0 Comm: swapper/17 Not tainted 3.10.26 #1 <4>[196727.311344] Hardware name: Supermicro X9DRi-LN4+/X9DR3-LN4+/X9DRi-LN4+/X9DR3-LN4+, BIOS 3.0 07/05/2013 <4>[196727.311364] task: ffff885e6f069700 ti: ffff885e6f072000 task.ti: ffff885e6f072000 <4>[196727.311377] RIP: 0010:[<ffffffff815f8c7f>] [<ffffffff815f8c7f>] ipv4_dst_destroy+0x4f/0x80 <4>[196727.311399] RSP: 0018:ffff885effd23a70 EFLAGS: 00010282 <4>[196727.311409] RAX: dead000000200200 RBX: ffff8854c398ecc0 RCX: 0000000000000040 <4>[196727.311423] RDX: dead000000100100 RSI: dead000000100100 RDI: dead000000200200 <4>[196727.311437] RBP: ffff885effd23a80 R08: ffffffff815fd9e0 R09: ffff885d5a590800 <4>[196727.311451] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 <4>[196727.311464] R13: ffffffff81c8c280 R14: 0000000000000000 R15: ffff880e85ee16ce <4>[196727.311510] FS: 0000000000000000(0000) GS:ffff885effd20000(0000) knlGS:0000000000000000 <4>[196727.311554] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[196727.311581] CR2: 00007a46751eb000 CR3: 0000005e65688000 CR4: 00000000000407e0 <4>[196727.311625] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 <4>[196727.311669] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 <4>[196727.311713] Stack: <4>[196727.311733] ffff8854c398ecc0 ffff8854c398ecc0 ffff885effd23ab0 ffffffff815b7f42 <4>[196727.311784] ffff88be6595bc00 ffff8854c398ecc0 0000000000000000 ffff8854c398ecc0 <4>[196727.311834] ffff885effd23ad0 ffffffff815b86c6 ffff885d5a590800 ffff8816827821c0 <4>[196727.311885] Call Trace: <4>[196727.311907] <IRQ> <4>[196727.311912] [<ffffffff815b7f42>] dst_destroy+0x32/0xe0 <4>[196727.311959] [<ffffffff815b86c6>] dst_release+0x56/0x80 <4>[196727.311986] [<ffffffff81620bd5>] tcp_v4_do_rcv+0x2a5/0x4a0 <4>[196727.312013] [<ffffffff81622b5a>] tcp_v4_rcv+0x7da/0x820 <4>[196727.312041] [<ffffffff815fd9e0>] ? ip_rcv_finish+0x360/0x360 <4>[196727.312070] [<ffffffff815de02d>] ? nf_hook_slow+0x7d/0x150 <4>[196727.312097] [<ffffffff815fd9e0>] ? ip_rcv_finish+0x360/0x360 <4>[196727.312125] [<ffffffff815fda92>] ip_local_deliver_finish+0xb2/0x230 <4>[196727.312154] [<ffffffff815fdd9a>] ip_local_deliver+0x4a/0x90 <4>[196727.312183] [<ffffffff815fd799>] ip_rcv_finish+0x119/0x360 <4>[196727.312212] [<ffffffff815fe00b>] ip_rcv+0x22b/0x340 <4>[196727.312242] [<ffffffffa0339680>] ? macvlan_broadcast+0x160/0x160 [macvlan] <4>[196727.312275] [<ffffffff815b0c62>] __netif_receive_skb_core+0x512/0x640 <4>[196727.312308] [<ffffffff811427fb>] ? kmem_cache_alloc+0x13b/0x150 <4>[196727.312338] [<ffffffff815b0db1>] __netif_receive_skb+0x21/0x70 <4>[196727.312368] [<ffffffff815b0fa1>] netif_receive_skb+0x31/0xa0 <4>[196727.312397] [<ffffffff815b1ae8>] napi_gro_receive+0xe8/0x140 <4>[196727.312433] [<ffffffffa00274f1>] ixgbe_poll+0x551/0x11f0 [ixgbe] <4>[196727.312463] [<ffffffff815fe00b>] ? ip_rcv+0x22b/0x340 <4>[196727.312491] [<ffffffff815b1691>] net_rx_action+0x111/0x210 <4>[196727.312521] [<ffffffff815b0db1>] ? __netif_receive_skb+0x21/0x70 <4>[196727.312552] [<ffffffff810519d0>] __do_softirq+0xd0/0x270 <4>[196727.312583] [<ffffffff816cef3c>] call_softirq+0x1c/0x30 <4>[196727.312613] [<ffffffff81004205>] do_softirq+0x55/0x90 <4>[196727.312640] [<ffffffff81051c85>] irq_exit+0x55/0x60 <4>[196727.312668] [<ffffffff816cf5c3>] do_IRQ+0x63/0xe0 <4>[196727.312696] [<ffffffff816c5aaa>] common_interrupt+0x6a/0x6a <4>[196727.312722] <EOI> <1>[196727.313071] RIP [<ffffffff815f8c7f>] ipv4_dst_destroy+0x4f/0x80 <4>[196727.313100] RSP <ffff885effd23a70> <4>[196727.313377] ---[ end trace 64b3f14fae0f2e29 ]--- <0>[196727.380908] Kernel panic - not syncing: Fatal exception in interrupt Reported-by: Alexey Preobrazhensky <preobr@google.com> Reported-by: dormando <dormando@rydia.ne> Signed-off-by: Eric Dumazet <edumazet@google.com> Fixes: 8141ed9fcedb2 ("ipv4: Add a socket release callback for datagram sockets") Cc: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-06-26ipip, sit: fix ipv4_{update_pmtu,redirect} callsDmitry Popov
[ Upstream commit 2346829e641b804ece9ac9298136b56d9567c278 ] ipv4_{update_pmtu,redirect} were called with tunnel's ifindex (t->dev is a tunnel netdevice). It caused wrong route lookup and failure of pmtu update or redirect. We should use the same ifindex that we use in ip_route_output_* in *tunnel_xmit code. It is t->parms.link . Signed-off-by: Dmitry Popov <ixaphire@qrator.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-06-26tcp: fix cwnd undo on DSACK in F-RTOYuchung Cheng
[ Upstream commit 0cfa5c07d6d1d7f8e710fc671c5ba1ce85e09fa4 ] This bug is discovered by an recent F-RTO issue on tcpm list https://www.ietf.org/mail-archive/web/tcpm/current/msg08794.html The bug is that currently F-RTO does not use DSACK to undo cwnd in certain cases: upon receiving an ACK after the RTO retransmission in F-RTO, and the ACK has DSACK indicating the retransmission is spurious, the sender only calls tcp_try_undo_loss() if some never retransmisted data is sacked (FLAG_ORIG_DATA_SACKED). The correct behavior is to unconditionally call tcp_try_undo_loss so the DSACK information is used properly to undo the cwnd reduction. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-06-26net: tunnels - enable module autoloadingTom Gundersen
[ Upstream commit f98f89a0104454f35a62d681683c844f6dbf4043 ] Enable the module alias hookup to allow tunnel modules to be autoloaded on demand. This is in line with how most other netdev kinds work, and will allow userspace to create tunnels without having CAP_SYS_MODULE. Signed-off-by: Tom Gundersen <teg@jklm.no> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-06-16netfilter: ipv4: defrag: set local_df flag on defragmented skbFlorian Westphal
commit 895162b1101b3ea5db08ca6822ae9672717efec0 upstream. else we may fail to forward skb even if original fragments do fit outgoing link mtu: 1. remote sends 2k packets in two 1000 byte frags, DF set 2. we want to forward but only see '2k > mtu and DF set' 3. we then send icmp error saying that outgoing link is 1500 But original sender never sent a packet that would not fit the outgoing link. Setting local_df makes outgoing path test size vs. IPCB(skb)->frag_max_size, so we will still send the correct error in case the largest original size did not fit outgoing link mtu. Reported-by: Maxime Bizon <mbizon@freebox.fr> Suggested-by: Maxime Bizon <mbizon@freebox.fr> Fixes: 5f2d04f1f9 (ipv4: fix path MTU discovery with connection tracking) Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-30ipv4: initialise the itag variable in __mkroute_inputLi RongQing
[ Upstream commit fbdc0ad095c0a299e9abf5d8ac8f58374951149a ] the value of itag is a random value from stack, and may not be initiated by fib_validate_source, which called fib_combine_itag if CONFIG_IP_ROUTE_CLASSID is not set This will make the cached dst uncertainty Signed-off-by: Li RongQing <roy.qing.li@gmail.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-30ipv4: fib_semantics: increment fib_info_cnt after fib_info allocationSergey Popovich
[ Upstream commit aeefa1ecfc799b0ea2c4979617f14cecd5cccbfd ] Increment fib_info_cnt in fib_create_info() right after successfuly alllocating fib_info structure, overwise fib_metrics allocation failure leads to fib_info_cnt incorrectly decremented in free_fib_info(), called on error path from fib_create_info(). Signed-off-by: Sergey Popovich <popovich_sergei@mail.ru> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-30net: ipv4: ip_forward: fix inverted local_df testFlorian Westphal
[ Upstream commit ca6c5d4ad216d5942ae544bbf02503041bd802aa ] local_df means 'ignore DF bit if set', so if its set we're allowed to perform ip fragmentation. This wasn't noticed earlier because the output path also drops such skbs (and emits needed icmp error) and because netfilter ip defrag did not set local_df until couple of days ago. Only difference is that DF-packets-larger-than MTU now discarded earlier (f.e. we avoid pointless netfilter postrouting trip). While at it, drop the repeated test ip_exceeds_mtu, checking it once is enough... Fixes: fe6cc55f3a9 ("net: ip, ipv6: handle gso skbs in forwarding path") Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-30tcp_cubic: fix the range of delayed_ackLiu Yu
[ Upstream commit 0cda345d1b2201dd15591b163e3c92bad5191745 ] commit b9f47a3aaeab (tcp_cubic: limit delayed_ack ratio to prevent divide error) try to prevent divide error, but there is still a little chance that delayed_ack can reach zero. In case the param cnt get negative value, then ratio+cnt would overflow and may happen to be zero. As a result, min(ratio, ACK_RATIO_LIMIT) will calculate to be zero. In some old kernels, such as 2.6.32, there is a bug that would pass negative param, which then ultimately leads to this divide error. commit 5b35e1e6e9c (tcp: fix tcp_trim_head() to adjust segment count with skb MSS) fixed the negative param issue. However, it's safe that we fix the range of delayed_ack as well, to make sure we do not hit a divide by zero. CC: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: Liu Yu <allanyuliu@tencent.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-30ipv4: return valid RTA_IIF on ip route getJulian Anastasov
[ Upstream commit 91146153da2feab18efab2e13b0945b6bb704ded ] Extend commit 13378cad02afc2adc6c0e07fca03903c7ada0b37 ("ipv4: Change rt->rt_iif encoding.") from 3.6 to return valid RTA_IIF on 'ip route get ... iif DEVICE' instead of rt_iif 0 which is displayed as 'iif *'. inet_iif is not appropriate to use because skb_iif is not set. Use the skb->dev->ifindex instead. Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-30net: ipv4: current group_info should be put after using.Wang, Xiaoming
[ Upstream commit b04c46190219a4f845e46a459e3102137b7f6cac ] Plug a group_info refcount leak in ping_init. group_info is only needed during initialization and the code failed to release the reference on exit. While here move grabbing the reference to a place where it is actually needed. Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com> Signed-off-by: Zhang Dongxing <dongxing.zhang@intel.com> Signed-off-by: xiaoming wang <xiaoming.wang@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-30vti: don't allow to add the same tunnel twiceNicolas Dichtel
[ Upstream commit 8d89dcdf80d88007647945a753821a06eb6cc5a5 ] Before the patch, it was possible to add two times the same tunnel: ip l a vti1 type vti remote 10.16.0.121 local 10.16.0.249 key 41 ip l a vti2 type vti remote 10.16.0.121 local 10.16.0.249 key 41 It was possible, because ip_tunnel_newlink() calls ip_tunnel_find() with the argument dev->type, which was set only later (when calling ndo_init handler in register_netdevice()). Let's set this type in the setup handler, which is called before newlink handler. Introduced by commit b9959fd3b0fa ("vti: switch to new ip tunnel code"). CC: Cong Wang <amwang@redhat.com> CC: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-30gre: don't allow to add the same tunnel twiceNicolas Dichtel
[ Upstream commit 5a4552752d8f7f4cef1d98775ece7adb7616fde2 ] Before the patch, it was possible to add two times the same tunnel: ip l a gre1 type gre remote 10.16.0.121 local 10.16.0.249 ip l a gre2 type gre remote 10.16.0.121 local 10.16.0.249 It was possible, because ip_tunnel_newlink() calls ip_tunnel_find() with the argument dev->type, which was set only later (when calling ndo_init handler in register_netdevice()). Let's set this type in the setup handler, which is called before newlink handler. Introduced by commit c54419321455 ("GRE: Refactor GRE tunneling code."). CC: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-30netfilter: Can't fail and free after table replacementThomas Graf
commit c58dd2dd443c26d856a168db108a0cd11c285bf3 upstream. All xtables variants suffer from the defect that the copy_to_user() to copy the counters to user memory may fail after the table has already been exchanged and thus exposed. Return an error at this point will result in freeing the already exposed table. Any subsequent packet processing will result in a kernel panic. We can't copy the counters before exposing the new tables as we want provide the counter state after the old table has been unhooked. Therefore convert this into a silent error. Cc: Florian Westphal <fw@strlen.de> Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-04-14ipmr: fix mfc notification flagsNicolas Dichtel
[ Upstream commit 65886f439ab0fdc2dff20d1fa87afb98c6717472 ] Commit 8cd3ac9f9b7b ("ipmr: advertise new mfc entries via rtnl") reuses the function ipmr_fill_mroute() to notify mfc events. But this function was used only for dump and thus was always setting the flag NLM_F_MULTI, which is wrong in case of a single notification. Libraries like libnl will wait forever for NLMSG_DONE. CC: Thomas Graf <tgraf@suug.ch> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-04-14tcp: tcp_release_cb() should release socket ownershipEric Dumazet
[ Upstream commit c3f9b01849ef3bc69024990092b9f42e20df7797 ] Lars Persson reported following deadlock : -000 |M:0x0:0x802B6AF8(asm) <-- arch_spin_lock -001 |tcp_v4_rcv(skb = 0x8BD527A0) <-- sk = 0x8BE6B2A0 -002 |ip_local_deliver_finish(skb = 0x8BD527A0) -003 |__netif_receive_skb_core(skb = 0x8BD527A0, ?) -004 |netif_receive_skb(skb = 0x8BD527A0) -005 |elk_poll(napi = 0x8C770500, budget = 64) -006 |net_rx_action(?) -007 |__do_softirq() -008 |do_softirq() -009 |local_bh_enable() -010 |tcp_rcv_established(sk = 0x8BE6B2A0, skb = 0x87D3A9E0, th = 0x814EBE14, ?) -011 |tcp_v4_do_rcv(sk = 0x8BE6B2A0, skb = 0x87D3A9E0) -012 |tcp_delack_timer_handler(sk = 0x8BE6B2A0) -013 |tcp_release_cb(sk = 0x8BE6B2A0) -014 |release_sock(sk = 0x8BE6B2A0) -015 |tcp_sendmsg(?, sk = 0x8BE6B2A0, ?, ?) -016 |sock_sendmsg(sock = 0x8518C4C0, msg = 0x87D8DAA8, size = 4096) -017 |kernel_sendmsg(?, ?, ?, ?, size = 4096) -018 |smb_send_kvec() -019 |smb_send_rqst(server = 0x87C4D400, rqst = 0x87D8DBA0) -020 |cifs_call_async() -021 |cifs_async_writev(wdata = 0x87FD6580) -022 |cifs_writepages(mapping = 0x852096E4, wbc = 0x87D8DC88) -023 |__writeback_single_inode(inode = 0x852095D0, wbc = 0x87D8DC88) -024 |writeback_sb_inodes(sb = 0x87D6D800, wb = 0x87E4A9C0, work = 0x87D8DD88) -025 |__writeback_inodes_wb(wb = 0x87E4A9C0, work = 0x87D8DD88) -026 |wb_writeback(wb = 0x87E4A9C0, work = 0x87D8DD88) -027 |wb_do_writeback(wb = 0x87E4A9C0, force_wait = 0) -028 |bdi_writeback_workfn(work = 0x87E4A9CC) -029 |process_one_work(worker = 0x8B045880, work = 0x87E4A9CC) -030 |worker_thread(__worker = 0x8B045880) -031 |kthread(_create = 0x87CADD90) -032 |ret_from_kernel_thread(asm) Bug occurs because __tcp_checksum_complete_user() enables BH, assuming it is running from softirq context. Lars trace involved a NIC without RX checksum support but other points are problematic as well, like the prequeue stuff. Problem is triggered by a timer, that found socket being owned by user. tcp_release_cb() should call tcp_write_timer_handler() or tcp_delack_timer_handler() in the appropriate context : BH disabled and socket lock held, but 'owned' field cleared, as if they were running from timer handlers. Fixes: 6f458dfb4092 ("tcp: improve latencies of timer triggered events") Reported-by: Lars Persson <lars.persson@axis.com> Tested-by: Lars Persson <lars.persson@axis.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-04-14inet: frag: make sure forced eviction removes all fragsFlorian Westphal
[ Upstream commit e588e2f286ed7da011ed357c24c5b9a554e26595 ] Quoting Alexander Aring: While fragmentation and unloading of 6lowpan module I got this kernel Oops after few seconds: BUG: unable to handle kernel paging request at f88bbc30 [..] Modules linked in: ipv6 [last unloaded: 6lowpan] Call Trace: [<c012af4c>] ? call_timer_fn+0x54/0xb3 [<c012aef8>] ? process_timeout+0xa/0xa [<c012b66b>] run_timer_softirq+0x140/0x15f Problem is that incomplete frags are still around after unload; when their frag expire timer fires, we get crash. When a netns is removed (also done when unloading module), inet_frag calls the evictor with 'force' argument to purge remaining frags. The evictor loop terminates when accounted memory ('work') drops to 0 or the lru-list becomes empty. However, the mem accounting is done via percpu counters and may not be accurate, i.e. loop may terminate prematurely. Alter evictor to only stop once the lru list is empty when force is requested. Reported-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de> Reported-by: Alexander Aring <alex.aring@gmail.com> Tested-by: Alexander Aring <alex.aring@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-04-14net: fix for a race condition in the inet frag codeNikolay Aleksandrov
[ Upstream commit 24b9bf43e93e0edd89072da51cf1fab95fc69dec ] I stumbled upon this very serious bug while hunting for another one, it's a very subtle race condition between inet_frag_evictor, inet_frag_intern and the IPv4/6 frag_queue and expire functions (basically the users of inet_frag_kill/inet_frag_put). What happens is that after a fragment has been added to the hash chain but before it's been added to the lru_list (inet_frag_lru_add) in inet_frag_intern, it may get deleted (either by an expired timer if the system load is high or the timer sufficiently low, or by the fraq_queue function for different reasons) before it's added to the lru_list, then after it gets added it's a matter of time for the evictor to get to a piece of memory which has been freed leading to a number of different bugs depending on what's left there. I've been able to trigger this on both IPv4 and IPv6 (which is normal as the frag code is the same), but it's been much more difficult to trigger on IPv4 due to the protocol differences about how fragments are treated. The setup I used to reproduce this is: 2 machines with 4 x 10G bonded in a RR bond, so the same flow can be seen on multiple cards at the same time. Then I used multiple instances of ping/ping6 to generate fragmented packets and flood the machines with them while running other processes to load the attacked machine. *It is very important to have the _same flow_ coming in on multiple CPUs concurrently. Usually the attacked machine would die in less than 30 minutes, if configured properly to have many evictor calls and timeouts it could happen in 10 minutes or so. An important point to make is that any caller (frag_queue or timer) of inet_frag_kill will remove both the timer refcount and the original/guarding refcount thus removing everything that's keeping the frag from being freed at the next inet_frag_put. All of this could happen before the frag was ever added to the LRU list, then it gets added and the evictor uses a freed fragment. An example for IPv6 would be if a fragment is being added and is at the stage of being inserted in the hash after the hash lock is released, but before inet_frag_lru_add executes (or is able to obtain the lru lock) another overlapping fragment for the same flow arrives at a different CPU which finds it in the hash, but since it's overlapping it drops it invoking inet_frag_kill and thus removing all guarding refcounts, and afterwards freeing it by invoking inet_frag_put which removes the last refcount added previously by inet_frag_find, then inet_frag_lru_add gets executed by inet_frag_intern and we have a freed fragment in the lru_list. The fix is simple, just move the lru_add under the hash chain locked region so when a removing function is called it'll have to wait for the fragment to be added to the lru_list, and then it'll remove it (it works because the hash chain removal is done before the lru_list one and there's no window between the two list adds when the frag can get dropped). With this fix applied I couldn't kill the same machine in 24 hours with the same setup. Fixes: 3ef0eb0db4bf ("net: frag, move LRU list maintenance outside of rwlock") CC: Florian Westphal <fw@strlen.de> CC: Jesper Dangaard Brouer <brouer@redhat.com> CC: David S. Miller <davem@davemloft.net> Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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