user/sven/linux.git/include/net, branch v3.12.48

netfilter: nf_conntrack: don't release a conntrack with non-zero refcnt

2015-09-14T14:28:42Z

[ Upstream commit e53376bef2cd97d3e3f61fdc677fb8da7d03d0da ] With this patch, the conntrack refcount is initially set to zero and it is bumped once it is added to any of the list, so we fulfill Eric's golden rule which is that all released objects always have a refcount that equals zero. Andrey Vagin reports that nf_conntrack_free can't be called for a conntrack with non-zero ref-counter, because it can race with nf_conntrack_find_get(). A conntrack slab is created with SLAB_DESTROY_BY_RCU. Non-zero ref-counter says that this conntrack is used. So when we release a conntrack with non-zero counter, we break this assumption. CPU1 CPU2 ____nf_conntrack_find() nf_ct_put() destroy_conntrack() ... init_conntrack __nf_conntrack_alloc (set use = 1) atomic_inc_not_zero(&ct->use) (use = 2) if (!l4proto->new(ct, skb, dataoff, timeouts)) nf_conntrack_free(ct); (use = 2 !!!) ... __nf_conntrack_alloc (set use = 1) if (!nf_ct_key_equal(h, tuple, zone)) nf_ct_put(ct); (use = 0) destroy_conntrack() /* continue to work with CT */ After applying the path "[PATCH] netfilter: nf_conntrack: fix RCU race in nf_conntrack_find_get" another bug was triggered in destroy_conntrack(): <4>[67096.759334] ------------[ cut here ]------------ <2>[67096.759353] kernel BUG at net/netfilter/nf_conntrack_core.c:211! ... <4>[67096.759837] Pid: 498649, comm: atdd veid: 666 Tainted: G C --------------- 2.6.32-042stab084.18 #1 042stab084_18 /DQ45CB <4>[67096.759932] RIP: 0010:[] [] destroy_conntrack+0x15c/0x190 [nf_conntrack] <4>[67096.760255] Call Trace: <4>[67096.760255] [] nf_conntrack_destroy+0x17/0x30 <4>[67096.760255] [] nf_conntrack_find_get+0x85/0x130 [nf_conntrack] <4>[67096.760255] [] nf_conntrack_in+0x352/0xb60 [nf_conntrack] <4>[67096.760255] [] ipv4_conntrack_local+0x51/0x60 [nf_conntrack_ipv4] <4>[67096.760255] [] nf_iterate+0x69/0xb0 <4>[67096.760255] [] ? dst_output+0x0/0x20 <4>[67096.760255] [] nf_hook_slow+0x74/0x110 <4>[67096.760255] [] ? dst_output+0x0/0x20 <4>[67096.760255] [] raw_sendmsg+0x775/0x910 <4>[67096.760255] [] ? flush_tlb_others_ipi+0x128/0x130 <4>[67096.760255] [] ? apic_timer_interrupt+0xe/0x20 <4>[67096.760255] [] ? apic_timer_interrupt+0xe/0x20 <4>[67096.760255] [] inet_sendmsg+0x4a/0xb0 <4>[67096.760255] [] ? sock_sendmsg+0x13/0x140 <4>[67096.760255] [] sock_sendmsg+0x117/0x140 <4>[67096.760255] [] ? native_smp_send_reschedule+0x49/0x60 <4>[67096.760255] [] ? _spin_unlock_bh+0x1b/0x20 <4>[67096.760255] [] ? autoremove_wake_function+0x0/0x40 <4>[67096.760255] [] ? do_ip_setsockopt+0x90/0xd80 <4>[67096.760255] [] ? apic_timer_interrupt+0xe/0x20 <4>[67096.760255] [] ? apic_timer_interrupt+0xe/0x20 <4>[67096.760255] [] sys_sendto+0x139/0x190 <4>[67096.760255] [] ? audit_syscall_entry+0x1d7/0x200 <4>[67096.760255] [] ? __audit_syscall_exit+0x265/0x290 <4>[67096.760255] [] compat_sys_socketcall+0x13f/0x210 <4>[67096.760255] [] ia32_sysret+0x0/0x5 I have reused the original title for the RFC patch that Andrey posted and most of the original patch description. Cc: Eric Dumazet Cc: Andrew Vagin Cc: Florian Westphal Reported-by: Andrew Vagin Signed-off-by: Pablo Neira Ayuso Reviewed-by: Eric Dumazet Acked-by: Andrew Vagin Signed-off-by: Jiri Slaby

ipv6: lock socket in ip6_datagram_connect()

2015-08-27T07:27:01Z

[ Upstream commit 03645a11a570d52e70631838cb786eb4253eb463 ] ip6_datagram_connect() is doing a lot of socket changes without socket being locked. This looks wrong, at least for udp_lib_rehash() which could corrupt lists because of concurrent udp_sk(sk)->udp_portaddr_hash accesses. Signed-off-by: Eric Dumazet Acked-by: Herbert Xu Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby

sctp: fix ASCONF list handling

2015-07-30T12:10:37Z

[ Upstream commit 2d45a02d0166caf2627fe91897c6ffc3b19514c4 ] ->auto_asconf_splist is per namespace and mangled by functions like sctp_setsockopt_auto_asconf() which doesn't guarantee any serialization. Also, the call to inet_sk_copy_descendant() was backuping ->auto_asconf_list through the copy but was not honoring ->do_auto_asconf, which could lead to list corruption if it was different between both sockets. This commit thus fixes the list handling by using ->addr_wq_lock spinlock to protect the list. A special handling is done upon socket creation and destruction for that. Error handlig on sctp_init_sock() will never return an error after having initialized asconf, so sctp_destroy_sock() can be called without addrq_wq_lock. The lock now will be take on sctp_close_sock(), before locking the socket, so we don't do it in inverse order compared to sctp_addr_wq_timeout_handler(). Instead of taking the lock on sctp_sock_migrate() for copying and restoring the list values, it's preferred to avoid rewritting it by implementing sctp_copy_descendant(). Issue was found with a test application that kept flipping sysctl default_auto_asconf on and off, but one could trigger it by issuing simultaneous setsockopt() calls on multiple sockets or by creating/destroying sockets fast enough. This is only triggerable locally. Fixes: 9f7d653b67ae ("sctp: Add Auto-ASCONF support (core).") Reported-by: Ji Jianwen Suggested-by: Neil Horman Suggested-by: Hannes Frederic Sowa Acked-by: Hannes Frederic Sowa Signed-off-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby

xfrm: release dst_orig in case of error in xfrm_lookup()

2015-07-30T11:21:26Z

commit ac37e2515c1a89c477459a2020b6bfdedabdb91b upstream. dst_orig should be released on error. Function like __xfrm_route_forward() expects that behavior. Since a recent commit, xfrm_lookup() may also be called by xfrm_lookup_route(), which expects the opposite. Let's introduce a new flag (XFRM_LOOKUP_KEEP_DST_REF) to tell what should be done in case of error. Fixes: f92ee61982d("xfrm: Generate blackhole routes only from route lookup functions") Signed-off-by: huaibin Wang Signed-off-by: Nicolas Dichtel Signed-off-by: Steffen Klassert Signed-off-by: Jiri Slaby

net: fix sparse warning in sk_dst_set()

2015-04-09T12:13:51Z

commit 5925a0555bdaf0b396a84318cbc21ba085f6c0d3 upstream. sk_dst_cache has __rcu annotation, so we need a cast to avoid following sparse error : include/net/sock.h:1774:19: warning: incorrect type in initializer (different address spaces) include/net/sock.h:1774:19: expected struct dst_entry [noderef] *__ret include/net/sock.h:1774:19: got struct dst_entry *dst Signed-off-by: Eric Dumazet Reported-by: kbuild test robot Fixes: 7f502361531e ("ipv4: irq safe sk_dst_[re]set() and ipv4_sk_update_pmtu() fix") Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby

ipv4: tcp: get rid of ugly unicast_sock

2015-02-10T10:16:52Z

[ 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 Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby

ipv4: try to cache dst_entries which would cause a redirect

2015-02-10T10:16:49Z

[ 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 Signed-off-by: Marcelo Leitner Signed-off-by: Florian Westphal Signed-off-by: Hannes Frederic Sowa Signed-off-by: Julian Anastasov Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby

net: sctp: fix skb_over_panic when receiving malformed ASCONF chunks

2014-11-19T17:38:27Z

commit 9de7922bc709eee2f609cd01d98aaedc4cf5ea74 upstream. Commit 6f4c618ddb0 ("SCTP : Add paramters validity check for ASCONF chunk") added basic verification of ASCONF chunks, however, it is still possible to remotely crash a server by sending a special crafted ASCONF chunk, even up to pre 2.6.12 kernels: skb_over_panic: text:ffffffffa01ea1c3 len:31056 put:30768 head:ffff88011bd81800 data:ffff88011bd81800 tail:0x7950 end:0x440 dev: ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:129! [...] Call Trace: [] skb_put+0x5c/0x70 [] sctp_addto_chunk+0x63/0xd0 [sctp] [] sctp_process_asconf+0x1af/0x540 [sctp] [] ? _read_unlock_bh+0x15/0x20 [] sctp_sf_do_asconf+0x168/0x240 [sctp] [] sctp_do_sm+0x71/0x1210 [sctp] [] ? fib_rules_lookup+0xad/0xf0 [] ? sctp_cmp_addr_exact+0x32/0x40 [sctp] [] sctp_assoc_bh_rcv+0xd3/0x180 [sctp] [] sctp_inq_push+0x56/0x80 [sctp] [] sctp_rcv+0x982/0xa10 [sctp] [] ? ipt_local_in_hook+0x23/0x28 [iptable_filter] [] ? nf_iterate+0x69/0xb0 [] ? ip_local_deliver_finish+0x0/0x2d0 [] ? nf_hook_slow+0x76/0x120 [] ? ip_local_deliver_finish+0x0/0x2d0 [] ip_local_deliver_finish+0xdd/0x2d0 [] ip_local_deliver+0x98/0xa0 [] ip_rcv_finish+0x12d/0x440 [] ip_rcv+0x275/0x350 [] __netif_receive_skb+0x4ab/0x750 [] netif_receive_skb+0x58/0x60 This can be triggered e.g., through a simple scripted nmap connection scan injecting the chunk after the handshake, for example, ... -------------- INIT[ASCONF; ASCONF_ACK] -------------> <----------- INIT-ACK[ASCONF; ASCONF_ACK] ------------ -------------------- COOKIE-ECHO --------------------> <-------------------- COOKIE-ACK --------------------- ------------------ ASCONF; UNKNOWN ------------------> ... where ASCONF chunk of length 280 contains 2 parameters ... 1) Add IP address parameter (param length: 16) 2) Add/del IP address parameter (param length: 255) ... followed by an UNKNOWN chunk of e.g. 4 bytes. Here, the Address Parameter in the ASCONF chunk is even missing, too. This is just an example and similarly-crafted ASCONF chunks could be used just as well. The ASCONF chunk passes through sctp_verify_asconf() as all parameters passed sanity checks, and after walking, we ended up successfully at the chunk end boundary, and thus may invoke sctp_process_asconf(). Parameter walking is done with WORD_ROUND() to take padding into account. In sctp_process_asconf()'s TLV processing, we may fail in sctp_process_asconf_param() e.g., due to removal of the IP address that is also the source address of the packet containing the ASCONF chunk, and thus we need to add all TLVs after the failure to our ASCONF response to remote via helper function sctp_add_asconf_response(), which basically invokes a sctp_addto_chunk() adding the error parameters to the given skb. When walking to the next parameter this time, we proceed with ... length = ntohs(asconf_param->param_hdr.length); asconf_param = (void *)asconf_param + length; ... instead of the WORD_ROUND()'ed length, thus resulting here in an off-by-one that leads to reading the follow-up garbage parameter length of 12336, and thus throwing an skb_over_panic for the reply when trying to sctp_addto_chunk() next time, which implicitly calls the skb_put() with that length. Fix it by using sctp_walk_params() [ which is also used in INIT parameter processing ] macro in the verification *and* in ASCONF processing: it will make sure we don't spill over, that we walk parameters WORD_ROUND()'ed. Moreover, we're being more defensive and guard against unknown parameter types and missized addresses. Joint work with Vlad Yasevich. Fixes: b896b82be4ae ("[SCTP] ADDIP: Support for processing incoming ASCONF_ACK chunks.") Signed-off-by: Daniel Borkmann Signed-off-by: Vlad Yasevich Acked-by: Neil Horman Signed-off-by: David S. Miller Cc: Josh Boyer Signed-off-by: Jiri Slaby

net: sctp: fix panic on duplicate ASCONF chunks

2014-11-19T17:38:27Z

commit b69040d8e39f20d5215a03502a8e8b4c6ab78395 upstream. When receiving a e.g. semi-good formed connection scan in the form of ... -------------- INIT[ASCONF; ASCONF_ACK] -------------> <----------- INIT-ACK[ASCONF; ASCONF_ACK] ------------ -------------------- COOKIE-ECHO --------------------> <-------------------- COOKIE-ACK --------------------- ---------------- ASCONF_a; ASCONF_b -----------------> ... where ASCONF_a equals ASCONF_b chunk (at least both serials need to be equal), we panic an SCTP server! The problem is that good-formed ASCONF chunks that we reply with ASCONF_ACK chunks are cached per serial. Thus, when we receive a same ASCONF chunk twice (e.g. through a lost ASCONF_ACK), we do not need to process them again on the server side (that was the idea, also proposed in the RFC). Instead, we know it was cached and we just resend the cached chunk instead. So far, so good. Where things get nasty is in SCTP's side effect interpreter, that is, sctp_cmd_interpreter(): While incoming ASCONF_a (chunk = event_arg) is being marked !end_of_packet and !singleton, and we have an association context, we do not flush the outqueue the first time after processing the ASCONF_ACK singleton chunk via SCTP_CMD_REPLY. Instead, we keep it queued up, although we set local_cork to 1. Commit 2e3216cd54b1 changed the precedence, so that as long as we get bundled, incoming chunks we try possible bundling on outgoing queue as well. Before this commit, we would just flush the output queue. Now, while ASCONF_a's ASCONF_ACK sits in the corked outq, we continue to process the same ASCONF_b chunk from the packet. As we have cached the previous ASCONF_ACK, we find it, grab it and do another SCTP_CMD_REPLY command on it. So, effectively, we rip the chunk->list pointers and requeue the same ASCONF_ACK chunk another time. Since we process ASCONF_b, it's correctly marked with end_of_packet and we enforce an uncork, and thus flush, thus crashing the kernel. Fix it by testing if the ASCONF_ACK is currently pending and if that is the case, do not requeue it. When flushing the output queue we may relink the chunk for preparing an outgoing packet, but eventually unlink it when it's copied into the skb right before transmission. Joint work with Vlad Yasevich. Fixes: 2e3216cd54b1 ("sctp: Follow security requirement of responding with 1 packet") Signed-off-by: Daniel Borkmann Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller Cc: Josh Boyer Signed-off-by: Jiri Slaby

drivers/net, ipv6: Select IPv6 fragment idents for virtio UFO packets

2014-11-13T18:01:51Z

[ Upstream commit 5188cd44c55db3e92cd9e77a40b5baa7ed4340f7 ] UFO is now disabled on all drivers that work with virtio net headers, but userland may try to send UFO/IPv6 packets anyway. Instead of sending with ID=0, we should select identifiers on their behalf (as we used to). Signed-off-by: Ben Hutchings Fixes: 916e4cf46d02 ("ipv6: reuse ip6_frag_id from ip6_ufo_append_data") Signed-off-by: David S. Miller