kernel/linux.git/include/net/ip.h, branch v3.12.62

ipv6: lock socket in ip6_datagram_connect()

2015-08-27T07:27:01+00:00

[ 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

ipv4: tcp: get rid of ugly unicast_sock

2015-02-10T10:16:52+00:00

[ 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

2015-02-10T10:16:49+00:00

[ 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

ip: make IP identifiers less predictable

2014-08-19T15:15:00+00:00

[ 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 Reported-by: Jeffrey Knockel Reported-by: Jedidiah R. Crandall Cc: Willy Tarreau Cc: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby

inetpeer: get rid of ip_id_count

2014-08-19T15:15:00+00:00

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

inet: fix addr_len/msg->msg_namelen assignment in recv_error and rxpmtu functions

2013-12-08T15:29:13+00:00

[ Upstream commit 85fbaa75037d0b6b786ff18658ddf0b4014ce2a4 ] Commit bceaa90240b6019ed73b49965eac7d167610be69 ("inet: prevent leakage of uninitialized memory to user in recv syscalls") conditionally updated addr_len if the msg_name is written to. The recv_error and rxpmtu functions relied on the recvmsg functions to set up addr_len before. As this does not happen any more we have to pass addr_len to those functions as well and set it to the size of the corresponding sockaddr length. This broke traceroute and such. Fixes: bceaa90240b6 ("inet: prevent leakage of uninitialized memory to user in recv syscalls") Reported-by: Brad Spengler Reported-by: Tom Labanowski Cc: mpb Cc: David S. Miller Cc: Eric Dumazet Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ip: generate unique IP identificator if local fragmentation is allowed

2013-09-19T18:11:15+00:00

If local fragmentation is allowed, then ip_select_ident() and ip_select_ident_more() need to generate unique IDs to ensure correct defragmentation on the peer. For example, if IPsec (tunnel mode) has to encrypt large skbs that have local_df bit set, then all IP fragments that belonged to different ESP datagrams would have used the same identificator. If one of these IP fragments would get lost or reordered, then peer could possibly stitch together wrong IP fragments that did not belong to the same datagram. This would lead to a packet loss or data corruption. Signed-off-by: Ansis Atteka Signed-off-by: David S. Miller

net: make snmp_mib_free static inline

2013-09-03T04:00:50+00:00

Fengguang reported: net/built-in.o: In function `in6_dev_finish_destroy': (.text+0x4ca7d): undefined reference to `snmp_mib_free' this is due to snmp_mib_free() is defined when CONFIG_INET is enabled, but in6_dev_finish_destroy() is now moved to core kernel. I think snmp_mib_free() is small enough to be inlined, so just make it static inline. Reported-by: kbuild test robot Signed-off-by: Cong Wang Signed-off-by: David S. Miller

ipv4: Add a socket release callback for datagram sockets

2013-01-21T19:17:05+00:00

This implements a socket release callback function to check if the socket cached route got invalid during the time we owned the socket. The function is used from udp, raw and ping sockets. Signed-off-by: Steffen Klassert Signed-off-by: David S. Miller

ipv4: fix path MTU discovery with connection tracking

2012-08-26T17:13:55+00:00

IPv4 conntrack defragments incoming packet at the PRE_ROUTING hook and (in case of forwarded packets) refragments them at POST_ROUTING independent of the IP_DF flag. Refragmentation uses the dst_mtu() of the local route without caring about the original fragment sizes, thereby breaking PMTUD. This patch fixes this by keeping track of the largest received fragment with IP_DF set and generates an ICMP fragmentation required error during refragmentation if that size exceeds the MTU. Signed-off-by: Patrick McHardy Acked-by: Eric Dumazet Acked-by: David S. Miller