user/sven/linux.git/include/net, branch v3.2.63

ip: make IP identifiers less predictable

2014-09-13T22:41:48Z

[ 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: Ben Hutchings

inetpeer: get rid of ip_id_count

2014-09-13T22:41:48Z

[ 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: Ben Hutchings

netlabel: fix a problem when setting bits below the previously lowest bit

2014-09-13T22:41:42Z

commit 41c3bd2039e0d7b3dc32313141773f20716ec524 upstream. The NetLabel category (catmap) functions have a problem in that they assume categories will be set in an increasing manner, e.g. the next category set will always be larger than the last. Unfortunately, this is not a valid assumption and could result in problems when attempting to set categories less than the startbit in the lowest catmap node. In some cases kernel panics and other nasties can result. This patch corrects the problem by checking for this and allocating a new catmap node instance and placing it at the front of the list. Reported-by: Christian Evans Signed-off-by: Paul Moore Tested-by: Casey Schaufler [bwh: Backported to 3.2: adjust filename for SMACK] Signed-off-by: Ben Hutchings

net: fix inet_getid() and ipv6_select_ident() bugs

2014-07-11T12:33:57Z

[ Upstream commit 39c36094d78c39e038c1e499b2364e13bce36f54 ] I noticed we were sending wrong IPv4 ID in TCP flows when MTU discovery is disabled. Note how GSO/TSO packets do not have monotonically incrementing ID. 06:37:41.575531 IP (id 14227, proto: TCP (6), length: 4396) 06:37:41.575534 IP (id 14272, proto: TCP (6), length: 65212) 06:37:41.575544 IP (id 14312, proto: TCP (6), length: 57972) 06:37:41.575678 IP (id 14317, proto: TCP (6), length: 7292) 06:37:41.575683 IP (id 14361, proto: TCP (6), length: 63764) It appears I introduced this bug in linux-3.1. inet_getid() must return the old value of peer->ip_id_count, not the new one. Lets revert this part, and remove the prevention of a null identification field in IPv6 Fragment Extension Header, which is dubious and not even done properly. Fixes: 87c48fa3b463 ("ipv6: make fragment identifications less predictable") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings

ipv6: Limit mtu to 65575 bytes

2014-06-09T12:28:56Z

[ Upstream commit 30f78d8ebf7f514801e71b88a10c948275168518 ] Francois reported that setting big mtu on loopback device could prevent tcp sessions making progress. We do not support (yet ?) IPv6 Jumbograms and cook corrupted packets. We must limit the IPv6 MTU to (65535 + 40) bytes in theory. Tested: ifconfig lo mtu 70000 netperf -H ::1 Before patch : Throughput : 0.05 Mbits After patch : Throughput : 35484 Mbits Reported-by: Francois WELLENREITER Signed-off-by: Eric Dumazet Acked-by: YOSHIFUJI Hideaki Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings

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

2014-01-03T04:33:33Z

[ 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: Ben Hutchings

net: fix cipso packet validation when !NETLABEL

2013-11-28T14:01:58Z

[ Upstream commit f2e5ddcc0d12f9c4c7b254358ad245c9dddce13b ] When CONFIG_NETLABEL is disabled, the cipso_v4_validate() function could loop forever in the main loop if opt[opt_iter +1] == 0, this will causing a kernel crash in an SMP system, since the CPU executing this function will stall /not respond to IPIs. This problem can be reproduced by running the IP Stack Integrity Checker (http://isic.sourceforge.net) using the following command on a Linux machine connected to DUT: "icmpsic -s rand -d -r 123456" wait (1-2 min) Signed-off-by: Seif Mazareeb Acked-by: Paul Moore Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings

net: dst: provide accessor function to dst->xfrm

2013-11-28T14:01:57Z

[ Upstream commit e87b3998d795123b4139bc3f25490dd236f68212 ] dst->xfrm is conditionally defined. Provide accessor funtion that is always available. Signed-off-by: Vlad Yasevich Acked-by: Neil Horman Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings

ip: generate unique IP identificator if local fragmentation is allowed

2013-10-26T20:06:08Z

[ Upstream commit 703133de331a7a7df47f31fb9de51dc6f68a9de8 ] 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 Signed-off-by: Ben Hutchings

inetpeer: fix a race in inetpeer_gc_worker()

2013-10-26T20:05:57Z

[ Upstream commit 55432d2b543a4b6dfae54f5c432a566877a85d90 ] commit 5faa5df1fa2024 (inetpeer: Invalidate the inetpeer tree along with the routing cache) added a race : Before freeing an inetpeer, we must respect a RCU grace period, and make sure no user will attempt to increase refcnt. inetpeer_invalidate_tree() waits for a RCU grace period before inserting inetpeer tree into gc_list and waking the worker. At that time, no concurrent lookup can find a inetpeer in this tree. Signed-off-by: Eric Dumazet Cc: Steffen Klassert Acked-by: Steffen Klassert Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings