linux/include/net, branch mybooklive-amatus

ip: make IP identifiers less predictable

2014-07-29T01:46:34Z

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

Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf

2014-07-16T22:27:16Z

Pablo Neira Ayuso says: ==================== Netfilter/nf_tables fixes The following patchset contains nf_tables fixes, they are: 1) Fix wrong transaction handling when the table flags are not modified. 2) Fix missing rcu read_lock section in the netlink dump path, which is not protected by the nfnl_lock. 3) Set NLM_F_DUMP_INTR in the netlink dump path to indicate interferences with updates. 4) Fix 64 bits chain counters when they are retrieved from a 32 bits arch, from Eric Dumazet. ==================== Signed-off-by: David S. Miller

neigh: sysctl - simplify address calculation of gc_* variables

2014-07-14T21:32:51Z

The code in neigh_sysctl_register() relies on a specific layout of struct neigh_table, namely that the 'gc_*' variables are directly following the 'parms' member in a specific order. The code, though, expresses this in the most ugly way. Get rid of the ugly casts and use the 'tbl' pointer to get a handle to the table. This way we can refer to the 'gc_*' variables directly. Similarly seen in the grsecurity patch, written by Brad Spengler. Signed-off-by: Mathias Krause Cc: Brad Spengler Signed-off-by: David S. Miller

netfilter: nf_tables: 64bit stats need some extra synchronization

2014-07-14T10:00:17Z

Use generic u64_stats_sync infrastructure to get proper 64bit stats, even on 32bit arches, at no extra cost for 64bit arches. Without this fix, 32bit arches can have some wrong counters at the time the carry is propagated into upper word. Signed-off-by: Eric Dumazet Signed-off-by: Pablo Neira Ayuso

netfilter: nf_tables: set NLM_F_DUMP_INTR if netlink dumping is stale

2014-07-14T10:00:16Z

An updater may interfer with the dumping of any of the object lists. Fix this by using a per-net generation counter and use the nl_dump_check_consistent() interface so the NLM_F_DUMP_INTR flag is set to notify userspace that it has to restart the dump since an updater has interfered. This patch also replaces the existing consistency checking code in the rule dumping path since it is broken. Basically, the value that the dump callback returns is not propagated to userspace via netlink_dump_start(). Signed-off-by: Pablo Neira Ayuso

ieee802154: reassembly: fix possible buffer overflow

2014-07-03T01:34:25Z

The max_dsize attribute in ctl_table for lowpan_frags_ns_ctl_table is configured with integer accessing methods. This patch change the max_dsize attribute to int to avoid a possible buffer overflow. Signed-off-by: Alexander Aring Signed-off-by: David S. Miller

net: fix sparse warning in sk_dst_set()

2014-07-03T00:03:06Z

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

ipv4: irq safe sk_dst_[re]set() and ipv4_sk_update_pmtu() fix

2014-07-01T06:40:58Z

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 Cc: Steffen Klassert Fixes: 9cb3a50c5f63e ("ipv4: Invalidate the socket cached route on pmtu events if possible") Signed-off-by: David S. Miller

ipv4: fix dst race in sk_dst_get()

2014-06-26T00:41:44Z

When IP route cache had been removed in linux-3.6, we broke assumption that dst entries were all freed after rcu grace period. DST_NOCACHE dst were supposed to be freed from dst_release(). But it appears we want to keep such dst around, either in UDP sockets or tunnels. In sk_dst_get() we need to make sure dst refcount is not 0 before incrementing it, or else we might end up freeing a dst twice. DST_NOCACHE set on a dst does not mean this dst can not be attached to a socket or a tunnel. Then, before actual freeing, we need to observe a rcu grace period to make sure all other cpus can catch the fact the dst is no longer usable. Signed-off-by: Eric Dumazet Reported-by: Dormando Signed-off-by: David S. Miller

netfilter: nf_tables: use u32 for chain use counter

2014-06-16T11:07:44Z

Since 4fefee5 ("netfilter: nf_tables: allow to delete several objects from a batch"), every new rule bumps the chain use counter. However, this is limited to 16 bits, which means that it will overrun after 2^16 rules. Use a u32 chain counter and check for overflows (just like we do for table objects). Signed-off-by: Pablo Neira Ayuso