linux.git/net/ipv6/reassembly.c, branch v3.9

net: drop dst before queueing fragments

2013-04-17T05:15:29+00:00

Commit 4a94445c9a5c (net: Use ip_route_input_noref() in input path)
added a bug in IP defragmentation handling, as non refcounted
dst could escape an RCU protected section.

Commit 64f3b9e203bd068 (net: ip_expire() must revalidate route) fixed
the case of timeouts, but not the general problem.

Tom Parkin noticed crashes in UDP stack and provided a patch,
but further analysis permitted us to pinpoint the root cause.

Before queueing a packet into a frag list, we must drop its dst,
as this dst has limited lifetime (RCU protected)

When/if a packet is finally reassembled, we use the dst of the very
last skb, still protected by RCU and valid, as the dst of the
reassembled packet.

Use same logic in IPv6, as there is no need to hold dst references.

Reported-by: Tom Parkin 
Tested-by: Tom Parkin 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inet: limit length of fragment queue hash table bucket lists

2013-03-19T14:28:36+00:00

This patch introduces a constant limit of the fragment queue hash
table bucket list lengths. Currently the limit 128 is choosen somewhat
arbitrary and just ensures that we can fill up the fragment cache with
empty packets up to the default ip_frag_high_thresh limits. It should
just protect from list iteration eating considerable amounts of cpu.

If we reach the maximum length in one hash bucket a warning is printed.
This is implemented on the caller side of inet_frag_find to distinguish
between the different users of inet_fragment.c.

I dropped the out of memory warning in the ipv4 fragment lookup path,
because we already get a warning by the slab allocator.

Cc: Eric Dumazet 
Cc: Jesper Dangaard Brouer 
Signed-off-by: Hannes Frederic Sowa 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv6: fix a sparse warning

2013-02-18T20:28:00+00:00

net/ipv6/reassembly.c:82:72: warning: incorrect type in argument 3 (different base types)
net/ipv6/reassembly.c:82:72:    expected unsigned int [unsigned] [usertype] c
net/ipv6/reassembly.c:82:72:    got restricted __be32 [usertype] id

Signed-off-by: Eric Dumazet 
Reported-by: Fengguang Wu 
Signed-off-by: David S. Miller

ipv6: optimize inet6_hash_frag()

2013-02-18T17:23:51+00:00

Use ipv6_addr_hash() and a single jhash invocation.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: Add skb_unclone() helper function.

2013-02-15T20:10:37+00:00

This function will be used in next GRE_GSO patch. This patch does
not change any functionality.

Signed-off-by: Pravin B Shelar 
Acked-by: Eric Dumazet

net: frag, move LRU list maintenance outside of rwlock

2013-01-29T18:36:24+00:00

Updating the fragmentation queues LRU (Least-Recently-Used) list,
required taking the hash writer lock.  However, the LRU list isn't
tied to the hash at all, so we can use a separate lock for it.

Original-idea-by: Florian Westphal 
Signed-off-by: Jesper Dangaard Brouer 
Signed-off-by: David S. Miller

net: frag helper functions for mem limit tracking

2013-01-29T18:36:24+00:00

This change is primarily a preparation to ease the extension of memory
limit tracking.

The change does reduce the number atomic operation, during freeing of
a frag queue.  This does introduce a some performance improvement, as
these atomic operations are at the core of the performance problems
seen on NUMA systems.

Signed-off-by: Jesper Dangaard Brouer 
Signed-off-by: David S. Miller

net: Don't export sysctls to unprivileged users

2012-11-19T01:30:55+00:00

In preparation for supporting the creation of network namespaces
by unprivileged users, modify all of the per net sysctl exports
and refuse to allow them to unprivileged users.

This makes it safe for unprivileged users in general to access
per net sysctls, and allows sysctls to be exported to unprivileged
users on an individual basis as they are deemed safe.

Signed-off-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller

ipv6: unify fragment thresh handling code

2012-09-19T21:23:28+00:00

Cc: Herbert Xu 
Cc: Michal Kubeček 
Cc: David Miller 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller

ipv6: make ip6_frag_nqueues() and ip6_frag_mem() static inline

2012-09-19T21:23:28+00:00

Cc: Herbert Xu 
Cc: Michal Kubeček 
Cc: David Miller 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller