linux-stable.git/net/ipv4/udp.c, branch linux-4.2.y Linux kernel stable tree udp: fix dst races with multicast early demux 2015-08-04T05:16:50+00:00 Eric Dumazet edumazet@google.com 2015-08-01T10:14:33+00:00 10e2eb878f3ca07ac2f05fa5ca5e6c4c9174a27a Multicast dst are not cached. They carry DST_NOCACHE. As mentioned in commit f8864972126899 ("ipv4: fix dst race in sk_dst_get()"), these dst need special care before caching them into a socket. Caching them is allowed only if their refcnt was not 0, ie we must use atomic_inc_not_zero() Also, we must use READ_ONCE() to fetch sk->sk_rx_dst, as mentioned in commit d0c294c53a771 ("tcp: prevent fetching dst twice in early demux code") Fixes: 421b3885bf6d ("udp: ipv4: Add udp early demux") Tested-by: Gregory Hoggarth <Gregory.Hoggarth@alliedtelesis.co.nz> Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Gregory Hoggarth <Gregory.Hoggarth@alliedtelesis.co.nz> Reported-by: Alex Gartrell <agartrell@fb.com> Cc: Michal Kubeček <mkubecek@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net> 
Multicast dst are not cached. They carry DST_NOCACHE.

As mentioned in commit f8864972126899 ("ipv4: fix dst race in
sk_dst_get()"), these dst need special care before caching them
into a socket.

Caching them is allowed only if their refcnt was not 0, ie we
must use atomic_inc_not_zero()

Also, we must use READ_ONCE() to fetch sk->sk_rx_dst, as mentioned
in commit d0c294c53a771 ("tcp: prevent fetching dst twice in early demux
code")

Fixes: 421b3885bf6d ("udp: ipv4: Add udp early demux")
Tested-by: Gregory Hoggarth <Gregory.Hoggarth@alliedtelesis.co.nz>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Gregory Hoggarth <Gregory.Hoggarth@alliedtelesis.co.nz>
Reported-by: Alex Gartrell <agartrell@fb.com>
Cc: Michal Kubeček <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv4/udp: Verify multicast group is ours in upd_v4_early_demux() 2015-06-04T07:46:26+00:00 Shawn Bohrer sbohrer@rgmadvisors.com 2015-06-03T21:27:38+00:00 6e540309326188f769e03bb4c6dd8ff6752930c2 421b3885bf6d56391297844f43fb7154a6396e12 "udp: ipv4: Add udp early demux" introduced a regression that allowed sockets bound to INADDR_ANY to receive packets from multicast groups that the socket had not joined. For example a socket that had joined 224.168.2.9 could also receive packets from 225.168.2.9 despite not having joined that group if ip_early_demux is enabled. Fix this by calling ip_check_mc_rcu() in udp_v4_early_demux() to verify that the multicast packet is indeed ours. Signed-off-by: Shawn Bohrer <sbohrer@rgmadvisors.com> Reported-by: Yurij M. Plotnikov <Yurij.Plotnikov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net> 
421b3885bf6d56391297844f43fb7154a6396e12 "udp: ipv4: Add udp early
demux" introduced a regression that allowed sockets bound to INADDR_ANY
to receive packets from multicast groups that the socket had not joined.
For example a socket that had joined 224.168.2.9 could also receive
packets from 225.168.2.9 despite not having joined that group if
ip_early_demux is enabled.

Fix this by calling ip_check_mc_rcu() in udp_v4_early_demux() to verify
that the multicast packet is indeed ours.

Signed-off-by: Shawn Bohrer <sbohrer@rgmadvisors.com>
Reported-by: Yurij M. Plotnikov <Yurij.Plotnikov@oktetlabs.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
udp: fix behavior of wrong checksums 2015-06-01T04:42:18+00:00 Eric Dumazet edumazet@google.com 2015-05-30T16:16:53+00:00 beb39db59d14990e401e235faf66a6b9b31240b0 We have two problems in UDP stack related to bogus checksums : 1) We return -EAGAIN to application even if receive queue is not empty. This breaks applications using edge trigger epoll() 2) Under UDP flood, we can loop forever without yielding to other processes, potentially hanging the host, especially on non SMP. This patch is an attempt to make things better. We might in the future add extra support for rt applications wanting to better control time spent doing a recv() in a hostile environment. For example we could validate checksums before queuing packets in socket receive queue. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
We have two problems in UDP stack related to bogus checksums :

1) We return -EAGAIN to application even if receive queue is not empty.
   This breaks applications using edge trigger epoll()

2) Under UDP flood, we can loop forever without yielding to other
   processes, potentially hanging the host, especially on non SMP.

This patch is an attempt to make things better.

We might in the future add extra support for rt applications
wanting to better control time spent doing a recv() in a hostile
environment. For example we could validate checksums before queuing
packets in socket receive queue.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: remove extra newlines 2015-04-08T02:24:37+00:00 Sheng Yong shengyong1@huawei.com 2015-04-08T01:26:18+00:00 8bc0034cf6951a107e0c75c2d10b17b57d681229 Signed-off-by: Sheng Yong <shengyong1@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv4: coding style: comparison for inequality with NULL 2015-04-03T16:11:15+00:00 Ian Morris ipm@chirality.org.uk 2015-04-03T08:17:27+00:00 00db41243e8d5032c2e0f5bf6063bb19324bfdb3 The ipv4 code uses a mixture of coding styles. In some instances check for non-NULL pointer is done as x != NULL and sometimes as x. x is preferred according to checkpatch and this patch makes the code consistent by adopting the latter form. No changes detected by objdiff. Signed-off-by: Ian Morris <ipm@chirality.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net> 
The ipv4 code uses a mixture of coding styles. In some instances check
for non-NULL pointer is done as x != NULL and sometimes as x. x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.

No changes detected by objdiff.

Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
ipv4: coding style: comparison for equality with NULL 2015-04-03T16:11:15+00:00 Ian Morris ipm@chirality.org.uk 2015-04-03T08:17:26+00:00 51456b2914a34d16b1255b7c55d5cbf6a681d306 The ipv4 code uses a mixture of coding styles. In some instances check for NULL pointer is done as x == NULL and sometimes as !x. !x is preferred according to checkpatch and this patch makes the code consistent by adopting the latter form. No changes detected by objdiff. Signed-off-by: Ian Morris <ipm@chirality.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net> 
The ipv4 code uses a mixture of coding styles. In some instances check
for NULL pointer is done as x == NULL and sometimes as !x. !x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.

No changes detected by objdiff.

Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
netns: constify net_hash_mix() and various callers 2015-03-19T02:00:34+00:00 Eric Dumazet edumazet@google.com 2015-03-18T21:05:33+00:00 6eada0110c8984477f5f1e57a0b7f7b2fc841e30 const qualifiers ease code review by making clear which objects are not written in a function. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
const qualifiers ease code review by making clear
which objects are not written in a function.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: Remove iocb argument from sendmsg and recvmsg 2015-03-02T18:06:31+00:00 Ying Xue ying.xue@windriver.com 2015-03-02T07:37:48+00:00 1b784140474e4fc94281a49e96c67d29df0efbde After TIPC doesn't depend on iocb argument in its internal implementations of sendmsg() and recvmsg() hooks defined in proto structure, no any user is using iocb argument in them at all now. Then we can drop the redundant iocb argument completely from kinds of implementations of both sendmsg() and recvmsg() in the entire networking stack. Cc: Christoph Hellwig <hch@lst.de> Suggested-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
After TIPC doesn't depend on iocb argument in its internal
implementations of sendmsg() and recvmsg() hooks defined in proto
structure, no any user is using iocb argument in them at all now.
Then we can drop the redundant iocb argument completely from kinds of
implementations of both sendmsg() and recvmsg() in the entire
networking stack.

Cc: Christoph Hellwig <hch@lst.de>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
udp: In udp_flow_src_port use random hash value if skb_get_hash fails 2015-02-27T21:00:01+00:00 Tom Herbert therbert@google.com 2015-02-24T17:17:31+00:00 723b8e460d87e957f251dc5764f4ab86af6ab44e In the unlikely event that skb_get_hash is unable to deduce a hash in udp_flow_src_port we use a consistent random value instead. This is specified in GRE/UDP draft section 3.2.1: https://tools.ietf.org/html/draft-ietf-tsvwg-gre-in-udp-encap-04 Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
In the unlikely event that skb_get_hash is unable to deduce a hash
in udp_flow_src_port we use a consistent random value instead.
This is specified in GRE/UDP draft section 3.2.1:
https://tools.ietf.org/html/draft-ietf-tsvwg-gre-in-udp-encap-04

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip: Add offset parameter to ip_cmsg_recv 2015-01-06T03:44:46+00:00 Tom Herbert therbert@google.com 2015-01-05T21:56:17+00:00 ad6f939ab193750cc94a265f58e007fb598c97b7 Add ip_cmsg_recv_offset function which takes an offset argument that indicates the starting offset in skb where data is being received from. This will be useful in the case of UDP and provided checksum to user space. ip_cmsg_recv is an inline call to ip_cmsg_recv_offset with offset of zero. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Add ip_cmsg_recv_offset function which takes an offset argument
that indicates the starting offset in skb where data is being received
from. This will be useful in the case of UDP and provided checksum
to user space.

ip_cmsg_recv is an inline call to ip_cmsg_recv_offset with offset of
zero.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>