linux/net/dccp, branch v4.5

tcp/dccp: fix another race at listener dismantle

2016-02-18T16:35:51Z

Ilya reported following lockdep splat: kernel: ========================= kernel: [ BUG: held lock freed! ] kernel: 4.5.0-rc1-ceph-00026-g5e0a311 #1 Not tainted kernel: ------------------------- kernel: swapper/5/0 is freeing memory ffff880035c9d200-ffff880035c9dbff, with a lock still held there! kernel: (&(&queue->rskq_lock)->rlock){+.-...}, at: [] inet_csk_reqsk_queue_add+0x28/0xa0 kernel: 4 locks held by swapper/5/0: kernel: #0: (rcu_read_lock){......}, at: [] netif_receive_skb_internal+0x4b/0x1f0 kernel: #1: (rcu_read_lock){......}, at: [] ip_local_deliver_finish+0x3f/0x380 kernel: #2: (slock-AF_INET){+.-...}, at: [] sk_clone_lock+0x19b/0x440 kernel: #3: (&(&queue->rskq_lock)->rlock){+.-...}, at: [] inet_csk_reqsk_queue_add+0x28/0xa0 To properly fix this issue, inet_csk_reqsk_queue_add() needs to return to its callers if the child as been queued into accept queue. We also need to make sure listener is still there before calling sk->sk_data_ready(), by holding a reference on it, since the reference carried by the child can disappear as soon as the child is put on accept queue. Reported-by: Ilya Dryomov Fixes: ebb516af60e1 ("tcp/dccp: fix race at listener dismantle phase") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2015-12-04T02:09:12Z

Conflicts: drivers/net/ethernet/renesas/ravb_main.c kernel/bpf/syscall.c net/ipv4/ipmr.c All three conflicts were cases of overlapping changes. Signed-off-by: David S. Miller

ipv6: kill sk_dst_lock

2015-12-03T16:32:06Z

While testing the np->opt RCU conversion, I found that UDP/IPv6 was using a mixture of xchg() and sk_dst_lock to protect concurrent changes to sk->sk_dst_cache, leading to possible corruptions and crashes. ip6_sk_dst_lookup_flow() uses sk_dst_check() anyway, so the simplest way to fix the mess is to remove sk_dst_lock completely, as we did for IPv4. __ip6_dst_store() and ip6_dst_store() share same implementation. sk_setup_caps() being called with socket lock being held or not, we have to use sk_dst_set() instead of __sk_dst_set() Note that I had to move the "np->dst_cookie = rt6_get_cookie(rt);" in ip6_dst_store() before the sk_setup_caps(sk, dst) call. This is because ip6_dst_store() can be called from process context, without any lock held. As soon as the dst is installed in sk->sk_dst_cache, dst can be freed from another cpu doing a concurrent ip6_dst_store() Doing the dst dereference before doing the install is needed to make sure no use after free would trigger. Signed-off-by: Eric Dumazet Reported-by: Dmitry Vyukov Signed-off-by: David S. Miller

ipv6: add complete rcu protection around np->opt

2015-12-03T04:37:16Z

This patch addresses multiple problems : UDP/RAW sendmsg() need to get a stable struct ipv6_txoptions while socket is not locked : Other threads can change np->opt concurrently. Dmitry posted a syzkaller (http://github.com/google/syzkaller) program desmonstrating use-after-free. Starting with TCP/DCCP lockless listeners, tcp_v6_syn_recv_sock() and dccp_v6_request_recv_sock() also need to use RCU protection to dereference np->opt once (before calling ipv6_dup_options()) This patch adds full RCU protection to np->opt Reported-by: Dmitry Vyukov Signed-off-by: Eric Dumazet Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller

net: rename SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA

2015-12-01T20:45:05Z

This patch is a cleanup to make following patch easier to review. Goal is to move SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA from (struct socket)->flags to a (struct socket_wq)->flags to benefit from RCU protection in sock_wake_async() To ease backports, we rename both constants. Two new helpers, sk_set_bit(int nr, struct sock *sk) and sk_clear_bit(int net, struct sock *sk) are added so that following patch can change their implementation. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: Generalise wq_has_sleeper helper

2015-11-30T19:47:33Z

The memory barrier in the helper wq_has_sleeper is needed by just about every user of waitqueue_active. This patch generalises it by making it take a wait_queue_head_t directly. The existing helper is renamed to skwq_has_sleeper. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller

tcp/dccp: fix ireq->pktopts race

2015-11-02T20:38:26Z

IPv6 request sockets store a pointer to skb containing the SYN packet to be able to transfer it to full blown socket when 3WHS is done (ireq->pktopts -> np->pktoptions) As explained in commit 5e0724d027f0 ("tcp/dccp: fix hashdance race for passive sessions"), we must transfer the skb only if we won the hashdance race, if multiple cpus receive the 'ack' packet completing 3WHS at the same time. Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets") Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

Use 64-bit timekeeping

2015-11-01T22:01:16Z

This patch changes the use of struct timespec in dccp_probe to use struct timespec64 instead. timespec uses a 32-bit seconds field which will overflow in the year 2038 and beyond. timespec64 uses a 64-bit seconds field. Note that the correctness of the code isn't changed, since the original code only uses the timestamps to compute a small elapsed interval. This patch is part of a larger attempt to remove instances of 32-bit timekeeping structures (timespec, timeval, time_t) from the kernel so it is easier to identify where the real 2038 issues are. Signed-off-by: Tina Ruchandani Signed-off-by: David S. Miller

tcp/dccp: fix hashdance race for passive sessions

2015-10-23T12:42:21Z

Multiple cpus can process duplicates of incoming ACK messages matching a SYN_RECV request socket. This is a rare event under normal operations, but definitely can happen. Only one must win the race, otherwise corruption would occur. To fix this without adding new atomic ops, we use logic in inet_ehash_nolisten() to detect the request was present in the same ehash bucket where we try to insert the new child. If request socket was not found, we have to undo the child creation. This actually removes a spin_lock()/spin_unlock() pair in reqsk_queue_unlink() for the fast path. Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets") Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

tcp/dccp: add inet_csk_reqsk_queue_drop_and_put() helper

2015-10-16T07:52:18Z

Let's reduce the confusion about inet_csk_reqsk_queue_drop() : In many cases we also need to release reference on request socket, so add a helper to do this, reducing code size and complexity. Fixes: 4bdc3d66147b ("tcp/dccp: fix behavior of stale SYN_RECV request sockets") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller