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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-04-21 09:45:37 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-04-28 13:16:35 -0700 |
| commit | f6d8bd051c391c1c0458a30b2a7abcd939329259 (patch) | |
| tree | 1dc4daecdeb0b42c2c6b59d7d6b41e091c11db5f /net/dccp/ipv4.c | |
| parent | 0a14842f5a3c0e88a1e59fac5c3025db39721f74 (diff) | |
| download | lwn-f6d8bd051c391c1c0458a30b2a7abcd939329259.tar.gz lwn-f6d8bd051c391c1c0458a30b2a7abcd939329259.zip | |
inet: add RCU protection to inet->opt
We lack proper synchronization to manipulate inet->opt ip_options
Problem is ip_make_skb() calls ip_setup_cork() and
ip_setup_cork() possibly makes a copy of ipc->opt (struct ip_options),
without any protection against another thread manipulating inet->opt.
Another thread can change inet->opt pointer and free old one under us.
Use RCU to protect inet->opt (changed to inet->inet_opt).
Instead of handling atomic refcounts, just copy ip_options when
necessary, to avoid cache line dirtying.
We cant insert an rcu_head in struct ip_options since its included in
skb->cb[], so this patch is large because I had to introduce a new
ip_options_rcu structure.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp/ipv4.c')
| -rw-r--r-- | net/dccp/ipv4.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c index b92ab655d44e..cbbcc6c036e0 100644 --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -48,6 +48,7 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) struct flowi4 fl4; struct rtable *rt; int err; + struct ip_options_rcu *inet_opt; dp->dccps_role = DCCP_ROLE_CLIENT; @@ -58,10 +59,13 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) return -EAFNOSUPPORT; nexthop = daddr = usin->sin_addr.s_addr; - if (inet->opt != NULL && inet->opt->srr) { + + inet_opt = rcu_dereference_protected(inet->inet_opt, + sock_owned_by_user(sk)); + if (inet_opt != NULL && inet_opt->opt.srr) { if (daddr == 0) return -EINVAL; - nexthop = inet->opt->faddr; + nexthop = inet_opt->opt.faddr; } orig_sport = inet->inet_sport; @@ -78,7 +82,7 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) return -ENETUNREACH; } - if (inet->opt == NULL || !inet->opt->srr) + if (inet_opt == NULL || !inet_opt->opt.srr) daddr = rt->rt_dst; if (inet->inet_saddr == 0) @@ -89,8 +93,8 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) inet->inet_daddr = daddr; inet_csk(sk)->icsk_ext_hdr_len = 0; - if (inet->opt != NULL) - inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen; + if (inet_opt) + inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen; /* * Socket identity is still unknown (sport may be zero). * However we set state to DCCP_REQUESTING and not releasing socket @@ -405,7 +409,7 @@ struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb, newinet->inet_daddr = ireq->rmt_addr; newinet->inet_rcv_saddr = ireq->loc_addr; newinet->inet_saddr = ireq->loc_addr; - newinet->opt = ireq->opt; + newinet->inet_opt = ireq->opt; ireq->opt = NULL; newinet->mc_index = inet_iif(skb); newinet->mc_ttl = ip_hdr(skb)->ttl; |