diff options
author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-04-21 09:45:37 +0000 |
---|---|---|
committer | Paul Gortmaker <paul.gortmaker@windriver.com> | 2014-02-10 16:10:42 -0500 |
commit | 01f69c1211fdcbcb6f7f5624234499264687b258 (patch) | |
tree | 466b06a94c7eec3605e50e11c7c74f563acbef67 /net/ipv4/tcp_ipv4.c | |
parent | e7c0580a0fc5a0415e0462437417cad04f97141e (diff) |
inet: add RCU protection to inet->opt
commit f6d8bd051c391c1c0458a30b2a7abcd939329259 upstream.
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>
[dannf/bwh: backported to Debian's 2.6.32]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Willy Tarreau <w@1wt.eu>
[PG: use 2.6.32 patch, since it is closer to 2.6.34 than original
baseline; drop net/l2tp/l2tp_ip.c chunk as we don't have that file]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
-rw-r--r-- | net/ipv4/tcp_ipv4.c | 33 |
1 files changed, 19 insertions, 14 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index ab7165565d2..8a0bff62373 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -153,6 +153,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) __be32 daddr, nexthop; int tmp; int err; + struct ip_options_rcu *inet_opt; if (addr_len < sizeof(struct sockaddr_in)) return -EINVAL; @@ -161,10 +162,11 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) return -EAFNOSUPPORT; nexthop = daddr = usin->sin_addr.s_addr; - if (inet->opt && inet->opt->srr) { + inet_opt = inet->inet_opt; + if (inet_opt && inet_opt->opt.srr) { if (!daddr) return -EINVAL; - nexthop = inet->opt->faddr; + nexthop = inet_opt->opt.faddr; } tmp = ip_route_connect(&rt, nexthop, inet->inet_saddr, @@ -182,7 +184,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) return -ENETUNREACH; } - if (!inet->opt || !inet->opt->srr) + if (!inet_opt || !inet_opt->opt.srr) daddr = rt->rt_dst; if (!inet->inet_saddr) @@ -216,8 +218,8 @@ int tcp_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) - inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen; + if (inet_opt) + inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen; tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT; @@ -812,17 +814,18 @@ static void syn_flood_warning(struct sk_buff *skb) /* * Save and compile IPv4 options into the request_sock if needed. */ -static struct ip_options *tcp_v4_save_options(struct sock *sk, - struct sk_buff *skb) +static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk, + struct sk_buff *skb) { - struct ip_options *opt = &(IPCB(skb)->opt); - struct ip_options *dopt = NULL; + const struct ip_options *opt = &(IPCB(skb)->opt); + struct ip_options_rcu *dopt = NULL; if (opt && opt->optlen) { - int opt_size = optlength(opt); + int opt_size = sizeof(*dopt) + opt->optlen; + dopt = kmalloc(opt_size, GFP_ATOMIC); if (dopt) { - if (ip_options_echo(dopt, skb)) { + if (ip_options_echo(&dopt->opt, skb)) { kfree(dopt); dopt = NULL; } @@ -1412,6 +1415,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, #ifdef CONFIG_TCP_MD5SIG struct tcp_md5sig_key *key; #endif + struct ip_options_rcu *inet_opt; if (sk_acceptq_is_full(sk)) goto exit_overflow; @@ -1432,13 +1436,14 @@ struct sock *tcp_v4_syn_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; + inet_opt = ireq->opt; + rcu_assign_pointer(newinet->inet_opt, inet_opt); ireq->opt = NULL; newinet->mc_index = inet_iif(skb); newinet->mc_ttl = ip_hdr(skb)->ttl; inet_csk(newsk)->icsk_ext_hdr_len = 0; - if (newinet->opt) - inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen; + if (inet_opt) + inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; newinet->inet_id = newtp->write_seq ^ jiffies; tcp_mtup_init(newsk); |