From f6d8bd051c391c1c0458a30b2a7abcd939329259 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 21 Apr 2011 09:45:37 +0000 Subject: 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 Cc: Herbert Xu Signed-off-by: David S. Miller --- include/net/ip.h | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'include/net/ip.h') diff --git a/include/net/ip.h b/include/net/ip.h index 7c416583b710..3a59bf99aa3a 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -52,7 +52,7 @@ static inline unsigned int ip_hdrlen(const struct sk_buff *skb) struct ipcm_cookie { __be32 addr; int oif; - struct ip_options *opt; + struct ip_options_rcu *opt; __u8 tx_flags; }; @@ -92,7 +92,7 @@ extern int igmp_mc_proc_init(void); extern int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, __be32 saddr, __be32 daddr, - struct ip_options *opt); + struct ip_options_rcu *opt); extern int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev); extern int ip_local_deliver(struct sk_buff *skb); @@ -416,14 +416,15 @@ extern int ip_forward(struct sk_buff *skb); * Functions provided by ip_options.c */ -extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, __be32 daddr, struct rtable *rt, int is_frag); +extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, + __be32 daddr, struct rtable *rt, int is_frag); extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb); extern void ip_options_fragment(struct sk_buff *skb); extern int ip_options_compile(struct net *net, struct ip_options *opt, struct sk_buff *skb); -extern int ip_options_get(struct net *net, struct ip_options **optp, +extern int ip_options_get(struct net *net, struct ip_options_rcu **optp, unsigned char *data, int optlen); -extern int ip_options_get_from_user(struct net *net, struct ip_options **optp, +extern int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp, unsigned char __user *data, int optlen); extern void ip_options_undo(struct ip_options * opt); extern void ip_forward_options(struct sk_buff *skb); -- cgit v1.2.3