GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-26 00:21:17 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

inet: add RCU protection to inet->opt

Browse source 
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>
This commit is contained in:
Eric Dumazet 2011-04-21 09:45:37 +00:00 • committed by David S. Miller
parent 0a14842f5a
commit f6d8bd051c
17 changed files with 241 additions and 168 deletions
Download patch file Download diff file Expand all files Collapse all files

34
net/ipv4/tcp_ipv4.c
View file

@ -154,6 +154,7 @@ int tcp_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;
if (addr_len < sizeof(struct sockaddr_in))
return -EINVAL;
@ -162,10 +163,12 @@ 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 = rcu_dereference_protected(inet->inet_opt,
sock_owned_by_user(sk));
if (inet_opt && inet_opt->opt.srr) {
if (!daddr)
return -EINVAL;
nexthop = inet->opt->faddr;
nexthop = inet_opt->opt.faddr;
}
orig_sport = inet->inet_sport;
@ -186,7 +189,7 @@ 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)
@ -222,8 +225,8 @@ 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;
@ -820,17 +823,18 @@ static void syn_flood_warning(const 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;
}
@ -1411,6 +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;
@ -1431,13 +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);