diff options
| author | Eric Dumazet <edumazet@google.com> | 2015-11-30 06:37:57 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-12-03 07:37:16 +0300 |
| commit | 45f6fad84cc305103b28d73482b344d7f5b76f39 (patch) | |
| tree | 283dbc3a6cd4a26288a3526d0de48cf8c2e27b75 /net/ipv6/inet6_connection_sock.c | |
| parent | 01b3f52157ff5a47d6d8d796f396a4b34a53c61d (diff) | |
| download | linux-45f6fad84cc305103b28d73482b344d7f5b76f39.tar.xz | |
ipv6: add complete rcu protection around np->opt
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 <dvyukov@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/inet6_connection_sock.c')
| -rw-r--r-- | net/ipv6/inet6_connection_sock.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c index 5d1c7cee2cb2..3ff5208772bb 100644 --- a/net/ipv6/inet6_connection_sock.c +++ b/net/ipv6/inet6_connection_sock.c @@ -78,7 +78,9 @@ struct dst_entry *inet6_csk_route_req(const struct sock *sk, memset(fl6, 0, sizeof(*fl6)); fl6->flowi6_proto = proto; fl6->daddr = ireq->ir_v6_rmt_addr; - final_p = fl6_update_dst(fl6, np->opt, &final); + rcu_read_lock(); + final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final); + rcu_read_unlock(); fl6->saddr = ireq->ir_v6_loc_addr; fl6->flowi6_oif = ireq->ir_iif; fl6->flowi6_mark = ireq->ir_mark; @@ -142,7 +144,9 @@ static struct dst_entry *inet6_csk_route_socket(struct sock *sk, fl6->fl6_dport = inet->inet_dport; security_sk_classify_flow(sk, flowi6_to_flowi(fl6)); - final_p = fl6_update_dst(fl6, np->opt, &final); + rcu_read_lock(); + final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final); + rcu_read_unlock(); dst = __inet6_csk_dst_check(sk, np->dst_cookie); if (!dst) { @@ -175,7 +179,8 @@ int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused /* Restore final destination back after routing done */ fl6.daddr = sk->sk_v6_daddr; - res = ip6_xmit(sk, skb, &fl6, np->opt, np->tclass); + res = ip6_xmit(sk, skb, &fl6, rcu_dereference(np->opt), + np->tclass); rcu_read_unlock(); return res; } |