xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ipv6: add complete rcu protection around np->opt

Browse Source 
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>
This commit is contained in:
Eric Dumazet
2015-11-29 19:37:57 -08:00
committed by David S. Miller
parent 01b3f52157
commit 45f6fad84c
13 changed files with 122 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
net/ipv6/inet6_connection_sock.c
View File

@@ -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;
}