diff options
| author | Eric Dumazet <edumazet@google.com> | 2015-11-29 19:37:57 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-12-02 23:37:16 -0500 |
| commit | 45f6fad84cc305103b28d73482b344d7f5b76f39 (patch) | |
| tree | 283dbc3a6cd4a26288a3526d0de48cf8c2e27b75 /net/ipv6/af_inet6.c | |
| parent | 01b3f52157ff5a47d6d8d796f396a4b34a53c61d (diff) | |
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/af_inet6.c')
| -rw-r--r-- | net/ipv6/af_inet6.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 44bb66bde0e2..38d66ddfb937 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -428,9 +428,11 @@ void inet6_destroy_sock(struct sock *sk) /* Free tx options */ - opt = xchg(&np->opt, NULL); - if (opt) - sock_kfree_s(sk, opt, opt->tot_len); + opt = xchg((__force struct ipv6_txoptions **)&np->opt, NULL); + if (opt) { + atomic_sub(opt->tot_len, &sk->sk_omem_alloc); + txopt_put(opt); + } } EXPORT_SYMBOL_GPL(inet6_destroy_sock); @@ -659,7 +661,10 @@ int inet6_sk_rebuild_header(struct sock *sk) fl6.fl6_sport = inet->inet_sport; 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 = ip6_dst_lookup_flow(sk, &fl6, final_p); if (IS_ERR(dst)) { |