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/exthdrs.c | |
| parent | 01b3f52157ff5a47d6d8d796f396a4b34a53c61d (diff) | |
| download | linux-45f6fad84cc305103b28d73482b344d7f5b76f39.tar.bz2 | |
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/exthdrs.c')
| -rw-r--r-- | net/ipv6/exthdrs.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c index ce203b0402be..ea7c4d64a00a 100644 --- a/net/ipv6/exthdrs.c +++ b/net/ipv6/exthdrs.c @@ -727,6 +727,7 @@ ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) *((char **)&opt2->dst1opt) += dif; if (opt2->srcrt) *((char **)&opt2->srcrt) += dif; + atomic_set(&opt2->refcnt, 1); } return opt2; } @@ -790,7 +791,7 @@ ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, return ERR_PTR(-ENOBUFS); memset(opt2, 0, tot_len); - + atomic_set(&opt2->refcnt, 1); opt2->tot_len = tot_len; p = (char *)(opt2 + 1); |