diff options
| author | Eric Dumazet <edumazet@google.com> | 2015-11-29 19:37:57 -0800 |
|---|---|---|
| committer | Mister Oyster <oysterized@gmail.com> | 2016-12-11 13:24:42 +0100 |
| commit | 1776a7190214a2baefc033ffc651eca2b4152e5b (patch) | |
| tree | aa11acebbcb08d0398fe6d59a6a0b09df85f3705 /net/ipv6/raw.c | |
| parent | ac094a58d17aa221423c18a004cf7f8747e62298 (diff) | |
ipv6: add complete rcu protection around np->opt
[ Upstream commit 45f6fad84cc305103b28d73482b344d7f5b76f39 ]
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
BUG: 28746669
Change-Id: I207da29ac48bb6dd7c40d65f9e27c4e3ff508da0
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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Pierre Imai <imaipi@google.com>
Diffstat (limited to 'net/ipv6/raw.c')
| -rw-r--r-- | net/ipv6/raw.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 32c0d4e14..6bfe997eb 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -726,6 +726,7 @@ static int rawv6_probe_proto_opt(struct flowi6 *fl6, struct msghdr *msg) static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t len) { + struct ipv6_txoptions *opt_to_free = NULL; struct ipv6_txoptions opt_space; struct sockaddr_in6 * sin6 = (struct sockaddr_in6 *) msg->msg_name; struct in6_addr *daddr, *final_p, final; @@ -833,8 +834,10 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk, if (!(opt->opt_nflen|opt->opt_flen)) opt = NULL; } - if (opt == NULL) - opt = np->opt; + if (!opt) { + opt = txopt_get(np); + opt_to_free = opt; + } if (flowlabel) opt = fl6_merge_options(&opt_space, flowlabel, opt); opt = ipv6_fixup_options(&opt_space, opt); @@ -901,6 +904,7 @@ done: dst_release(dst); out: fl6_sock_release(flowlabel); + txopt_put(opt_to_free); return err<0?err:len; do_confirm: dst_confirm(dst); |