aboutsummaryrefslogtreecommitdiffstats
path: root/net/core/sock.c
diff options
context:
space:
mode:
authorMaciej ┼╗enczykowski <maze@google.com>2018-06-03 10:47:05 -0700
committerDavid S. Miller <davem@davemloft.net>2018-06-04 17:14:22 -0400
commitf396922d862aa05b53ad740596652691a723ee23 (patch)
tree0de99698fcb5b64fde318ceea9a1fab5e81bff02 /net/core/sock.c
parentnet-tcp: extend tcp_tw_reuse sysctl to enable loopback only optimization (diff)
downloadlinux-dev-f396922d862aa05b53ad740596652691a723ee23.tar.xz
linux-dev-f396922d862aa05b53ad740596652691a723ee23.zip
net: do not allow changing SO_REUSEADDR/SO_REUSEPORT on bound sockets
It is not safe to do so because such sockets are already in the hash tables and changing these options can result in invalidating the tb->fastreuse(port) caching. This can have later far reaching consequences wrt. bind conflict checks which rely on these caches (for optimization purposes). Not to mention that you can currently end up with two identical non-reuseport listening sockets bound to the same local ip:port by clearing reuseport on them after they've already both been bound. There is unfortunately no EISBOUND error or anything similar, and EISCONN seems to be misleading for a bound-but-not-connected socket, so use EUCLEAN 'Structure needs cleaning' which AFAICT is the closest you can get to meaning 'socket in bad state'. (although perhaps EINVAL wouldn't be a bad choice either?) This does unfortunately run the risk of breaking buggy userspace programs... Signed-off-by: Maciej ┼╗enczykowski <maze@google.com> Cc: Eric Dumazet <edumazet@google.com> Change-Id: I77c2b3429b2fdf42671eee0fa7a8ba721c94963b Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/sock.c')
-rw-r--r--net/core/sock.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index 435a0ba85e52..feca4c98f8a0 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -728,9 +728,22 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
sock_valbool_flag(sk, SOCK_DBG, valbool);
break;
case SO_REUSEADDR:
- sk->sk_reuse = (valbool ? SK_CAN_REUSE : SK_NO_REUSE);
+ val = (valbool ? SK_CAN_REUSE : SK_NO_REUSE);
+ if ((sk->sk_family == PF_INET || sk->sk_family == PF_INET6) &&
+ inet_sk(sk)->inet_num &&
+ (sk->sk_reuse != val)) {
+ ret = (sk->sk_state == TCP_ESTABLISHED) ? -EISCONN : -EUCLEAN;
+ break;
+ }
+ sk->sk_reuse = val;
break;
case SO_REUSEPORT:
+ if ((sk->sk_family == PF_INET || sk->sk_family == PF_INET6) &&
+ inet_sk(sk)->inet_num &&
+ (sk->sk_reuseport != valbool)) {
+ ret = (sk->sk_state == TCP_ESTABLISHED) ? -EISCONN : -EUCLEAN;
+ break;
+ }
sk->sk_reuseport = valbool;
break;
case SO_TYPE: