Hi, On Tue, Nov 17, 2015 at 12:32:16PM +0000, Christian Pellegrin wrote: > Looks better than just adding AF_UNSPEC case but I noted many other > FIXMEs about AF_UNSPEC that could be solved this way. So let me know > if there is any reason to not use the ai_family field (and just add > the AF_UNSPEC case in set_mtu_discovery)
No, AF_UNSPEC in set_mtu_discovery is not the right thing (because it
would have to bei either a no-op, or try ipv4 *and* ipv6 to see which
one succeeds). We really need to set info.af properly, as your patch
has a little side effect...
> +++ b/src/openvpn/socket.c
> @@ -1670,7 +1670,7 @@ phase2_set_socket_flags (struct link_socket* sock)
> set_cloexec (sock->ctrl_sd);
>
> /* set Path MTU discovery options on the socket */
> - set_mtu_discover_type (sock->sd, sock->mtu_discover_type, sock->info.af);
> + set_mtu_discover_type (sock->sd, sock->mtu_discover_type,
> sock->info.lsa->bind_local->ai_family);
... on a client with --nobind, this immediately crashes as lsa->bind_local
is not set...
Sat Nov 21 21:01:48 2015 OpenVPN 2.3_git [git:master/48c23dc92006e1d8+]
i686-pc-linux-gnu [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [MH] [IPv6] built on Nov
21 2015
Sat Nov 21 21:01:48 2015 library versions: OpenSSL 1.0.2d 9 Jul 2015, LZO 2.08
Sat Nov 21 21:01:48 2015 TCP/UDP: Preserving recently used remote address:
[AF_INET]199.102.77.82:51194
Sat Nov 21 21:01:48 2015 Socket Buffers: R=[110592->110592] S=[110592->110592]
Program received signal SIGSEGV, Segmentation fault.
0x0809c165 in phase2_set_socket_flags (sock=0x80ee270)
at ../../../openvpn/src/openvpn/socket.c:1673
1673 set_mtu_discover_type (sock->sd, sock->mtu_discover_type,
sock->info.lsa->bind_local->ai_family);
(gdb) print sock->info.lsa->bind_local
$1 = (struct addrinfo *) 0x0
So, overruling Arne's ACK and not applying it :-)
I wonder if the *right* fix for this case wouldn't be to extend this
code block (before calling phase2_set_socket_flags(), socket.c line 1880):
if (sock->bind_local && !sock->remote_host &&
sock->info.lsa->bind_local)
{
/* Warn if this is because neither v4 or v6 was specified
* and we should not connect a remote */
if (sock->info.af == AF_UNSPEC)
msg (M_WARN, "Could not determine IPv4/IPv6 protocol. Using %s",
addr_family_name(sock->info.lsa->bind_local->ai_family));
create_socket (sock, sock->info.lsa->bind_local);
}
into...
if (sock->info.af == AF_UNSPEC)
+ {
msg (M_WARN, "Could not determine IPv4/IPv6 protocol. Using
%s",
addr_family_name(sock->info.lsa->bind_local->ai_family));
+ sock->info.af = sock->info.lsa->bind_local->ai_family;
+ }
which would catch your case, but also the "--nobind and we have a remote"
case (client).
Arne, what do you think?
gert
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Gert Doering - Munich, Germany g...@greenie.muc.de
fax: +49-89-35655025 g...@net.informatik.tu-muenchen.de
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