Handle incoming SSH2_MSG_CHANNEL_REQUEST (by refusing all requests).

Should have done this ages ago; the OpenSSH 3.0 ClientAliveInterval
mechanism requires it so now it's really necessary.

git-svn-id: svn://svn.tartarus.org/sgt/putty@1380 cda61777-01e9-0310-a592-d414129be87e

diff --git a/ssh.c b/ssh.c
index b270ac5..9b16d83 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -4797,8 +4797,6 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
                ssh_state = SSH_STATE_CLOSED;
                logevent("Received disconnect message");
                crReturnV;
-           } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
-               continue;              /* exit status et al; ignore (FIXME?) */
            } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
                unsigned i = ssh2_pkt_getuint32();
                struct ssh_channel *c;
@@ -4917,6 +4915,46 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
 
                del234(ssh_channels, c);
                sfree(c);
+           } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
+               unsigned localid;
+               char *type;
+               int typelen, want_reply;
+               struct ssh_channel *c;
+
+               localid = ssh2_pkt_getuint32();
+               ssh2_pkt_getstring(&type, &typelen);
+               want_reply = ssh2_pkt_getbool();
+
+               /*
+                * First, check that the channel exists. Otherwise,
+                * we can instantly disconnect with a rude message.
+                */
+               c = find234(ssh_channels, &localid, ssh_channelfind);
+               if (!c) {
+                   char buf[80];
+                   sprintf(buf, "Received channel request for nonexistent"
+                           " channel %d", localid);
+                   logevent(buf);
+                   ssh2_pkt_init(SSH2_MSG_DISCONNECT);
+                   ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
+                   ssh2_pkt_addstring(buf);
+                   ssh2_pkt_addstring("en");   /* language tag */
+                   ssh2_pkt_send();
+                   connection_fatal(buf);
+                   ssh_state = SSH_STATE_CLOSED;
+                   crReturnV;
+               }
+
+               /*
+                * We don't recognise any form of channel request,
+                * so we now either ignore the request or respond
+                * with CHANNEL_FAILURE, depending on want_reply.
+                */
+               if (want_reply) {
+                   ssh2_pkt_init(SSH2_MSG_CHANNEL_FAILURE);
+                   ssh2_pkt_adduint32(c->remoteid);
+                   ssh2_pkt_send();
+               }
            } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
                char *type;
                int typelen;