Miscellaneous fixes for better interoperation with commercial SSH 2

[u/mdw/putty] / ssh.c

diff --git a/ssh.c b/ssh.c
index 509ea3a..29cddc4 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -25,7 +25,7 @@
                       if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
                       fprintf(stderr, "%s\n", s); }
 
-#define bombout(msg) ( ssh_state == SSH_STATE_CLOSED, closesocket(s), \
+#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, closesocket(s), \
                        s = INVALID_SOCKET, connection_fatal msg )
 
 #define SSH1_MSG_DISCONNECT                       1    /* 0x1 */
@@ -167,7 +167,7 @@ const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman };
 extern const struct ssh_hostkey ssh_dss;
 const static struct ssh_hostkey *hostkey_algs[] = { &ssh_dss };
 
-extern const struct ssh_mac ssh_sha1;
+extern const struct ssh_mac ssh_sha1, ssh_sha1_buggy;
 
 static void nullmac_key(unsigned char *key) { }
 static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { }
@@ -176,6 +176,7 @@ const static struct ssh_mac ssh_mac_none = {
     nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
 };
 const static struct ssh_mac *macs[] = { &ssh_sha1, &ssh_mac_none };
+const static struct ssh_mac *buggymacs[] = { &ssh_sha1_buggy, &ssh_mac_none };
 
 const static struct ssh_compress ssh_comp_none = {
     "none"
@@ -1828,6 +1829,7 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
     static int i, len;
     static char *str;
     static Bignum e, f, K;
+    static const struct ssh_mac **maclist;
     static const struct ssh_cipher *cscipher_tobe = NULL;
     static const struct ssh_cipher *sccipher_tobe = NULL;
     static const struct ssh_mac *csmac_tobe = NULL;
@@ -1858,6 +1860,14 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
         preferred_cipher = &ssh_3des_ssh2;
     }
 
+    /*
+     * Be prepared to work around the buggy MAC problem.
+     */
+    if (cfg.buggymac)
+        maclist = buggymacs;
+    else
+        maclist = macs;
+
     begin_key_exchange:
     /*
      * Construct and send our key exchange packet.
@@ -1897,16 +1907,16 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
     }
     /* List client->server MAC algorithms. */
     ssh2_pkt_addstring_start();
-    for (i = 0; i < lenof(macs); i++) {
-        ssh2_pkt_addstring_str(macs[i]->name);
-        if (i < lenof(macs)-1)
+    for (i = 0; i < lenof(maclist); i++) {
+        ssh2_pkt_addstring_str(maclist[i]->name);
+        if (i < lenof(maclist)-1)
             ssh2_pkt_addstring_str(",");
     }
     /* List server->client MAC algorithms. */
     ssh2_pkt_addstring_start();
-    for (i = 0; i < lenof(macs); i++) {
-        ssh2_pkt_addstring_str(macs[i]->name);
-        if (i < lenof(macs)-1)
+    for (i = 0; i < lenof(maclist); i++) {
+        ssh2_pkt_addstring_str(maclist[i]->name);
+        if (i < lenof(maclist)-1)
             ssh2_pkt_addstring_str(",");
     }
     /* List client->server compression algorithms. */
@@ -1979,16 +1989,16 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
         }
     }
     ssh2_pkt_getstring(&str, &len);    /* client->server mac */
-    for (i = 0; i < lenof(macs); i++) {
-        if (in_commasep_string(macs[i]->name, str, len)) {
-            csmac_tobe = macs[i];
+    for (i = 0; i < lenof(maclist); i++) {
+        if (in_commasep_string(maclist[i]->name, str, len)) {
+            csmac_tobe = maclist[i];
             break;
         }
     }
     ssh2_pkt_getstring(&str, &len);    /* server->client mac */
-    for (i = 0; i < lenof(macs); i++) {
-        if (in_commasep_string(macs[i]->name, str, len)) {
-            scmac_tobe = macs[i];
+    for (i = 0; i < lenof(maclist); i++) {
+        if (in_commasep_string(maclist[i]->name, str, len)) {
+            scmac_tobe = maclist[i];
             break;
         }
     }
@@ -2275,7 +2285,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
     ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
     ssh2_pkt_addstring("session");
     ssh2_pkt_adduint32(mainchan->localid);
-    ssh2_pkt_adduint32(0x7FFFFFFFUL);  /* our window size */
+    ssh2_pkt_adduint32(0x8000UL);  /* our window size */
     ssh2_pkt_adduint32(0x4000UL);  /* our max pkt size */
     ssh2_pkt_send();
     crWaitUntilV(ispkt);
@@ -2419,6 +2429,9 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
                     logevent("All channels closed. Disconnecting");
                     ssh2_pkt_init(SSH2_MSG_DISCONNECT);
                     ssh2_pkt_send();
+                    ssh_state = SSH_STATE_CLOSED;
+                    closesocket(s);
+                    s = INVALID_SOCKET;
                 }
                 continue;              /* remote sends close; ignore (FIXME) */
            } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {