Update to reflect the last batch of proxy stuff we got from Justin Bradford.

[u/mdw/putty] / ssh.c

diff --git a/ssh.c b/ssh.c
index acc4598..d998d08 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -182,6 +182,7 @@ static const char *const ssh2_disconnect_reasons[] = {
 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD            4
 #define BUG_CHOKES_ON_RSA                        8
 #define BUG_SSH2_RSA_PADDING                    16
+#define BUG_SSH2_DERIVEKEY                       32
 
 static int ssh_pkt_ctx = 0;
 
@@ -803,11 +804,11 @@ static int ssh1_rdpkt(unsigned char **data, int *datalen)
 
     if (pktin.type == SSH1_MSG_DEBUG) {
        /* log debug message */
-       char buf[80];
+       char buf[512];
        int stringlen = GET_32BIT(pktin.body);
-       strcpy(buf, "Remote: ");
-       if (stringlen > 70)
-           stringlen = 70;
+       strcpy(buf, "Remote debug message: ");
+       if (stringlen > 480)
+           stringlen = 480;
        memcpy(buf + 8, pktin.body + 4, stringlen);
        buf[8 + stringlen] = '\0';
        logevent(buf);
@@ -1701,6 +1702,16 @@ static void ssh_detect_bugs(char *vstring)
        logevent("We believe remote version has SSH2 HMAC bug");
     }
 
+    if (!strncmp(imp, "2.0.", 4)) {
+       /*
+        * These versions have the key-derivation bug (failing to
+        * include the literal shared secret in the hashes that
+        * generate the keys).
+        */
+       ssh_remote_bugs |= BUG_SSH2_DERIVEKEY;
+       logevent("We believe remote version has SSH2 key-derivation bug");
+    }
+
     if ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') ||
        (!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')) {
        /*
@@ -3497,14 +3508,16 @@ static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr,
     SHA_State s;
     /* First 20 bytes. */
     SHA_Init(&s);
-    sha_mpint(&s, K);
+    if (!(ssh_remote_bugs & BUG_SSH2_DERIVEKEY))
+       sha_mpint(&s, K);
     SHA_Bytes(&s, H, 20);
     SHA_Bytes(&s, &chr, 1);
     SHA_Bytes(&s, sessid, 20);
     SHA_Final(&s, keyspace);
     /* Next 20 bytes. */
     SHA_Init(&s);
-    sha_mpint(&s, K);
+    if (!(ssh_remote_bugs & BUG_SSH2_DERIVEKEY))
+       sha_mpint(&s, K);
     SHA_Bytes(&s, H, 20);
     SHA_Bytes(&s, keyspace, 20);
     SHA_Final(&s, keyspace + 20);