+void logevent(char *string) { }
+
+void verify_ssh_host_key(char *host, int port, char *keytype,
+ char *keystr, char *fingerprint) {
+ int ret;
+
+ static const char absentmsg[] =
+ "The server's host key is not cached in the registry. You\n"
+ "have no guarantee that the server is the computer you\n"
+ "think it is.\n"
+ "The server's key fingerprint is:\n"
+ "%s\n"
+ "If you trust this host, enter \"y\" to add the key to\n"
+ "PuTTY's cache and carry on connecting.\n"
+ "If you do not trust this host, enter \"n\" to abandon the\n"
+ "connection.\n"
+ "Continue connecting? (y/n) ";
+
+ static const char wrongmsg[] =
+ "WARNING - POTENTIAL SECURITY BREACH!\n"
+ "The server's host key does not match the one PuTTY has\n"
+ "cached in the registry. This means that either the\n"
+ "server administrator has changed the host key, or you\n"
+ "have actually connected to another computer pretending\n"
+ "to be the server.\n"
+ "The new key fingerprint is:\n"
+ "%s\n"
+ "If you were expecting this change and trust the new key,\n"
+ "enter \"y\" to update PuTTY's cache and continue connecting.\n"
+ "If you want to carry on connecting but without updating\n"
+ "the cache, enter \"n\".\n"
+ "If you want to abandon the connection completely, press\n"
+ "Return to cancel. Pressing Return is the ONLY guaranteed\n"
+ "safe choice.\n"
+ "Update cached key? (y/n, Return cancels connection) ";
+
+ static const char abandoned[] = "Connection abandoned.\n";
+
+ char line[32];
+
+ /*
+ * Verify the key against the registry.
+ */
+ ret = verify_host_key(host, port, keytype, keystr);
+
+ if (ret == 0) /* success - key matched OK */
+ return;
+ if (ret == 2) { /* key was different */
+ fprintf(stderr, wrongmsg, fingerprint);
+ if (fgets(line, sizeof(line), stdin) &&
+ line[0] != '\0' && line[0] != '\n') {
+ if (line[0] == 'y' || line[0] == 'Y')
+ store_host_key(host, port, keytype, keystr);
+ } else {
+ fprintf(stderr, abandoned);
+ exit(0);
+ }
+ }
+ if (ret == 1) { /* key was absent */
+ fprintf(stderr, absentmsg, fingerprint);
+ if (fgets(line, sizeof(line), stdin) &&
+ (line[0] == 'y' || line[0] == 'Y'))
+ store_host_key(host, port, keytype, keystr);
+ else {
+ fprintf(stderr, abandoned);
+ exit(0);
+ }
+ }
+}