doc: Updated guided tour for knownhosts changes

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>

doc/guided_tour.dox

@@ -158,7 +158,7 @@ you just connected to is known and safe to use (remember, SSH is about security
 authentication).
 
 There are two ways of doing this:
- - The first way (recommended) is to use the ssh_is_server_known()
+ - The first way (recommended) is to use the ssh_session_is_known_server()
    function. This function will look into the known host file
    (~/.ssh/known_hosts on UNIX), look for the server hostname's pattern,
    and determine whether this host is present or not in the list.
@@ -185,74 +185,89 @@ examples/ directory:
 
 int verify_knownhost(ssh_session session)
 {
-  int state, hlen;
-  unsigned char *hash = NULL;
-  char *hexa;
-  char buf[10];
+    enum ssh_known_hosts_e state;
+    unsigned char *hash = NULL;
+    ssh_key srv_pubkey = NULL;
+    size_t hlen;
+    char buf[10];
+    char *hexa;
+    char *p;
+    int cmp;
+    int rc;
 
-  state = ssh_is_server_known(session);
-
-  hlen = ssh_get_pubkey_hash(session, &hash);
-  if (hlen < 0)
-    return -1;
-
-  switch (state)
-  {
-    case SSH_SERVER_KNOWN_OK:
-      break; /* ok */
-
-    case SSH_SERVER_KNOWN_CHANGED:
-      fprintf(stderr, "Host key for server changed: it is now:\n");
-      ssh_print_hexa("Public key hash", hash, hlen);
-      fprintf(stderr, "For security reasons, connection will be stopped\n");
-      free(hash);
-      return -1;
-
-    case SSH_SERVER_FOUND_OTHER:
-      fprintf(stderr, "The host key for this server was not found but an other"
-        "type of key exists.\n");
-      fprintf(stderr, "An attacker might change the default server key to"
-        "confuse your client into thinking the key does not exist\n");
-      free(hash);
-      return -1;
-
-    case SSH_SERVER_FILE_NOT_FOUND:
-      fprintf(stderr, "Could not find known host file.\n");
-      fprintf(stderr, "If you accept the host key here, the file will be"
-       "automatically created.\n");
-      /* fallback to SSH_SERVER_NOT_KNOWN behavior */
-
-    case SSH_SERVER_NOT_KNOWN:
-      hexa = ssh_get_hexa(hash, hlen);
-      fprintf(stderr,"The server is unknown. Do you trust the host key?\n");
-      fprintf(stderr, "Public key hash: %s\n", hexa);
-      free(hexa);
-      if (fgets(buf, sizeof(buf), stdin) == NULL)
-      {
-        free(hash);
+    rc = ssh_get_server_publickey(session, &srv_pubkey);
+    if (rc < 0) {
         return -1;
-      }
-      if (strncasecmp(buf, "yes", 3) != 0)
-      {
-        free(hash);
-        return -1;
-      }
-      if (ssh_write_knownhost(session) < 0)
-      {
-        fprintf(stderr, "Error %s\n", strerror(errno));
-        free(hash);
-        return -1;
-      }
-      break;
+    }
 
-    case SSH_SERVER_ERROR:
-      fprintf(stderr, "Error %s", ssh_get_error(session));
-      free(hash);
-      return -1;
-  }
+    rc = ssh_get_publickey_hash(srv_pubkey,
+                                SSH_PUBLICKEY_HASH_SHA1,
+                                &hash,
+                                &hlen);
+    ssh_key_free(srv_pubkey);
+    if (rc < 0) {
+        return -1;
+    }
 
-  free(hash);
-  return 0;
+    state = ssh_session_is_known_server(session);
+    switch (state) {
+        case SSH_KNOWN_HOSTS_OK:
+            /* OK */
+
+            break;
+        case SSH_KNOWN_HOSTS_CHANGED:
+            fprintf(stderr, "Host key for server changed: it is now:\n");
+            ssh_print_hexa("Public key hash", hash, hlen);
+            fprintf(stderr, "For security reasons, connection will be stopped\n");
+            ssh_clean_pubkey_hash(&hash);
+
+            return -1;
+        case SSH_KNOWN_HOSTS_OTHER:
+            fprintf(stderr, "The host key for this server was not found but an other"
+                    "type of key exists.\n");
+            fprintf(stderr, "An attacker might change the default server key to"
+                    "confuse your client into thinking the key does not exist\n");
+            ssh_clean_pubkey_hash(&hash);
+
+            return -1;
+        case SSH_KNOWN_HOSTS_NOT_FOUND:
+            fprintf(stderr, "Could not find known host file.\n");
+            fprintf(stderr, "If you accept the host key here, the file will be"
+                    "automatically created.\n");
+
+            /* FALL THROUGH to SSH_SERVER_NOT_KNOWN behavior */
+
+        case SSH_KNOWN_HOSTS_UNKNOWN:
+            hexa = ssh_get_hexa(hash, hlen);
+            fprintf(stderr,"The server is unknown. Do you trust the host key?\n");
+            fprintf(stderr, "Public key hash: %s\n", hexa);
+            ssh_string_free_char(hexa);
+            ssh_clean_pubkey_hash(&hash);
+            p = fgets(buf, sizeof(buf), stdin);
+            if (p == NULL) {
+                return -1;
+            }
+
+            cmp = strncasecmp(buf, "yes", 3);
+            if (cmp != 0) {
+                return -1;
+            }
+
+            rc = ssh_session_update_known_hosts(session);
+            if (rc < 0) {
+                fprintf(stderr, "Error %s\n", strerror(errno));
+                return -1;
+            }
+
+            break;
+        case SSH_KNOWN_HOSTS_ERROR:
+            fprintf(stderr, "Error %s", ssh_get_error(session));
+            ssh_clean_pubkey_hash(&hash);
+            return -1;
+    }
+
+    ssh_clean_pubkey_hash(&hash);
+    return 0;
 }
 @endcode
 
@@ -260,9 +275,10 @@ int verify_knownhost(ssh_session session)
 @see ssh_disconnect
 @see ssh_get_error
 @see ssh_get_error_code
-@see ssh_get_pubkey_hash
-@see ssh_is_server_known
-@see ssh_write_knownhost
+@see ssh_get_server_publickey
+@see ssh_get_publickey_hash
+@see ssh_session_is_known_server
+@see ssh_session_update_known_hosts
 
 
 @subsection auth Authenticating the user