From 98dbf15d0b2127854cca340a0255b94aeb342705 Mon Sep 17 00:00:00 2001
From: Nick Couchman <vnick@apache.org>
Date: Wed, 1 Jul 2020 17:33:22 -0400
Subject: [PATCH] GUACAMOLE-221: Fix up SSH terminal prompt fallback.

---
 src/common-ssh/common-ssh/ssh.h |  7 +++++-
 src/common-ssh/ssh.c            |  9 +++++--
 src/protocols/ssh/ssh.c         | 44 +++++++++++++++++++--------------
 3 files changed, 38 insertions(+), 22 deletions(-)

diff --git a/src/common-ssh/common-ssh/ssh.h b/src/common-ssh/common-ssh/ssh.h
index 609e1a1e..e354cf1a 100644
--- a/src/common-ssh/common-ssh/ssh.h
+++ b/src/common-ssh/common-ssh/ssh.h
@@ -34,8 +34,13 @@
  * 
  * @param cred_name
  *     The connection parameter that is being requested from the client.
+ * 
+ * @return
+ *     A newly-allocated string containing the credentials request from the
+ *     client, or NULL if the credentials will be updated via the required
+ *     instruction.
  */
-typedef void guac_ssh_credential_handler(guac_client* client, char* cred_name);
+typedef char* guac_ssh_credential_handler(guac_client* client, char* cred_name);
 
 /**
  * An SSH session, backed by libssh2 and associated with a particular
diff --git a/src/common-ssh/ssh.c b/src/common-ssh/ssh.c
index 07188d98..32f8d550 100644
--- a/src/common-ssh/ssh.c
+++ b/src/common-ssh/ssh.c
@@ -360,8 +360,13 @@ static int guac_common_ssh_authenticate(guac_common_ssh_session* common_session)
     }
 
     /* Attempt authentication with username + password. */
-    if (user->password == NULL && common_session->credential_handler)
-        common_session->credential_handler(client, GUAC_SSH_PARAMETER_NAME_PASSWORD);
+    if (user->password == NULL && common_session->credential_handler) {
+        
+        char* password = common_session->credential_handler(client, GUAC_SSH_PARAMETER_NAME_PASSWORD);
+        if (password != NULL)
+            user->password = password;
+        
+    }
     
     /* Authenticate with password, if provided */
     if (user->password != NULL) {
diff --git a/src/protocols/ssh/ssh.c b/src/protocols/ssh/ssh.c
index 57effd54..4b69b8ed 100644
--- a/src/protocols/ssh/ssh.c
+++ b/src/protocols/ssh/ssh.c
@@ -99,10 +99,26 @@ guac_ssh_credential_prompt_map ssh_credential_prompt_map[] = {
  * @param cred_name
  *     The name of the parameter to prompt for in the client.
  */
-static void guac_ssh_get_credential(guac_client *client, char* cred_name) {
+static char* guac_ssh_get_credential(guac_client *client, char* cred_name) {
 
     guac_ssh_client* ssh_client = (guac_ssh_client*) client->data;
     
+    /* If client owner does not support required, use terminal prompt. */
+    if (!guac_client_owner_supports_required(client)) {
+        
+        /* Loop to find correct prompt for credential name. */
+        guac_ssh_credential_prompt_map* current = ssh_credential_prompt_map;
+        while (current->name != NULL) {
+            if (strcmp(current->name, cred_name) == 0)
+                return guac_terminal_prompt(ssh_client->term,
+                    current->prompt, true);
+            current++;
+        }
+        
+        /* No matching credential was found, so return NULL. */
+        return NULL;
+    }
+    
     /* Lock the terminal thread while prompting for the credential. */
     pthread_mutex_lock(&(ssh_client->ssh_credential_lock));
     
@@ -113,6 +129,8 @@ static void guac_ssh_get_credential(guac_client *client, char* cred_name) {
     pthread_cond_wait(&(ssh_client->ssh_credential_cond), &(ssh_client->ssh_credential_lock));
     pthread_mutex_unlock(&(ssh_client->ssh_credential_lock));
     
+    return NULL;
+    
 }
 
 /**
@@ -137,16 +155,9 @@ static guac_common_ssh_user* guac_ssh_get_user(guac_client* client) {
     /* Get username */
     while (settings->username == NULL) {
         
-        /* Client owner supports required instruction, so send prompt(s) that way. */
-        if (guac_client_owner_supports_required(client)) {
-            guac_ssh_get_credential(client, GUAC_SSH_PARAMETER_NAME_USERNAME);
-        }
-        
-        /* Fall back to terminal prompting. */
-        else {
-            settings->username = guac_terminal_prompt(ssh_client->term,
-                "Login as: ", true);
-        }
+        char* username = guac_ssh_get_credential(client, GUAC_SSH_PARAMETER_NAME_USERNAME);
+        if (username != NULL)
+            settings->username = username;
 
     }
     
@@ -174,14 +185,9 @@ static guac_common_ssh_user* guac_ssh_get_user(guac_client* client) {
             /* Prompt for passphrase if missing */
             while (settings->key_passphrase == NULL) {
                 
-                /* Send prompt via required instruction, if supported */
-                if (guac_client_owner_supports_required(client))
-                    guac_ssh_get_credential(client, GUAC_SSH_PARAMETER_NAME_PASSPHRASE);
-                
-                /* Fall back to terminal prompt */
-                else
-                    settings->key_passphrase = guac_terminal_prompt(ssh_client->term,
-                        "Key passphrase: ", true);
+                char* passphrase = guac_ssh_get_credential(client, GUAC_SSH_PARAMETER_NAME_PASSPHRASE);
+                if (passphrase != NULL)
+                    settings->key_passphrase = passphrase;
                 
             }