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GUACAMOLE-221: Rollback changes to SSH protocol prompting

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This commit is contained in:
Nick Couchman 2020-09-15 14:50:56 -04:00
parent b6d3edb749
commit 6605f217c5
8 changed files with 45 additions and 181 deletions
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10
src/common-ssh/common-ssh/ssh.h
View File

@ -26,19 +26,19 @@
#include <libssh2.h>
/**
* A handler function for retrieving additional credentials from the client.
* Handler for retrieving additional credentials.
*
* @param client
* The Guacamole Client associated with this need for additional
* credentials.
*
* @param cred_name
* The connection parameter that is being requested from the client.
* The name of the credential being requested, which will be shared
* with the client in order to generate a meaningful prompt.
*
* @return
* A newly-allocated string containing the credentials to be requested from
* the client, or NULL if the credentials will be updated via the required
* instruction.
* A newly-allocated string containing the credentials provided by
* the user, which must be freed by a call to free().
*/
typedef char* guac_ssh_credential_handler(guac_client* client, char* cred_name);

9
src/common-ssh/ssh.c
View File

@ -359,13 +359,8 @@ 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) {
char* password = common_session->credential_handler(client, "password");
if (password != NULL)
guac_common_ssh_user_set_password(user, password);
}
if (user->password == NULL && common_session->credential_handler)
user->password = common_session->credential_handler(client, "Password: ");
/* Authenticate with password, if provided */
if (user->password != NULL) {

26
src/protocols/ssh/argv.c
View File

@ -18,10 +18,7 @@
*/
#include "config.h"
#include "argv.h"
#include "common-ssh/user.h"
#include "settings.h"
#include "ssh.h"
#include "terminal/terminal.h"
@ -39,30 +36,9 @@ int guac_ssh_argv_callback(guac_user* user, const char* mimetype,
guac_client* client = user->client;
guac_ssh_client* ssh_client = (guac_ssh_client*) client->data;
guac_terminal* terminal = ssh_client->term;
guac_ssh_settings* settings = ssh_client->settings;
/* Update username */
if (strcmp(name, GUAC_SSH_ARGV_USERNAME) == 0) {
free(settings->username);
settings->username = strdup(value);
pthread_cond_signal(&ssh_client->ssh_credential_cond);
}
/* Update password */
else if (strcmp(name, GUAC_SSH_ARGV_PASSWORD) == 0) {
guac_common_ssh_user_set_password(ssh_client->user, value);
pthread_cond_signal(&ssh_client->ssh_credential_cond);
}
/* Update private key passphrase */
else if (strcmp(name, GUAC_SSH_ARGV_PASSPHRASE) == 0) {
free(settings->key_passphrase);
settings->key_passphrase = strdup(value);
pthread_cond_signal(&ssh_client->ssh_credential_cond);
}
/* Update color scheme */
else if (strcmp(name, GUAC_SSH_ARGV_COLOR_SCHEME) == 0)
if (strcmp(name, GUAC_SSH_ARGV_COLOR_SCHEME) == 0)
guac_terminal_apply_color_scheme(terminal, value);
/* Update font name */

18
src/protocols/ssh/argv.h
View File

@ -44,24 +44,6 @@
*/
#define GUAC_SSH_ARGV_FONT_SIZE "font-size"
/**
* The name of the parameter that specifies/updates the username used by the
* connection.
*/
#define GUAC_SSH_ARGV_USERNAME "username"
/**
* The name of the parameter that specifies/updates the password used by the
* connection.
*/
#define GUAC_SSH_ARGV_PASSWORD "password"
/**
* The name of the parameter that specifies/updates the private key passphrase
* used by the connection.
*/
#define GUAC_SSH_ARGV_PASSPHRASE "passphrase"
/**
* Handles a received argument value from a Guacamole "argv" instruction,
* updating the given connection parameter.

9
src/protocols/ssh/client.c
View File

@ -47,15 +47,12 @@ int guac_client_init(guac_client* client) {
/* Init clipboard */
ssh_client->clipboard = guac_common_clipboard_alloc(GUAC_SSH_CLIPBOARD_MAX_LENGTH);
/* Set handlers */
client->join_handler = guac_ssh_user_join_handler;
client->free_handler = guac_ssh_client_free_handler;
/* Register handlers for argument values that may be sent after the handshake */
guac_argv_register(GUAC_SSH_ARGV_USERNAME, guac_ssh_argv_callback, NULL, 0);
guac_argv_register(GUAC_SSH_ARGV_PASSWORD, guac_ssh_argv_callback, NULL, 0);
guac_argv_register(GUAC_SSH_ARGV_PASSPHRASE, guac_ssh_argv_callback, NULL, 0);
guac_argv_register(GUAC_SSH_ARGV_COLOR_SCHEME, guac_ssh_argv_callback, NULL, GUAC_ARGV_OPTION_ECHO);
guac_argv_register(GUAC_SSH_ARGV_FONT_NAME, guac_ssh_argv_callback, NULL, GUAC_ARGV_OPTION_ECHO);
guac_argv_register(GUAC_SSH_ARGV_FONT_SIZE, guac_ssh_argv_callback, NULL, GUAC_ARGV_OPTION_ECHO);
@ -123,10 +120,6 @@ int guac_ssh_client_free_handler(guac_client* client) {
guac_common_clipboard_free(ssh_client->clipboard);
free(ssh_client);
/* Destroy the pthread conditional handler */
pthread_cond_destroy(&(ssh_client->ssh_credential_cond));
pthread_mutex_destroy(&(ssh_client->ssh_credential_lock));
guac_common_ssh_uninit();
return 0;
}

6
src/protocols/ssh/settings.c
View File

@ -36,8 +36,8 @@ const char* GUAC_SSH_CLIENT_ARGS[] = {
"hostname",
"host-key",
"port",
GUAC_SSH_ARGV_USERNAME,
GUAC_SSH_ARGV_PASSWORD,
"username",
"password",
GUAC_SSH_ARGV_FONT_NAME,
GUAC_SSH_ARGV_FONT_SIZE,
"enable-sftp",
@ -45,7 +45,7 @@ const char* GUAC_SSH_CLIENT_ARGS[] = {
"sftp-disable-download",
"sftp-disable-upload",
"private-key",
GUAC_SSH_ARGV_PASSPHRASE,
"passphrase",
#ifdef ENABLE_SSH_AGENT
"enable-agent",
#endif

136
src/protocols/ssh/ssh.c
View File

@ -57,92 +57,6 @@
#include <sys/socket.h>
#include <sys/time.h>
/**
* A data structure that maps parameter names of credentials that will be
* prompted to the actual text that will be displayed on the screen.
*/
typedef struct guac_ssh_credential_prompt_map {
/**
* The parameter name of the credential that is being prompted for.
*/
char* name;
/**
* The text that will display to the user during the prompt.
*/
char* prompt;
} guac_ssh_credential_prompt_map;
/**
* The map of credentials the user can be prompted for to the text displayed
* on the screen.
*/
guac_ssh_credential_prompt_map ssh_credential_prompt_map[] = {
{ GUAC_SSH_ARGV_USERNAME, "Login as: " },
{ GUAC_SSH_ARGV_PASSWORD, "Password: " },
{ GUAC_SSH_ARGV_PASSPHRASE, "Key passphrase: " },
{ NULL, NULL}
};
/**
* Prompts the user for the credential specified in the cred_name parameter in
* order to continue a SSH connection. If the owner of the connection is running
* a client that supports the "required" instruction this credential will be
* sent to the client with that instruction and updated directly via the argv
* handler. If the client does not support the "required" instruction the prompt
* will be generated directly on the terminal and the value returned through
* this function.
*
* @param client
* The guac_client object associated with the current connection
* where additional credentials are required.
*
* @param cred_name
* The name of the parameter to prompt for in the client.
*
* @return
* If the client does not support the "required" instruction, the value
* provided by the user on the terminal will be returned. NULL will be
* returned if either the client supports the "required" instruction and
* the parameter will be updated directly, or if the parameter specified
* is invalid.
*/
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 SSH client thread while prompting for the credential. */
pthread_mutex_lock(&(ssh_client->ssh_credential_lock));
/* Let the owner know what we require. */
guac_client_owner_send_required(client, (const char* []) {cred_name, NULL});
/* Wait for the response, and then unlock the thread. */
pthread_cond_wait(&(ssh_client->ssh_credential_cond), &(ssh_client->ssh_credential_lock));
pthread_mutex_unlock(&(ssh_client->ssh_credential_lock));
return NULL;
}
/**
* Produces a new user object containing a username and password or private
* key, prompting the user as necessary to obtain that information.
@ -163,14 +77,10 @@ static guac_common_ssh_user* guac_ssh_get_user(guac_client* client) {
guac_common_ssh_user* user;
/* Get username */
if (settings->username == NULL) {
char* username = guac_ssh_get_credential(client, GUAC_SSH_ARGV_USERNAME);
if (username != NULL)
settings->username = username;
if (settings->username == NULL)
settings->username = guac_terminal_prompt(ssh_client->term,
"Login as: ", true);
}
/* Create user object from username */
user = guac_common_ssh_create_user(settings->username);
@ -193,13 +103,10 @@ static guac_common_ssh_user* guac_ssh_get_user(guac_client* client) {
"Re-attempting private key import (WITH passphrase)");
/* Prompt for passphrase if missing */
if (settings->key_passphrase == NULL) {
char* passphrase = guac_ssh_get_credential(client, GUAC_SSH_ARGV_PASSPHRASE);
if (passphrase != NULL)
settings->key_passphrase = passphrase;
}
if (settings->key_passphrase == NULL)
settings->key_passphrase =
guac_terminal_prompt(ssh_client->term,
"Key passphrase: ", false);
/* Reattempt import with passphrase */
if (guac_common_ssh_user_import_key(user,
@ -237,6 +144,29 @@ static guac_common_ssh_user* guac_ssh_get_user(guac_client* client) {
}
/**
* A function used to generate a terminal prompt to gather additional
* credentials from the guac_client during a connection, and using
* the specified string to generate the prompt for the user.
*
* @param client
* The guac_client object associated with the current connection
* where additional credentials are required.
*
* @param cred_name
* The prompt text to display to the screen when prompting for the
* additional credentials.
*
* @return
* The string of credentials gathered from the user.
*/
static char* guac_ssh_get_credential(guac_client *client, char* cred_name) {
guac_ssh_client* ssh_client = (guac_ssh_client*) client->data;
return guac_terminal_prompt(ssh_client->term, cred_name, false);
}
void* ssh_input_thread(void* data) {
guac_client* client = (guac_client*) data;
@ -338,6 +268,9 @@ void* ssh_client_thread(void* data) {
return NULL;
}
/* Ensure connection is kept alive during lengthy connects */
guac_socket_require_keep_alive(client->socket);
/* Open SSH session */
ssh_client->session = guac_common_ssh_create_session(client,
settings->hostname, settings->port, ssh_client->user, settings->server_alive_interval,
@ -348,8 +281,6 @@ void* ssh_client_thread(void* data) {
}
pthread_mutex_init(&ssh_client->term_channel_lock, NULL);
pthread_mutex_init(&ssh_client->ssh_credential_lock, NULL);
pthread_cond_init(&ssh_client->ssh_credential_cond, NULL);
/* Open channel for terminal */
ssh_client->term_channel =
@ -564,7 +495,6 @@ void* ssh_client_thread(void* data) {
guac_client_stop(client);
pthread_join(input_thread, NULL);
pthread_cond_destroy(&ssh_client->ssh_credential_cond);
pthread_mutex_destroy(&ssh_client->term_channel_lock);
guac_client_log(client, GUAC_LOG_INFO, "SSH connection ended.");

12
src/protocols/ssh/ssh.h
View File

@ -89,18 +89,6 @@ typedef struct guac_ssh_client {
* Lock dictating access to the SSH terminal channel.
*/
pthread_mutex_t term_channel_lock;
/**
* Lock that controls access to updating credential parameters for the
* SSH connection.
*/
pthread_mutex_t ssh_credential_lock;
/**
* Condition used when the SSH client thread needs to wait for Guacamole
* client to pass additional credentials before continuing the connection.
*/
pthread_cond_t ssh_credential_cond;
/**
* The current clipboard contents.