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GUACAMOLE-422: Change handshake to ignore order of opcodes.

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This commit is contained in:
Nick Couchman 2019-03-28 20:09:32 -04:00
parent 5480b288e8
commit 0ee47e0186
2 changed files with 198 additions and 121 deletions
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73
src/libguac/guacamole/user.h
View File

@ -505,6 +505,79 @@ struct guac_user {
};
/**
* Handler for Guacamole protocol opcode specific to the handshake that
* happens between client and server at the beginning of the connection. The
* handler will be invoked when the matching opcode is received during the
* handshake process.
*
* @param user
* The user that initiated the handshake.
*
* @param parser
* The parser allocated for parsing the data provided by the client.
*
* @param timeout
* The timeout, in microseconds, for parsing the value.
*
* @return
* Zero if the handshake instruction is successfully parsed; otherwise
* false.
*/
typedef int __guac_handshake_handler(guac_user* user, int argc, char** argv);
/**
* Structure that maps opcodes received during the handshake phase of the
* connection to callback functions used when those opcodes are received.
*/
typedef struct __guac_handshake_mapping {
/**
* The instruction opcode which maps to the handler.
*/
char* opcode;
/**
* The handler function used when specified opcode is received.
*/
__guac_handshake_handler* handler;
} __guac_handshake_mapping;
/**
* Internal handler function that is called when the size instruction is
* received during the handshake process.
*/
__guac_handshake_handler __guac_handshake_size_handler;
/**
* Internal handler function that is called when the audio instruction is
* received during the handshake process, specifying the audio mimetypes
* available to the client.
*/
__guac_handshake_handler __guac_handshake_audio_handler;
/**
* Internal handler function that is called when the video instruction is
* received during the handshake process, specifying the video mimetypes
* available to the client.
*/
__guac_handshake_handler __guac_handshake_video_handler;
/**
* Internal handler function that is called when the image instruction is
* received during the handshake process, specifying the image mimetypes
* available to the client.
*/
__guac_handshake_handler __guac_handshake_image_handler;
/**
* Internal handler function that is called when the timezone instruction is
* received during the handshake process, specifying the timezone of the
* client.
*/
__guac_handshake_handler __guac_handshake_timezone_handler;
/**
* Allocates a new, blank user, not associated with any specific client or
* socket.

232
src/libguac/user-handshake.c
View File

@ -171,6 +171,80 @@ static void guac_free_mimetypes(char** mimetypes) {
}
/* Guacamole handshake handler functions. */
int __guac_handshake_size_handler(guac_user* user, int argc, char** argv) {
/* Validate size of instruction. */
if (argc < 2) {
guac_user_log(user, GUAC_LOG_ERROR, "Received \"size\" "
"instruction lacked required arguments.");
return 1;
}
/* Parse optimal screen dimensions from size instruction */
user->info.optimal_width = atoi(argv[0]);
user->info.optimal_height = atoi(argv[1]);
/* If DPI given, set the user resolution */
if (argc >= 3)
user->info.optimal_resolution = atoi(argv[2]);
/* Otherwise, use a safe default for rough backwards compatibility */
else
user->info.optimal_resolution = 96;
return 0;
}
int __guac_handshake_audio_handler(guac_user* user, int argc, char** argv) {
/* Store audio mimetypes */
user->info.audio_mimetypes = (const char**) guac_copy_mimetypes(argv, argc);
return 0;
}
int __guac_handshake_video_handler(guac_user* user, int argc, char** argv) {
/* Store video mimetypes */
user->info.video_mimetypes = (const char**) guac_copy_mimetypes(argv, argc);
return 0;
}
int __guac_handshake_image_handler(guac_user* user, int argc, char** argv) {
/* Store image mimetypes */
user->info.image_mimetypes = (const char**) guac_copy_mimetypes(argv, argc);
return 0;
}
int __guac_handshake_timezone_handler(guac_user* user, int argc, char** argv) {
/* Store timezone, if present */
if (argc > 0 && strcmp(argv[0], ""))
user->info.timezone = (const char*) strdup(argv[0]);
return 0;
}
/* Guacamole handshake handler mappings. */
__guac_handshake_mapping __guac_handshake_map[] = {
{"size", __guac_handshake_size_handler},
{"audio", __guac_handshake_audio_handler},
{"video", __guac_handshake_video_handler},
{"image", __guac_handshake_image_handler},
{"timezone", __guac_handshake_timezone_handler},
{NULL, NULL}
};
/**
* The thread which handles all user input, calling event handlers for received
* instructions.
@ -305,122 +379,53 @@ int guac_user_handle_connection(guac_user* user, int usec_timeout) {
guac_parser* parser = guac_parser_alloc();
/* Get optimal screen size */
if (guac_parser_expect(parser, socket, usec_timeout, "size")) {
/* Handle each of the opcodes. */
while (1) {
if (guac_parser_read(parser, socket, usec_timeout)) {
guac_user_log_handshake_failure(user);
guac_user_log_guac_error(user, GUAC_LOG_DEBUG,
"Error while reading opcode instruction.");
guac_parser_free(parser);
return 1;
}
/* Log error */
guac_user_log_handshake_failure(user);
guac_user_log_guac_error(user, GUAC_LOG_DEBUG,
"Error reading \"size\"");
/* If we receive the connect opcode, we're done. */
if (strcmp(parser->opcode, "connect") == 0)
break;
guac_parser_free(parser);
return 1;
}
/* Loop available opcodes and run handler if/when match found. */
__guac_handshake_mapping* current = __guac_handshake_map;
while (current->opcode != NULL) {
/* Validate content of size instruction */
if (parser->argc < 2) {
guac_user_log(user, GUAC_LOG_ERROR, "Received \"size\" "
"instruction lacked required arguments.");
guac_parser_free(parser);
return 1;
}
/* Check if loop opcode matches parsed opcode. */
if (strcmp(parser->opcode, current->opcode) == 0) {
/* Parse optimal screen dimensions from size instruction */
user->info.optimal_width = atoi(parser->argv[0]);
user->info.optimal_height = atoi(parser->argv[1]);
/* If calling the handler fails, log it and return. */
if (current->handler(user, parser->argc, parser->argv)) {
/* If DPI given, set the user resolution */
if (parser->argc >= 3)
user->info.optimal_resolution = atoi(parser->argv[2]);
guac_user_log_handshake_failure(user);
guac_user_log_guac_error(user, GUAC_LOG_DEBUG,
"Error handling handling opcode during handshake.");
guac_user_log(user, GUAC_LOG_DEBUG, "Failed opcode: %s",
current->opcode);
/* Otherwise, use a safe default for rough backwards compatibility */
else
user->info.optimal_resolution = 96;
guac_parser_free(parser);
return 1;
}
/* Get supported audio formats */
if (guac_parser_expect(parser, socket, usec_timeout, "audio")) {
/* If calling the handler has succeeded, log it and break. */
else {
guac_user_log(user, GUAC_LOG_DEBUG,
"Successfully processed instruction: \"%s\"",
current->opcode);
break;
}
/* Log error */
guac_user_log_handshake_failure(user);
guac_user_log_guac_error(user, GUAC_LOG_DEBUG,
"Error reading \"audio\"");
}
guac_parser_free(parser);
return 1;
}
/* Store audio mimetypes */
char** audio_mimetypes = guac_copy_mimetypes(parser->argv, parser->argc);
user->info.audio_mimetypes = (const char**) audio_mimetypes;
/* Get supported video formats */
if (guac_parser_expect(parser, socket, usec_timeout, "video")) {
/* Log error */
guac_user_log_handshake_failure(user);
guac_user_log_guac_error(user, GUAC_LOG_DEBUG,
"Error reading \"video\"");
guac_parser_free(parser);
return 1;
}
/* Store video mimetypes */
char** video_mimetypes = guac_copy_mimetypes(parser->argv, parser->argc);
user->info.video_mimetypes = (const char**) video_mimetypes;
/* Get supported image formats */
if (guac_parser_expect(parser, socket, usec_timeout, "image")) {
/* Log error */
guac_user_log_handshake_failure(user);
guac_user_log_guac_error(user, GUAC_LOG_DEBUG,
"Error reading \"image\"");
guac_parser_free(parser);
return 1;
}
/* Store image mimetypes */
char** image_mimetypes = guac_copy_mimetypes(parser->argv, parser->argc);
user->info.image_mimetypes = (const char**) image_mimetypes;
/* Get client timezone */
if (guac_parser_expect(parser, socket, usec_timeout, "timezone")) {
/* Log error */
guac_user_log_handshake_failure(user);
guac_user_log_guac_error(user, GUAC_LOG_DEBUG,
"Error reading \"timezone\"");
guac_parser_free(parser);
return 1;
}
/* Check number of timezone arguments */
if (parser->argc < 1) {
guac_user_log(user, GUAC_LOG_ERROR, "Received \"timezone\" instruction "
"lacked required arguments.");
guac_parser_free(parser);
return 1;
}
/* Store timezone, if present */
char* timezone = parser->argv[0];
if (!strcmp(timezone, ""))
user->info.timezone = (const char*) timezone;
/* Get args from connect instruction */
if (guac_parser_expect(parser, socket, usec_timeout, "connect")) {
/* Log error */
guac_user_log_handshake_failure(user);
guac_user_log_guac_error(user, GUAC_LOG_DEBUG,
"Error reading \"connect\"");
guac_parser_free(parser);
return 1;
/* Move to next opcode. */
current++;
}
}
/* Acknowledge connection availability */
@ -449,14 +454,13 @@ int guac_user_handle_connection(guac_user* user, int usec_timeout) {
}
/* Free mimetype lists */
guac_free_mimetypes(audio_mimetypes);
guac_free_mimetypes(video_mimetypes);
guac_free_mimetypes(image_mimetypes);
/* Free mimetype character arrays. */
guac_free_mimetypes((char **) user->info.audio_mimetypes);
guac_free_mimetypes((char **) user->info.image_mimetypes);
guac_free_mimetypes((char **) user->info.video_mimetypes);
/* Free timezone */
if (timezone != NULL)
free(timezone);
/* Free timezone info. */
free((char *) user->info.timezone);
guac_parser_free(parser);