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Patch of various fixes, cleanups and unused code removals:

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- add MAX_COMMAND_LENGTH to define maximum command length
 - print auth failed message to stderr instead of stdout
 - remove unused net_send() function
 - remove unused net_clean_incoming() function
 - rewrite net_send_packet() function
 - net_recv_packet(): change the type of variable "ret" from int to ssize_t
 - net_recv_packet(): fail immediately if the packet size is out of spec
 - packet_print(): rename variable "def_color" to "default_color"
 - packet_print(): remove unecessary casts
 - packet_build(): use MAX_COMMAND_LENGTH
 - packet_build(): be more explicit in calculation of packet.size
 - packet_build(): use memcpy() instead of strncpy()
 - cast second argument of send()/recv() calls to (char *) so Windows is happy
 - rcon_auth(): change the return type from int to bool
 - run_terminal_mode(): use MAX_COMMAND_LENGTH
This commit is contained in:
Tiiffi
2024-12-02 07:32:07 +02:00
parent c83d96cc91
commit 5c7ab407d7
1 changed files with 81 additions and 146 deletions
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227
mcrcon.c
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2012-2021, Tiiffi <tiiffi at gmail>
* Copyright (c) 2012-2024, Tiiffi <tiiffi at gmail>
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
@ -24,6 +24,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <strings.h>
#include <signal.h>
@ -32,13 +33,9 @@
#include <limits.h>
#ifdef _WIN32
// for name resolving on windows
// enable this if you get compiler whine about getaddrinfo() on windows
//#define _WIN32_WINNT 0x0501
#include <ws2tcpip.h>
#include <winsock2.h>
#include <winsock2.h>
#include <windows.h>
#include <ws2tcpip.h>
#else
#include <sys/types.h>
#include <sys/socket.h>
@ -57,46 +54,19 @@
#define RCON_AUTH_RESPONSE 2
#define RCON_PID 0xBADC0DE
/* NOTE: This is confusing. What is the real max packet size?
* Are null bytes included? Are both null bytes included?
* Perhaps payload end indicator is uin16_t with zero value?
*/
#define DATA_BUFFSIZE 4098 // 2 bytes extra over 4096
#define MAX_PACKET_SIZE 4106
#define MIN_PACKET_SIZE 10
#define MAX_COMMAND_LENGTH 4096
#define DATA_BUFFSIZE MAX_COMMAND_LENGTH + 2 // plus two null terminators
#define MAX_PACKET_SIZE 4106 // id (4) + cmd (4) + DATA_BUFFSIZE
#define MIN_PACKET_SIZE 10 // id (4) + cmd (4) + two empty strings (2)
// rcon packet structure,
// NOTE(Tiiffi): Alignment problem!
typedef struct _rc_packet {
// rcon packet structure
typedef struct {
int32_t size;
int32_t id;
int32_t cmd;
char data[DATA_BUFFSIZE];
uint8_t data[DATA_BUFFSIZE];
// ignoring string2 for now
} rc_packet;
// __attribute__((packed))
/* TODO(Tiiffi):
*
* Correct packet structure is propably something like this:
*
* +---------------------------+
* | Size (4 bytes, int) | Total packet size (excluding this field)
* +---------------------------+
* | ID (4 bytes, int) |
* +---------------------------+
* | Type (4 bytes, int) |
* +---------------------------+
* | Payload (variable length) | Command or response string (up to 4096 bytes)
* | (null-terminated string) |
* +---------------------------+
* | Null Terminator (2 bytes, | 16-bit integer set to zero (0x0000)
* | 16-bit int) | Could be also interpreted as two null bytes
* +---------------------------+
*
* Maximum size 4110 including size field, 4106 excluding size field.
* Take care with the aligment!
*/
// ===================================
// FUNCTION DEFINITIONS
@ -108,10 +78,8 @@ void net_init_WSA(void);
#endif
void net_close(int sd);
int net_connect(const char *host, const char *port);
int net_send(int sd, const uint8_t *buffer, size_t size);
int net_send_packet(int sd, rc_packet *packet);
bool net_send_packet(int sd, rc_packet *packet);
rc_packet* net_recv_packet(int sd);
int net_clean_incoming(int sd, int size);
// Misc stuff
void usage(void);
@ -125,7 +93,7 @@ int run_commands(int argc, char *argv[]);
// Rcon protocol related functions
rc_packet* packet_build(int id, int cmd, char *s1);
void packet_print(rc_packet *packet);
int rcon_auth(int sock, char *passwd);
bool rcon_auth(int sock, char *passwd);
int rcon_command(int sock, char *command);
@ -151,7 +119,7 @@ void exit_proc(void)
net_close(global_rsock);
}
// Check windows & linux behaviour !!!
// TODO: check exact windows and linux behaviour
void sighandler(int sig)
{
if (sig == SIGINT)
@ -241,8 +209,9 @@ int main(int argc, char *argv[])
exit(EXIT_FAILURE);
}
if(optind == argc && terminal_mode == 0)
if(optind == argc && terminal_mode == 0) {
terminal_mode = 1;
}
// safety features to prevent "IO: Connection reset" bug on the server side
atexit(&exit_proc);
@ -264,13 +233,11 @@ int main(int argc, char *argv[])
// auth & commands
if (rcon_auth(global_rsock, pass)) {
if (terminal_mode)
run_terminal_mode(global_rsock);
else
exit_code = run_commands(argc, argv);
if (terminal_mode) run_terminal_mode(global_rsock);
else exit_code = run_commands(argc, argv);
}
else { // auth failed
fprintf(stdout, "Authentication failed!\n");
fprintf(stderr, "Authentication failed!\n");
exit_code = EXIT_FAILURE;
}
@ -342,7 +309,6 @@ void net_close(int sd)
#endif
}
// Opens and connects socket
// http://man7.org/linux/man-pages/man3/getaddrinfo.3.html
// https://bugs.chromium.org/p/chromium/issues/detail?id=44489
int net_connect(const char *host, const char *port)
@ -404,51 +370,32 @@ int net_connect(const char *host, const char *port)
return sd;
}
int net_send(int sd, const uint8_t *buff, size_t size)
bool net_send_packet(int sd, rc_packet *packet)
{
size_t sent = 0;
size_t size = packet->size + sizeof(int32_t);
size_t left = size;
while (sent < size) {
int result = send(sd, (const char *) buff + sent, left, 0);
char *p = (char *) packet;
if (result == -1)
return -1;
while (sent < size) {
ssize_t result = send(sd, p + sent, left, 0);
if (result == -1) return false;
sent += result;
left -= sent;
}
return 0;
}
int net_send_packet(int sd, rc_packet *packet)
{
int len;
int total = 0; // bytes we've sent
int bytesleft; // bytes left to send
int ret = -1;
bytesleft = len = packet->size + sizeof(int32_t);
while (total < len) {
ret = send(sd, (char *) packet + total, bytesleft, 0);
if(ret == -1) break;
total += ret;
bytesleft -= ret;
}
return ret == -1 ? -1 : 1;
return true;
}
rc_packet *net_recv_packet(int sd)
{
int32_t psize;
static rc_packet packet = {0, 0, 0, { 0x00 }};
static rc_packet packet = {0};
// packet.size = packet.id = packet.cmd = 0;
int ret = recv(sd, (char *) &psize, sizeof(psize), 0);
ssize_t ret = recv(sd, (char *) &psize, sizeof(psize), 0);
if (ret == 0) {
fprintf(stderr, "Connection lost.\n");
@ -457,27 +404,23 @@ rc_packet *net_recv_packet(int sd)
}
if (ret != sizeof(psize)) {
fprintf(stderr, "Error: recv() failed. Invalid packet size (%d).\n", ret);
fprintf(stderr, "Error: recv() failed.\n");
global_connection_alive = 0;
return NULL;
}
// NOTE(Tiiffi): This should fail if size is out of spec!
if (psize < MIN_PACKET_SIZE || psize > MAX_PACKET_SIZE) {
fprintf(stderr, "Warning: invalid packet size (%d). Must over 10 and less than %d.\n", psize, MAX_PACKET_SIZE);
// WARNING(Tiiffi): This is probably not the way to go. Probably should just fail and exit.
if(psize > MAX_PACKET_SIZE || psize < 0) psize = MAX_PACKET_SIZE;
net_clean_incoming(sd, psize);
fprintf(stderr, "Error: Invalid packet size (%d).\n", psize);
global_connection_alive = 0;
return NULL;
}
packet.size = psize;
char *p = (char *) &packet;
int received = 0;
while (received < psize) {
ret = recv(sd, (char *) &packet + sizeof(int32_t) + received, psize - received, 0);
ret = recv(sd, p + sizeof(int32_t) + received, psize - received, 0);
if (ret == 0) {
fprintf(stderr, "Connection lost.\n");
global_connection_alive = 0;
@ -490,19 +433,6 @@ rc_packet *net_recv_packet(int sd)
return &packet;
}
int net_clean_incoming(int sd, int size)
{
char tmp[size];
int ret = recv(sd, tmp, size, 0);
if(ret == 0) {
fprintf(stderr, "Connection lost.\n");
global_connection_alive = 0;
}
return ret;
}
void print_color(int color)
{
// sh compatible color array
@ -527,8 +457,9 @@ void print_color(int color)
"\033[4m" /* 16 UNDERLINE 0x6e */
};
/* 0x72: 'r' */
if (color == 0 || color == 0x72) fputs("\033[0m", stdout); /* CANCEL COLOR */
if (color == 0 || color == 0x72) {
fputs("\033[0m", stdout); // cancel color
}
else
#endif
{
@ -536,7 +467,7 @@ void print_color(int color)
else if (color >= 0x30 && color <= 0x39)
color -= 0x30;
else if (color == 0x6e)
color = 16; /* 0x6e: 'n' */
color = 16;
else return;
#ifndef _WIN32
@ -550,85 +481,89 @@ void print_color(int color)
// this hacky mess might use some optimizing
void packet_print(rc_packet *packet)
{
if (global_raw_output == 1) {
for (int i = 0; packet->data[i] != 0; ++i)
putchar(packet->data[i]);
uint8_t *data = packet->data;
if (global_raw_output == 1) {
for (int i = 0; data[i] != 0; ++i) {
putchar(data[i]);
}
return;
}
int i;
int def_color = 0;
int default_color = 0;
#ifdef _WIN32
CONSOLE_SCREEN_BUFFER_INFO console_info;
if (GetConsoleScreenBufferInfo(console_handle, &console_info) != 0) {
def_color = console_info.wAttributes + 0x30;
} else def_color = 0x37;
default_color = console_info.wAttributes + 0x30;
} else default_color = 0x37;
#endif
// colors enabled so try to handle the bukkit colors for terminal
if (global_disable_colors == 0) {
for (i = 0; (unsigned char) packet->data[i] != 0; ++i) {
if (packet->data[i] == 0x0A) print_color(def_color);
else if((unsigned char) packet->data[i] == 0xc2 && (unsigned char) packet->data[i+1] == 0xa7) {
print_color(packet->data[i+=2]);
for (i = 0; data[i] != 0; ++i) {
if (data[i] == 0x0A) print_color(default_color);
else if(data[i] == 0xc2 && data[i + 1] == 0xa7) {
i += 2;
print_color(data[i]);
continue;
}
putchar(packet->data[i]);
putchar(data[i]);
}
print_color(def_color); // cancel coloring
print_color(default_color); // cancel coloring
}
// strip colors
else {
for (i = 0; (unsigned char) packet->data[i] != 0; ++i) {
if ((unsigned char) packet->data[i] == 0xc2 && (unsigned char) packet->data[i+1] == 0xa7) {
i+=2;
for (i = 0; data[i] != 0; ++i) {
if (data[i] == 0xc2 && data[i + 1] == 0xa7) {
i += 2;
continue;
}
putchar(packet->data[i]);
putchar(data[i]);
}
}
// print newline if string has no newline
if (packet->data[i-1] != 10 && packet->data[i-1] != 13) putchar('\n');
if (data[i - 1] != 10 && data[i - 1] != 13) {
putchar('\n');
}
}
rc_packet *packet_build(int id, int cmd, char *s1)
rc_packet *packet_build(int id, int cmd, char *s)
{
static rc_packet packet = {0, 0, 0, { 0x00 }};
static rc_packet packet = {0};
// NOTE(Tiiffi): Issue report states that outgoing payload has max size of 1460 bytes:
// NOTE(Tiiffi): Issue report states that maximum command packet size is 1460 bytes:
// https://github.com/Tiiffi/mcrcon/issues/45#issuecomment-1000940814
// https://mctools.readthedocs.io/en/master/rcon.html
// Have to do some testing to confirm!
// size + id + cmd + s1 + s2 NULL terminator
int len = strlen(s1);
if (len >= DATA_BUFFSIZE) {
fprintf(stderr, "Warning: Command string too long (%d). Maximum allowed: %d.\n", len, DATA_BUFFSIZE - 1);
int len = strlen(s);
if (len > MAX_COMMAND_LENGTH) {
fprintf(stderr, "Warning: Command string too long (%d). Maximum allowed: %d.\n", len, MAX_COMMAND_LENGTH);
return NULL;
}
packet.size = sizeof packet.size * 2 + len + 2;
packet.size = sizeof packet.id + sizeof packet.cmd + len + 2;
packet.id = id;
packet.cmd = cmd;
strncpy(packet.data, s1, DATA_BUFFSIZE - 1);
memcpy(packet.data, s, len);
packet.data[len] = 0;
packet.data[len + 1] = 0;
return &packet;
}
int rcon_auth(int sock, char *passwd)
bool rcon_auth(int sock, char *passwd)
{
int ret;
rc_packet *packet = packet_build(RCON_PID, RCON_AUTHENTICATE, passwd);
if (packet == NULL)
return 0;
ret = net_send_packet(sock, packet);
if (!ret)
if (!net_send_packet(sock, packet)) {
return 0; // send failed
}
receive:
packet = net_recv_packet(sock);
@ -642,19 +577,19 @@ receive:
goto receive;
}
// return 1 if authentication OK
return packet->id == -1 ? 0 : 1;
// return true if authentication OK
return packet->id == -1 ? false : true;
}
// TODO: Add proper error handling and reporting!
int rcon_command(int sock, char *command)
{
rc_packet *packet = packet_build(RCON_PID, RCON_EXEC_COMMAND, command);
if (packet == NULL) {
global_connection_alive = 0;
if (packet == NULL)
return 0;
}
net_send_packet(sock, packet);
if (!net_send_packet(sock, packet))
return 0;
packet = net_recv_packet(sock);
if (packet == NULL)
@ -696,14 +631,14 @@ int run_commands(int argc, char *argv[])
int run_terminal_mode(int sock)
{
int ret = 0;
char command[DATA_BUFFSIZE] = {0};
char command[MAX_COMMAND_LENGTH] = {0};
puts("Logged in.\nType 'Q' or press Ctrl-D / Ctrl-C to disconnect.");
while (global_connection_alive) {
putchar('>');
int len = get_line(command, DATA_BUFFSIZE);
int len = get_line(command, MAX_COMMAND_LENGTH);
if (len < 1) continue;
if (strcasecmp(command, "Q") == 0)