mirror of
https://github.com/zerotier/ZeroTierOne.git
synced 2024-12-23 23:02:23 +00:00
282 lines
7.4 KiB
C
282 lines
7.4 KiB
C
#include <stdio.h>
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#include <unistd.h>
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#include <sys/un.h>
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#include <pthread.h>
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#include <errno.h>
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#include <sys/syscall.h>
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#include <fcntl.h>
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#include <dlfcn.h>
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#include <stdint.h>
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#include <sys/socket.h>
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#include <strings.h>
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#include "RPC.h"
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#define SERVICE_CONNECT_ATTEMPTS 30
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#define CONNECT_SIG int __fd, const struct sockaddr * __addr, socklen_t __len
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#define SOCKET_SIG int socket_family, int socket_type, int protocol
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static int (*realconnect)(CONNECT_SIG) = 0;
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static int (*realsocket)(SOCKET_SIG) = 0;
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#ifdef NETCON_INTERCEPT
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static int rpc_count;
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#endif
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static pthread_mutex_t lock;
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void rpc_mutex_init() {
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if(pthread_mutex_init(&lock, NULL) != 0) {
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fprintf(stderr, "error while initializing service call mutex\n");
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}
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}
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void rpc_mutex_destroy() {
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pthread_mutex_destroy(&lock);
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}
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/*
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* Reads a new file descriptor from the service
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*/
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int get_new_fd(int sock)
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{
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char buf[BUF_SZ];
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int newfd;
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ssize_t size = sock_fd_read(sock, buf, sizeof(buf), &newfd);
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if(size > 0){
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return newfd;
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}
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fprintf(stderr, "get_new_fd(): Error, unable to read fd over (%d)\n", sock);
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return -1;
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}
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/*
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* Reads a return value from the service and sets errno (if applicable)
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*/
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int get_retval(int rpc_sock)
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{
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if(rpc_sock >= 0) {
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int retval;
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int sz = sizeof(char) + sizeof(retval) + sizeof(errno);
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char retbuf[BUF_SZ];
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memset(&retbuf, 0, sz);
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int n_read = read(rpc_sock, &retbuf, sz);
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if(n_read > 0) {
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memcpy(&retval, &retbuf[1], sizeof(retval));
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memcpy(&errno, &retbuf[1+sizeof(retval)], sizeof(errno));
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return retval;
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}
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}
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return -1;
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}
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int load_symbols_rpc()
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{
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#ifdef NETCON_INTERCEPT
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realsocket = dlsym(RTLD_NEXT, "socket");
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realconnect = dlsym(RTLD_NEXT, "connect");
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if(!realconnect || !realsocket)
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return -1;
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#endif
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return 1;
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}
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int rpc_join(const char * sockname)
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{
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if(!load_symbols_rpc())
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return -1;
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struct sockaddr_un addr;
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int conn_err = -1, attempts = 0;
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memset(&addr, 0, sizeof(addr));
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addr.sun_family = AF_UNIX;
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strncpy(addr.sun_path, sockname, sizeof(addr.sun_path)-1);
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int sock;
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if((sock = realsocket(AF_UNIX, SOCK_STREAM, 0)) < 0){
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fprintf(stderr, "Error while creating RPC socket\n");
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return -1;
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}
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while((conn_err != 0) && (attempts < SERVICE_CONNECT_ATTEMPTS)){
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if((conn_err = realconnect(sock, (struct sockaddr*)&addr, sizeof(addr))) != 0) {
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fprintf(stderr, "Error while connecting to RPC socket. Re-attempting...\n");
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sleep(1);
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}
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else
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return sock;
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attempts++;
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}
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return -1;
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}
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/*
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* Send a command to the service
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*/
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int rpc_send_command(char *path, int cmd, int forfd, void *data, int len)
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{
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pthread_mutex_lock(&lock);
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char c, padding[] = {0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89};
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char cmdbuf[BUF_SZ], CANARY[TOKEN_SIZE], metabuf[BUF_SZ];
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memcpy(CANARY+CANARY_SIZE, padding, sizeof(padding));
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uint64_t canary_num;
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// ephemeral RPC socket used only for this command
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int rpc_sock = rpc_join(path);
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// Generate token
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int fdrand = open("/dev/urandom", O_RDONLY);
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if(read(fdrand, &CANARY, CANARY_SIZE) < 0) {
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fprintf(stderr,"unable to read from /dev/urandom for RPC canary data\n");
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return -1;
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}
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memcpy(&canary_num, CANARY, CANARY_SIZE);
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cmdbuf[CMD_ID_IDX] = cmd;
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memcpy(&cmdbuf[CANARY_IDX], &canary_num, CANARY_SIZE);
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memcpy(&cmdbuf[STRUCT_IDX], data, len);
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#ifdef VERBOSE
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memset(metabuf, 0, BUF_SZ);
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pid_t pid = syscall(SYS_getpid);
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pid_t tid = syscall(SYS_gettid);
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rpc_count++;
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char timestring[20];
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time_t timestamp;
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timestamp = time(NULL);
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strftime(timestring, sizeof(timestring), "%H:%M:%S", localtime(×tamp));
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memcpy(metabuf, RPC_PHRASE, RPC_PHRASE_SIZE); // Write signal phrase
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memcpy(&metabuf[IDX_PID], &pid, sizeof(pid_t) ); /* pid */
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memcpy(&metabuf[IDX_TID], &tid, sizeof(pid_t) ); /* tid */
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memcpy(&metabuf[IDX_COUNT], &rpc_count, sizeof(rpc_count) ); /* rpc_count */
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memcpy(&metabuf[IDX_TIME], ×tring, 20 ); /* timestamp */
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#endif
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/* Combine command flag+payload with RPC metadata */
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memcpy(&metabuf[IDX_PAYLOAD], cmdbuf, len + 1 + CANARY_SIZE);
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// Write RPC
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int n_write = write(rpc_sock, &metabuf, BUF_SZ);
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if(n_write < 0) {
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fprintf(stderr, "Error writing command to service (CMD = %d)\n", cmdbuf[CMD_ID_IDX]);
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errno = 0;
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}
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// Write token to corresponding data stream
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if(read(rpc_sock, &c, 1) < 0) {
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fprintf(stderr, "unable to read RPC ACK byte from service.\n");
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return -1;
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}
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if(c == 'z' && n_write > 0 && forfd > -1){
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if(send(forfd, &CANARY, TOKEN_SIZE, 0) < 0) {
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fprintf(stderr,"unable to write canary to stream\n");
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return -1;
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}
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}
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// Process response from service
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int ret = ERR_OK;
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if(n_write > 0) {
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if(cmdbuf[CMD_ID_IDX]==RPC_SOCKET) {
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pthread_mutex_unlock(&lock);
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return rpc_sock; // Used as new socket
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}
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if(cmdbuf[CMD_ID_IDX]==RPC_CONNECT
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|| cmdbuf[CMD_ID_IDX]==RPC_BIND
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|| cmdbuf[CMD_ID_IDX]==RPC_LISTEN) {
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ret = get_retval(rpc_sock);
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}
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if(cmdbuf[CMD_ID_IDX]==RPC_GETSOCKNAME) {
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pthread_mutex_unlock(&lock);
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return rpc_sock; // Don't close rpc here, we'll use it to read getsockopt_st
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}
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}
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else
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ret = -1;
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close(rpc_sock); // We're done with this RPC socket, close it (if type-R)
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pthread_mutex_unlock(&lock);
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return ret;
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}
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/*
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* Send file descriptor
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*/
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ssize_t sock_fd_write(int sock, int fd)
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{
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ssize_t size;
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struct msghdr msg;
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struct iovec iov;
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char buf = '\0';
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int buflen = 1;
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union {
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struct cmsghdr cmsghdr;
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char control[CMSG_SPACE(sizeof (int))];
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} cmsgu;
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struct cmsghdr *cmsg;
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iov.iov_base = &buf;
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iov.iov_len = buflen;
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msg.msg_name = NULL;
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msg.msg_namelen = 0;
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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if (fd != -1) {
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msg.msg_control = cmsgu.control;
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msg.msg_controllen = sizeof(cmsgu.control);
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cmsg = CMSG_FIRSTHDR(&msg);
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cmsg->cmsg_len = CMSG_LEN(sizeof (int));
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cmsg->cmsg_level = SOL_SOCKET;
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cmsg->cmsg_type = SCM_RIGHTS;
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*((int *) CMSG_DATA(cmsg)) = fd;
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} else {
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msg.msg_control = NULL;
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msg.msg_controllen = 0;
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}
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size = sendmsg(sock, &msg, 0);
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if (size < 0)
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perror ("sendmsg");
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return size;
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}
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/*
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* Read a file descriptor
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*/
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ssize_t sock_fd_read(int sock, void *buf, ssize_t bufsize, int *fd)
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{
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ssize_t size;
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if (fd) {
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struct msghdr msg;
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struct iovec iov;
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union {
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struct cmsghdr cmsghdr;
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char control[CMSG_SPACE(sizeof (int))];
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} cmsgu;
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struct cmsghdr *cmsg;
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iov.iov_base = buf;
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iov.iov_len = bufsize;
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msg.msg_name = NULL;
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msg.msg_namelen = 0;
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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msg.msg_control = cmsgu.control;
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msg.msg_controllen = sizeof(cmsgu.control);
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size = recvmsg (sock, &msg, 0);
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if (size < 0) {
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fprintf(stderr, "sock_fd_read(): recvmsg: Error\n");
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return -1;
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}
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cmsg = CMSG_FIRSTHDR(&msg);
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if (cmsg && cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
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if (cmsg->cmsg_level != SOL_SOCKET) {
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fprintf (stderr, "invalid cmsg_level %d\n",cmsg->cmsg_level);
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return -1;
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}
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if (cmsg->cmsg_type != SCM_RIGHTS) {
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fprintf (stderr, "invalid cmsg_type %d\n",cmsg->cmsg_type);
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return -1;
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}
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*fd = *((int *) CMSG_DATA(cmsg));
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} else *fd = -1;
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} else {
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size = read (sock, buf, bufsize);
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if (size < 0) {
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fprintf(stderr, "sock_fd_read(): read: Error\n");
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return -1;
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}
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}
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return size;
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}
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