1 #ifndef lint 2 static char sccsid[] = "@(#)rexecd.c 4.8 83/02/21"; 3 #endif 4 5 #include <sys/ioctl.h> 6 #include <sys/param.h> 7 #include <sys/socket.h> 8 9 #include <netinet/in.h> 10 11 #include <stdio.h> 12 #include <errno.h> 13 #include <pwd.h> 14 #include <wait.h> 15 #include <signal.h> 16 #include <netdb.h> 17 18 extern errno; 19 struct sockaddr_in sin = { AF_INET }; 20 struct passwd *getpwnam(); 21 char *crypt(), *rindex(), *sprintf(); 22 /* VARARGS 1 */ 23 int error(); 24 int reapchild(); 25 /* 26 * remote execute server: 27 * username\0 28 * password\0 29 * command\0 30 * data 31 */ 32 main(argc, argv) 33 int argc; 34 char **argv; 35 { 36 int f; 37 struct sockaddr_in from; 38 struct servent *sp; 39 40 sp = getservbyname("exec", "tcp"); 41 if (sp == 0) { 42 fprintf(stderr, "tcp/exec: unknown service\n"); 43 exit(1); 44 } 45 sin.sin_port = sp->s_port; 46 #ifndef DEBUG 47 if (fork()) 48 exit(0); 49 for (f = 0; f < 10; f++) 50 (void) close(f); 51 (void) open("/", 0); 52 (void) dup2(0, 1); 53 (void) dup2(0, 2); 54 { int t = open("/dev/tty", 2); 55 if (t >= 0) { 56 ioctl(t, TIOCNOTTY, (char *)0); 57 (void) close(t); 58 } 59 } 60 #endif 61 argc--, argv++; 62 f = socket(AF_INET, SOCK_STREAM, 0, 0); 63 if (f < 0) { 64 perror("rexecd: socket"); 65 exit(1); 66 } 67 if (bind(f, &sin, sizeof (sin), 0) < 0) { 68 perror("rexecd: bind:"); 69 exit(1); 70 } 71 sigset(SIGCHLD, reapchild); 72 listen(f, 10); 73 for (;;) { 74 int s, len = sizeof (from); 75 76 s = accept(f, &from, &len, 0); 77 if (s < 0) { 78 if (errno == EINTR) 79 continue; 80 perror("rexecd: accept"); 81 sleep(1); 82 continue; 83 } 84 if (fork() == 0) { 85 signal(SIGCHLD, SIG_IGN); 86 doit(s, &from); 87 } 88 (void) close(s); 89 } 90 } 91 92 reapchild() 93 { 94 union wait status; 95 96 while (wait3(&status, WNOHANG, 0) > 0) 97 ; 98 } 99 100 char username[20] = "USER="; 101 char homedir[64] = "HOME="; 102 char shell[64] = "SHELL="; 103 char *envinit[] = 104 {homedir, shell, "PATH=:/usr/ucb:/bin:/usr/bin", username, 0}; 105 char **environ; 106 107 struct sockaddr_in asin = { AF_INET }; 108 109 doit(f, fromp) 110 int f; 111 struct sockaddr_in *fromp; 112 { 113 char cmdbuf[NCARGS+1], *cp, *namep; 114 char user[16], pass[16]; 115 struct passwd *pwd; 116 int s; 117 short port; 118 int pv[2], pid, ready, readfrom, cc; 119 char buf[BUFSIZ], sig; 120 int one = 1; 121 122 (void) signal(SIGINT, SIG_DFL); 123 (void) signal(SIGQUIT, SIG_DFL); 124 (void) signal(SIGTERM, SIG_DFL); 125 #ifdef DEBUG 126 { int t = open("/dev/tty", 2); 127 if (t >= 0) { 128 ioctl(t, TIOCNOTTY, (char *)0); 129 (void) close(t); 130 } 131 } 132 #endif 133 dup2(f, 0); 134 dup2(f, 1); 135 dup2(f, 2); 136 (void) alarm(60); 137 port = 0; 138 for (;;) { 139 char c; 140 if (read(f, &c, 1) != 1) 141 exit(1); 142 if (c == 0) 143 break; 144 port = port * 10 + c - '0'; 145 } 146 (void) alarm(0); 147 if (port != 0) { 148 s = socket(AF_INET, SOCK_STREAM, 0, 0); 149 if (s < 0) 150 exit(1); 151 if (bind(s, &asin, sizeof (asin), 0) < 0) 152 exit(1); 153 (void) alarm(60); 154 fromp->sin_port = htons((u_short)port); 155 if (connect(s, fromp, sizeof (*fromp), 0) < 0) 156 exit(1); 157 (void) alarm(0); 158 } 159 getstr(user, sizeof(user), "username"); 160 getstr(pass, sizeof(pass), "password"); 161 getstr(cmdbuf, sizeof(cmdbuf), "command"); 162 setpwent(); 163 pwd = getpwnam(user); 164 if (pwd == NULL) { 165 error("Login incorrect.\n"); 166 exit(1); 167 } 168 endpwent(); 169 if (*pwd->pw_passwd != '\0') { 170 namep = crypt(pass, pwd->pw_passwd); 171 if (strcmp(namep, pwd->pw_passwd)) { 172 error("Password incorrect.\n"); 173 exit(1); 174 } 175 } 176 if (chdir(pwd->pw_dir) < 0) { 177 error("No remote directory.\n"); 178 exit(1); 179 } 180 (void) write(2, "\0", 1); 181 if (port) { 182 (void) pipe(pv); 183 pid = fork(); 184 if (pid == -1) { 185 error("Try again.\n"); 186 exit(1); 187 } 188 if (pid) { 189 (void) close(0); (void) close(1); (void) close(2); 190 (void) close(f); (void) close(pv[1]); 191 readfrom = (1<<s) | (1<<pv[0]); 192 ioctl(pv[1], FIONBIO, (char *)&one); 193 /* should set s nbio! */ 194 do { 195 ready = readfrom; 196 (void) select(16, &ready, 0, 0, 0); 197 if (ready & (1<<s)) { 198 if (read(s, &sig, 1) <= 0) 199 readfrom &= ~(1<<s); 200 else 201 killpg(pid, sig); 202 } 203 if (ready & (1<<pv[0])) { 204 cc = read(pv[0], buf, sizeof (buf)); 205 if (cc <= 0) { 206 shutdown(s, 1+1); 207 readfrom &= ~(1<<pv[0]); 208 } else 209 (void) write(s, buf, cc); 210 } 211 } while (readfrom); 212 exit(0); 213 } 214 setpgrp(0, getpid()); 215 (void) close(s); (void)close(pv[0]); 216 dup2(pv[1], 2); 217 } 218 if (*pwd->pw_shell == '\0') 219 pwd->pw_shell = "/bin/sh"; 220 (void) close(f); 221 initgroups(pwd->pw_name, pwd->pw_gid); 222 (void) setuid(pwd->pw_uid); 223 (void) setgid(pwd->pw_gid); 224 environ = envinit; 225 strncat(homedir, pwd->pw_dir, sizeof(homedir)-6); 226 strncat(shell, pwd->pw_shell, sizeof(shell)-7); 227 strncat(username, pwd->pw_name, sizeof(username)-6); 228 cp = rindex(pwd->pw_shell, '/'); 229 if (cp) 230 cp++; 231 else 232 cp = pwd->pw_shell; 233 execl(pwd->pw_shell, cp, "-c", cmdbuf, 0); 234 perror(pwd->pw_shell); 235 exit(1); 236 } 237 238 /* VARARGS 1 */ 239 error(fmt, a1, a2, a3) 240 char *fmt; 241 int a1, a2, a3; 242 { 243 char buf[BUFSIZ]; 244 245 buf[0] = 1; 246 (void) sprintf(buf+1, fmt, a1, a2, a3); 247 (void) write(2, buf, strlen(buf)); 248 } 249 250 getstr(buf, cnt, err) 251 char *buf; 252 int cnt; 253 char *err; 254 { 255 char c; 256 257 do { 258 if (read(0, &c, 1) != 1) 259 exit(1); 260 *buf++ = c; 261 if (--cnt == 0) { 262 error("%s too long\n", err); 263 exit(1); 264 } 265 } while (c != 0); 266 } 267