1 #ifndef lint 2 static char sccsid[] = "@(#)rexecd.c 4.3 82/11/15"; 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 /* 25 * remote execute server: 26 * username\0 27 * password\0 28 * command\0 29 * data 30 */ 31 main(argc, argv) 32 int argc; 33 char **argv; 34 { 35 union wait status; 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 = htons((u_short)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(0, 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 listen(f, 10); 72 for (;;) { 73 int s, len = sizeof (from); 74 75 s = accept(f, &from, &len, 0); 76 if (s < 0) { 77 perror("rexecd: accept"); 78 sleep(1); 79 continue; 80 } 81 if (fork() == 0) 82 doit(s, &from); 83 (void) close(s); 84 while (wait3(status, WNOHANG, 0) > 0) 85 continue; 86 } 87 } 88 89 char username[20] = "USER="; 90 char homedir[64] = "HOME="; 91 char shell[64] = "SHELL="; 92 char *envinit[] = 93 {homedir, shell, "PATH=:/usr/ucb:/bin:/usr/bin", username, 0}; 94 char **environ; 95 96 struct sockaddr_in asin = { AF_INET }; 97 98 doit(f, fromp) 99 int f; 100 struct sockaddr_in *fromp; 101 { 102 char cmdbuf[NCARGS+1], *cp, *namep; 103 char user[16], pass[16]; 104 struct passwd *pwd; 105 int s; 106 short port; 107 int pv[2], pid, ready, readfrom, cc; 108 char buf[BUFSIZ], sig; 109 int one = 1; 110 111 (void) signal(SIGINT, SIG_DFL); 112 (void) signal(SIGQUIT, SIG_DFL); 113 (void) signal(SIGTERM, SIG_DFL); 114 #ifdef DEBUG 115 { int t = open("/dev/tty", 2); 116 if (t >= 0) { 117 ioctl(t, TIOCNOTTY, (char *)0); 118 (void) close(t); 119 } 120 } 121 #endif 122 dup2(f, 0); 123 dup2(f, 1); 124 dup2(f, 2); 125 #if vax 126 fromp->sin_port = ntohs((u_short)fromp->sin_port); 127 #endif 128 (void) alarm(60); 129 port = 0; 130 for (;;) { 131 char c; 132 if (read(f, &c, 1) != 1) 133 exit(1); 134 if (c == 0) 135 break; 136 port = port * 10 + c - '0'; 137 } 138 (void) alarm(0); 139 if (port != 0) { 140 s = socket(SOCK_STREAM, 0, &asin, 0); 141 if (s < 0) 142 exit(1); 143 (void) alarm(60); 144 fromp->sin_port = ntohs((u_short)port); 145 if (connect(s, fromp, sizeof (*fromp), 0) < 0) 146 exit(1); 147 (void) alarm(0); 148 } 149 getstr(user, sizeof(user), "username"); 150 getstr(pass, sizeof(pass), "password"); 151 getstr(cmdbuf, sizeof(cmdbuf), "command"); 152 setpwent(); 153 pwd = getpwnam(user); 154 if (pwd == NULL) { 155 error("Login incorrect.\n"); 156 exit(1); 157 } 158 endpwent(); 159 if (*pwd->pw_passwd != '\0') { 160 namep = crypt(pass, pwd->pw_passwd); 161 if (strcmp(namep, pwd->pw_passwd)) { 162 error("Password incorrect.\n"); 163 exit(1); 164 } 165 } 166 if (chdir(pwd->pw_dir) < 0) { 167 error("No remote directory.\n"); 168 exit(1); 169 } 170 (void) write(2, "\0", 1); 171 if (port) { 172 (void) pipe(pv); 173 pid = fork(); 174 if (pid == -1) { 175 error("Try again.\n"); 176 exit(1); 177 } 178 if (pid) { 179 (void) close(0); (void) close(1); (void) close(2); 180 (void) close(f); (void) close(pv[1]); 181 readfrom = (1<<s) | (1<<pv[0]); 182 ioctl(pv[1], FIONBIO, (char *)&one); 183 /* should set s nbio! */ 184 do { 185 ready = readfrom; 186 (void) select(16, &ready, 0, 0, 0); 187 if (ready & (1<<s)) { 188 if (read(s, &sig, 1) <= 0) 189 readfrom &= ~(1<<s); 190 else 191 killpg(pid, sig); 192 } 193 if (ready & (1<<pv[0])) { 194 cc = read(pv[0], buf, sizeof (buf)); 195 if (cc <= 0) { 196 int done = 1+1; 197 ioctl(s, SIOCDONE, (char *)&done); 198 readfrom &= ~(1<<pv[0]); 199 } else 200 (void) write(s, buf, cc); 201 } 202 } while (readfrom); 203 exit(0); 204 } 205 setpgrp(0, getpid()); 206 (void) close(s); (void)close(pv[0]); 207 dup2(pv[1], 2); 208 } 209 if (*pwd->pw_shell == '\0') 210 pwd->pw_shell = "/bin/sh"; 211 (void) close(f); 212 initgroups(pwd->pw_name, pwd->pw_gid); 213 (void) setuid(pwd->pw_uid); 214 (void) setgid(pwd->pw_gid); 215 environ = envinit; 216 strncat(homedir, pwd->pw_dir, sizeof(homedir)-6); 217 strncat(shell, pwd->pw_shell, sizeof(shell)-7); 218 strncat(username, pwd->pw_name, sizeof(username)-6); 219 cp = rindex(pwd->pw_shell, '/'); 220 if (cp) 221 cp++; 222 else 223 cp = pwd->pw_shell; 224 execl(pwd->pw_shell, cp, "-c", cmdbuf, 0); 225 perror(pwd->pw_shell); 226 exit(1); 227 } 228 229 /* VARARGS 1 */ 230 error(fmt, a1, a2, a3) 231 char *fmt; 232 int a1, a2, a3; 233 { 234 char buf[BUFSIZ]; 235 236 buf[0] = 1; 237 (void) sprintf(buf+1, fmt, a1, a2, a3); 238 (void) write(2, buf, strlen(buf)); 239 } 240 241 getstr(buf, cnt, err) 242 char *buf; 243 int cnt; 244 char *err; 245 { 246 char c; 247 248 do { 249 if (read(0, &c, 1) != 1) 250 exit(1); 251 *buf++ = c; 252 if (--cnt == 0) { 253 error("%s too long\n", err); 254 exit(1); 255 } 256 } while (c != 0); 257 } 258