1 #ifndef lint 2 static char sccsid[] = "@(#)rexecd.c 4.12 (Berkeley) 09/11/84"; 3 #endif 4 5 #include <sys/ioctl.h> 6 #include <sys/param.h> 7 #include <sys/socket.h> 8 #include <sys/wait.h> 9 10 #include <netinet/in.h> 11 12 #include <stdio.h> 13 #include <errno.h> 14 #include <pwd.h> 15 #include <signal.h> 16 #include <netdb.h> 17 18 extern errno; 19 struct passwd *getpwnam(); 20 char *crypt(), *rindex(), *sprintf(); 21 /* VARARGS 1 */ 22 int error(); 23 int reapchild(); 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 struct sockaddr_in from; 36 int fromlen; 37 38 fromlen = sizeof (from); 39 if (getpeername(0, &from, &fromlen) < 0) { 40 fprintf(stderr, "%s: ", argv[0]); 41 perror("getpeername"); 42 exit(1); 43 } 44 doit(0, &from); 45 } 46 47 reapchild() 48 { 49 union wait status; 50 51 while (wait3(&status, WNOHANG, 0) > 0) 52 ; 53 } 54 55 char username[20] = "USER="; 56 char homedir[64] = "HOME="; 57 char shell[64] = "SHELL="; 58 char *envinit[] = 59 {homedir, shell, "PATH=:/usr/ucb:/bin:/usr/bin", username, 0}; 60 char **environ; 61 62 struct sockaddr_in asin = { AF_INET }; 63 64 doit(f, fromp) 65 int f; 66 struct sockaddr_in *fromp; 67 { 68 char cmdbuf[NCARGS+1], *cp, *namep; 69 char user[16], pass[16]; 70 struct passwd *pwd; 71 int s; 72 short port; 73 int pv[2], pid, ready, readfrom, cc; 74 char buf[BUFSIZ], sig; 75 int one = 1; 76 77 (void) signal(SIGINT, SIG_DFL); 78 (void) signal(SIGQUIT, SIG_DFL); 79 (void) signal(SIGTERM, SIG_DFL); 80 #ifdef DEBUG 81 { int t = open("/dev/tty", 2); 82 if (t >= 0) { 83 ioctl(t, TIOCNOTTY, (char *)0); 84 (void) close(t); 85 } 86 } 87 #endif 88 dup2(f, 0); 89 dup2(f, 1); 90 dup2(f, 2); 91 (void) alarm(60); 92 port = 0; 93 for (;;) { 94 char c; 95 if (read(f, &c, 1) != 1) 96 exit(1); 97 if (c == 0) 98 break; 99 port = port * 10 + c - '0'; 100 } 101 (void) alarm(0); 102 if (port != 0) { 103 s = socket(AF_INET, SOCK_STREAM, 0, 0); 104 if (s < 0) 105 exit(1); 106 if (bind(s, &asin, sizeof (asin), 0) < 0) 107 exit(1); 108 (void) alarm(60); 109 fromp->sin_port = htons((u_short)port); 110 if (connect(s, fromp, sizeof (*fromp), 0) < 0) 111 exit(1); 112 (void) alarm(0); 113 } 114 getstr(user, sizeof(user), "username"); 115 getstr(pass, sizeof(pass), "password"); 116 getstr(cmdbuf, sizeof(cmdbuf), "command"); 117 setpwent(); 118 pwd = getpwnam(user); 119 if (pwd == NULL) { 120 error("Login incorrect.\n"); 121 exit(1); 122 } 123 endpwent(); 124 if (*pwd->pw_passwd != '\0') { 125 namep = crypt(pass, pwd->pw_passwd); 126 if (strcmp(namep, pwd->pw_passwd)) { 127 error("Password incorrect.\n"); 128 exit(1); 129 } 130 } 131 if (chdir(pwd->pw_dir) < 0) { 132 error("No remote directory.\n"); 133 exit(1); 134 } 135 (void) write(2, "\0", 1); 136 if (port) { 137 (void) pipe(pv); 138 pid = fork(); 139 if (pid == -1) { 140 error("Try again.\n"); 141 exit(1); 142 } 143 if (pid) { 144 (void) close(0); (void) close(1); (void) close(2); 145 (void) close(f); (void) close(pv[1]); 146 readfrom = (1<<s) | (1<<pv[0]); 147 ioctl(pv[1], FIONBIO, (char *)&one); 148 /* should set s nbio! */ 149 do { 150 ready = readfrom; 151 (void) select(16, &ready, 0, 0, 0); 152 if (ready & (1<<s)) { 153 if (read(s, &sig, 1) <= 0) 154 readfrom &= ~(1<<s); 155 else 156 killpg(pid, sig); 157 } 158 if (ready & (1<<pv[0])) { 159 cc = read(pv[0], buf, sizeof (buf)); 160 if (cc <= 0) { 161 shutdown(s, 1+1); 162 readfrom &= ~(1<<pv[0]); 163 } else 164 (void) write(s, buf, cc); 165 } 166 } while (readfrom); 167 exit(0); 168 } 169 setpgrp(0, getpid()); 170 (void) close(s); (void)close(pv[0]); 171 dup2(pv[1], 2); 172 } 173 if (*pwd->pw_shell == '\0') 174 pwd->pw_shell = "/bin/sh"; 175 if (f > 2) 176 (void) close(f); 177 initgroups(pwd->pw_name, pwd->pw_gid); 178 (void) setuid(pwd->pw_uid); 179 (void) setgid(pwd->pw_gid); 180 environ = envinit; 181 strncat(homedir, pwd->pw_dir, sizeof(homedir)-6); 182 strncat(shell, pwd->pw_shell, sizeof(shell)-7); 183 strncat(username, pwd->pw_name, sizeof(username)-6); 184 cp = rindex(pwd->pw_shell, '/'); 185 if (cp) 186 cp++; 187 else 188 cp = pwd->pw_shell; 189 execl(pwd->pw_shell, cp, "-c", cmdbuf, 0); 190 perror(pwd->pw_shell); 191 exit(1); 192 } 193 194 /* VARARGS 1 */ 195 error(fmt, a1, a2, a3) 196 char *fmt; 197 int a1, a2, a3; 198 { 199 char buf[BUFSIZ]; 200 201 buf[0] = 1; 202 (void) sprintf(buf+1, fmt, a1, a2, a3); 203 (void) write(2, buf, strlen(buf)); 204 } 205 206 getstr(buf, cnt, err) 207 char *buf; 208 int cnt; 209 char *err; 210 { 211 char c; 212 213 do { 214 if (read(0, &c, 1) != 1) 215 exit(1); 216 *buf++ = c; 217 if (--cnt == 0) { 218 error("%s too long\n", err); 219 exit(1); 220 } 221 } while (c != 0); 222 } 223