1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1988, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software written by Ken Arnold and 8 * published in UNIX Review, Vol. 6, No. 8. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #ifndef lint 36 #if 0 37 static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 4/6/94"; 38 #endif 39 #endif /* not lint */ 40 41 #include <sys/cdefs.h> 42 #include <sys/types.h> 43 #include <sys/wait.h> 44 #include <netinet/in.h> 45 46 #include <errno.h> 47 #include <glob.h> 48 #include <signal.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 54 #include "extern.h" 55 #include "pathnames.h" 56 #include <syslog.h> 57 #include <time.h> 58 59 #define MAXUSRARGS 100 60 #define MAXGLOBARGS 1000 61 62 /* 63 * Special version of popen which avoids call to shell. This ensures no one 64 * may create a pipe to a hidden program as a side effect of a list or dir 65 * command. 66 */ 67 static int *pids; 68 static int fds; 69 70 FILE * 71 ftpd_popen(char *program, char *type) 72 { 73 char *cp; 74 FILE *iop; 75 int argc, gargc, pdes[2], pid; 76 char **pop, *argv[MAXUSRARGS], *gargv[MAXGLOBARGS]; 77 78 if (((*type != 'r') && (*type != 'w')) || type[1]) 79 return (NULL); 80 81 if (!pids) { 82 if ((fds = getdtablesize()) <= 0) 83 return (NULL); 84 if ((pids = calloc(fds, sizeof(int))) == NULL) 85 return (NULL); 86 } 87 if (pipe(pdes) < 0) 88 return (NULL); 89 90 /* break up string into pieces */ 91 for (argc = 0, cp = program; argc < MAXUSRARGS; cp = NULL) { 92 if (!(argv[argc++] = strtok(cp, " \t\n"))) 93 break; 94 } 95 argv[argc - 1] = NULL; 96 97 /* glob each piece */ 98 gargv[0] = argv[0]; 99 for (gargc = argc = 1; argv[argc] && gargc < (MAXGLOBARGS-1); argc++) { 100 glob_t gl; 101 int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_TILDE; 102 103 memset(&gl, 0, sizeof(gl)); 104 gl.gl_matchc = MAXGLOBARGS; 105 flags |= GLOB_LIMIT; 106 if (glob(argv[argc], flags, NULL, &gl)) 107 gargv[gargc++] = strdup(argv[argc]); 108 else if (gl.gl_pathc > 0) { 109 for (pop = gl.gl_pathv; *pop && gargc < (MAXGLOBARGS-1); 110 pop++) 111 gargv[gargc++] = strdup(*pop); 112 } 113 globfree(&gl); 114 } 115 gargv[gargc] = NULL; 116 117 iop = NULL; 118 fflush(NULL); 119 pid = (strcmp(gargv[0], _PATH_LS) == 0) ? fork() : vfork(); 120 switch(pid) { 121 case -1: /* error */ 122 (void)close(pdes[0]); 123 (void)close(pdes[1]); 124 goto pfree; 125 /* NOTREACHED */ 126 case 0: /* child */ 127 if (*type == 'r') { 128 if (pdes[1] != STDOUT_FILENO) { 129 dup2(pdes[1], STDOUT_FILENO); 130 (void)close(pdes[1]); 131 } 132 dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */ 133 (void)close(pdes[0]); 134 } else { 135 if (pdes[0] != STDIN_FILENO) { 136 dup2(pdes[0], STDIN_FILENO); 137 (void)close(pdes[0]); 138 } 139 (void)close(pdes[1]); 140 } 141 /* Drop privileges before proceeding */ 142 if (getuid() != geteuid() && setuid(geteuid()) < 0) 143 _exit(1); 144 if (strcmp(gargv[0], _PATH_LS) == 0) { 145 /* Reset getopt for ls_main() */ 146 optreset = optind = optopt = 1; 147 /* Close syslogging to remove pwd.db missing msgs */ 148 closelog(); 149 /* Trigger to sense new /etc/localtime after chroot */ 150 if (getenv("TZ") == NULL) { 151 setenv("TZ", "", 0); 152 tzset(); 153 unsetenv("TZ"); 154 tzset(); 155 } 156 exit(ls_main(gargc, gargv)); 157 } 158 execv(gargv[0], gargv); 159 _exit(1); 160 } 161 /* parent; assume fdopen can't fail... */ 162 if (*type == 'r') { 163 iop = fdopen(pdes[0], type); 164 (void)close(pdes[1]); 165 } else { 166 iop = fdopen(pdes[1], type); 167 (void)close(pdes[0]); 168 } 169 pids[fileno(iop)] = pid; 170 171 pfree: for (argc = 1; gargv[argc] != NULL; argc++) 172 free(gargv[argc]); 173 174 return (iop); 175 } 176 177 int 178 ftpd_pclose(FILE *iop) 179 { 180 int fdes, omask, status; 181 pid_t pid; 182 183 /* 184 * pclose returns -1 if stream is not associated with a 185 * `popened' command, or, if already `pclosed'. 186 */ 187 if (pids == NULL || pids[fdes = fileno(iop)] == 0) 188 return (-1); 189 (void)fclose(iop); 190 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 191 while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR) 192 continue; 193 (void)sigsetmask(omask); 194 pids[fdes] = 0; 195 if (pid < 0) 196 return (pid); 197 if (WIFEXITED(status)) 198 return (WEXITSTATUS(status)); 199 return (1); 200 } 201