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 __FBSDID("$FreeBSD$"); 43 44 #include <sys/types.h> 45 #include <sys/wait.h> 46 #include <netinet/in.h> 47 48 #include <errno.h> 49 #include <glob.h> 50 #include <signal.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <unistd.h> 55 56 #include "extern.h" 57 #include "pathnames.h" 58 #include <syslog.h> 59 #include <time.h> 60 61 #define MAXUSRARGS 100 62 #define MAXGLOBARGS 1000 63 64 /* 65 * Special version of popen which avoids call to shell. This ensures no one 66 * may create a pipe to a hidden program as a side effect of a list or dir 67 * command. 68 */ 69 static int *pids; 70 static int fds; 71 72 FILE * 73 ftpd_popen(char *program, char *type) 74 { 75 char *cp; 76 FILE *iop; 77 int argc, gargc, pdes[2], pid; 78 char **pop, *argv[MAXUSRARGS], *gargv[MAXGLOBARGS]; 79 80 if (((*type != 'r') && (*type != 'w')) || type[1]) 81 return (NULL); 82 83 if (!pids) { 84 if ((fds = getdtablesize()) <= 0) 85 return (NULL); 86 if ((pids = calloc(fds, sizeof(int))) == NULL) 87 return (NULL); 88 } 89 if (pipe(pdes) < 0) 90 return (NULL); 91 92 /* break up string into pieces */ 93 for (argc = 0, cp = program; argc < MAXUSRARGS; cp = NULL) { 94 if (!(argv[argc++] = strtok(cp, " \t\n"))) 95 break; 96 } 97 argv[argc - 1] = NULL; 98 99 /* glob each piece */ 100 gargv[0] = argv[0]; 101 for (gargc = argc = 1; argv[argc] && gargc < (MAXGLOBARGS-1); argc++) { 102 glob_t gl; 103 int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_TILDE; 104 105 memset(&gl, 0, sizeof(gl)); 106 gl.gl_matchc = MAXGLOBARGS; 107 flags |= GLOB_LIMIT; 108 if (glob(argv[argc], flags, NULL, &gl)) 109 gargv[gargc++] = strdup(argv[argc]); 110 else if (gl.gl_pathc > 0) { 111 for (pop = gl.gl_pathv; *pop && gargc < (MAXGLOBARGS-1); 112 pop++) 113 gargv[gargc++] = strdup(*pop); 114 } 115 globfree(&gl); 116 } 117 gargv[gargc] = NULL; 118 119 iop = NULL; 120 fflush(NULL); 121 pid = (strcmp(gargv[0], _PATH_LS) == 0) ? fork() : vfork(); 122 switch(pid) { 123 case -1: /* error */ 124 (void)close(pdes[0]); 125 (void)close(pdes[1]); 126 goto pfree; 127 /* NOTREACHED */ 128 case 0: /* child */ 129 if (*type == 'r') { 130 if (pdes[1] != STDOUT_FILENO) { 131 dup2(pdes[1], STDOUT_FILENO); 132 (void)close(pdes[1]); 133 } 134 dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */ 135 (void)close(pdes[0]); 136 } else { 137 if (pdes[0] != STDIN_FILENO) { 138 dup2(pdes[0], STDIN_FILENO); 139 (void)close(pdes[0]); 140 } 141 (void)close(pdes[1]); 142 } 143 /* Drop privileges before proceeding */ 144 if (getuid() != geteuid() && setuid(geteuid()) < 0) 145 _exit(1); 146 if (strcmp(gargv[0], _PATH_LS) == 0) { 147 /* Reset getopt for ls_main() */ 148 optreset = optind = optopt = 1; 149 /* Close syslogging to remove pwd.db missing msgs */ 150 closelog(); 151 /* Trigger to sense new /etc/localtime after chroot */ 152 if (getenv("TZ") == NULL) { 153 setenv("TZ", "", 0); 154 tzset(); 155 unsetenv("TZ"); 156 tzset(); 157 } 158 exit(ls_main(gargc, gargv)); 159 } 160 execv(gargv[0], gargv); 161 _exit(1); 162 } 163 /* parent; assume fdopen can't fail... */ 164 if (*type == 'r') { 165 iop = fdopen(pdes[0], type); 166 (void)close(pdes[1]); 167 } else { 168 iop = fdopen(pdes[1], type); 169 (void)close(pdes[0]); 170 } 171 pids[fileno(iop)] = pid; 172 173 pfree: for (argc = 1; gargv[argc] != NULL; argc++) 174 free(gargv[argc]); 175 176 return (iop); 177 } 178 179 int 180 ftpd_pclose(FILE *iop) 181 { 182 int fdes, omask, status; 183 pid_t pid; 184 185 /* 186 * pclose returns -1 if stream is not associated with a 187 * `popened' command, or, if already `pclosed'. 188 */ 189 if (pids == NULL || pids[fdes = fileno(iop)] == 0) 190 return (-1); 191 (void)fclose(iop); 192 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 193 while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR) 194 continue; 195 (void)sigsetmask(omask); 196 pids[fdes] = 0; 197 if (pid < 0) 198 return (pid); 199 if (WIFEXITED(status)) 200 return (WEXITSTATUS(status)); 201 return (1); 202 } 203