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 #endif /* not lint */ 37 38 #include <sys/cdefs.h> 39 #include <sys/types.h> 40 #include <sys/wait.h> 41 #include <netinet/in.h> 42 43 #include <errno.h> 44 #include <glob.h> 45 #include <signal.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <unistd.h> 50 51 #include "extern.h" 52 #include "pathnames.h" 53 #include <syslog.h> 54 #include <time.h> 55 56 #define MAXUSRARGS 100 57 #define MAXGLOBARGS 1000 58 59 /* 60 * Special version of popen which avoids call to shell. This ensures no one 61 * may create a pipe to a hidden program as a side effect of a list or dir 62 * command. 63 */ 64 static int *pids; 65 static int fds; 66 67 FILE * 68 ftpd_popen(char *program, char *type) 69 { 70 char *cp; 71 FILE *iop; 72 int argc, gargc, pdes[2], pid; 73 char **pop, *argv[MAXUSRARGS], *gargv[MAXGLOBARGS]; 74 75 if (((*type != 'r') && (*type != 'w')) || type[1]) 76 return (NULL); 77 78 if (!pids) { 79 if ((fds = getdtablesize()) <= 0) 80 return (NULL); 81 if ((pids = calloc(fds, sizeof(int))) == NULL) 82 return (NULL); 83 } 84 if (pipe(pdes) < 0) 85 return (NULL); 86 87 /* break up string into pieces */ 88 for (argc = 0, cp = program; argc < MAXUSRARGS; cp = NULL) { 89 if (!(argv[argc++] = strtok(cp, " \t\n"))) 90 break; 91 } 92 argv[argc - 1] = NULL; 93 94 /* glob each piece */ 95 gargv[0] = argv[0]; 96 for (gargc = argc = 1; argv[argc] && gargc < (MAXGLOBARGS-1); argc++) { 97 glob_t gl; 98 int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_TILDE; 99 100 memset(&gl, 0, sizeof(gl)); 101 gl.gl_matchc = MAXGLOBARGS; 102 flags |= GLOB_LIMIT; 103 if (glob(argv[argc], flags, NULL, &gl)) 104 gargv[gargc++] = strdup(argv[argc]); 105 else if (gl.gl_pathc > 0) { 106 for (pop = gl.gl_pathv; *pop && gargc < (MAXGLOBARGS-1); 107 pop++) 108 gargv[gargc++] = strdup(*pop); 109 } 110 globfree(&gl); 111 } 112 gargv[gargc] = NULL; 113 114 iop = NULL; 115 fflush(NULL); 116 pid = (strcmp(gargv[0], _PATH_LS) == 0) ? fork() : vfork(); 117 switch(pid) { 118 case -1: /* error */ 119 (void)close(pdes[0]); 120 (void)close(pdes[1]); 121 goto pfree; 122 /* NOTREACHED */ 123 case 0: /* child */ 124 if (*type == 'r') { 125 if (pdes[1] != STDOUT_FILENO) { 126 dup2(pdes[1], STDOUT_FILENO); 127 (void)close(pdes[1]); 128 } 129 dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */ 130 (void)close(pdes[0]); 131 } else { 132 if (pdes[0] != STDIN_FILENO) { 133 dup2(pdes[0], STDIN_FILENO); 134 (void)close(pdes[0]); 135 } 136 (void)close(pdes[1]); 137 } 138 /* Drop privileges before proceeding */ 139 if (getuid() != geteuid() && setuid(geteuid()) < 0) 140 _exit(1); 141 if (strcmp(gargv[0], _PATH_LS) == 0) { 142 /* Reset getopt for ls_main() */ 143 optreset = optind = optopt = 1; 144 /* Close syslogging to remove pwd.db missing msgs */ 145 closelog(); 146 /* Trigger to sense new /etc/localtime after chroot */ 147 if (getenv("TZ") == NULL) { 148 setenv("TZ", "", 0); 149 tzset(); 150 unsetenv("TZ"); 151 tzset(); 152 } 153 exit(ls_main(gargc, gargv)); 154 } 155 execv(gargv[0], gargv); 156 _exit(1); 157 } 158 /* parent; assume fdopen can't fail... */ 159 if (*type == 'r') { 160 iop = fdopen(pdes[0], type); 161 (void)close(pdes[1]); 162 } else { 163 iop = fdopen(pdes[1], type); 164 (void)close(pdes[0]); 165 } 166 pids[fileno(iop)] = pid; 167 168 pfree: for (argc = 1; gargv[argc] != NULL; argc++) 169 free(gargv[argc]); 170 171 return (iop); 172 } 173 174 int 175 ftpd_pclose(FILE *iop) 176 { 177 int fdes, omask, status; 178 pid_t pid; 179 180 /* 181 * pclose returns -1 if stream is not associated with a 182 * `popened' command, or, if already `pclosed'. 183 */ 184 if (pids == NULL || pids[fdes = fileno(iop)] == 0) 185 return (-1); 186 (void)fclose(iop); 187 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 188 while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR) 189 continue; 190 (void)sigsetmask(omask); 191 pids[fdes] = 0; 192 if (pid < 0) 193 return (pid); 194 if (WIFEXITED(status)) 195 return (WEXITSTATUS(status)); 196 return (1); 197 } 198