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 #include <sys/types.h> 36 #include <sys/wait.h> 37 #include <netinet/in.h> 38 39 #include <errno.h> 40 #include <glob.h> 41 #include <signal.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <unistd.h> 46 47 #include "extern.h" 48 #include "pathnames.h" 49 #include <syslog.h> 50 #include <time.h> 51 52 #define MAXUSRARGS 100 53 #define MAXGLOBARGS 1000 54 55 /* 56 * Special version of popen which avoids call to shell. This ensures no one 57 * may create a pipe to a hidden program as a side effect of a list or dir 58 * command. 59 */ 60 static int *pids; 61 static int fds; 62 63 FILE * 64 ftpd_popen(char *program, char *type) 65 { 66 char *cp; 67 FILE *iop; 68 int argc, gargc, pdes[2], pid; 69 char **pop, *argv[MAXUSRARGS], *gargv[MAXGLOBARGS]; 70 71 if (((*type != 'r') && (*type != 'w')) || type[1]) 72 return (NULL); 73 74 if (!pids) { 75 if ((fds = getdtablesize()) <= 0) 76 return (NULL); 77 if ((pids = calloc(fds, sizeof(int))) == NULL) 78 return (NULL); 79 } 80 if (pipe(pdes) < 0) 81 return (NULL); 82 83 /* break up string into pieces */ 84 for (argc = 0, cp = program; argc < MAXUSRARGS; cp = NULL) { 85 if (!(argv[argc++] = strtok(cp, " \t\n"))) 86 break; 87 } 88 argv[argc - 1] = NULL; 89 90 /* glob each piece */ 91 gargv[0] = argv[0]; 92 for (gargc = argc = 1; argv[argc] && gargc < (MAXGLOBARGS-1); argc++) { 93 glob_t gl; 94 int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_TILDE; 95 96 memset(&gl, 0, sizeof(gl)); 97 gl.gl_matchc = MAXGLOBARGS; 98 flags |= GLOB_LIMIT; 99 if (glob(argv[argc], flags, NULL, &gl)) 100 gargv[gargc++] = strdup(argv[argc]); 101 else if (gl.gl_pathc > 0) { 102 for (pop = gl.gl_pathv; *pop && gargc < (MAXGLOBARGS-1); 103 pop++) 104 gargv[gargc++] = strdup(*pop); 105 } 106 globfree(&gl); 107 } 108 gargv[gargc] = NULL; 109 110 iop = NULL; 111 fflush(NULL); 112 pid = (strcmp(gargv[0], _PATH_LS) == 0) ? fork() : vfork(); 113 switch(pid) { 114 case -1: /* error */ 115 (void)close(pdes[0]); 116 (void)close(pdes[1]); 117 goto pfree; 118 /* NOTREACHED */ 119 case 0: /* child */ 120 if (*type == 'r') { 121 if (pdes[1] != STDOUT_FILENO) { 122 dup2(pdes[1], STDOUT_FILENO); 123 (void)close(pdes[1]); 124 } 125 dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */ 126 (void)close(pdes[0]); 127 } else { 128 if (pdes[0] != STDIN_FILENO) { 129 dup2(pdes[0], STDIN_FILENO); 130 (void)close(pdes[0]); 131 } 132 (void)close(pdes[1]); 133 } 134 /* Drop privileges before proceeding */ 135 if (getuid() != geteuid() && setuid(geteuid()) < 0) 136 _exit(1); 137 if (strcmp(gargv[0], _PATH_LS) == 0) { 138 /* Reset getopt for ls_main() */ 139 optreset = optind = optopt = 1; 140 /* Close syslogging to remove pwd.db missing msgs */ 141 closelog(); 142 /* Trigger to sense new /etc/localtime after chroot */ 143 if (getenv("TZ") == NULL) { 144 setenv("TZ", "", 0); 145 tzset(); 146 unsetenv("TZ"); 147 tzset(); 148 } 149 exit(ls_main(gargc, gargv)); 150 } 151 execv(gargv[0], gargv); 152 _exit(1); 153 } 154 /* parent; assume fdopen can't fail... */ 155 if (*type == 'r') { 156 iop = fdopen(pdes[0], type); 157 (void)close(pdes[1]); 158 } else { 159 iop = fdopen(pdes[1], type); 160 (void)close(pdes[0]); 161 } 162 pids[fileno(iop)] = pid; 163 164 pfree: for (argc = 1; gargv[argc] != NULL; argc++) 165 free(gargv[argc]); 166 167 return (iop); 168 } 169 170 int 171 ftpd_pclose(FILE *iop) 172 { 173 int fdes, omask, status; 174 pid_t pid; 175 176 /* 177 * pclose returns -1 if stream is not associated with a 178 * `popened' command, or, if already `pclosed'. 179 */ 180 if (pids == NULL || pids[fdes = fileno(iop)] == 0) 181 return (-1); 182 (void)fclose(iop); 183 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 184 while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR) 185 continue; 186 (void)sigsetmask(omask); 187 pids[fdes] = 0; 188 if (pid < 0) 189 return (pid); 190 if (WIFEXITED(status)) 191 return (WEXITSTATUS(status)); 192 return (1); 193 } 194