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 *
ftpd_popen(char * program,char * type)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
ftpd_pclose(FILE * iop)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