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