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