1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
/* $OpenBSD: rcmdsh.c,v 1.14 2015/03/23 22:29:32 halex Exp $ */
/*
* Copyright (c) 2001, MagniComp
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the distribution.
* 3. Neither the name of the MagniComp nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* This is an rcmd() replacement originally by
* Chris Siebenmann <cks@utcc.utoronto.ca>.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <signal.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pwd.h>
#include <paths.h>
#include <unistd.h>
/*
* This is a replacement rcmd() function that uses the ssh(1)
* program in place of a direct rcmd(3) function call so as to
* avoid having to be root. Note that rport is ignored.
*/
/* ARGSUSED */
int
rcmdsh(char **ahost, int rport, const char *locuser, const char *remuser,
const char *cmd, char *rshprog)
{
struct hostent *hp;
int sp[2];
pid_t cpid;
char *p;
struct passwd *pw;
/* What rsh/shell to use. */
if (rshprog == NULL)
rshprog = _PATH_RSH;
/* locuser must exist on this host. */
if ((pw = getpwnam(locuser)) == NULL) {
(void) fprintf(stderr, "rcmdsh: unknown user: %s\n", locuser);
return(-1);
}
/* Validate remote hostname. */
if (strcmp(*ahost, "localhost") != 0) {
if ((hp = gethostbyname2(*ahost, AF_INET)) ||
(hp = gethostbyname2(*ahost, AF_INET6)))
*ahost = hp->h_name;
}
/* Get a socketpair we'll use for stdin and stdout. */
if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, sp) < 0) {
perror("rcmdsh: socketpair");
return(-1);
}
cpid = fork();
if (cpid < 0) {
perror("rcmdsh: fork failed");
return(-1);
} else if (cpid == 0) {
/*
* Child. We use sp[1] to be stdin/stdout, and close sp[0].
*/
(void) close(sp[0]);
if (dup2(sp[1], 0) < 0 || dup2(0, 1) < 0) {
perror("rcmdsh: dup2 failed");
_exit(255);
}
/* Fork again to lose parent. */
cpid = fork();
if (cpid < 0) {
perror("rcmdsh: fork to lose parent failed");
_exit(255);
}
if (cpid > 0)
_exit(0);
/* In grandchild here. Become local user for rshprog. */
if (setuid(pw->pw_uid)) {
(void) fprintf(stderr, "rcmdsh: setuid(%u): %s\n",
pw->pw_uid, strerror(errno));
_exit(255);
}
/*
* If remote host is "localhost" and local and remote user
* are the same, avoid running remote shell for efficiency.
*/
if (!strcmp(*ahost, "localhost") && !strcmp(locuser, remuser)) {
char *argv[4];
if (pw->pw_shell[0] == '\0')
rshprog = _PATH_BSHELL;
else
rshprog = pw->pw_shell;
p = strrchr(rshprog, '/');
argv[0] = p ? p + 1 : rshprog;
argv[1] = "-c";
argv[2] = (char *)cmd;
argv[3] = NULL;
execvp(rshprog, argv);
} else if ((p = strchr(rshprog, ' ')) == NULL) {
/* simple case */
char *argv[6];
p = strrchr(rshprog, '/');
argv[0] = p ? p + 1 : rshprog;
argv[1] = "-l";
argv[2] = (char *)remuser;
argv[3] = *ahost;
argv[4] = (char *)cmd;
argv[5] = NULL;
execvp(rshprog, argv);
} else {
/* must pull args out of rshprog and dyn alloc argv */
char **argv, **ap;
int n;
for (n = 7; (p = strchr(++p, ' ')) != NULL; n++)
continue;
rshprog = strdup(rshprog);
ap = argv = calloc(sizeof(char *), n);
if (rshprog == NULL || argv == NULL) {
perror("rcmdsh");
_exit(255);
}
while ((p = strsep(&rshprog, " ")) != NULL) {
if (*p == '\0')
continue;
*ap++ = p;
}
if (ap != argv) /* all spaces?!? */
rshprog = argv[0];
if ((p = strrchr(argv[0], '/')) != NULL)
argv[0] = p + 1;
*ap++ = "-l";
*ap++ = (char *)remuser;
*ap++ = *ahost;
*ap++ = (char *)cmd;
*ap++ = NULL;
execvp(rshprog, argv);
}
(void) fprintf(stderr, "rcmdsh: execvp %s failed: %s\n",
rshprog, strerror(errno));
_exit(255);
} else {
/* Parent. close sp[1], return sp[0]. */
(void) close(sp[1]);
/* Reap child. */
(void) wait(NULL);
return(sp[0]);
}
/* NOTREACHED */
}
|
