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
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
/* $OpenBSD: skeyaudit.c,v 1.22 2005/10/26 17:06:39 millert Exp $ */
/*
* Copyright (c) 1997, 2000, 2003 Todd C. Miller <Todd.Miller@courtesan.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
* FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*/
#include <sys/param.h>
#include <sys/wait.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <login_cap.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <skey.h>
void notify(struct passwd *, int, int);
FILE *runsendmail(struct passwd *, int *);
__dead void usage(void);
int
main(int argc, char **argv)
{
struct passwd *pw;
struct skey key;
char *name;
int ch, left, aflag, iflag, limit;
aflag = iflag = 0;
limit = 12;
while ((ch = getopt(argc, argv, "ail:")) != -1)
switch(ch) {
case 'a':
if (getuid() != 0)
errx(1, "only root may use the -a flag");
aflag = 1;
break;
case 'i':
iflag = 1;
break;
case 'l':
errno = 0;
if ((limit = (int)strtol(optarg, NULL, 10)) == 0)
errno = ERANGE;
if (errno) {
warn("key limit");
usage();
}
break;
default:
usage();
}
/*
* Make sure STDIN_FILENO, STDOUT_FILENO, and STDERR_FILENO are open.
* If not, open /dev/null in their place or bail.
* If we are in interactive mode, STDOUT_FILENO *must* be open.
*/
for (ch = STDIN_FILENO; ch <= STDERR_FILENO; ch++) {
if (fcntl(ch, F_GETFL, 0) == -1 && errno == EBADF) {
if (ch == STDOUT_FILENO && iflag)
exit(1); /* need stdout for -i */
if (open(_PATH_DEVNULL, O_RDWR, 0644) == -1)
exit(1); /* just bail */
}
}
if (argc - optind > 0)
usage();
/* Need key.keyfile zero'd at the very least */
(void)memset(&key, 0, sizeof(key));
left = 0;
if (aflag) {
while ((ch = skeygetnext(&key)) == 0) {
left = key.n - 1;
if ((pw = getpwnam(key.logname)) == NULL)
continue;
if (left >= limit)
continue;
(void)fclose(key.keyfile);
key.keyfile = NULL;
notify(pw, left, iflag);
}
if (ch == -1)
errx(-1, "cannot open %s", _PATH_SKEYDIR);
} else {
if ((pw = getpwuid(getuid())) == NULL)
errx(1, "no passwd entry for uid %u", getuid());
if ((name = strdup(pw->pw_name)) == NULL)
err(1, "cannot allocate memory");
sevenbit(name);
switch (skeylookup(&key, name)) {
case 0: /* Success! */
left = key.n - 1;
break;
case -1: /* File error */
errx(1, "cannot open %s/%s", _PATH_SKEYDIR,
name);
break;
case 1: /* Unknown user */
errx(1, "user %s is not listed in %s", name,
_PATH_SKEYDIR);
}
(void)fclose(key.keyfile);
if (left < limit)
notify(pw, left, iflag);
}
exit(0);
}
void
notify(struct passwd *pw, int seq, int interactive)
{
static char hostname[MAXHOSTNAMELEN];
pid_t pid;
FILE *out;
/* Only set this once */
if (hostname[0] == '\0' && gethostname(hostname, sizeof(hostname)) == -1)
strlcpy(hostname, "unknown", sizeof(hostname));
if (interactive)
out = stdout;
else
out = runsendmail(pw, &pid);
if (!interactive)
(void)fprintf(out,
"To: %s\nSubject: IMPORTANT action required\n", pw->pw_name);
if (seq)
(void)fprintf(out,
"\nYou are nearing the end of your current S/Key sequence for account\n\
%s on system %s.\n\n\
Your S/Key sequence number is now %d. When it reaches zero\n\
you will no longer be able to use S/Key to log into the system.\n\n",
pw->pw_name, hostname, seq);
else
(void)fprintf(out,
"\nYou are at the end of your current S/Key sequence for account\n\
%s on system %s.\n\n\
At this point you can no longer use S/Key to log into the system.\n\n",
pw->pw_name, hostname);
(void)fprintf(out,
"Type \"skeyinit -s\" to reinitialize your sequence number.\n\n");
if (!interactive) {
(void)fclose(out);
(void)waitpid(pid, NULL, 0);
}
}
FILE *
runsendmail(struct passwd *pw, pid_t *pidp)
{
FILE *fp;
int pfd[2];
pid_t pid;
if (pipe(pfd) < 0)
return(NULL);
switch (pid = fork()) {
case -1: /* fork(2) failed */
(void)close(pfd[0]);
(void)close(pfd[1]);
return(NULL);
case 0: /* In child */
(void)close(pfd[1]);
(void)dup2(pfd[0], STDIN_FILENO);
(void)close(pfd[0]);
/* Run sendmail as target user not root */
if (getuid() == 0 &&
setusercontext(NULL, pw, pw->pw_uid, LOGIN_SETALL) != 0) {
warn("cannot set user context");
_exit(127);
}
execl(_PATH_SENDMAIL, "sendmail", "-t", (char *)NULL);
warn("cannot run \"%s -t\"", _PATH_SENDMAIL);
_exit(127);
}
/* In parent */
*pidp = pid;
fp = fdopen(pfd[1], "w");
(void)close(pfd[0]);
return(fp);
}
__dead void
usage(void)
{
extern char *__progname;
(void)fprintf(stderr, "Usage: %s [-ai] [-l limit]\n",
__progname);
exit(1);
}
|
