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efa7a97b | 1 | /* -*-c-*- |
2 | * | |
efa7a97b | 3 | * Choose and check temporary directories |
4 | * | |
5 | * (c) 1999 Mark Wooding | |
6 | */ | |
7 | ||
263d6e0d | 8 | /*----- Licensing notice --------------------------------------------------* |
efa7a97b | 9 | * |
10 | * This file is part of chkpath. | |
11 | * | |
12 | * chkpath is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License as published by | |
14 | * the Free Software Foundation; either version 2 of the License, or | |
15 | * (at your option) any later version. | |
263d6e0d | 16 | * |
efa7a97b | 17 | * chkpath is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU General Public License for more details. | |
263d6e0d | 21 | * |
efa7a97b | 22 | * You should have received a copy of the GNU General Public License |
23 | * along with chkpath; if not, write to the Free Software Foundation, | |
24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
25 | */ | |
26 | ||
efa7a97b | 27 | /*----- Header files ------------------------------------------------------*/ |
28 | ||
9c42854d MW |
29 | #include "config.h" |
30 | ||
efa7a97b | 31 | #include <errno.h> |
7d5bdc25 | 32 | #include <ctype.h> |
efa7a97b | 33 | #include <stdio.h> |
34 | #include <stdlib.h> | |
35 | #include <string.h> | |
36 | ||
37 | #include <sys/types.h> | |
38 | #include <sys/stat.h> | |
39 | #include <unistd.h> | |
40 | #include <pwd.h> | |
7d5bdc25 | 41 | #include <grp.h> |
efa7a97b | 42 | |
43 | #include <mLib/alloc.h> | |
44 | #include <mLib/dstr.h> | |
d8e11317 | 45 | #include <mLib/macros.h> |
efa7a97b | 46 | #include <mLib/mdwopt.h> |
47 | #include <mLib/quis.h> | |
48 | #include <mLib/report.h> | |
49 | ||
d7b5ee0c | 50 | #include "checkpath.h" |
caa14ca2 | 51 | #include "utils.h" |
efa7a97b | 52 | |
53 | /*----- Static variables --------------------------------------------------*/ | |
54 | ||
55 | static uid_t me; | |
d7b5ee0c | 56 | static struct checkpath cp; |
efa7a97b | 57 | static struct passwd *pw; |
58 | ||
59 | /*----- Main code ---------------------------------------------------------*/ | |
60 | ||
61 | /* --- @ok@ --- * | |
62 | * | |
63 | * Arguments: @const char *p@ = pathname to check | |
64 | * @int *f@ = try-to-create flag | |
65 | * | |
66 | * Returns: Nonzero if the directory is OK | |
67 | * | |
68 | * Use: Ensures that a directory is OK. If @f@ is a real pointer, | |
69 | * and @*f@ is set, then try to create the directory. | |
70 | */ | |
71 | ||
72 | static int ok(const char *p, int *f) | |
73 | { | |
74 | struct stat st; | |
75 | ||
76 | /* --- Read the directory status --- */ | |
77 | ||
78 | if (lstat(p, &st)) { | |
79 | ||
80 | /* --- Maybe create it if it doesn't exist --- */ | |
81 | ||
82 | if (errno != ENOENT || !f || !*f) | |
83 | return (0); | |
84 | if (mkdir(p, 0700)) { | |
85 | *f = 0; | |
86 | return (0); | |
87 | } | |
88 | ||
89 | /* --- Now read the new status --- * | |
90 | * | |
91 | * This fixes a race condition between the previous @lstat@ call and | |
92 | * the @mkdir@. | |
93 | */ | |
94 | ||
95 | if (lstat(p, &st)) | |
96 | return (0); | |
97 | } | |
98 | ||
99 | /* --- Make sure the directory is good --- * | |
100 | * | |
101 | * It must be a genuine directory (not a link); it must be readable | |
102 | * and writable only by its owner, and that owner must be me. | |
103 | */ | |
104 | ||
105 | if (S_ISDIR(st.st_mode) && (st.st_mode & 0777) == 0700 && st.st_uid == me) | |
106 | return (1); | |
107 | return (0); | |
108 | } | |
109 | ||
110 | /* --- @trytmp@ --- * | |
111 | * | |
112 | * Arguments: @const char *parent@ = parent directory name | |
113 | * @const char *base@ = subdirectory base name | |
114 | * | |
115 | * Returns: Pointer to directory name, or null. (String needs freeing.) | |
116 | * | |
117 | * Use: Tries to find or create an appropriate temporary directory. | |
118 | */ | |
119 | ||
120 | static char *trytmp(const char *parent, const char *base) | |
121 | { | |
122 | static char c[] = { "0123456789" | |
123 | "abcdefghijklmnopqrstuvwxyz" | |
124 | "ABCDEFGHIJKLMNOPQRSTUVWXYZ" }; | |
125 | char *p, *q; | |
126 | char *qq; | |
72462155 | 127 | dstr d = DSTR_INIT; |
efa7a97b | 128 | int createflag = 1; |
129 | ||
130 | /* --- Make sure the parent directory is sane --- * | |
131 | * | |
132 | * Must make sure that all the lead-up to the temporary directory is safe. | |
133 | * Otherwise other people can play with symlinks or rename directories | |
134 | * after I've done all this careful work to make the endpoint directory | |
135 | * safe. | |
136 | */ | |
137 | ||
d7b5ee0c | 138 | if (checkpath(parent, &cp)) |
efa7a97b | 139 | return (0); |
140 | ||
141 | /* --- See whether the trivial version will work --- */ | |
142 | ||
efa7a97b | 143 | dstr_putf(&d, "%s/%s", parent, base); |
144 | if (ok(d.buf, &createflag)) | |
145 | goto good; | |
146 | ||
147 | /* --- Now try with various suffixes --- */ | |
148 | ||
149 | DENSURE(&d, 4); | |
150 | qq = d.buf + d.len; | |
151 | *qq++ = '-'; | |
152 | ||
153 | for (p = c; *p; p++) { | |
154 | qq[0] = *p; | |
155 | qq[1] = 0; | |
156 | if (ok(d.buf, &createflag)) | |
157 | goto good; | |
158 | for (q = c; *q; q++) { | |
159 | qq[1] = *q; | |
160 | qq[2] = 0; | |
161 | if (ok(d.buf, &createflag)) | |
162 | goto good; | |
163 | } | |
164 | } | |
165 | ||
166 | /* --- No joy --- */ | |
167 | ||
168 | dstr_destroy(&d); | |
169 | return (0); | |
170 | ||
171 | good: | |
172 | p = xstrdup(d.buf); | |
173 | dstr_destroy(&d); | |
174 | return (p); | |
175 | } | |
176 | ||
177 | /* --- @fullcheck@ --- * | |
178 | * | |
179 | * Arguments: @const char *p@ = pointer to path to check | |
180 | * | |
181 | * Returns: Zero if it's a bad directory. | |
182 | * | |
183 | * Use: Runs a thorough check on a directory. | |
184 | */ | |
185 | ||
186 | static int fullcheck(const char *p) | |
5dd99356 | 187 | { return (checkpath(p, &cp) == 0 && ok(p, 0)); } |
efa7a97b | 188 | |
189 | /* --- @goodtmp@ --- * | |
190 | * | |
191 | * Arguments: --- | |
192 | * | |
193 | * Returns: Pointer to a known-good secure temporary directory, or | |
194 | * null. | |
195 | * | |
196 | * Use: Finds a good place to store temporary files. | |
197 | */ | |
198 | ||
199 | static char *goodtmp(void) | |
200 | { | |
201 | char *p, *q; | |
202 | ||
203 | /* --- First of all, try the user's current choice --- */ | |
204 | ||
205 | if ((p = getenv("TMPDIR")) != 0 && fullcheck(p)) | |
206 | return (p); | |
207 | ||
208 | /* --- Try making a directory in `/tmp' --- */ | |
209 | ||
557179af | 210 | if ((q = trytmp("/tmp", pw->pw_name)) != 0) |
efa7a97b | 211 | return (q); |
212 | ||
213 | /* --- That failed: try a directory in the user's home --- */ | |
214 | ||
557179af | 215 | if ((q = trytmp(pw->pw_dir, "tmp")) != 0) |
efa7a97b | 216 | return (q); |
217 | ||
218 | /* --- Still no joy: give up --- * | |
219 | * | |
220 | * To be fair, if the user can't find a safe place in his own home | |
221 | * directory then he's pretty stuffed. | |
222 | */ | |
223 | ||
224 | return (0); | |
225 | } | |
226 | ||
3d62246f MW |
227 | /* --- @report@ --- */ |
228 | ||
229 | static void report(unsigned what, int verbose, | |
230 | const char *p, const char *msg, | |
231 | void *arg) | |
232 | { moan("%s", msg); } | |
233 | ||
efa7a97b | 234 | /* --- @usage@ --- */ |
235 | ||
236 | static void usage(FILE *fp) | |
73e1a557 | 237 | { fprintf(fp, "Usage: %s [-bcv] [-g NAME] [-C PATH]\n", QUIS); } |
efa7a97b | 238 | |
239 | /* --- @version@ --- */ | |
240 | ||
241 | static void version(FILE *fp) | |
5dd99356 | 242 | { fprintf(fp, "%s version %s\n", QUIS, VERSION); } |
efa7a97b | 243 | |
244 | /* --- @help@ --- */ | |
245 | ||
246 | static void help(FILE *fp) | |
247 | { | |
248 | version(fp); | |
249 | putc('\n', fp); | |
250 | usage(fp); | |
251 | fputs("\n\ | |
252 | Sets a suitable and secure temporary directory, or checks that a given\n\ | |
253 | directory is suitable for use with temporary files. A directory is\n\ | |
254 | considered good for a particular user if it's readable and writable only\n\ | |
255 | by that user, and if all its parents are modifiable only by the user or\n\ | |
256 | root.\n\ | |
257 | \n\ | |
258 | Options supported:\n\ | |
259 | \n\ | |
260 | -h, --help Display this help text.\n\ | |
261 | -V, --version Display the program's version number.\n\ | |
262 | -u, --usage Display a terse usage summary.\n\ | |
263 | \n\ | |
264 | -b, --bourne Output a `TMPDIR' setting for Bourne shell users.\n\ | |
265 | -c, --cshell Output a `TMPDIR' setting for C shell users.\n\ | |
3d62246f | 266 | -v, --verbose Report problems to standard error.\n\ |
7d5bdc25 | 267 | -g, --group NAME Trust group NAME to be honest and true.\n\ |
3d62246f | 268 | -C, --check PATH Check whether PATH is good, setting exit status.\n\ |
efa7a97b | 269 | \n\ |
270 | The default action is to examine the caller's shell and output a suitable\n\ | |
271 | setting for that shell type.\n\ | |
272 | ", | |
273 | fp); | |
274 | } | |
275 | ||
276 | /* --- @main@ --- * | |
277 | * | |
278 | * Arguments: @int argc@ = number of command line arguments | |
279 | * @char *argv[]@ = the actual argument strings | |
280 | * | |
281 | * Returns: Zero if all went well, else nonzero. | |
282 | * | |
283 | * Use: Performs helpful operations on temporary directories. | |
284 | */ | |
285 | ||
286 | int main(int argc, char *argv[]) | |
287 | { | |
288 | int shell = 0; | |
289 | int duff = 0; | |
d8e11317 | 290 | char *p; |
efa7a97b | 291 | |
292 | enum { | |
293 | sh_unknown, | |
294 | sh_bourne, | |
295 | sh_csh | |
296 | }; | |
297 | ||
298 | /* --- Initialize variables --- */ | |
299 | ||
300 | ego(argv[0]); | |
cf4df2cf | 301 | me = cp.cp_uid = geteuid(); |
7d5bdc25 MW |
302 | cp.cp_what = (CP_WRWORLD | CP_WROTHGRP | CP_WROTHUSR | |
303 | CP_STICKYOK | CP_REPORT); | |
efa7a97b | 304 | cp.cp_verbose = 0; |
3d62246f | 305 | cp.cp_report = report; |
7d5bdc25 | 306 | cp.cp_gids = 0; /* ignore group membership */ |
efa7a97b | 307 | pw = getpwuid(me); |
308 | if (!pw) | |
309 | die(1, "you don't exist"); | |
310 | ||
311 | /* --- Parse arguments --- */ | |
312 | ||
313 | for (;;) { | |
314 | static struct option opts[] = { | |
315 | { "help", 0, 0, 'h' }, | |
316 | { "version", 0, 0, 'V' }, | |
317 | { "usage", 0, 0, 'u' }, | |
318 | { "bourne", 0, 0, 'b' }, | |
319 | { "cshell", 0, 0, 'c' }, | |
3d62246f MW |
320 | { "check", OPTF_ARGREQ, 0, 'C' }, |
321 | { "verify", OPTF_ARGREQ, 0, 'C' }, | |
322 | { "verbose", 0, 0, 'v' }, | |
7d5bdc25 MW |
323 | { "trust-groups", 0, 0, 't' }, |
324 | { "group", OPTF_ARGREQ, 0, 'g' }, | |
efa7a97b | 325 | { 0, 0, 0, 0 } |
326 | }; | |
60538794 | 327 | int i = mdwopt(argc, argv, "hVu" "bcvtg:c:", opts, 0, 0, 0); |
efa7a97b | 328 | |
329 | if (i < 0) | |
330 | break; | |
331 | switch (i) { | |
332 | case 'h': | |
333 | help(stdout); | |
334 | exit(0); | |
335 | case 'V': | |
336 | version(stdout); | |
337 | exit(0); | |
338 | case 'u': | |
339 | usage(stdout); | |
340 | exit(0); | |
341 | case 'b': | |
342 | shell = sh_bourne; | |
343 | break; | |
344 | case 'c': | |
345 | shell = sh_csh; | |
346 | break; | |
3d62246f | 347 | case 'C': |
efa7a97b | 348 | return (!fullcheck(optarg)); |
349 | break; | |
7d5bdc25 | 350 | case 'g': |
caa14ca2 | 351 | allowgroup(&cp, optarg); |
7d5bdc25 | 352 | break; |
3d62246f MW |
353 | case 'v': |
354 | cp.cp_verbose++; | |
355 | break; | |
efa7a97b | 356 | default: |
357 | duff = 1; | |
358 | break; | |
359 | } | |
360 | } | |
361 | ||
362 | if (duff || optind != argc) { | |
363 | usage(stderr); | |
364 | exit(1); | |
365 | } | |
366 | ||
367 | /* --- Choose a shell --- */ | |
368 | ||
369 | if (!shell) { | |
efa7a97b | 370 | if (!(p = getenv("SHELL"))) |
371 | p = pw->pw_shell; | |
372 | if (strstr(p, "csh")) | |
373 | shell = sh_csh; | |
374 | else | |
375 | shell = sh_bourne; | |
376 | } | |
377 | ||
378 | /* --- Start the checking --- */ | |
379 | ||
d8e11317 MW |
380 | if ((p = goodtmp()) == 0) |
381 | die(1, "no good tmp directory"); | |
382 | switch (shell) { | |
383 | case sh_bourne: | |
384 | printf("TMPDIR=\"%s\"; export TMPDIR\n", p); | |
385 | break; | |
386 | case sh_csh: | |
387 | printf("setenv TMPDIR \"%s\"\n", p); | |
efa7a97b | 388 | break; |
d8e11317 | 389 | } |
efa7a97b | 390 | |
391 | return (0); | |
392 | } | |
393 | ||
394 | /*----- That's all, folks -------------------------------------------------*/ |