Commit | Line | Data |
---|---|---|
efa7a97b | 1 | /* -*-c-*- |
efa7a97b | 2 | * |
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" |
efa7a97b | 51 | |
52 | /*----- Static variables --------------------------------------------------*/ | |
53 | ||
54 | static uid_t me; | |
d7b5ee0c | 55 | static struct checkpath cp; |
efa7a97b | 56 | static struct passwd *pw; |
57 | ||
58 | /*----- Main code ---------------------------------------------------------*/ | |
59 | ||
60 | /* --- @ok@ --- * | |
61 | * | |
62 | * Arguments: @const char *p@ = pathname to check | |
63 | * @int *f@ = try-to-create flag | |
64 | * | |
65 | * Returns: Nonzero if the directory is OK | |
66 | * | |
67 | * Use: Ensures that a directory is OK. If @f@ is a real pointer, | |
68 | * and @*f@ is set, then try to create the directory. | |
69 | */ | |
70 | ||
71 | static int ok(const char *p, int *f) | |
72 | { | |
73 | struct stat st; | |
74 | ||
75 | /* --- Read the directory status --- */ | |
76 | ||
77 | if (lstat(p, &st)) { | |
78 | ||
79 | /* --- Maybe create it if it doesn't exist --- */ | |
80 | ||
81 | if (errno != ENOENT || !f || !*f) | |
82 | return (0); | |
83 | if (mkdir(p, 0700)) { | |
84 | *f = 0; | |
85 | return (0); | |
86 | } | |
87 | ||
88 | /* --- Now read the new status --- * | |
89 | * | |
90 | * This fixes a race condition between the previous @lstat@ call and | |
91 | * the @mkdir@. | |
92 | */ | |
93 | ||
94 | if (lstat(p, &st)) | |
95 | return (0); | |
96 | } | |
97 | ||
98 | /* --- Make sure the directory is good --- * | |
99 | * | |
100 | * It must be a genuine directory (not a link); it must be readable | |
101 | * and writable only by its owner, and that owner must be me. | |
102 | */ | |
103 | ||
104 | if (S_ISDIR(st.st_mode) && (st.st_mode & 0777) == 0700 && st.st_uid == me) | |
105 | return (1); | |
106 | return (0); | |
107 | } | |
108 | ||
109 | /* --- @trytmp@ --- * | |
110 | * | |
111 | * Arguments: @const char *parent@ = parent directory name | |
112 | * @const char *base@ = subdirectory base name | |
113 | * | |
114 | * Returns: Pointer to directory name, or null. (String needs freeing.) | |
115 | * | |
116 | * Use: Tries to find or create an appropriate temporary directory. | |
117 | */ | |
118 | ||
119 | static char *trytmp(const char *parent, const char *base) | |
120 | { | |
121 | static char c[] = { "0123456789" | |
122 | "abcdefghijklmnopqrstuvwxyz" | |
123 | "ABCDEFGHIJKLMNOPQRSTUVWXYZ" }; | |
124 | char *p, *q; | |
125 | char *qq; | |
72462155 | 126 | dstr d = DSTR_INIT; |
efa7a97b | 127 | int createflag = 1; |
128 | ||
129 | /* --- Make sure the parent directory is sane --- * | |
130 | * | |
131 | * Must make sure that all the lead-up to the temporary directory is safe. | |
132 | * Otherwise other people can play with symlinks or rename directories | |
133 | * after I've done all this careful work to make the endpoint directory | |
134 | * safe. | |
135 | */ | |
136 | ||
d7b5ee0c | 137 | if (checkpath(parent, &cp)) |
efa7a97b | 138 | return (0); |
139 | ||
140 | /* --- See whether the trivial version will work --- */ | |
141 | ||
efa7a97b | 142 | dstr_putf(&d, "%s/%s", parent, base); |
143 | if (ok(d.buf, &createflag)) | |
144 | goto good; | |
145 | ||
146 | /* --- Now try with various suffixes --- */ | |
147 | ||
148 | DENSURE(&d, 4); | |
149 | qq = d.buf + d.len; | |
150 | *qq++ = '-'; | |
151 | ||
152 | for (p = c; *p; p++) { | |
153 | qq[0] = *p; | |
154 | qq[1] = 0; | |
155 | if (ok(d.buf, &createflag)) | |
156 | goto good; | |
157 | for (q = c; *q; q++) { | |
158 | qq[1] = *q; | |
159 | qq[2] = 0; | |
160 | if (ok(d.buf, &createflag)) | |
161 | goto good; | |
162 | } | |
163 | } | |
164 | ||
165 | /* --- No joy --- */ | |
166 | ||
167 | dstr_destroy(&d); | |
168 | return (0); | |
169 | ||
170 | good: | |
171 | p = xstrdup(d.buf); | |
172 | dstr_destroy(&d); | |
173 | return (p); | |
174 | } | |
175 | ||
176 | /* --- @fullcheck@ --- * | |
177 | * | |
178 | * Arguments: @const char *p@ = pointer to path to check | |
179 | * | |
180 | * Returns: Zero if it's a bad directory. | |
181 | * | |
182 | * Use: Runs a thorough check on a directory. | |
183 | */ | |
184 | ||
185 | static int fullcheck(const char *p) | |
5dd99356 | 186 | { return (checkpath(p, &cp) == 0 && ok(p, 0)); } |
efa7a97b | 187 | |
188 | /* --- @goodtmp@ --- * | |
189 | * | |
190 | * Arguments: --- | |
191 | * | |
192 | * Returns: Pointer to a known-good secure temporary directory, or | |
193 | * null. | |
194 | * | |
195 | * Use: Finds a good place to store temporary files. | |
196 | */ | |
197 | ||
198 | static char *goodtmp(void) | |
199 | { | |
200 | char *p, *q; | |
201 | ||
202 | /* --- First of all, try the user's current choice --- */ | |
203 | ||
204 | if ((p = getenv("TMPDIR")) != 0 && fullcheck(p)) | |
205 | return (p); | |
206 | ||
207 | /* --- Try making a directory in `/tmp' --- */ | |
208 | ||
557179af | 209 | if ((q = trytmp("/tmp", pw->pw_name)) != 0) |
efa7a97b | 210 | return (q); |
211 | ||
212 | /* --- That failed: try a directory in the user's home --- */ | |
213 | ||
557179af | 214 | if ((q = trytmp(pw->pw_dir, "tmp")) != 0) |
efa7a97b | 215 | return (q); |
216 | ||
217 | /* --- Still no joy: give up --- * | |
218 | * | |
219 | * To be fair, if the user can't find a safe place in his own home | |
220 | * directory then he's pretty stuffed. | |
221 | */ | |
222 | ||
223 | return (0); | |
224 | } | |
225 | ||
3d62246f MW |
226 | /* --- @report@ --- */ |
227 | ||
228 | static void report(unsigned what, int verbose, | |
229 | const char *p, const char *msg, | |
230 | void *arg) | |
231 | { moan("%s", msg); } | |
232 | ||
efa7a97b | 233 | /* --- @usage@ --- */ |
234 | ||
235 | static void usage(FILE *fp) | |
5dd99356 | 236 | { fprintf(fp, "Usage: %s [-bc] [-v PATH]\n", QUIS); } |
efa7a97b | 237 | |
238 | /* --- @version@ --- */ | |
239 | ||
240 | static void version(FILE *fp) | |
5dd99356 | 241 | { fprintf(fp, "%s version %s\n", QUIS, VERSION); } |
efa7a97b | 242 | |
243 | /* --- @help@ --- */ | |
244 | ||
245 | static void help(FILE *fp) | |
246 | { | |
247 | version(fp); | |
248 | putc('\n', fp); | |
249 | usage(fp); | |
250 | fputs("\n\ | |
251 | Sets a suitable and secure temporary directory, or checks that a given\n\ | |
252 | directory is suitable for use with temporary files. A directory is\n\ | |
253 | considered good for a particular user if it's readable and writable only\n\ | |
254 | by that user, and if all its parents are modifiable only by the user or\n\ | |
255 | root.\n\ | |
256 | \n\ | |
257 | Options supported:\n\ | |
258 | \n\ | |
259 | -h, --help Display this help text.\n\ | |
260 | -V, --version Display the program's version number.\n\ | |
261 | -u, --usage Display a terse usage summary.\n\ | |
262 | \n\ | |
263 | -b, --bourne Output a `TMPDIR' setting for Bourne shell users.\n\ | |
264 | -c, --cshell Output a `TMPDIR' setting for C shell users.\n\ | |
3d62246f | 265 | -v, --verbose Report problems to standard error.\n\ |
7d5bdc25 | 266 | -g, --group NAME Trust group NAME to be honest and true.\n\ |
3d62246f | 267 | -C, --check PATH Check whether PATH is good, setting exit status.\n\ |
efa7a97b | 268 | \n\ |
269 | The default action is to examine the caller's shell and output a suitable\n\ | |
270 | setting for that shell type.\n\ | |
271 | ", | |
272 | fp); | |
273 | } | |
274 | ||
7d5bdc25 MW |
275 | /* --- @allowgroup@ --- * |
276 | * | |
277 | * Arguments: @const char *gname@ = trust group @gname@ | |
278 | * | |
279 | * Returns: --- | |
280 | * | |
281 | * Use: Adds the gid corresponding to @gname@ (which may be a number) | |
282 | * to the list of things we trust. | |
283 | */ | |
284 | ||
285 | static void allowgroup(const char *gname) | |
286 | { | |
287 | struct group *gr; | |
288 | const char *p; | |
289 | gid_t g; | |
290 | ||
291 | /* --- Check for numeric group spec --- */ | |
292 | ||
293 | for (p = gname; *p; p++) { | |
294 | if (!isdigit((unsigned char)*p)) | |
295 | goto lookup; | |
296 | } | |
297 | g = atoi(gname); | |
298 | goto insert; | |
299 | ||
300 | /* --- Look up a group by name --- */ | |
301 | ||
302 | lookup: | |
303 | if ((gr = getgrnam(gname)) == 0) | |
304 | die(1, "group %s not found", gname); | |
305 | g = gr->gr_gid; | |
306 | ||
307 | /* --- Insert the group into the table --- */ | |
308 | ||
309 | insert: | |
310 | if (cp.cp_gids >= N(cp.cp_gid)) | |
311 | die(1, "too many groups"); | |
312 | cp.cp_gid[cp.cp_gids++] = g; | |
313 | } | |
314 | ||
efa7a97b | 315 | /* --- @main@ --- * |
316 | * | |
317 | * Arguments: @int argc@ = number of command line arguments | |
318 | * @char *argv[]@ = the actual argument strings | |
319 | * | |
320 | * Returns: Zero if all went well, else nonzero. | |
321 | * | |
322 | * Use: Performs helpful operations on temporary directories. | |
323 | */ | |
324 | ||
325 | int main(int argc, char *argv[]) | |
326 | { | |
327 | int shell = 0; | |
328 | int duff = 0; | |
d8e11317 | 329 | char *p; |
efa7a97b | 330 | |
331 | enum { | |
332 | sh_unknown, | |
333 | sh_bourne, | |
334 | sh_csh | |
335 | }; | |
336 | ||
337 | /* --- Initialize variables --- */ | |
338 | ||
339 | ego(argv[0]); | |
557179af | 340 | me = geteuid(); |
7d5bdc25 MW |
341 | cp.cp_what = (CP_WRWORLD | CP_WROTHGRP | CP_WROTHUSR | |
342 | CP_STICKYOK | CP_REPORT); | |
efa7a97b | 343 | cp.cp_verbose = 0; |
3d62246f | 344 | cp.cp_report = report; |
d7b5ee0c | 345 | checkpath_setids(&cp); |
7d5bdc25 | 346 | cp.cp_gids = 0; /* ignore group membership */ |
efa7a97b | 347 | pw = getpwuid(me); |
348 | if (!pw) | |
349 | die(1, "you don't exist"); | |
350 | ||
351 | /* --- Parse arguments --- */ | |
352 | ||
353 | for (;;) { | |
354 | static struct option opts[] = { | |
355 | { "help", 0, 0, 'h' }, | |
356 | { "version", 0, 0, 'V' }, | |
357 | { "usage", 0, 0, 'u' }, | |
358 | { "bourne", 0, 0, 'b' }, | |
359 | { "cshell", 0, 0, 'c' }, | |
3d62246f MW |
360 | { "check", OPTF_ARGREQ, 0, 'C' }, |
361 | { "verify", OPTF_ARGREQ, 0, 'C' }, | |
362 | { "verbose", 0, 0, 'v' }, | |
7d5bdc25 MW |
363 | { "trust-groups", 0, 0, 't' }, |
364 | { "group", OPTF_ARGREQ, 0, 'g' }, | |
efa7a97b | 365 | { 0, 0, 0, 0 } |
366 | }; | |
60538794 | 367 | int i = mdwopt(argc, argv, "hVu" "bcvtg:c:", opts, 0, 0, 0); |
efa7a97b | 368 | |
369 | if (i < 0) | |
370 | break; | |
371 | switch (i) { | |
372 | case 'h': | |
373 | help(stdout); | |
374 | exit(0); | |
375 | case 'V': | |
376 | version(stdout); | |
377 | exit(0); | |
378 | case 'u': | |
379 | usage(stdout); | |
380 | exit(0); | |
381 | case 'b': | |
382 | shell = sh_bourne; | |
383 | break; | |
384 | case 'c': | |
385 | shell = sh_csh; | |
386 | break; | |
3d62246f | 387 | case 'C': |
efa7a97b | 388 | return (!fullcheck(optarg)); |
389 | break; | |
7d5bdc25 MW |
390 | case 'g': |
391 | allowgroup(optarg); | |
392 | break; | |
3d62246f MW |
393 | case 'v': |
394 | cp.cp_verbose++; | |
395 | break; | |
efa7a97b | 396 | default: |
397 | duff = 1; | |
398 | break; | |
399 | } | |
400 | } | |
401 | ||
402 | if (duff || optind != argc) { | |
403 | usage(stderr); | |
404 | exit(1); | |
405 | } | |
406 | ||
407 | /* --- Choose a shell --- */ | |
408 | ||
409 | if (!shell) { | |
efa7a97b | 410 | if (!(p = getenv("SHELL"))) |
411 | p = pw->pw_shell; | |
412 | if (strstr(p, "csh")) | |
413 | shell = sh_csh; | |
414 | else | |
415 | shell = sh_bourne; | |
416 | } | |
417 | ||
418 | /* --- Start the checking --- */ | |
419 | ||
d8e11317 MW |
420 | if ((p = goodtmp()) == 0) |
421 | die(1, "no good tmp directory"); | |
422 | switch (shell) { | |
423 | case sh_bourne: | |
424 | printf("TMPDIR=\"%s\"; export TMPDIR\n", p); | |
425 | break; | |
426 | case sh_csh: | |
427 | printf("setenv TMPDIR \"%s\"\n", p); | |
efa7a97b | 428 | break; |
d8e11317 | 429 | } |
efa7a97b | 430 | |
431 | return (0); | |
432 | } | |
433 | ||
434 | /*----- That's all, folks -------------------------------------------------*/ |