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efa7a97b | 1 | /* -*-c-*- |
2 | * | |
194363d4 | 3 | * $Id: tmpdir.c,v 1.5 2004/04/08 01:36:22 mdw Exp $ |
efa7a97b | 4 | * |
5 | * Choose and check temporary directories | |
6 | * | |
7 | * (c) 1999 Mark Wooding | |
8 | */ | |
9 | ||
263d6e0d | 10 | /*----- Licensing notice --------------------------------------------------* |
efa7a97b | 11 | * |
12 | * This file is part of chkpath. | |
13 | * | |
14 | * chkpath is free software; you can redistribute it and/or modify | |
15 | * it under the terms of the GNU General Public License as published by | |
16 | * the Free Software Foundation; either version 2 of the License, or | |
17 | * (at your option) any later version. | |
263d6e0d | 18 | * |
efa7a97b | 19 | * chkpath is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
22 | * GNU General Public License for more details. | |
263d6e0d | 23 | * |
efa7a97b | 24 | * You should have received a copy of the GNU General Public License |
25 | * along with chkpath; if not, write to the Free Software Foundation, | |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
27 | */ | |
28 | ||
efa7a97b | 29 | /*----- Header files ------------------------------------------------------*/ |
30 | ||
9c42854d MW |
31 | #include "config.h" |
32 | ||
efa7a97b | 33 | #include <errno.h> |
34 | #include <stdio.h> | |
35 | #include <stdlib.h> | |
36 | #include <string.h> | |
37 | ||
38 | #include <sys/types.h> | |
39 | #include <sys/stat.h> | |
40 | #include <unistd.h> | |
41 | #include <pwd.h> | |
42 | ||
43 | #include <mLib/alloc.h> | |
44 | #include <mLib/dstr.h> | |
45 | #include <mLib/mdwopt.h> | |
46 | #include <mLib/quis.h> | |
47 | #include <mLib/report.h> | |
48 | ||
d7b5ee0c | 49 | #include "checkpath.h" |
efa7a97b | 50 | |
51 | /*----- Static variables --------------------------------------------------*/ | |
52 | ||
53 | static uid_t me; | |
d7b5ee0c | 54 | static struct checkpath cp; |
efa7a97b | 55 | static struct passwd *pw; |
56 | ||
57 | /*----- Main code ---------------------------------------------------------*/ | |
58 | ||
59 | /* --- @ok@ --- * | |
60 | * | |
61 | * Arguments: @const char *p@ = pathname to check | |
62 | * @int *f@ = try-to-create flag | |
63 | * | |
64 | * Returns: Nonzero if the directory is OK | |
65 | * | |
66 | * Use: Ensures that a directory is OK. If @f@ is a real pointer, | |
67 | * and @*f@ is set, then try to create the directory. | |
68 | */ | |
69 | ||
70 | static int ok(const char *p, int *f) | |
71 | { | |
72 | struct stat st; | |
73 | ||
74 | /* --- Read the directory status --- */ | |
75 | ||
76 | if (lstat(p, &st)) { | |
77 | ||
78 | /* --- Maybe create it if it doesn't exist --- */ | |
79 | ||
80 | if (errno != ENOENT || !f || !*f) | |
81 | return (0); | |
82 | if (mkdir(p, 0700)) { | |
83 | *f = 0; | |
84 | return (0); | |
85 | } | |
86 | ||
87 | /* --- Now read the new status --- * | |
88 | * | |
89 | * This fixes a race condition between the previous @lstat@ call and | |
90 | * the @mkdir@. | |
91 | */ | |
92 | ||
93 | if (lstat(p, &st)) | |
94 | return (0); | |
95 | } | |
96 | ||
97 | /* --- Make sure the directory is good --- * | |
98 | * | |
99 | * It must be a genuine directory (not a link); it must be readable | |
100 | * and writable only by its owner, and that owner must be me. | |
101 | */ | |
102 | ||
103 | if (S_ISDIR(st.st_mode) && (st.st_mode & 0777) == 0700 && st.st_uid == me) | |
104 | return (1); | |
105 | return (0); | |
106 | } | |
107 | ||
108 | /* --- @trytmp@ --- * | |
109 | * | |
110 | * Arguments: @const char *parent@ = parent directory name | |
111 | * @const char *base@ = subdirectory base name | |
112 | * | |
113 | * Returns: Pointer to directory name, or null. (String needs freeing.) | |
114 | * | |
115 | * Use: Tries to find or create an appropriate temporary directory. | |
116 | */ | |
117 | ||
118 | static char *trytmp(const char *parent, const char *base) | |
119 | { | |
120 | static char c[] = { "0123456789" | |
121 | "abcdefghijklmnopqrstuvwxyz" | |
122 | "ABCDEFGHIJKLMNOPQRSTUVWXYZ" }; | |
123 | char *p, *q; | |
124 | char *qq; | |
72462155 | 125 | dstr d = DSTR_INIT; |
efa7a97b | 126 | int createflag = 1; |
127 | ||
128 | /* --- Make sure the parent directory is sane --- * | |
129 | * | |
130 | * Must make sure that all the lead-up to the temporary directory is safe. | |
131 | * Otherwise other people can play with symlinks or rename directories | |
132 | * after I've done all this careful work to make the endpoint directory | |
133 | * safe. | |
134 | */ | |
135 | ||
d7b5ee0c | 136 | if (checkpath(parent, &cp)) |
efa7a97b | 137 | return (0); |
138 | ||
139 | /* --- See whether the trivial version will work --- */ | |
140 | ||
efa7a97b | 141 | dstr_putf(&d, "%s/%s", parent, base); |
142 | if (ok(d.buf, &createflag)) | |
143 | goto good; | |
144 | ||
145 | /* --- Now try with various suffixes --- */ | |
146 | ||
147 | DENSURE(&d, 4); | |
148 | qq = d.buf + d.len; | |
149 | *qq++ = '-'; | |
150 | ||
151 | for (p = c; *p; p++) { | |
152 | qq[0] = *p; | |
153 | qq[1] = 0; | |
154 | if (ok(d.buf, &createflag)) | |
155 | goto good; | |
156 | for (q = c; *q; q++) { | |
157 | qq[1] = *q; | |
158 | qq[2] = 0; | |
159 | if (ok(d.buf, &createflag)) | |
160 | goto good; | |
161 | } | |
162 | } | |
163 | ||
164 | /* --- No joy --- */ | |
165 | ||
166 | dstr_destroy(&d); | |
167 | return (0); | |
168 | ||
169 | good: | |
170 | p = xstrdup(d.buf); | |
171 | dstr_destroy(&d); | |
172 | return (p); | |
173 | } | |
174 | ||
175 | /* --- @fullcheck@ --- * | |
176 | * | |
177 | * Arguments: @const char *p@ = pointer to path to check | |
178 | * | |
179 | * Returns: Zero if it's a bad directory. | |
180 | * | |
181 | * Use: Runs a thorough check on a directory. | |
182 | */ | |
183 | ||
184 | static int fullcheck(const char *p) | |
5dd99356 | 185 | { return (checkpath(p, &cp) == 0 && ok(p, 0)); } |
efa7a97b | 186 | |
187 | /* --- @goodtmp@ --- * | |
188 | * | |
189 | * Arguments: --- | |
190 | * | |
191 | * Returns: Pointer to a known-good secure temporary directory, or | |
192 | * null. | |
193 | * | |
194 | * Use: Finds a good place to store temporary files. | |
195 | */ | |
196 | ||
197 | static char *goodtmp(void) | |
198 | { | |
199 | char *p, *q; | |
200 | ||
201 | /* --- First of all, try the user's current choice --- */ | |
202 | ||
203 | if ((p = getenv("TMPDIR")) != 0 && fullcheck(p)) | |
204 | return (p); | |
205 | ||
206 | /* --- Try making a directory in `/tmp' --- */ | |
207 | ||
557179af | 208 | if ((q = trytmp("/tmp", pw->pw_name)) != 0) |
efa7a97b | 209 | return (q); |
210 | ||
211 | /* --- That failed: try a directory in the user's home --- */ | |
212 | ||
557179af | 213 | if ((q = trytmp(pw->pw_dir, "tmp")) != 0) |
efa7a97b | 214 | return (q); |
215 | ||
216 | /* --- Still no joy: give up --- * | |
217 | * | |
218 | * To be fair, if the user can't find a safe place in his own home | |
219 | * directory then he's pretty stuffed. | |
220 | */ | |
221 | ||
222 | return (0); | |
223 | } | |
224 | ||
225 | /* --- @usage@ --- */ | |
226 | ||
227 | static void usage(FILE *fp) | |
5dd99356 | 228 | { fprintf(fp, "Usage: %s [-bc] [-v PATH]\n", QUIS); } |
efa7a97b | 229 | |
230 | /* --- @version@ --- */ | |
231 | ||
232 | static void version(FILE *fp) | |
5dd99356 | 233 | { fprintf(fp, "%s version %s\n", QUIS, VERSION); } |
efa7a97b | 234 | |
235 | /* --- @help@ --- */ | |
236 | ||
237 | static void help(FILE *fp) | |
238 | { | |
239 | version(fp); | |
240 | putc('\n', fp); | |
241 | usage(fp); | |
242 | fputs("\n\ | |
243 | Sets a suitable and secure temporary directory, or checks that a given\n\ | |
244 | directory is suitable for use with temporary files. A directory is\n\ | |
245 | considered good for a particular user if it's readable and writable only\n\ | |
246 | by that user, and if all its parents are modifiable only by the user or\n\ | |
247 | root.\n\ | |
248 | \n\ | |
249 | Options supported:\n\ | |
250 | \n\ | |
251 | -h, --help Display this help text.\n\ | |
252 | -V, --version Display the program's version number.\n\ | |
253 | -u, --usage Display a terse usage summary.\n\ | |
254 | \n\ | |
255 | -b, --bourne Output a `TMPDIR' setting for Bourne shell users.\n\ | |
256 | -c, --cshell Output a `TMPDIR' setting for C shell users.\n\ | |
257 | -v, --verify PATH Check whether PATH is good, setting exit status.\n\ | |
258 | \n\ | |
259 | The default action is to examine the caller's shell and output a suitable\n\ | |
260 | setting for that shell type.\n\ | |
261 | ", | |
262 | fp); | |
263 | } | |
264 | ||
265 | /* --- @main@ --- * | |
266 | * | |
267 | * Arguments: @int argc@ = number of command line arguments | |
268 | * @char *argv[]@ = the actual argument strings | |
269 | * | |
270 | * Returns: Zero if all went well, else nonzero. | |
271 | * | |
272 | * Use: Performs helpful operations on temporary directories. | |
273 | */ | |
274 | ||
275 | int main(int argc, char *argv[]) | |
276 | { | |
277 | int shell = 0; | |
278 | int duff = 0; | |
279 | ||
280 | enum { | |
281 | sh_unknown, | |
282 | sh_bourne, | |
283 | sh_csh | |
284 | }; | |
285 | ||
286 | /* --- Initialize variables --- */ | |
287 | ||
288 | ego(argv[0]); | |
557179af | 289 | me = geteuid(); |
efa7a97b | 290 | cp.cp_what = CP_WRWORLD | CP_WRGRP | CP_WROTHUSR | CP_STICKYOK; |
291 | cp.cp_verbose = 0; | |
292 | cp.cp_report = 0; | |
d7b5ee0c | 293 | checkpath_setids(&cp); |
efa7a97b | 294 | pw = getpwuid(me); |
295 | if (!pw) | |
296 | die(1, "you don't exist"); | |
297 | ||
298 | /* --- Parse arguments --- */ | |
299 | ||
300 | for (;;) { | |
301 | static struct option opts[] = { | |
302 | { "help", 0, 0, 'h' }, | |
303 | { "version", 0, 0, 'V' }, | |
304 | { "usage", 0, 0, 'u' }, | |
305 | { "bourne", 0, 0, 'b' }, | |
306 | { "cshell", 0, 0, 'c' }, | |
cef4f797 | 307 | { "verify", OPTF_ARGREQ, 0, 'v' }, |
efa7a97b | 308 | { 0, 0, 0, 0 } |
309 | }; | |
5dd99356 | 310 | int i = mdwopt(argc, argv, "hVu" "bcv:", opts, 0, 0, 0); |
efa7a97b | 311 | |
312 | if (i < 0) | |
313 | break; | |
314 | switch (i) { | |
315 | case 'h': | |
316 | help(stdout); | |
317 | exit(0); | |
318 | case 'V': | |
319 | version(stdout); | |
320 | exit(0); | |
321 | case 'u': | |
322 | usage(stdout); | |
323 | exit(0); | |
324 | case 'b': | |
325 | shell = sh_bourne; | |
326 | break; | |
327 | case 'c': | |
328 | shell = sh_csh; | |
329 | break; | |
330 | case 'v': | |
331 | return (!fullcheck(optarg)); | |
332 | break; | |
333 | default: | |
334 | duff = 1; | |
335 | break; | |
336 | } | |
337 | } | |
338 | ||
339 | if (duff || optind != argc) { | |
340 | usage(stderr); | |
341 | exit(1); | |
342 | } | |
343 | ||
344 | /* --- Choose a shell --- */ | |
345 | ||
346 | if (!shell) { | |
347 | char *p; | |
348 | if (!(p = getenv("SHELL"))) | |
349 | p = pw->pw_shell; | |
350 | if (strstr(p, "csh")) | |
351 | shell = sh_csh; | |
352 | else | |
353 | shell = sh_bourne; | |
354 | } | |
355 | ||
356 | /* --- Start the checking --- */ | |
357 | ||
358 | { | |
359 | char *p = goodtmp(); | |
360 | if (!p) | |
361 | die(1, "no good tmp directory"); | |
362 | switch (shell) { | |
363 | case sh_bourne: | |
364 | printf("TMPDIR=\"%s\"; export TMPDIR\n", p); | |
365 | break; | |
366 | case sh_csh: | |
367 | printf("setenv TMPDIR \"%s\"\n", p); | |
368 | break; | |
369 | } | |
370 | } | |
371 | ||
372 | return (0); | |
373 | } | |
374 | ||
375 | /*----- That's all, folks -------------------------------------------------*/ |