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efa7a97b | 1 | /* -*-c-*- |
efa7a97b | 2 | * |
3 | * Choose and check temporary directories | |
4 | * | |
5 | * (c) 1999 Mark Wooding | |
6 | */ | |
7 | ||
8 | /*----- Licensing notice --------------------------------------------------* | |
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. | |
16 | * | |
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. | |
21 | * | |
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 | ||
29 | #include <errno.h> | |
30 | #include <stdio.h> | |
31 | #include <stdlib.h> | |
32 | #include <string.h> | |
33 | ||
34 | #include <sys/types.h> | |
35 | #include <sys/stat.h> | |
36 | #include <unistd.h> | |
37 | #include <pwd.h> | |
38 | ||
39 | #include <mLib/alloc.h> | |
40 | #include <mLib/dstr.h> | |
d8e11317 | 41 | #include <mLib/macros.h> |
efa7a97b | 42 | #include <mLib/mdwopt.h> |
43 | #include <mLib/quis.h> | |
44 | #include <mLib/report.h> | |
45 | ||
d7b5ee0c | 46 | #include "checkpath.h" |
efa7a97b | 47 | |
48 | /*----- Static variables --------------------------------------------------*/ | |
49 | ||
50 | static uid_t me; | |
d7b5ee0c | 51 | static struct checkpath cp; |
efa7a97b | 52 | static struct passwd *pw; |
53 | ||
54 | /*----- Main code ---------------------------------------------------------*/ | |
55 | ||
56 | /* --- @ok@ --- * | |
57 | * | |
58 | * Arguments: @const char *p@ = pathname to check | |
59 | * @int *f@ = try-to-create flag | |
60 | * | |
61 | * Returns: Nonzero if the directory is OK | |
62 | * | |
63 | * Use: Ensures that a directory is OK. If @f@ is a real pointer, | |
64 | * and @*f@ is set, then try to create the directory. | |
65 | */ | |
66 | ||
67 | static int ok(const char *p, int *f) | |
68 | { | |
69 | struct stat st; | |
70 | ||
71 | /* --- Read the directory status --- */ | |
72 | ||
73 | if (lstat(p, &st)) { | |
74 | ||
75 | /* --- Maybe create it if it doesn't exist --- */ | |
76 | ||
77 | if (errno != ENOENT || !f || !*f) | |
78 | return (0); | |
79 | if (mkdir(p, 0700)) { | |
80 | *f = 0; | |
81 | return (0); | |
82 | } | |
83 | ||
84 | /* --- Now read the new status --- * | |
85 | * | |
86 | * This fixes a race condition between the previous @lstat@ call and | |
87 | * the @mkdir@. | |
88 | */ | |
89 | ||
90 | if (lstat(p, &st)) | |
91 | return (0); | |
92 | } | |
93 | ||
94 | /* --- Make sure the directory is good --- * | |
95 | * | |
96 | * It must be a genuine directory (not a link); it must be readable | |
97 | * and writable only by its owner, and that owner must be me. | |
98 | */ | |
99 | ||
100 | if (S_ISDIR(st.st_mode) && (st.st_mode & 0777) == 0700 && st.st_uid == me) | |
101 | return (1); | |
102 | return (0); | |
103 | } | |
104 | ||
105 | /* --- @trytmp@ --- * | |
106 | * | |
107 | * Arguments: @const char *parent@ = parent directory name | |
108 | * @const char *base@ = subdirectory base name | |
109 | * | |
110 | * Returns: Pointer to directory name, or null. (String needs freeing.) | |
111 | * | |
112 | * Use: Tries to find or create an appropriate temporary directory. | |
113 | */ | |
114 | ||
115 | static char *trytmp(const char *parent, const char *base) | |
116 | { | |
117 | static char c[] = { "0123456789" | |
118 | "abcdefghijklmnopqrstuvwxyz" | |
119 | "ABCDEFGHIJKLMNOPQRSTUVWXYZ" }; | |
120 | char *p, *q; | |
121 | char *qq; | |
72462155 | 122 | dstr d = DSTR_INIT; |
efa7a97b | 123 | int createflag = 1; |
124 | ||
125 | /* --- Make sure the parent directory is sane --- * | |
126 | * | |
127 | * Must make sure that all the lead-up to the temporary directory is safe. | |
128 | * Otherwise other people can play with symlinks or rename directories | |
129 | * after I've done all this careful work to make the endpoint directory | |
130 | * safe. | |
131 | */ | |
132 | ||
d7b5ee0c | 133 | if (checkpath(parent, &cp)) |
efa7a97b | 134 | return (0); |
135 | ||
136 | /* --- See whether the trivial version will work --- */ | |
137 | ||
efa7a97b | 138 | dstr_putf(&d, "%s/%s", parent, base); |
139 | if (ok(d.buf, &createflag)) | |
140 | goto good; | |
141 | ||
142 | /* --- Now try with various suffixes --- */ | |
143 | ||
144 | DENSURE(&d, 4); | |
145 | qq = d.buf + d.len; | |
146 | *qq++ = '-'; | |
147 | ||
148 | for (p = c; *p; p++) { | |
149 | qq[0] = *p; | |
150 | qq[1] = 0; | |
151 | if (ok(d.buf, &createflag)) | |
152 | goto good; | |
153 | for (q = c; *q; q++) { | |
154 | qq[1] = *q; | |
155 | qq[2] = 0; | |
156 | if (ok(d.buf, &createflag)) | |
157 | goto good; | |
158 | } | |
159 | } | |
160 | ||
161 | /* --- No joy --- */ | |
162 | ||
163 | dstr_destroy(&d); | |
164 | return (0); | |
165 | ||
166 | good: | |
167 | p = xstrdup(d.buf); | |
168 | dstr_destroy(&d); | |
169 | return (p); | |
170 | } | |
171 | ||
172 | /* --- @fullcheck@ --- * | |
173 | * | |
174 | * Arguments: @const char *p@ = pointer to path to check | |
175 | * | |
176 | * Returns: Zero if it's a bad directory. | |
177 | * | |
178 | * Use: Runs a thorough check on a directory. | |
179 | */ | |
180 | ||
181 | static int fullcheck(const char *p) | |
182 | { | |
d7b5ee0c | 183 | return (checkpath(p, &cp) == 0 && ok(p, 0)); |
efa7a97b | 184 | } |
185 | ||
186 | /* --- @goodtmp@ --- * | |
187 | * | |
188 | * Arguments: --- | |
189 | * | |
190 | * Returns: Pointer to a known-good secure temporary directory, or | |
191 | * null. | |
192 | * | |
193 | * Use: Finds a good place to store temporary files. | |
194 | */ | |
195 | ||
196 | static char *goodtmp(void) | |
197 | { | |
198 | char *p, *q; | |
199 | ||
200 | /* --- First of all, try the user's current choice --- */ | |
201 | ||
202 | if ((p = getenv("TMPDIR")) != 0 && fullcheck(p)) | |
203 | return (p); | |
204 | ||
205 | /* --- Try making a directory in `/tmp' --- */ | |
206 | ||
207 | if (!(q = getenv("USER")) && !(q = getenv("LOGNAME"))) | |
208 | q = pw->pw_name; | |
209 | if ((q = trytmp("/tmp", q)) != 0) | |
210 | return (q); | |
211 | ||
212 | /* --- That failed: try a directory in the user's home --- */ | |
213 | ||
214 | if (!(q = getenv("HOME"))) | |
215 | q = pw->pw_dir; | |
216 | if ((q = trytmp(q, "tmp")) != 0) | |
217 | return (q); | |
218 | ||
219 | /* --- Still no joy: give up --- * | |
220 | * | |
221 | * To be fair, if the user can't find a safe place in his own home | |
222 | * directory then he's pretty stuffed. | |
223 | */ | |
224 | ||
225 | return (0); | |
226 | } | |
227 | ||
3d62246f MW |
228 | /* --- @report@ --- */ |
229 | ||
230 | static void report(unsigned what, int verbose, | |
231 | const char *p, const char *msg, | |
232 | void *arg) | |
233 | { moan("%s", msg); } | |
234 | ||
efa7a97b | 235 | /* --- @usage@ --- */ |
236 | ||
237 | static void usage(FILE *fp) | |
d8e11317 | 238 | { fprintf(fp, "Usage: %s [-bc] [-v PATH]\n", QUIS); } |
efa7a97b | 239 | |
240 | /* --- @version@ --- */ | |
241 | ||
242 | static void version(FILE *fp) | |
d8e11317 | 243 | { fprintf(fp, "%s version %s\n", QUIS, VERSION); } |
efa7a97b | 244 | |
245 | /* --- @help@ --- */ | |
246 | ||
247 | static void help(FILE *fp) | |
248 | { | |
249 | version(fp); | |
250 | putc('\n', fp); | |
251 | usage(fp); | |
252 | fputs("\n\ | |
253 | Sets a suitable and secure temporary directory, or checks that a given\n\ | |
254 | directory is suitable for use with temporary files. A directory is\n\ | |
255 | considered good for a particular user if it's readable and writable only\n\ | |
256 | by that user, and if all its parents are modifiable only by the user or\n\ | |
257 | root.\n\ | |
258 | \n\ | |
259 | Options supported:\n\ | |
260 | \n\ | |
261 | -h, --help Display this help text.\n\ | |
262 | -V, --version Display the program's version number.\n\ | |
263 | -u, --usage Display a terse usage summary.\n\ | |
264 | \n\ | |
265 | -b, --bourne Output a `TMPDIR' setting for Bourne shell users.\n\ | |
266 | -c, --cshell Output a `TMPDIR' setting for C shell users.\n\ | |
3d62246f MW |
267 | -v, --verbose Report problems to standard error.\n\ |
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]); | |
301 | me = getuid(); | |
3d62246f | 302 | cp.cp_what = CP_WRWORLD | CP_WRGRP | CP_WROTHUSR | CP_STICKYOK | CP_REPORT; |
efa7a97b | 303 | cp.cp_verbose = 0; |
3d62246f | 304 | cp.cp_report = report; |
d7b5ee0c | 305 | checkpath_setids(&cp); |
efa7a97b | 306 | pw = getpwuid(me); |
307 | if (!pw) | |
308 | die(1, "you don't exist"); | |
309 | ||
310 | /* --- Parse arguments --- */ | |
311 | ||
312 | for (;;) { | |
313 | static struct option opts[] = { | |
314 | { "help", 0, 0, 'h' }, | |
315 | { "version", 0, 0, 'V' }, | |
316 | { "usage", 0, 0, 'u' }, | |
317 | { "bourne", 0, 0, 'b' }, | |
318 | { "cshell", 0, 0, 'c' }, | |
3d62246f MW |
319 | { "check", OPTF_ARGREQ, 0, 'C' }, |
320 | { "verify", OPTF_ARGREQ, 0, 'C' }, | |
321 | { "verbose", 0, 0, 'v' }, | |
efa7a97b | 322 | { 0, 0, 0, 0 } |
323 | }; | |
3d62246f | 324 | int i = mdwopt(argc, argv, "hVu bcvc:", opts, 0, 0, 0); |
efa7a97b | 325 | |
326 | if (i < 0) | |
327 | break; | |
328 | switch (i) { | |
329 | case 'h': | |
330 | help(stdout); | |
331 | exit(0); | |
332 | case 'V': | |
333 | version(stdout); | |
334 | exit(0); | |
335 | case 'u': | |
336 | usage(stdout); | |
337 | exit(0); | |
338 | case 'b': | |
339 | shell = sh_bourne; | |
340 | break; | |
341 | case 'c': | |
342 | shell = sh_csh; | |
343 | break; | |
3d62246f | 344 | case 'C': |
efa7a97b | 345 | return (!fullcheck(optarg)); |
346 | break; | |
3d62246f MW |
347 | case 'v': |
348 | cp.cp_verbose++; | |
349 | break; | |
efa7a97b | 350 | default: |
351 | duff = 1; | |
352 | break; | |
353 | } | |
354 | } | |
355 | ||
356 | if (duff || optind != argc) { | |
357 | usage(stderr); | |
358 | exit(1); | |
359 | } | |
360 | ||
361 | /* --- Choose a shell --- */ | |
362 | ||
363 | if (!shell) { | |
efa7a97b | 364 | if (!(p = getenv("SHELL"))) |
365 | p = pw->pw_shell; | |
366 | if (strstr(p, "csh")) | |
367 | shell = sh_csh; | |
368 | else | |
369 | shell = sh_bourne; | |
370 | } | |
371 | ||
372 | /* --- Start the checking --- */ | |
373 | ||
d8e11317 MW |
374 | if ((p = goodtmp()) == 0) |
375 | die(1, "no good tmp directory"); | |
376 | switch (shell) { | |
377 | case sh_bourne: | |
378 | printf("TMPDIR=\"%s\"; export TMPDIR\n", p); | |
379 | break; | |
380 | case sh_csh: | |
381 | printf("setenv TMPDIR \"%s\"\n", p); | |
efa7a97b | 382 | break; |
d8e11317 | 383 | } |
efa7a97b | 384 | |
385 | return (0); | |
386 | } | |
387 | ||
388 | /*----- That's all, folks -------------------------------------------------*/ |