2 * Copyright 2000, International Business Machines Corporation and others.
5 * This software has been released under the terms of the IBM Public
6 * License. For details, see the LICENSE file in the top-level source
7 * directory or online at http://www.openafs.org/dl/license10.html
14 /* These two needed for rxgen output to work */
15 #include <afsconfig.h>
16 #include <afs/param.h>
22 #include <afs/fs_utils.h>
24 #include <afs/venus.h>
28 #include <afs/prs_fs.h>
29 #include <afs/sys_prototypes.h>
30 #include <afs/afs_consts.h>
36 static int using_child = 0;
37 static FILE *childin, *childout; /* file pointers on pipe to kpwvalid */
39 /* this removes symlinks from the tail end of path names.
40 * PRECONDITION: name must be either absolute ('/something') or
41 * explictly relative to current directory ('./something')
44 simplify_name(char *orig_name, char *true_name)
50 if (stat(orig_name, &statbuff) < 0) {
54 strcpy(true_name, orig_name);
61 if (lstat(orig_name, &statbuff) < 0) {
62 /* if lstat fails, it's possible that it's transient, but
63 * unlikely. Let's hope it isn't, and continue... */
69 * The lstat succeeded. If the given file is a symlink, substitute
70 * the contents of the link for the file name.
72 if ((statbuff.st_mode & S_IFMT) == S_IFLNK) {
73 link_chars_read = readlink(orig_name, true_name, 1024);
74 if (link_chars_read <= 0) {
79 true_name[link_chars_read++] = '\0';
82 * If the symlink is an absolute pathname, we're fine. Otherwise, we
83 * have to create a full pathname using the original name and the
84 * relative symlink name. Find the rightmost slash in the original
85 * name (we know there is one) and splice in the symlink contents.
87 if (true_name[0] != '/') {
88 last_component = (char *)strrchr(orig_name, '/');
89 strcpy(++last_component, true_name);
90 strcpy(true_name, orig_name);
93 strcpy(true_name, orig_name);
95 return 1; /* found it */
101 /* We find our own location by:
102 * 1. checking for an absolute or relative path name in argv[0]
103 * this is moderately system-dependant: argv[0] is just a convention.
104 * 2. successively checking each component of PATH, and concatenating argv[0]
105 * onto it, then stating the result.
106 * if it exists, it must be us, eh?
107 * NB there may be possible security implications involving
108 * symlinks; I think they are only relevant if the symlink points
109 * directly at kpasswd, not when it points at kpasswd's parent directory.
112 find_me(char *arg, char *parent_dir)
114 char *bp; /* basename pointer */
115 char *dp; /* dirname pointer */
116 char *pathelt, orig_name[1024], truename[1022];
118 #define explicitname(a,b,c) \
122 ( ((b) == '.') && ((c) == '/') ) \
127 if (strlen(arg) > 510) /* just give up */
133 if (explicitname(arg[0], arg[1], arg[2])) {
134 strcpy(orig_name, arg);
135 simplify_name(orig_name, truename);
137 bp = (char *)strrchr(arg, '/');
141 strcpy(orig_name + 2, arg);
142 simplify_name(orig_name, truename);
146 if (!truename[0]) { /* didn't find it */
152 strncpy(path, dp, 2045);
154 for (pathelt = strtok(path, ":"); pathelt;
155 pathelt = strtok(NULL, ":")) {
156 strncpy(orig_name, pathelt, 510);
158 bp = orig_name + strlen(orig_name);
159 *bp = '/'; /* replace NUL with / */
160 strncpy(bp + 1, arg, 510);
162 if (simplify_name(orig_name, truename))
166 if (!truename[0]) /* didn't find it */
167 return 0; /* give up */
171 * Find rightmost slash, if any.
173 bp = (char *)strrchr(truename, '/');
176 * Found it. Designate everything before it as the parent directory,
177 * everything after it as the final component.
179 strncpy(parent_dir, truename, bp - truename);
180 parent_dir[bp - truename] = 0;
181 bp++; /*Skip the slash */
184 * No slash appears in the given file name. Set parent_dir to the current
185 * directory, and the last component as the given name.
187 strcpy(parent_dir, ".");
191 return 1; /* found it */
194 #define SkipLine(str) { while (*str !='\n') str++; str++; }
196 /* this function returns TRUE (1) if the file is in AFS, otherwise false (0) */
200 struct ViceIoctl blob;
202 char space[AFS_PIOCTL_MAXSIZE];
205 blob.out_size = AFS_PIOCTL_MAXSIZE;
208 code = pioctl(apath, VIOC_FILE_CELL_NAME, &blob, 1);
210 if ((errno == EINVAL) || (errno == ENOENT))
219 struct AclEntry *pluslist;
220 struct AclEntry *minuslist;
224 struct AclEntry *next;
232 int nplus, nminus, i, trights;
234 struct AclEntry *first, *last, *tl;
236 sscanf(astr, "%d", &nplus);
238 sscanf(astr, "%d", &nminus);
241 ta = (struct Acl *)malloc(sizeof(struct Acl));
246 for (i = 0; i < nplus; i++) {
247 sscanf(astr, "%100s %d", tname, &trights);
249 tl = (struct AclEntry *)malloc(sizeof(struct AclEntry));
252 strcpy(tl->name, tname);
253 tl->rights = trights;
259 ta->pluslist = first;
265 safestrtok(char *str, char *tok)
270 return (strtok(str, tok));
272 temp = strtok(NULL, tok);
281 /* If it exists, we do some fussing about whether or not this
282 * is a reasonably secure path - not that it makes *much* difference, since
283 * there's not much point in being more secure than the kpasswd executable.
285 /* 1. is this directory in AFS?
286 * 2. Is every component of the pathname secure
287 * (ie, only system:administrators have w or a rights)?
293 struct ViceIoctl blob;
299 if (!InAFS(dir)) /* final component *must* be in AFS */
303 for (temp = safestrtok(dir, "/"); temp; temp = safestrtok(NULL, "/")) {
304 /* strtok keeps sticking NUL in place of /, so we can look at
305 * ever-longer chunks of the path.
310 blob.out_size = AFS_PIOCTL_MAXSIZE;
313 code = pioctl(dir, VIOCGETAL, &blob, 1);
317 ta = ParseAcl(space);
321 for (te = ta->pluslist; te; te = te->next) {
322 if (((te->rights & PRSFS_INSERT) && (te->rights & PRSFS_DELETE))
323 || (te->rights & (PRSFS_WRITE | PRSFS_ADMINISTER)))
324 if (strcmp(te->name, "system:administrators"))
325 return 0; /* somebody who we can't trust has got power */
328 #endif /* INSECURE */
333 /* Then, once we've found our own location, we look for a program named
337 /* look for a password-checking program named kpwvalid.
338 * It has to be in a secure place (same place as this executable)
341 kpwvalid_is(char *dir)
343 struct stat statbuff;
346 len = (int)strlen(dir);
347 strcpy(dir + len, "/kpwvalid");
349 if (stat(dir, &statbuff) < 0) {
350 /* if lstat fails, it's possible that it's transient, but
351 * unlikely. Let's hope it isn't, and continue... */
361 /* We don't allow the use of kpwvalid executable scripts to set policy
362 * for passwd changes.
365 init_child(char *myname)
374 init_child(char *myname)
376 int pipe1[2], pipe2[2];
381 if (!(find_me(myname, dirpath) && is_secure(dirpath)
382 && kpwvalid_is(dirpath))) {
387 /* make a couple of pipes, one for the child's stdin, and the other
388 * for the child's stdout. The parent writes to the former, and
389 * reads from the latter, the child reads from the former, and
390 * writes to the latter.
399 perror("kpasswd: can't fork because ");
400 return (using_child);
402 if (pid == 0) { /* in child process */
403 /* tie stdin and stdout to these pipes */
404 /* if dup2 doesn't exist everywhere, close and then dup, but make */
405 /* sure that you really get stdin or stdout from the dup. */
406 if ((-1 == dup2(pipe1[0], 0)) || (-1 == dup2(pipe2[1], 1))) {
407 perror("kpasswd: can't exec kpwvalid because ");
411 strcat(dirpath, "/kpwvalid");
414 execv(dirpath, argv);
417 using_child = pid; /* save it for later */
418 childin = fdopen(pipe1[1], "w");
419 childout = fdopen(pipe2[0], "r");
420 return (using_child);
423 #endif /* not NT40 */
426 password_bad(char *pw)
432 fprintf(childin, "%s\n", pw);
434 fscanf(childout, "%d", &rc);
440 /* this is originally only used to give the child the old password, so she
441 * can compare putative new passwords against it.
444 give_to_child(char *pw)
450 fprintf(childin, "%s\n", pw);
457 /* quickly and painlessly
460 terminate_child(void)
467 rc = kill(using_child, SIGKILL);