source: server/fedora/ref-prepatch/kuserok.c @ 33

Last change on this file since 33 was 33, checked in by jbarnold, 16 years ago
added reference source files that are known to work with our patches
File size: 5.2 KB
Line 
1/*
2 * lib/krb5/os/kuserok.c
3 *
4 * Copyright 1990,1993 by the Massachusetts Institute of Technology.
5 * All Rights Reserved.
6 *
7 * Export of this software from the United States of America may
8 *   require a specific license from the United States Government.
9 *   It is the responsibility of any person or organization contemplating
10 *   export to obtain such a license before exporting.
11 *
12 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
13 * distribute this software and its documentation for any purpose and
14 * without fee is hereby granted, provided that the above copyright
15 * notice appear in all copies and that both that copyright notice and
16 * this permission notice appear in supporting documentation, and that
17 * the name of M.I.T. not be used in advertising or publicity pertaining
18 * to distribution of the software without specific, written prior
19 * permission.  Furthermore if you modify this software you must label
20 * your software as modified software and not distribute it in such a
21 * fashion that it might be confused with the original M.I.T. software.
22 * M.I.T. makes no representations about the suitability of
23 * this software for any purpose.  It is provided "as is" without express
24 * or implied warranty.
25 *
26 *
27 * krb5_kuserok()
28 */
29
30#include "k5-int.h"
31#if !defined(_WIN32)            /* Not yet for Windows */
32#include <stdio.h>
33#include <pwd.h>
34
35#if defined(_AIX) && defined(_IBMR2)
36#include <sys/access.h>
37/* xlc has a bug with "const" */
38#define getpwnam(user) getpwnam((char *)user)
39#endif
40
41#define MAX_USERNAME 65
42
43#if defined(__APPLE__) && defined(__MACH__)
44#include <hfs/hfs_mount.h>      /* XXX */
45#define FILE_OWNER_OK(UID)  ((UID) == 0 || (UID) == UNKNOWNUID)
46#else
47#define FILE_OWNER_OK(UID)  ((UID) == 0)
48#endif
49
50/*
51 * Given a Kerberos principal "principal", and a local username "luser",
52 * determine whether user is authorized to login according to the
53 * authorization file ("~luser/.k5login" by default).  Returns TRUE
54 * if authorized, FALSE if not authorized.
55 *
56 * If there is no account for "luser" on the local machine, returns
57 * FALSE.  If there is no authorization file, and the given Kerberos
58 * name "server" translates to the same name as "luser" (using
59 * krb5_aname_to_lname()), returns TRUE.  Otherwise, if the authorization file
60 * can't be accessed, returns FALSE.  Otherwise, the file is read for
61 * a matching principal name, instance, and realm.  If one is found,
62 * returns TRUE, if none is found, returns FALSE.
63 *
64 * The file entries are in the format produced by krb5_unparse_name(),
65 * one entry per line.
66 *
67 */
68
69krb5_boolean KRB5_CALLCONV
70krb5_kuserok(krb5_context context, krb5_principal principal, const char *luser)
71{
72    struct stat sbuf;
73    struct passwd *pwd;
74    char pbuf[MAXPATHLEN];
75    krb5_boolean isok = FALSE;
76    FILE *fp;
77    char kuser[MAX_USERNAME];
78    char *princname;
79    char linebuf[BUFSIZ];
80    char *newline;
81    int gobble;
82
83    /* no account => no access */
84    char pwbuf[BUFSIZ];
85    struct passwd pwx;
86    if (k5_getpwnam_r(luser, &pwx, pwbuf, sizeof(pwbuf), &pwd) != 0)
87        return(FALSE);
88    (void) strncpy(pbuf, pwd->pw_dir, sizeof(pbuf) - 1);
89    pbuf[sizeof(pbuf) - 1] = '\0';
90    (void) strncat(pbuf, "/.k5login", sizeof(pbuf) - 1 - strlen(pbuf));
91
92    if (access(pbuf, F_OK)) {    /* not accessible */
93        /*
94         * if he's trying to log in as himself, and there is no .k5login file,
95         * let him.  To find out, call
96         * krb5_aname_to_localname to convert the principal to a name
97         * which we can string compare.
98         */
99        if (!(krb5_aname_to_localname(context, principal,
100                                      sizeof(kuser), kuser))
101            && (strcmp(kuser, luser) == 0)) {
102            return(TRUE);
103        }
104    }
105    if (krb5_unparse_name(context, principal, &princname))
106        return(FALSE);                  /* no hope of matching */
107
108    /* open ~/.k5login */
109    if ((fp = fopen(pbuf, "r")) == NULL) {
110        free(princname);
111        return(FALSE);
112    }
113    /*
114     * For security reasons, the .k5login file must be owned either by
115     * the user himself, or by root.  Otherwise, don't grant access.
116     */
117    if (fstat(fileno(fp), &sbuf)) {
118        fclose(fp);
119        free(princname);
120        return(FALSE);
121    }
122    if (sbuf.st_uid != pwd->pw_uid && !FILE_OWNER_OK(sbuf.st_uid)) {
123        fclose(fp);
124        free(princname);
125        return(FALSE);
126    }
127
128    /* check each line */
129    while (!isok && (fgets(linebuf, BUFSIZ, fp) != NULL)) {
130        /* null-terminate the input string */
131        linebuf[BUFSIZ-1] = '\0';
132        newline = NULL;
133        /* nuke the newline if it exists */
134        if ((newline = strchr(linebuf, '\n')))
135            *newline = '\0';
136        if (!strcmp(linebuf, princname)) {
137            isok = TRUE;
138            continue;
139        }
140        /* clean up the rest of the line if necessary */
141        if (!newline)
142            while (((gobble = getc(fp)) != EOF) && gobble != '\n');
143    }
144    free(princname);
145    fclose(fp);
146    return(isok);
147}
148
149#else /* _WIN32 */
150
151/*
152 * If the given Kerberos name "server" translates to the same name as "luser"
153 * (using * krb5_aname_to_lname()), returns TRUE.
154 */
155krb5_boolean KRB5_CALLCONV
156krb5_kuserok(context, principal, luser)
157    krb5_context context;
158    krb5_principal principal;
159    const char *luser;
160{
161    char kuser[50];
162
163    if (krb5_aname_to_localname(context, principal, sizeof(kuser), kuser))
164        return FALSE;
165
166    if (strcmp(kuser, luser) == 0)
167            return TRUE;
168
169    return FALSE;
170}
171#endif /* _WIN32 */
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