source: server/fedora/ref-prepatch/kuserok.c @ 999

Last change on this file since 999 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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