1 /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2 /* lib/krb5/krb/unparse.c */
3 /*
4 * Copyright 1990, 2008 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 /*
28 * krb5_unparse_name() routine
29 *
30 * Rewritten by Theodore Ts'o to properly unparse principal names
31 * which have the component or realm separator as part of one of their
32 * components.
33 */
34
35
36 #include "k5-int.h"
37 #include <stdio.h>
38
39 /*
40 * converts the multi-part principal format used in the protocols to a
41 * single-string representation of the name.
42 *
43 * The name returned is in allocated storage and should be freed by
44 * the caller when finished.
45 *
46 * Conventions: / is used to separate components; @ is used to
47 * separate the realm from the rest of the name. If '/', '@', or '\0'
48 * appear in any the component, they will be representing using
49 * backslash encoding. ("\/", "\@", or '\0', respectively)
50 *
51 * returns error
52 * KRB_PARSE_MALFORMED principal is invalid (does not contain
53 * at least 2 components)
54 * also returns system errors
55 * ENOMEM unable to allocate memory for string
56 */
57
58 #define REALM_SEP '@'
59 #define COMPONENT_SEP '/'
60
61 static int
component_length_quoted(const krb5_data * src,int flags)62 component_length_quoted(const krb5_data *src, int flags)
63 {
64 const char *cp = src->data;
65 int length = src->length;
66 int j;
67 int size = length;
68
69 if ((flags & KRB5_PRINCIPAL_UNPARSE_DISPLAY) == 0) {
70 int no_realm = (flags & KRB5_PRINCIPAL_UNPARSE_NO_REALM) &&
71 !(flags & KRB5_PRINCIPAL_UNPARSE_SHORT);
72
73 for (j = 0; j < length; j++,cp++)
74 if ((!no_realm && *cp == REALM_SEP) ||
75 *cp == COMPONENT_SEP ||
76 *cp == '\0' || *cp == '\\' || *cp == '\t' ||
77 *cp == '\n' || *cp == '\b')
78 size++;
79 }
80
81 return size;
82 }
83
84 static int
copy_component_quoting(char * dest,const krb5_data * src,int flags)85 copy_component_quoting(char *dest, const krb5_data *src, int flags)
86 {
87 int j;
88 const char *cp = src->data;
89 char *q = dest;
90 int length = src->length;
91
92 if (flags & KRB5_PRINCIPAL_UNPARSE_DISPLAY) {
93 if (src->length > 0)
94 memcpy(dest, src->data, src->length);
95 return src->length;
96 }
97
98 for (j=0; j < length; j++,cp++) {
99 int no_realm = (flags & KRB5_PRINCIPAL_UNPARSE_NO_REALM) &&
100 !(flags & KRB5_PRINCIPAL_UNPARSE_SHORT);
101
102 switch (*cp) {
103 case REALM_SEP:
104 if (no_realm) {
105 *q++ = *cp;
106 break;
107 }
108 case COMPONENT_SEP:
109 case '\\':
110 *q++ = '\\';
111 *q++ = *cp;
112 break;
113 case '\t':
114 *q++ = '\\';
115 *q++ = 't';
116 break;
117 case '\n':
118 *q++ = '\\';
119 *q++ = 'n';
120 break;
121 case '\b':
122 *q++ = '\\';
123 *q++ = 'b';
124 break;
125 case '\0':
126 *q++ = '\\';
127 *q++ = '0';
128 break;
129 default:
130 *q++ = *cp;
131 }
132 }
133 return q - dest;
134 }
135
136 static krb5_error_code
k5_unparse_name(krb5_context context,krb5_const_principal principal,int flags,char ** name,unsigned int * size)137 k5_unparse_name(krb5_context context, krb5_const_principal principal,
138 int flags, char **name, unsigned int *size)
139 {
140 char *q;
141 krb5_int32 i;
142 unsigned int totalsize = 0;
143 char *default_realm = NULL;
144 krb5_error_code ret = 0;
145
146 if (!principal || !name)
147 return KRB5_PARSE_MALFORMED;
148
149 if (flags & KRB5_PRINCIPAL_UNPARSE_SHORT) {
150 /* omit realm if local realm */
151 krb5_principal_data p;
152
153 ret = krb5_get_default_realm(context, &default_realm);
154 if (ret != 0)
155 goto cleanup;
156
157 p.realm = string2data(default_realm);
158
159 if (krb5_realm_compare(context, &p, principal))
160 flags |= KRB5_PRINCIPAL_UNPARSE_NO_REALM;
161 }
162
163 if ((flags & KRB5_PRINCIPAL_UNPARSE_NO_REALM) == 0) {
164 totalsize += component_length_quoted(&principal->realm, flags);
165 totalsize++; /* This is for the separator */
166 }
167
168 for (i = 0; i < principal->length; i++) {
169 totalsize += component_length_quoted(&principal->data[i], flags);
170 totalsize++; /* This is for the separator */
171 }
172 if (principal->length == 0)
173 totalsize++;
174
175 /*
176 * Allocate space for the ascii string; if space has been
177 * provided, use it, realloc'ing it if necessary.
178 *
179 * We need only n-1 separators for n components, but we need
180 * an extra byte for the NUL at the end.
181 */
182 if (size) {
183 if (*name && (*size < totalsize)) {
184 *name = realloc(*name, totalsize);
185 } else {
186 *name = malloc(totalsize);
187 }
188 *size = totalsize;
189 } else {
190 *name = malloc(totalsize);
191 }
192
193 if (!*name) {
194 ret = ENOMEM;
195 goto cleanup;
196 }
197
198 q = *name;
199
200 for (i = 0; i < principal->length; i++) {
201 q += copy_component_quoting(q, &principal->data[i], flags);
202 *q++ = COMPONENT_SEP;
203 }
204
205 if (i > 0)
206 q--; /* Back up last component separator */
207 if ((flags & KRB5_PRINCIPAL_UNPARSE_NO_REALM) == 0) {
208 *q++ = REALM_SEP;
209 q += copy_component_quoting(q, &principal->realm, flags);
210 }
211 *q++ = '\0';
212
213 cleanup:
214 if (default_realm != NULL)
215 krb5_free_default_realm(context, default_realm);
216
217 return ret;
218 }
219
220 krb5_error_code KRB5_CALLCONV
krb5_unparse_name(krb5_context context,krb5_const_principal principal,char ** name)221 krb5_unparse_name(krb5_context context, krb5_const_principal principal,
222 char **name)
223 {
224 if (name != NULL) /* name == NULL will return error from _ext */
225 *name = NULL;
226
227 return k5_unparse_name(context, principal, 0, name, NULL);
228 }
229
230 krb5_error_code KRB5_CALLCONV
krb5_unparse_name_ext(krb5_context context,krb5_const_principal principal,char ** name,unsigned int * size)231 krb5_unparse_name_ext(krb5_context context, krb5_const_principal principal,
232 char **name, unsigned int *size)
233 {
234 return k5_unparse_name(context, principal, 0, name, size);
235 }
236
237 krb5_error_code KRB5_CALLCONV
krb5_unparse_name_flags(krb5_context context,krb5_const_principal principal,int flags,char ** name)238 krb5_unparse_name_flags(krb5_context context, krb5_const_principal principal,
239 int flags, char **name)
240 {
241 if (name != NULL)
242 *name = NULL;
243 return k5_unparse_name(context, principal, flags, name, NULL);
244 }
245
246 krb5_error_code KRB5_CALLCONV
krb5_unparse_name_flags_ext(krb5_context context,krb5_const_principal principal,int flags,char ** name,unsigned int * size)247 krb5_unparse_name_flags_ext(krb5_context context, krb5_const_principal principal,
248 int flags, char **name, unsigned int *size)
249 {
250 return k5_unparse_name(context, principal, flags, name, size);
251 }
252