xref: /illumos-gate/usr/src/lib/libresolv2/common/dst/support.c (revision b210e77709da8e42dfe621e10ccf4be504206058)
1 /*
2  * Portions Copyright (c) 1995-1998 by Trusted Information Systems, Inc.
3  *
4  * Permission to use, copy modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND TRUSTED INFORMATION SYSTEMS
9  * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
10  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL
11  * TRUSTED INFORMATION SYSTEMS BE LIABLE FOR ANY SPECIAL, DIRECT,
12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
13  * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
14  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
15  * WITH THE USE OR PERFORMANCE OF THE SOFTWARE.
16  */
17 
18 #include "port_before.h"
19 
20 #include <stdio.h>
21 #include <unistd.h>
22 #include <memory.h>
23 #include <string.h>
24 #include <errno.h>
25 #include <sys/stat.h>
26 #include <netinet/in.h>
27 #include <arpa/nameser.h>
28 #include <resolv.h>
29 
30 #include "dst_internal.h"
31 
32 #include "port_after.h"
33 
34 /*%
35  * dst_s_verify_str()
36  *     Validate that the input string(*str) is at the head of the input
37  *     buffer(**buf).  If so, move the buffer head pointer (*buf) to
38  *     the first byte of data following the string(*str).
39  * Parameters
40  *     buf     Input buffer.
41  *     str     Input string.
42  * Return
43  *	0       *str is not the head of **buff
44  *	1       *str is the head of **buff, *buf is is advanced to
45  *	the tail of **buf.
46  */
47 
48 int
49 dst_s_verify_str(const char **buf, const char *str)
50 {
51 	int b, s;
52 	if (*buf == NULL)	/*%< error checks */
53 		return (0);
54 	if (str == NULL || *str == '\0')
55 		return (1);
56 
57 	b = strlen(*buf);	/*%< get length of strings */
58 	s = strlen(str);
59 	if (s > b || strncmp(*buf, str, s))	/*%< check if same */
60 		return (0);	/*%< not a match */
61 	(*buf) += s;		/*%< advance pointer */
62 	return (1);
63 }
64 
65 /*%
66  * dst_s_calculate_bits
67  *     Given a binary number represented in a u_char[], determine
68  *     the number of significant bits used.
69  * Parameters
70  *     str       An input character string containing a binary number.
71  *     max_bits The maximum possible significant bits.
72  * Return
73  *     N       The number of significant bits in str.
74  */
75 
76 int
77 dst_s_calculate_bits(const u_char *str, const int max_bits)
78 {
79 	const u_char *p = str;
80 	u_char i, j = 0x80;
81 	int bits;
82 	for (bits = max_bits; *p == 0x00 && bits > 0; p++)
83 		bits -= 8;
84 	for (i = *p; (i & j) != j; j >>= 1)
85 		bits--;
86 	return (bits);
87 }
88 
89 /*%
90  * calculates a checksum used in dst for an id.
91  * takes an array of bytes and a length.
92  * returns a 16  bit checksum.
93  */
94 u_int16_t
95 dst_s_id_calc(const u_char *key, const int keysize)
96 {
97 	u_int32_t ac;
98 	const u_char *kp = key;
99 	int size = keysize;
100 
101 	if (!key || (keysize <= 0))
102 		return (0xffffU);
103 
104 	for (ac = 0; size > 1; size -= 2, kp += 2)
105 		ac += ((*kp) << 8) + *(kp + 1);
106 
107 	if (size > 0)
108 		ac += ((*kp) << 8);
109 	ac += (ac >> 16) & 0xffff;
110 
111 	return (ac & 0xffff);
112 }
113 
114 /*%
115  * dst_s_dns_key_id() Function to calculate DNSSEC footprint from KEY record
116  *   rdata
117  * Input:
118  *	dns_key_rdata: the raw data in wire format
119  *      rdata_len: the size of the input data
120  * Output:
121  *      the key footprint/id calculated from the key data
122  */
123 u_int16_t
124 dst_s_dns_key_id(const u_char *dns_key_rdata, const int rdata_len)
125 {
126 	if (!dns_key_rdata)
127 		return 0;
128 
129 	/* compute id */
130 	if (dns_key_rdata[3] == KEY_RSA)	/*%< Algorithm RSA */
131 		return dst_s_get_int16((const u_char *)
132 				       &dns_key_rdata[rdata_len - 3]);
133 	else if (dns_key_rdata[3] == KEY_HMAC_MD5)
134 		/* compatibility */
135 		return 0;
136 	else
137 		/* compute a checksum on the key part of the key rr */
138 		return dst_s_id_calc(dns_key_rdata, rdata_len);
139 }
140 
141 /*%
142  * dst_s_get_int16
143  *     This routine extracts a 16 bit integer from a two byte character
144  *     string.  The character string is assumed to be in network byte
145  *     order and may be unaligned.  The number returned is in host order.
146  * Parameter
147  *     buf     A two byte character string.
148  * Return
149  *     The converted integer value.
150  */
151 
152 u_int16_t
153 dst_s_get_int16(const u_char *buf)
154 {
155 	register u_int16_t a = 0;
156 	a = ((u_int16_t)(buf[0] << 8)) | ((u_int16_t)(buf[1]));
157 	return (a);
158 }
159 
160 /*%
161  * dst_s_get_int32
162  *     This routine extracts a 32 bit integer from a four byte character
163  *     string.  The character string is assumed to be in network byte
164  *     order and may be unaligned.  The number returned is in host order.
165  * Parameter
166  *     buf     A four byte character string.
167  * Return
168  *     The converted integer value.
169  */
170 
171 u_int32_t
172 dst_s_get_int32(const u_char *buf)
173 {
174 	register u_int32_t a = 0;
175 	a = ((u_int32_t)(buf[0] << 24)) | ((u_int32_t)(buf[1] << 16)) |
176 		((u_int32_t)(buf[2] << 8)) | ((u_int32_t)(buf[3]));
177 	return (a);
178 }
179 
180 /*%
181  * dst_s_put_int16
182  *     Take a 16 bit integer and store the value in a two byte
183  *     character string.  The integer is assumed to be in network
184  *     order and the string is returned in host order.
185  *
186  * Parameters
187  *     buf     Storage for a two byte character string.
188  *     val     16 bit integer.
189  */
190 
191 void
192 dst_s_put_int16(u_int8_t *buf, const u_int16_t val)
193 {
194 	buf[0] = (u_int8_t)(val >> 8);
195 	buf[1] = (u_int8_t)(val);
196 }
197 
198 /*%
199  * dst_s_put_int32
200  *     Take a 32 bit integer and store the value in a four byte
201  *     character string.  The integer is assumed to be in network
202  *     order and the string is returned in host order.
203  *
204  * Parameters
205  *     buf     Storage for a four byte character string.
206  *     val     32 bit integer.
207  */
208 
209 void
210 dst_s_put_int32(u_int8_t *buf, const u_int32_t val)
211 {
212 	buf[0] = (u_int8_t)(val >> 24);
213 	buf[1] = (u_int8_t)(val >> 16);
214 	buf[2] = (u_int8_t)(val >> 8);
215 	buf[3] = (u_int8_t)(val);
216 }
217 
218 /*%
219  *  dst_s_filename_length
220  *
221  *	This function returns the number of bytes needed to hold the
222  *	filename for a key file.  '/', '\' and ':' are not allowed.
223  *	form:  K&lt;keyname&gt;+&lt;alg&gt;+&lt;id&gt;.&lt;suffix&gt;
224  *
225  *	Returns 0 if the filename would contain either '\', '/' or ':'
226  */
227 size_t
228 dst_s_filename_length(const char *name, const char *suffix)
229 {
230 	if (name == NULL)
231 		return (0);
232 	if (strrchr(name, '\\'))
233 		return (0);
234 	if (strrchr(name, '/'))
235 		return (0);
236 	if (strrchr(name, ':'))
237 		return (0);
238 	if (suffix == NULL)
239 		return (0);
240 	if (strrchr(suffix, '\\'))
241 		return (0);
242 	if (strrchr(suffix, '/'))
243 		return (0);
244 	if (strrchr(suffix, ':'))
245 		return (0);
246 	return (1 + strlen(name) + 6 + strlen(suffix));
247 }
248 
249 /*%
250  *  dst_s_build_filename ()
251  *	Builds a key filename from the key name, it's id, and a
252  *	suffix.  '\', '/' and ':' are not allowed. fA filename is of the
253  *	form:  K&lt;keyname&gt;&lt;id&gt;.&lt;suffix&gt;
254  *	form: K&lt;keyname&gt;+&lt;alg&gt;+&lt;id&gt;.&lt;suffix&gt;
255  *
256  *	Returns -1 if the conversion fails:
257  *	  if the filename would be too long for space allotted
258  *	  if the filename would contain a '\', '/' or ':'
259  *	Returns 0 on success
260  */
261 
262 int
263 dst_s_build_filename(char *filename, const char *name, u_int16_t id,
264 		     int alg, const char *suffix, size_t filename_length)
265 {
266 	u_int32_t my_id;
267 	if (filename == NULL)
268 		return (-1);
269 	memset(filename, 0, filename_length);
270 	if (name == NULL)
271 		return (-1);
272 	if (suffix == NULL)
273 		return (-1);
274 	if (filename_length < 1 + strlen(name) + 4 + 6 + 1 + strlen(suffix))
275 		return (-1);
276 	my_id = id;
277 	sprintf(filename, "K%s+%03d+%05d.%s", name, alg, my_id,
278 		(const char *) suffix);
279 	if (strrchr(filename, '/'))
280 		return (-1);
281 	if (strrchr(filename, '\\'))
282 		return (-1);
283 	if (strrchr(filename, ':'))
284 		return (-1);
285 	return (0);
286 }
287 
288 /*%
289  *  dst_s_fopen ()
290  *     Open a file in the dst_path directory.  If perm is specified, the
291  *     file is checked for existence first, and not opened if it exists.
292  *  Parameters
293  *     filename  File to open
294  *     mode       Mode to open the file (passed directly to fopen)
295  *     perm       File permission, if creating a new file.
296  *  Returns
297  *     NULL       Failure
298  *     NON-NULL  (FILE *) of opened file.
299  */
300 FILE *
301 dst_s_fopen(const char *filename, const char *mode, int perm)
302 {
303 	FILE *fp;
304 	char pathname[PATH_MAX];
305 
306 	if (strlen(filename) + strlen(dst_path) >= sizeof(pathname))
307 		return (NULL);
308 
309 	if (*dst_path != '\0') {
310 		strcpy(pathname, dst_path);
311 		strcat(pathname, filename);
312 	} else
313 		strcpy(pathname, filename);
314 
315 	fp = fopen(pathname, mode);
316 	if (perm)
317 		chmod(pathname, perm);
318 	return (fp);
319 }
320 
321 void
322 dst_s_dump(const int mode, const u_char *data, const int size,
323 	    const char *msg)
324 {
325 	UNUSED(data);
326 
327 	if (size > 0) {
328 #ifdef LONG_TEST
329 		static u_char scratch[1000];
330 		int n ;
331 		n = b64_ntop(data, scratch, size, sizeof(scratch));
332 		printf("%s: %x %d %s\n", msg, mode, n, scratch);
333 #else
334 		printf("%s,%x %d\n", msg, mode, size);
335 #endif
336 	}
337 }
338 
339 /*! \file */
340