1 /*
2  * Dynamic data buffer
3  * Copyright (c) 2007-2012, Jouni Malinen <j@w1.fi>
4  *
5  * This software may be distributed under the terms of the BSD license.
6  * See README for more details.
7  */
8 
9 #include "includes.h"
10 
11 #include "common.h"
12 #include "trace.h"
13 #include "wpabuf.h"
14 
15 #ifdef WPA_TRACE
16 #define WPABUF_MAGIC 0x51a974e3
17 
18 struct wpabuf_trace {
19 	unsigned int magic;
20 } __attribute__((aligned(8)));
21 
wpabuf_get_trace(const struct wpabuf * buf)22 static struct wpabuf_trace * wpabuf_get_trace(const struct wpabuf *buf)
23 {
24 	return (struct wpabuf_trace *)
25 		((const u8 *) buf - sizeof(struct wpabuf_trace));
26 }
27 #endif /* WPA_TRACE */
28 
29 
wpabuf_overflow(const struct wpabuf * buf,size_t len)30 static void wpabuf_overflow(const struct wpabuf *buf, size_t len)
31 {
32 #ifdef WPA_TRACE
33 	struct wpabuf_trace *trace = wpabuf_get_trace(buf);
34 	if (trace->magic != WPABUF_MAGIC) {
35 		wpa_printf(MSG_ERROR, "wpabuf: invalid magic %x",
36 			   trace->magic);
37 	}
38 #endif /* WPA_TRACE */
39 	wpa_printf(MSG_ERROR, "wpabuf %p (size=%lu used=%lu) overflow len=%lu",
40 		   buf, (unsigned long) buf->size, (unsigned long) buf->used,
41 		   (unsigned long) len);
42 	wpa_trace_show("wpabuf overflow");
43 	abort();
44 }
45 
46 
wpabuf_resize(struct wpabuf ** _buf,size_t add_len)47 int wpabuf_resize(struct wpabuf **_buf, size_t add_len)
48 {
49 	struct wpabuf *buf = *_buf;
50 #ifdef WPA_TRACE
51 	struct wpabuf_trace *trace;
52 #endif /* WPA_TRACE */
53 
54 	if (buf == NULL) {
55 		*_buf = wpabuf_alloc(add_len);
56 		return *_buf == NULL ? -1 : 0;
57 	}
58 
59 #ifdef WPA_TRACE
60 	trace = wpabuf_get_trace(buf);
61 	if (trace->magic != WPABUF_MAGIC) {
62 		wpa_printf(MSG_ERROR, "wpabuf: invalid magic %x",
63 			   trace->magic);
64 		wpa_trace_show("wpabuf_resize invalid magic");
65 		abort();
66 	}
67 #endif /* WPA_TRACE */
68 
69 	if (buf->used + add_len > buf->size) {
70 		unsigned char *nbuf;
71 		if (buf->flags & WPABUF_FLAG_EXT_DATA) {
72 			nbuf = os_realloc(buf->buf, buf->used + add_len);
73 			if (nbuf == NULL)
74 				return -1;
75 			os_memset(nbuf + buf->used, 0, add_len);
76 			buf->buf = nbuf;
77 		} else {
78 #ifdef WPA_TRACE
79 			nbuf = os_realloc(trace, sizeof(struct wpabuf_trace) +
80 					  sizeof(struct wpabuf) +
81 					  buf->used + add_len);
82 			if (nbuf == NULL)
83 				return -1;
84 			trace = (struct wpabuf_trace *) nbuf;
85 			buf = (struct wpabuf *) (trace + 1);
86 			os_memset(nbuf + sizeof(struct wpabuf_trace) +
87 				  sizeof(struct wpabuf) + buf->used, 0,
88 				  add_len);
89 #else /* WPA_TRACE */
90 			nbuf = os_realloc(buf, sizeof(struct wpabuf) +
91 					  buf->used + add_len);
92 			if (nbuf == NULL)
93 				return -1;
94 			buf = (struct wpabuf *) nbuf;
95 			os_memset(nbuf + sizeof(struct wpabuf) + buf->used, 0,
96 				  add_len);
97 #endif /* WPA_TRACE */
98 			buf->buf = (u8 *) (buf + 1);
99 			*_buf = buf;
100 		}
101 		buf->size = buf->used + add_len;
102 	}
103 
104 	return 0;
105 }
106 
107 
108 /**
109  * wpabuf_alloc - Allocate a wpabuf of the given size
110  * @len: Length for the allocated buffer
111  * Returns: Buffer to the allocated wpabuf or %NULL on failure
112  */
wpabuf_alloc(size_t len)113 struct wpabuf * wpabuf_alloc(size_t len)
114 {
115 #ifdef WPA_TRACE
116 	struct wpabuf_trace *trace = os_zalloc(sizeof(struct wpabuf_trace) +
117 					       sizeof(struct wpabuf) + len);
118 	struct wpabuf *buf;
119 	if (trace == NULL)
120 		return NULL;
121 	trace->magic = WPABUF_MAGIC;
122 	buf = (struct wpabuf *) (trace + 1);
123 #else /* WPA_TRACE */
124 	struct wpabuf *buf = os_zalloc(sizeof(struct wpabuf) + len);
125 	if (buf == NULL)
126 		return NULL;
127 #endif /* WPA_TRACE */
128 
129 	buf->size = len;
130 	buf->buf = (u8 *) (buf + 1);
131 	return buf;
132 }
133 
134 
wpabuf_alloc_ext_data(u8 * data,size_t len)135 struct wpabuf * wpabuf_alloc_ext_data(u8 *data, size_t len)
136 {
137 #ifdef WPA_TRACE
138 	struct wpabuf_trace *trace = os_zalloc(sizeof(struct wpabuf_trace) +
139 					       sizeof(struct wpabuf));
140 	struct wpabuf *buf;
141 	if (trace == NULL)
142 		return NULL;
143 	trace->magic = WPABUF_MAGIC;
144 	buf = (struct wpabuf *) (trace + 1);
145 #else /* WPA_TRACE */
146 	struct wpabuf *buf = os_zalloc(sizeof(struct wpabuf));
147 	if (buf == NULL)
148 		return NULL;
149 #endif /* WPA_TRACE */
150 
151 	buf->size = len;
152 	buf->used = len;
153 	buf->buf = data;
154 	buf->flags |= WPABUF_FLAG_EXT_DATA;
155 
156 	return buf;
157 }
158 
159 
wpabuf_alloc_copy(const void * data,size_t len)160 struct wpabuf * wpabuf_alloc_copy(const void *data, size_t len)
161 {
162 	struct wpabuf *buf = wpabuf_alloc(len);
163 	if (buf)
164 		wpabuf_put_data(buf, data, len);
165 	return buf;
166 }
167 
168 
wpabuf_dup(const struct wpabuf * src)169 struct wpabuf * wpabuf_dup(const struct wpabuf *src)
170 {
171 	struct wpabuf *buf = wpabuf_alloc(wpabuf_len(src));
172 	if (buf)
173 		wpabuf_put_data(buf, wpabuf_head(src), wpabuf_len(src));
174 	return buf;
175 }
176 
177 
178 /**
179  * wpabuf_free - Free a wpabuf
180  * @buf: wpabuf buffer
181  */
wpabuf_free(struct wpabuf * buf)182 void wpabuf_free(struct wpabuf *buf)
183 {
184 #ifdef WPA_TRACE
185 	struct wpabuf_trace *trace;
186 	if (buf == NULL)
187 		return;
188 	trace = wpabuf_get_trace(buf);
189 	if (trace->magic != WPABUF_MAGIC) {
190 		wpa_printf(MSG_ERROR, "wpabuf_free: invalid magic %x",
191 			   trace->magic);
192 		wpa_trace_show("wpabuf_free magic mismatch");
193 		abort();
194 	}
195 	if (buf->flags & WPABUF_FLAG_EXT_DATA)
196 		os_free(buf->buf);
197 	os_free(trace);
198 #else /* WPA_TRACE */
199 	if (buf == NULL)
200 		return;
201 	if (buf->flags & WPABUF_FLAG_EXT_DATA)
202 		os_free(buf->buf);
203 	os_free(buf);
204 #endif /* WPA_TRACE */
205 }
206 
207 
wpabuf_clear_free(struct wpabuf * buf)208 void wpabuf_clear_free(struct wpabuf *buf)
209 {
210 	if (buf) {
211 		os_memset(wpabuf_mhead(buf), 0, wpabuf_len(buf));
212 		wpabuf_free(buf);
213 	}
214 }
215 
216 
wpabuf_put(struct wpabuf * buf,size_t len)217 void * wpabuf_put(struct wpabuf *buf, size_t len)
218 {
219 	void *tmp = wpabuf_mhead_u8(buf) + wpabuf_len(buf);
220 	buf->used += len;
221 	if (buf->used > buf->size) {
222 		wpabuf_overflow(buf, len);
223 	}
224 	return tmp;
225 }
226 
227 
228 /**
229  * wpabuf_concat - Concatenate two buffers into a newly allocated one
230  * @a: First buffer
231  * @b: Second buffer
232  * Returns: wpabuf with concatenated a + b data or %NULL on failure
233  *
234  * Both buffers a and b will be freed regardless of the return value. Input
235  * buffers can be %NULL which is interpreted as an empty buffer.
236  */
wpabuf_concat(struct wpabuf * a,struct wpabuf * b)237 struct wpabuf * wpabuf_concat(struct wpabuf *a, struct wpabuf *b)
238 {
239 	struct wpabuf *n = NULL;
240 	size_t len = 0;
241 
242 	if (b == NULL)
243 		return a;
244 
245 	if (a)
246 		len += wpabuf_len(a);
247 	len += wpabuf_len(b);
248 
249 	n = wpabuf_alloc(len);
250 	if (n) {
251 		if (a)
252 			wpabuf_put_buf(n, a);
253 		wpabuf_put_buf(n, b);
254 	}
255 
256 	wpabuf_free(a);
257 	wpabuf_free(b);
258 
259 	return n;
260 }
261 
262 
263 /**
264  * wpabuf_zeropad - Pad buffer with 0x00 octets (prefix) to specified length
265  * @buf: Buffer to be padded
266  * @len: Length for the padded buffer
267  * Returns: wpabuf padded to len octets or %NULL on failure
268  *
269  * If buf is longer than len octets or of same size, it will be returned as-is.
270  * Otherwise a new buffer is allocated and prefixed with 0x00 octets followed
271  * by the source data. The source buffer will be freed on error, i.e., caller
272  * will only be responsible on freeing the returned buffer. If buf is %NULL,
273  * %NULL will be returned.
274  */
wpabuf_zeropad(struct wpabuf * buf,size_t len)275 struct wpabuf * wpabuf_zeropad(struct wpabuf *buf, size_t len)
276 {
277 	struct wpabuf *ret;
278 	size_t blen;
279 
280 	if (buf == NULL)
281 		return NULL;
282 
283 	blen = wpabuf_len(buf);
284 	if (blen >= len)
285 		return buf;
286 
287 	ret = wpabuf_alloc(len);
288 	if (ret) {
289 		os_memset(wpabuf_put(ret, len - blen), 0, len - blen);
290 		wpabuf_put_buf(ret, buf);
291 	}
292 	wpabuf_free(buf);
293 
294 	return ret;
295 }
296 
297 
wpabuf_printf(struct wpabuf * buf,char * fmt,...)298 void wpabuf_printf(struct wpabuf *buf, char *fmt, ...)
299 {
300 	va_list ap;
301 	void *tmp = wpabuf_mhead_u8(buf) + wpabuf_len(buf);
302 	int res;
303 
304 	va_start(ap, fmt);
305 	res = vsnprintf(tmp, buf->size - buf->used, fmt, ap);
306 	va_end(ap);
307 	if (res < 0 || (size_t) res >= buf->size - buf->used)
308 		wpabuf_overflow(buf, res);
309 	buf->used += res;
310 }
311 
312 
313 /**
314  * wpabuf_parse_bin - Parse a null terminated string of binary data to a wpabuf
315  * @buf: Buffer with null terminated string (hexdump) of binary data
316  * Returns: wpabuf or %NULL on failure
317  *
318  * The string len must be a multiple of two and contain only hexadecimal digits.
319  */
wpabuf_parse_bin(const char * buf)320 struct wpabuf * wpabuf_parse_bin(const char *buf)
321 {
322 	size_t len;
323 	struct wpabuf *ret;
324 
325 	len = os_strlen(buf);
326 	if (len & 0x01)
327 		return NULL;
328 	len /= 2;
329 
330 	ret = wpabuf_alloc(len);
331 	if (ret == NULL)
332 		return NULL;
333 
334 	if (hexstr2bin(buf, wpabuf_put(ret, len), len)) {
335 		wpabuf_free(ret);
336 		return NULL;
337 	}
338 
339 	return ret;
340 }
341