xref: /openbsd/lib/libcrypto/evp/bio_b64.c (revision 7b36286a) 
1 /* crypto/evp/bio_b64.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3  * All rights reserved.
4  *
5  * This package is an SSL implementation written
6  * by Eric Young (eay@cryptsoft.com).
7  * The implementation was written so as to conform with Netscapes SSL.
8  *
9  * This library is free for commercial and non-commercial use as long as
10  * the following conditions are aheared to.  The following conditions
11  * apply to all code found in this distribution, be it the RC4, RSA,
12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13  * included with this distribution is covered by the same copyright terms
14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15  *
16  * Copyright remains Eric Young's, and as such any Copyright notices in
17  * the code are not to be removed.
18  * If this package is used in a product, Eric Young should be given attribution
19  * as the author of the parts of the library used.
20  * This can be in the form of a textual message at program startup or
21  * in documentation (online or textual) provided with the package.
22  *
23  * Redistribution and use in source and binary forms, with or without
24  * modification, are permitted provided that the following conditions
25  * are met:
26  * 1. Redistributions of source code must retain the copyright
27  *    notice, this list of conditions and the following disclaimer.
28  * 2. Redistributions in binary form must reproduce the above copyright
29  *    notice, this list of conditions and the following disclaimer in the
30  *    documentation and/or other materials provided with the distribution.
31  * 3. All advertising materials mentioning features or use of this software
32  *    must display the following acknowledgement:
33  *    "This product includes cryptographic software written by
34  *     Eric Young (eay@cryptsoft.com)"
35  *    The word 'cryptographic' can be left out if the rouines from the library
36  *    being used are not cryptographic related :-).
37  * 4. If you include any Windows specific code (or a derivative thereof) from
38  *    the apps directory (application code) you must include an acknowledgement:
39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40  *
41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51  * SUCH DAMAGE.
52  *
53  * The licence and distribution terms for any publically available version or
54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
55  * copied and put under another distribution licence
56  * [including the GNU Public Licence.]
57  */
58 
59 #include <stdio.h>
60 #include <errno.h>
61 #include "cryptlib.h"
62 #include <openssl/buffer.h>
63 #include <openssl/evp.h>
64 
65 static int b64_write(BIO *h, const char *buf, int num);
66 static int b64_read(BIO *h, char *buf, int size);
67 /*static int b64_puts(BIO *h, const char *str); */
68 /*static int b64_gets(BIO *h, char *str, int size); */
69 static long b64_ctrl(BIO *h, int cmd, long arg1, void *arg2);
70 static int b64_new(BIO *h);
71 static int b64_free(BIO *data);
72 static long b64_callback_ctrl(BIO *h,int cmd,bio_info_cb *fp);
73 #define B64_BLOCK_SIZE	1024
74 #define B64_BLOCK_SIZE2	768
75 #define B64_NONE	0
76 #define B64_ENCODE	1
77 #define B64_DECODE	2
78 
79 typedef struct b64_struct
80 	{
81 	/*BIO *bio; moved to the BIO structure */
82 	int buf_len;
83 	int buf_off;
84 	int tmp_len;		/* used to find the start when decoding */
85 	int tmp_nl;		/* If true, scan until '\n' */
86 	int encode;
87 	int start;		/* have we started decoding yet? */
88 	int cont;		/* <= 0 when finished */
89 	EVP_ENCODE_CTX base64;
90 	char buf[EVP_ENCODE_LENGTH(B64_BLOCK_SIZE)+10];
91 	char tmp[B64_BLOCK_SIZE];
92 	} BIO_B64_CTX;
93 
94 static BIO_METHOD methods_b64=
95 	{
96 	BIO_TYPE_BASE64,"base64 encoding",
97 	b64_write,
98 	b64_read,
99 	NULL, /* b64_puts, */
100 	NULL, /* b64_gets, */
101 	b64_ctrl,
102 	b64_new,
103 	b64_free,
104 	b64_callback_ctrl,
105 	};
106 
107 BIO_METHOD *BIO_f_base64(void)
108 	{
109 	return(&methods_b64);
110 	}
111 
112 static int b64_new(BIO *bi)
113 	{
114 	BIO_B64_CTX *ctx;
115 
116 	ctx=(BIO_B64_CTX *)OPENSSL_malloc(sizeof(BIO_B64_CTX));
117 	if (ctx == NULL) return(0);
118 
119 	ctx->buf_len=0;
120 	ctx->tmp_len=0;
121 	ctx->tmp_nl=0;
122 	ctx->buf_off=0;
123 	ctx->cont=1;
124 	ctx->start=1;
125 	ctx->encode=0;
126 
127 	bi->init=1;
128 	bi->ptr=(char *)ctx;
129 	bi->flags=0;
130 	return(1);
131 	}
132 
133 static int b64_free(BIO *a)
134 	{
135 	if (a == NULL) return(0);
136 	OPENSSL_free(a->ptr);
137 	a->ptr=NULL;
138 	a->init=0;
139 	a->flags=0;
140 	return(1);
141 	}
142 
143 static int b64_read(BIO *b, char *out, int outl)
144 	{
145 	int ret=0,i,ii,j,k,x,n,num,ret_code=0;
146 	BIO_B64_CTX *ctx;
147 	unsigned char *p,*q;
148 
149 	if (out == NULL) return(0);
150 	ctx=(BIO_B64_CTX *)b->ptr;
151 
152 	if ((ctx == NULL) || (b->next_bio == NULL)) return(0);
153 
154 	if (ctx->encode != B64_DECODE)
155 		{
156 		ctx->encode=B64_DECODE;
157 		ctx->buf_len=0;
158 		ctx->buf_off=0;
159 		ctx->tmp_len=0;
160 		EVP_DecodeInit(&(ctx->base64));
161 		}
162 
163 	/* First check if there are bytes decoded/encoded */
164 	if (ctx->buf_len > 0)
165 		{
166 		i=ctx->buf_len-ctx->buf_off;
167 		if (i > outl) i=outl;
168 		OPENSSL_assert(ctx->buf_off+i < (int)sizeof(ctx->buf));
169 		memcpy(out,&(ctx->buf[ctx->buf_off]),i);
170 		ret=i;
171 		out+=i;
172 		outl-=i;
173 		ctx->buf_off+=i;
174 		if (ctx->buf_len == ctx->buf_off)
175 			{
176 			ctx->buf_len=0;
177 			ctx->buf_off=0;
178 			}
179 		}
180 
181 	/* At this point, we have room of outl bytes and an empty
182 	 * buffer, so we should read in some more. */
183 
184 	ret_code=0;
185 	while (outl > 0)
186 		{
187 
188 		if (ctx->cont <= 0)
189 			break;
190 
191 		i=BIO_read(b->next_bio,&(ctx->tmp[ctx->tmp_len]),
192 			B64_BLOCK_SIZE-ctx->tmp_len);
193 
194 		if (i <= 0)
195 			{
196 			ret_code=i;
197 
198 			/* Should be continue next time we are called? */
199 			if (!BIO_should_retry(b->next_bio))
200 				{
201 				ctx->cont=i;
202 				/* If buffer empty break */
203 				if(ctx->tmp_len == 0)
204 					break;
205 				/* Fall through and process what we have */
206 				else
207 					i = 0;
208 				}
209 			/* else we retry and add more data to buffer */
210 			else
211 				break;
212 			}
213 		i+=ctx->tmp_len;
214 		ctx->tmp_len = i;
215 
216 		/* We need to scan, a line at a time until we
217 		 * have a valid line if we are starting. */
218 		if (ctx->start && (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL))
219 			{
220 			/* ctx->start=1; */
221 			ctx->tmp_len=0;
222 			}
223 		else if (ctx->start)
224 			{
225 			q=p=(unsigned char *)ctx->tmp;
226 			for (j=0; j<i; j++)
227 				{
228 				if (*(q++) != '\n') continue;
229 
230 				/* due to a previous very long line,
231 				 * we need to keep on scanning for a '\n'
232 				 * before we even start looking for
233 				 * base64 encoded stuff. */
234 				if (ctx->tmp_nl)
235 					{
236 					p=q;
237 					ctx->tmp_nl=0;
238 					continue;
239 					}
240 
241 				k=EVP_DecodeUpdate(&(ctx->base64),
242 					(unsigned char *)ctx->buf,
243 					&num,p,q-p);
244 				if ((k <= 0) && (num == 0) && (ctx->start))
245 					EVP_DecodeInit(&ctx->base64);
246 				else
247 					{
248 					if (p != (unsigned char *)
249 						&(ctx->tmp[0]))
250 						{
251 						i-=(p- (unsigned char *)
252 							&(ctx->tmp[0]));
253 						for (x=0; x < i; x++)
254 							ctx->tmp[x]=p[x];
255 						}
256 					EVP_DecodeInit(&ctx->base64);
257 					ctx->start=0;
258 					break;
259 					}
260 				p=q;
261 				}
262 
263 			/* we fell off the end without starting */
264 			if (j == i)
265 				{
266 				/* Is this is one long chunk?, if so, keep on
267 				 * reading until a new line. */
268 				if (p == (unsigned char *)&(ctx->tmp[0]))
269 					{
270 					/* Check buffer full */
271 					if (i == B64_BLOCK_SIZE)
272 						{
273 						ctx->tmp_nl=1;
274 						ctx->tmp_len=0;
275 						}
276 					}
277 				else if (p != q) /* finished on a '\n' */
278 					{
279 					n=q-p;
280 					for (ii=0; ii<n; ii++)
281 						ctx->tmp[ii]=p[ii];
282 					ctx->tmp_len=n;
283 					}
284 				/* else finished on a '\n' */
285 				continue;
286 				}
287 			else
288 				ctx->tmp_len=0;
289 			}
290 		/* If buffer isn't full and we can retry then
291 		 * restart to read in more data.
292 		 */
293 		else if ((i < B64_BLOCK_SIZE) && (ctx->cont > 0))
294 			continue;
295 
296 		if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL)
297 			{
298 			int z,jj;
299 
300 			jj=(i>>2)<<2;
301 			z=EVP_DecodeBlock((unsigned char *)ctx->buf,
302 				(unsigned char *)ctx->tmp,jj);
303 			if (jj > 2)
304 				{
305 				if (ctx->tmp[jj-1] == '=')
306 					{
307 					z--;
308 					if (ctx->tmp[jj-2] == '=')
309 						z--;
310 					}
311 				}
312 			/* z is now number of output bytes and jj is the
313 			 * number consumed */
314 			if (jj != i)
315 				{
316 				memcpy((unsigned char *)ctx->tmp,
317 					(unsigned char *)&(ctx->tmp[jj]),i-jj);
318 				ctx->tmp_len=i-jj;
319 				}
320 			ctx->buf_len=0;
321 			if (z > 0)
322 				{
323 				ctx->buf_len=z;
324 				i=1;
325 				}
326 			else
327 				i=z;
328 			}
329 		else
330 			{
331 			i=EVP_DecodeUpdate(&(ctx->base64),
332 				(unsigned char *)ctx->buf,&ctx->buf_len,
333 				(unsigned char *)ctx->tmp,i);
334 			ctx->tmp_len = 0;
335 			}
336 		ctx->buf_off=0;
337 		if (i < 0)
338 			{
339 			ret_code=0;
340 			ctx->buf_len=0;
341 			break;
342 			}
343 
344 		if (ctx->buf_len <= outl)
345 			i=ctx->buf_len;
346 		else
347 			i=outl;
348 
349 		memcpy(out,ctx->buf,i);
350 		ret+=i;
351 		ctx->buf_off=i;
352 		if (ctx->buf_off == ctx->buf_len)
353 			{
354 			ctx->buf_len=0;
355 			ctx->buf_off=0;
356 			}
357 		outl-=i;
358 		out+=i;
359 		}
360 	BIO_clear_retry_flags(b);
361 	BIO_copy_next_retry(b);
362 	return((ret == 0)?ret_code:ret);
363 	}
364 
365 static int b64_write(BIO *b, const char *in, int inl)
366 	{
367 	int ret=inl,n,i;
368 	BIO_B64_CTX *ctx;
369 
370 	ctx=(BIO_B64_CTX *)b->ptr;
371 	BIO_clear_retry_flags(b);
372 
373 	if (ctx->encode != B64_ENCODE)
374 		{
375 		ctx->encode=B64_ENCODE;
376 		ctx->buf_len=0;
377 		ctx->buf_off=0;
378 		ctx->tmp_len=0;
379 		EVP_EncodeInit(&(ctx->base64));
380 		}
381 
382 	n=ctx->buf_len-ctx->buf_off;
383 	while (n > 0)
384 		{
385 		i=BIO_write(b->next_bio,&(ctx->buf[ctx->buf_off]),n);
386 		if (i <= 0)
387 			{
388 			BIO_copy_next_retry(b);
389 			return(i);
390 			}
391 		ctx->buf_off+=i;
392 		n-=i;
393 		}
394 	/* at this point all pending data has been written */
395 	ctx->buf_off=0;
396 	ctx->buf_len=0;
397 
398 	if ((in == NULL) || (inl <= 0)) return(0);
399 
400 	while (inl > 0)
401 		{
402 		n=(inl > B64_BLOCK_SIZE)?B64_BLOCK_SIZE:inl;
403 
404 		if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL)
405 			{
406 			if (ctx->tmp_len > 0)
407 				{
408 				n=3-ctx->tmp_len;
409 				/* There's a teoretical possibility for this */
410 				if (n > inl)
411 					n=inl;
412 				memcpy(&(ctx->tmp[ctx->tmp_len]),in,n);
413 				ctx->tmp_len+=n;
414 				if (ctx->tmp_len < 3)
415 					break;
416 				ctx->buf_len=EVP_EncodeBlock(
417 					(unsigned char *)ctx->buf,
418 					(unsigned char *)ctx->tmp,
419 					ctx->tmp_len);
420 				/* Since we're now done using the temporary
421 				   buffer, the length should be 0'd */
422 				ctx->tmp_len=0;
423 				}
424 			else
425 				{
426 				if (n < 3)
427 					{
428 					memcpy(&(ctx->tmp[0]),in,n);
429 					ctx->tmp_len=n;
430 					break;
431 					}
432 				n-=n%3;
433 				ctx->buf_len=EVP_EncodeBlock(
434 					(unsigned char *)ctx->buf,
435 					(unsigned char *)in,n);
436 				}
437 			}
438 		else
439 			{
440 			EVP_EncodeUpdate(&(ctx->base64),
441 				(unsigned char *)ctx->buf,&ctx->buf_len,
442 				(unsigned char *)in,n);
443 			}
444 		inl-=n;
445 		in+=n;
446 
447 		ctx->buf_off=0;
448 		n=ctx->buf_len;
449 		while (n > 0)
450 			{
451 			i=BIO_write(b->next_bio,&(ctx->buf[ctx->buf_off]),n);
452 			if (i <= 0)
453 				{
454 				BIO_copy_next_retry(b);
455 				return((ret == 0)?i:ret);
456 				}
457 			n-=i;
458 			ctx->buf_off+=i;
459 			}
460 		ctx->buf_len=0;
461 		ctx->buf_off=0;
462 		}
463 	return(ret);
464 	}
465 
466 static long b64_ctrl(BIO *b, int cmd, long num, void *ptr)
467 	{
468 	BIO_B64_CTX *ctx;
469 	long ret=1;
470 	int i;
471 
472 	ctx=(BIO_B64_CTX *)b->ptr;
473 
474 	switch (cmd)
475 		{
476 	case BIO_CTRL_RESET:
477 		ctx->cont=1;
478 		ctx->start=1;
479 		ctx->encode=B64_NONE;
480 		ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
481 		break;
482 	case BIO_CTRL_EOF:	/* More to read */
483 		if (ctx->cont <= 0)
484 			ret=1;
485 		else
486 			ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
487 		break;
488 	case BIO_CTRL_WPENDING: /* More to write in buffer */
489 		ret=ctx->buf_len-ctx->buf_off;
490 		if ((ret == 0) && (ctx->encode != B64_NONE)
491 			&& (ctx->base64.num != 0))
492 			ret=1;
493 		else if (ret <= 0)
494 			ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
495 		break;
496 	case BIO_CTRL_PENDING: /* More to read in buffer */
497 		ret=ctx->buf_len-ctx->buf_off;
498 		if (ret <= 0)
499 			ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
500 		break;
501 	case BIO_CTRL_FLUSH:
502 		/* do a final write */
503 again:
504 		while (ctx->buf_len != ctx->buf_off)
505 			{
506 			i=b64_write(b,NULL,0);
507 			if (i < 0)
508 				return i;
509 			}
510 		if (BIO_get_flags(b) & BIO_FLAGS_BASE64_NO_NL)
511 			{
512 			if (ctx->tmp_len != 0)
513 				{
514 				ctx->buf_len=EVP_EncodeBlock(
515 					(unsigned char *)ctx->buf,
516 					(unsigned char *)ctx->tmp,
517 					ctx->tmp_len);
518 				ctx->buf_off=0;
519 				ctx->tmp_len=0;
520 				goto again;
521 				}
522 			}
523 		else if (ctx->encode != B64_NONE && ctx->base64.num != 0)
524 			{
525 			ctx->buf_off=0;
526 			EVP_EncodeFinal(&(ctx->base64),
527 				(unsigned char *)ctx->buf,
528 				&(ctx->buf_len));
529 			/* push out the bytes */
530 			goto again;
531 			}
532 		/* Finally flush the underlying BIO */
533 		ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
534 		break;
535 
536 	case BIO_C_DO_STATE_MACHINE:
537 		BIO_clear_retry_flags(b);
538 		ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
539 		BIO_copy_next_retry(b);
540 		break;
541 
542 	case BIO_CTRL_DUP:
543 		break;
544 	case BIO_CTRL_INFO:
545 	case BIO_CTRL_GET:
546 	case BIO_CTRL_SET:
547 	default:
548 		ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
549 		break;
550 		}
551 	return(ret);
552 	}
553 
554 static long b64_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
555 	{
556 	long ret=1;
557 
558 	if (b->next_bio == NULL) return(0);
559 	switch (cmd)
560 		{
561 	default:
562 		ret=BIO_callback_ctrl(b->next_bio,cmd,fp);
563 		break;
564 		}
565 	return(ret);
566 	}
567 
568