1 /* $OpenBSD: bio_enc.c,v 1.33 2024/04/12 11:10:34 tb Exp $ */
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 <errno.h>
60 #include <stdio.h>
61 #include <stdlib.h>
62 #include <string.h>
63
64 #include <openssl/buffer.h>
65 #include <openssl/evp.h>
66
67 #include "bio_local.h"
68 #include "evp_local.h"
69
70 static int enc_write(BIO *h, const char *buf, int num);
71 static int enc_read(BIO *h, char *buf, int size);
72 /*static int enc_puts(BIO *h, const char *str); */
73 /*static int enc_gets(BIO *h, char *str, int size); */
74 static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);
75 static int enc_new(BIO *h);
76 static int enc_free(BIO *data);
77 static long enc_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fps);
78 #define ENC_BLOCK_SIZE (1024*4)
79 #define BUF_OFFSET (EVP_MAX_BLOCK_LENGTH*2)
80
81 typedef struct enc_struct {
82 int buf_len;
83 int buf_off;
84 int cont; /* <= 0 when finished */
85 int finished;
86 int ok; /* bad decrypt */
87 EVP_CIPHER_CTX *cipher_ctx;
88 /* buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate
89 * can return up to a block more data than is presented to it
90 */
91 char buf[ENC_BLOCK_SIZE + BUF_OFFSET + 2];
92 } BIO_ENC_CTX;
93
94 static const BIO_METHOD methods_enc = {
95 .type = BIO_TYPE_CIPHER,
96 .name = "cipher",
97 .bwrite = enc_write,
98 .bread = enc_read,
99 .ctrl = enc_ctrl,
100 .create = enc_new,
101 .destroy = enc_free,
102 .callback_ctrl = enc_callback_ctrl
103 };
104
105 const BIO_METHOD *
BIO_f_cipher(void)106 BIO_f_cipher(void)
107 {
108 return &methods_enc;
109 }
110 LCRYPTO_ALIAS(BIO_f_cipher);
111
112 static void
bio_enc_ctx_free(BIO_ENC_CTX * ctx)113 bio_enc_ctx_free(BIO_ENC_CTX *ctx)
114 {
115 if (ctx == NULL)
116 return;
117
118 EVP_CIPHER_CTX_free(ctx->cipher_ctx);
119 freezero(ctx, sizeof(*ctx));
120 }
121
122 static int
enc_new(BIO * bio)123 enc_new(BIO *bio)
124 {
125 BIO_ENC_CTX *ctx;
126 int ret = 0;
127
128 if ((ctx = calloc(1, sizeof(BIO_ENC_CTX))) == NULL)
129 goto err;
130 if ((ctx->cipher_ctx = EVP_CIPHER_CTX_new()) == NULL)
131 goto err;
132
133 ctx->cont = 1;
134 ctx->ok = 1;
135
136 bio->ptr = ctx;
137 ctx = NULL;
138
139 ret = 1;
140
141 err:
142 bio_enc_ctx_free(ctx);
143
144 return ret;
145 }
146
147 static int
enc_free(BIO * bio)148 enc_free(BIO *bio)
149 {
150 if (bio == NULL)
151 return 0;
152
153 bio_enc_ctx_free(bio->ptr);
154 explicit_bzero(bio, sizeof(*bio));
155
156 return 1;
157 }
158
159 static int
enc_read(BIO * bio,char * out,int outl)160 enc_read(BIO *bio, char *out, int outl)
161 {
162 BIO_ENC_CTX *ctx;
163 int ret = 0, i;
164
165 if (out == NULL)
166 return 0;
167 ctx = bio->ptr;
168
169 if (ctx == NULL || bio->next_bio == NULL)
170 return 0;
171
172 /* First check if there are bytes decoded/encoded */
173 if (ctx->buf_len > 0) {
174 i = ctx->buf_len - ctx->buf_off;
175 if (i > outl)
176 i = outl;
177 memcpy(out, &(ctx->buf[ctx->buf_off]), i);
178 ret = i;
179 out += i;
180 outl -= i;
181 ctx->buf_off += i;
182 if (ctx->buf_len == ctx->buf_off) {
183 ctx->buf_len = 0;
184 ctx->buf_off = 0;
185 }
186 }
187
188 /* At this point, we have room of outl bytes and an empty
189 * buffer, so we should read in some more. */
190
191 while (outl > 0) {
192 if (ctx->cont <= 0)
193 break;
194
195 /* read in at IV offset, read the EVP_Cipher
196 * documentation about why */
197 i = BIO_read(bio->next_bio, &ctx->buf[BUF_OFFSET],
198 ENC_BLOCK_SIZE);
199
200 if (i <= 0) {
201 /* Should be continue next time we are called? */
202 if (!BIO_should_retry(bio->next_bio)) {
203 ctx->cont = i;
204 i = EVP_CipherFinal_ex(ctx->cipher_ctx,
205 (unsigned char *)ctx->buf,
206 &(ctx->buf_len));
207 ctx->ok = i;
208 ctx->buf_off = 0;
209 } else {
210 ret = (ret == 0) ? i : ret;
211 break;
212 }
213 } else {
214 EVP_CipherUpdate(ctx->cipher_ctx,
215 (unsigned char *)ctx->buf, &ctx->buf_len,
216 (unsigned char *)&ctx->buf[BUF_OFFSET], i);
217 ctx->cont = 1;
218 /* Note: it is possible for EVP_CipherUpdate to
219 * decrypt zero bytes because this is or looks like
220 * the final block: if this happens we should retry
221 * and either read more data or decrypt the final
222 * block
223 */
224 if (ctx->buf_len == 0)
225 continue;
226 }
227
228 if (ctx->buf_len <= outl)
229 i = ctx->buf_len;
230 else
231 i = outl;
232 if (i <= 0)
233 break;
234 memcpy(out, ctx->buf, i);
235 ret += i;
236 ctx->buf_off = i;
237 outl -= i;
238 out += i;
239 }
240
241 BIO_clear_retry_flags(bio);
242 BIO_copy_next_retry(bio);
243 return ret == 0 ? ctx->cont : ret;
244 }
245
246 static int
enc_write(BIO * bio,const char * in,int inl)247 enc_write(BIO *bio, const char *in, int inl)
248 {
249 BIO_ENC_CTX *ctx;
250 int ret = 0, n, i;
251
252 ctx = bio->ptr;
253 ret = inl;
254
255 BIO_clear_retry_flags(bio);
256 n = ctx->buf_len - ctx->buf_off;
257 while (n > 0) {
258 i = BIO_write(bio->next_bio, &(ctx->buf[ctx->buf_off]), n);
259 if (i <= 0) {
260 BIO_copy_next_retry(bio);
261 return i;
262 }
263 ctx->buf_off += i;
264 n -= i;
265 }
266 /* at this point all pending data has been written */
267
268 if (in == NULL || inl <= 0)
269 return 0;
270
271 ctx->buf_off = 0;
272 while (inl > 0) {
273 n = inl > ENC_BLOCK_SIZE ? ENC_BLOCK_SIZE : inl;
274 EVP_CipherUpdate(ctx->cipher_ctx,
275 (unsigned char *)ctx->buf, &ctx->buf_len,
276 (unsigned char *)in, n);
277 inl -= n;
278 in += n;
279
280 ctx->buf_off = 0;
281 n = ctx->buf_len;
282 while (n > 0) {
283 i = BIO_write(bio->next_bio, &ctx->buf[ctx->buf_off], n);
284 if (i <= 0) {
285 BIO_copy_next_retry(bio);
286 return ret == inl ? i : ret - inl;
287 }
288 n -= i;
289 ctx->buf_off += i;
290 }
291 ctx->buf_len = 0;
292 ctx->buf_off = 0;
293 }
294 BIO_copy_next_retry(bio);
295
296 return ret;
297 }
298
299 static long
enc_ctrl(BIO * bio,int cmd,long num,void * ptr)300 enc_ctrl(BIO *bio, int cmd, long num, void *ptr)
301 {
302 BIO *dbio;
303 BIO_ENC_CTX *ctx, *dctx;
304 EVP_CIPHER_CTX **c_ctx;
305 int i;
306 long ret = 1;
307
308 ctx = bio->ptr;
309
310 switch (cmd) {
311 case BIO_CTRL_RESET:
312 ctx->ok = 1;
313 ctx->finished = 0;
314 EVP_CipherInit_ex(ctx->cipher_ctx, NULL, NULL, NULL, NULL,
315 ctx->cipher_ctx->encrypt);
316 ret = BIO_ctrl(bio->next_bio, cmd, num, ptr);
317 break;
318 case BIO_CTRL_EOF: /* More to read */
319 if (ctx->cont <= 0)
320 ret = 1;
321 else
322 ret = BIO_ctrl(bio->next_bio, cmd, num, ptr);
323 break;
324 case BIO_CTRL_WPENDING:
325 ret = ctx->buf_len - ctx->buf_off;
326 if (ret <= 0)
327 ret = BIO_ctrl(bio->next_bio, cmd, num, ptr);
328 break;
329 case BIO_CTRL_PENDING: /* More to read in buffer */
330 ret = ctx->buf_len - ctx->buf_off;
331 if (ret <= 0)
332 ret = BIO_ctrl(bio->next_bio, cmd, num, ptr);
333 break;
334 case BIO_CTRL_FLUSH:
335 /* do a final write */
336 again:
337 while (ctx->buf_len != ctx->buf_off) {
338 i = enc_write(bio, NULL, 0);
339 if (i < 0)
340 return i;
341 }
342
343 if (!ctx->finished) {
344 ctx->finished = 1;
345 ctx->buf_off = 0;
346 ret = EVP_CipherFinal_ex(ctx->cipher_ctx,
347 (unsigned char *)ctx->buf,
348 &ctx->buf_len);
349 ctx->ok = (int)ret;
350 if (ret <= 0)
351 break;
352
353 /* push out the bytes */
354 goto again;
355 }
356
357 /* Finally flush the underlying BIO */
358 ret = BIO_ctrl(bio->next_bio, cmd, num, ptr);
359 break;
360 case BIO_C_GET_CIPHER_STATUS:
361 ret = (long)ctx->ok;
362 break;
363 case BIO_C_DO_STATE_MACHINE:
364 BIO_clear_retry_flags(bio);
365 ret = BIO_ctrl(bio->next_bio, cmd, num, ptr);
366 BIO_copy_next_retry(bio);
367 break;
368 case BIO_C_GET_CIPHER_CTX:
369 c_ctx = ptr;
370 *c_ctx = ctx->cipher_ctx;
371 bio->init = 1;
372 break;
373 case BIO_CTRL_DUP:
374 dbio = ptr;
375 dctx = dbio->ptr;
376 ret = EVP_CIPHER_CTX_copy(dctx->cipher_ctx, ctx->cipher_ctx);
377 if (ret)
378 dbio->init = 1;
379 break;
380 default:
381 ret = BIO_ctrl(bio->next_bio, cmd, num, ptr);
382 break;
383 }
384
385 return ret;
386 }
387
388 static long
enc_callback_ctrl(BIO * bio,int cmd,BIO_info_cb * fp)389 enc_callback_ctrl(BIO *bio, int cmd, BIO_info_cb *fp)
390 {
391 long ret = 1;
392
393 if (bio->next_bio == NULL)
394 return 0;
395
396 switch (cmd) {
397 default:
398 ret = BIO_callback_ctrl(bio->next_bio, cmd, fp);
399 break;
400 }
401
402 return ret;
403 }
404
405 int
BIO_set_cipher(BIO * bio,const EVP_CIPHER * c,const unsigned char * k,const unsigned char * i,int e)406 BIO_set_cipher(BIO *bio, const EVP_CIPHER *c, const unsigned char *k,
407 const unsigned char *i, int e)
408 {
409 BIO_ENC_CTX *ctx;
410 long (*cb)(BIO *, int, const char *, int, long, long);
411
412 if (bio == NULL)
413 return 0;
414
415 if ((ctx = BIO_get_data(bio)) == NULL)
416 return 0;
417
418 if ((cb = BIO_get_callback(bio)) != NULL) {
419 if (cb(bio, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 0L) <= 0)
420 return 0;
421 }
422
423 BIO_set_init(bio, 1);
424
425 if (!EVP_CipherInit_ex(ctx->cipher_ctx, c, NULL, k, i, e))
426 return 0;
427
428 if (cb != NULL)
429 return cb(bio, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);
430
431 return 1;
432 }
433 LCRYPTO_ALIAS(BIO_set_cipher);
434