1 /* $OpenBSD: bio_enc.c,v 1.26 2022/01/14 08:40:57 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 <string.h>
62
63 #include <openssl/buffer.h>
64 #include <openssl/evp.h>
65
66 #include "bio_local.h"
67 #include "evp_locl.h"
68
69 static int enc_write(BIO *h, const char *buf, int num);
70 static int enc_read(BIO *h, char *buf, int size);
71 /*static int enc_puts(BIO *h, const char *str); */
72 /*static int enc_gets(BIO *h, char *str, int size); */
73 static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);
74 static int enc_new(BIO *h);
75 static int enc_free(BIO *data);
76 static long enc_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fps);
77 #define ENC_BLOCK_SIZE (1024*4)
78 #define BUF_OFFSET (EVP_MAX_BLOCK_LENGTH*2)
79
80 typedef struct enc_struct {
81 int buf_len;
82 int buf_off;
83 int cont; /* <= 0 when finished */
84 int finished;
85 int ok; /* bad decrypt */
86 EVP_CIPHER_CTX cipher;
87 /* buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate
88 * can return up to a block more data than is presented to it
89 */
90 char buf[ENC_BLOCK_SIZE + BUF_OFFSET + 2];
91 } BIO_ENC_CTX;
92
93 static const BIO_METHOD methods_enc = {
94 .type = BIO_TYPE_CIPHER,
95 .name = "cipher",
96 .bwrite = enc_write,
97 .bread = enc_read,
98 .ctrl = enc_ctrl,
99 .create = enc_new,
100 .destroy = enc_free,
101 .callback_ctrl = enc_callback_ctrl
102 };
103
104 const BIO_METHOD *
BIO_f_cipher(void)105 BIO_f_cipher(void)
106 {
107 return (&methods_enc);
108 }
109
110 static int
enc_new(BIO * bi)111 enc_new(BIO *bi)
112 {
113 BIO_ENC_CTX *ctx;
114
115 ctx = malloc(sizeof(BIO_ENC_CTX));
116 if (ctx == NULL)
117 return (0);
118 EVP_CIPHER_CTX_init(&ctx->cipher);
119
120 ctx->buf_len = 0;
121 ctx->buf_off = 0;
122 ctx->cont = 1;
123 ctx->finished = 0;
124 ctx->ok = 1;
125
126 bi->init = 0;
127 bi->ptr = (char *)ctx;
128 bi->flags = 0;
129 return (1);
130 }
131
132 static int
enc_free(BIO * a)133 enc_free(BIO *a)
134 {
135 BIO_ENC_CTX *b;
136
137 if (a == NULL)
138 return (0);
139 b = (BIO_ENC_CTX *)a->ptr;
140 EVP_CIPHER_CTX_cleanup(&(b->cipher));
141 freezero(a->ptr, sizeof(BIO_ENC_CTX));
142 a->ptr = NULL;
143 a->init = 0;
144 a->flags = 0;
145 return (1);
146 }
147
148 static int
enc_read(BIO * b,char * out,int outl)149 enc_read(BIO *b, char *out, int outl)
150 {
151 int ret = 0, i;
152 BIO_ENC_CTX *ctx;
153
154 if (out == NULL)
155 return (0);
156 ctx = (BIO_ENC_CTX *)b->ptr;
157
158 if ((ctx == NULL) || (b->next_bio == NULL))
159 return (0);
160
161 /* First check if there are bytes decoded/encoded */
162 if (ctx->buf_len > 0) {
163 i = ctx->buf_len - ctx->buf_off;
164 if (i > outl)
165 i = outl;
166 memcpy(out, &(ctx->buf[ctx->buf_off]), i);
167 ret = i;
168 out += i;
169 outl -= i;
170 ctx->buf_off += i;
171 if (ctx->buf_len == ctx->buf_off) {
172 ctx->buf_len = 0;
173 ctx->buf_off = 0;
174 }
175 }
176
177 /* At this point, we have room of outl bytes and an empty
178 * buffer, so we should read in some more. */
179
180 while (outl > 0) {
181 if (ctx->cont <= 0)
182 break;
183
184 /* read in at IV offset, read the EVP_Cipher
185 * documentation about why */
186 i = BIO_read(b->next_bio, &(ctx->buf[BUF_OFFSET]), ENC_BLOCK_SIZE);
187
188 if (i <= 0) {
189 /* Should be continue next time we are called? */
190 if (!BIO_should_retry(b->next_bio)) {
191 ctx->cont = i;
192 i = EVP_CipherFinal_ex(&(ctx->cipher),
193 (unsigned char *)ctx->buf,
194 &(ctx->buf_len));
195 ctx->ok = i;
196 ctx->buf_off = 0;
197 } else {
198 ret = (ret == 0) ? i : ret;
199 break;
200 }
201 } else {
202 EVP_CipherUpdate(&(ctx->cipher),
203 (unsigned char *)ctx->buf, &ctx->buf_len,
204 (unsigned char *)&(ctx->buf[BUF_OFFSET]), i);
205 ctx->cont = 1;
206 /* Note: it is possible for EVP_CipherUpdate to
207 * decrypt zero bytes because this is or looks like
208 * the final block: if this happens we should retry
209 * and either read more data or decrypt the final
210 * block
211 */
212 if (ctx->buf_len == 0)
213 continue;
214 }
215
216 if (ctx->buf_len <= outl)
217 i = ctx->buf_len;
218 else
219 i = outl;
220 if (i <= 0)
221 break;
222 memcpy(out, ctx->buf, i);
223 ret += i;
224 ctx->buf_off = i;
225 outl -= i;
226 out += i;
227 }
228
229 BIO_clear_retry_flags(b);
230 BIO_copy_next_retry(b);
231 return ((ret == 0) ? ctx->cont : ret);
232 }
233
234 static int
enc_write(BIO * b,const char * in,int inl)235 enc_write(BIO *b, const char *in, int inl)
236 {
237 int ret = 0, n, i;
238 BIO_ENC_CTX *ctx;
239
240 ctx = (BIO_ENC_CTX *)b->ptr;
241 ret = inl;
242
243 BIO_clear_retry_flags(b);
244 n = ctx->buf_len - ctx->buf_off;
245 while (n > 0) {
246 i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);
247 if (i <= 0) {
248 BIO_copy_next_retry(b);
249 return (i);
250 }
251 ctx->buf_off += i;
252 n -= i;
253 }
254 /* at this point all pending data has been written */
255
256 if ((in == NULL) || (inl <= 0))
257 return (0);
258
259 ctx->buf_off = 0;
260 while (inl > 0) {
261 n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl;
262 EVP_CipherUpdate(&(ctx->cipher),
263 (unsigned char *)ctx->buf, &ctx->buf_len,
264 (unsigned char *)in, n);
265 inl -= n;
266 in += n;
267
268 ctx->buf_off = 0;
269 n = ctx->buf_len;
270 while (n > 0) {
271 i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);
272 if (i <= 0) {
273 BIO_copy_next_retry(b);
274 return (ret == inl) ? i : ret - inl;
275 }
276 n -= i;
277 ctx->buf_off += i;
278 }
279 ctx->buf_len = 0;
280 ctx->buf_off = 0;
281 }
282 BIO_copy_next_retry(b);
283 return (ret);
284 }
285
286 static long
enc_ctrl(BIO * b,int cmd,long num,void * ptr)287 enc_ctrl(BIO *b, int cmd, long num, void *ptr)
288 {
289 BIO *dbio;
290 BIO_ENC_CTX *ctx, *dctx;
291 long ret = 1;
292 int i;
293 EVP_CIPHER_CTX **c_ctx;
294
295 ctx = (BIO_ENC_CTX *)b->ptr;
296
297 switch (cmd) {
298 case BIO_CTRL_RESET:
299 ctx->ok = 1;
300 ctx->finished = 0;
301 EVP_CipherInit_ex(&(ctx->cipher), NULL, NULL, NULL, NULL,
302 ctx->cipher.encrypt);
303 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
304 break;
305 case BIO_CTRL_EOF: /* More to read */
306 if (ctx->cont <= 0)
307 ret = 1;
308 else
309 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
310 break;
311 case BIO_CTRL_WPENDING:
312 ret = ctx->buf_len - ctx->buf_off;
313 if (ret <= 0)
314 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
315 break;
316 case BIO_CTRL_PENDING: /* More to read in buffer */
317 ret = ctx->buf_len - ctx->buf_off;
318 if (ret <= 0)
319 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
320 break;
321 case BIO_CTRL_FLUSH:
322 /* do a final write */
323 again:
324 while (ctx->buf_len != ctx->buf_off) {
325 i = enc_write(b, NULL, 0);
326 if (i < 0)
327 return i;
328 }
329
330 if (!ctx->finished) {
331 ctx->finished = 1;
332 ctx->buf_off = 0;
333 ret = EVP_CipherFinal_ex(&(ctx->cipher),
334 (unsigned char *)ctx->buf,
335 &(ctx->buf_len));
336 ctx->ok = (int)ret;
337 if (ret <= 0)
338 break;
339
340 /* push out the bytes */
341 goto again;
342 }
343
344 /* Finally flush the underlying BIO */
345 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
346 break;
347 case BIO_C_GET_CIPHER_STATUS:
348 ret = (long)ctx->ok;
349 break;
350 case BIO_C_DO_STATE_MACHINE:
351 BIO_clear_retry_flags(b);
352 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
353 BIO_copy_next_retry(b);
354 break;
355 case BIO_C_GET_CIPHER_CTX:
356 c_ctx = (EVP_CIPHER_CTX **)ptr;
357 (*c_ctx) = &(ctx->cipher);
358 b->init = 1;
359 break;
360 case BIO_CTRL_DUP:
361 dbio = (BIO *)ptr;
362 dctx = (BIO_ENC_CTX *)dbio->ptr;
363 EVP_CIPHER_CTX_init(&dctx->cipher);
364 ret = EVP_CIPHER_CTX_copy(&dctx->cipher, &ctx->cipher);
365 if (ret)
366 dbio->init = 1;
367 break;
368 default:
369 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
370 break;
371 }
372 return (ret);
373 }
374
375 static long
enc_callback_ctrl(BIO * b,int cmd,BIO_info_cb * fp)376 enc_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
377 {
378 long ret = 1;
379
380 if (b->next_bio == NULL)
381 return (0);
382 switch (cmd) {
383 default:
384 ret = BIO_callback_ctrl(b->next_bio, cmd, fp);
385 break;
386 }
387 return (ret);
388 }
389
390 int
BIO_set_cipher(BIO * b,const EVP_CIPHER * c,const unsigned char * k,const unsigned char * i,int e)391 BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k,
392 const unsigned char *i, int e)
393 {
394 BIO_ENC_CTX *ctx;
395 long (*cb)(BIO *, int, const char *, int, long, long);
396
397 if (b == NULL)
398 return 0;
399
400 if ((ctx = BIO_get_data(b)) == NULL)
401 return 0;
402
403 if ((cb = BIO_get_callback(b)) != NULL) {
404 if (cb(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 0L)
405 <= 0)
406 return 0;
407 }
408
409 BIO_set_init(b, 1);
410
411 if (!EVP_CipherInit_ex(&(ctx->cipher), c, NULL, k, i, e))
412 return 0;
413
414 if (cb != NULL)
415 return cb(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);
416
417 return 1;
418 }
419