1/*
2 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <stdio.h>
11#include <errno.h>
12#include "internal/cryptlib.h"
13#include <openssl/buffer.h>
14#include <openssl/evp.h>
15#include "internal/bio.h"
16
17static int enc_write(BIO *h, const char *buf, int num);
18static int enc_read(BIO *h, char *buf, int size);
19static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);
20static int enc_new(BIO *h);
21static int enc_free(BIO *data);
22static long enc_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fps);
23#define ENC_BLOCK_SIZE (1024*4)
24#define ENC_MIN_CHUNK (256)
25#define BUF_OFFSET (ENC_MIN_CHUNK + EVP_MAX_BLOCK_LENGTH)
26
27typedef struct enc_struct {
28 int buf_len;
29 int buf_off;
30 int cont; /* <= 0 when finished */
31 int finished;
32 int ok; /* bad decrypt */
33 EVP_CIPHER_CTX *cipher;
34 unsigned char *read_start, *read_end;
35 /*
36 * buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate can return
37 * up to a block more data than is presented to it
38 */
39 unsigned char buf[BUF_OFFSET + ENC_BLOCK_SIZE];
40} BIO_ENC_CTX;
41
42static const BIO_METHOD methods_enc = {
43 BIO_TYPE_CIPHER,
44 "cipher",
45 /* TODO: Convert to new style write function */
46 bwrite_conv,
47 enc_write,
48 /* TODO: Convert to new style read function */
49 bread_conv,
50 enc_read,
51 NULL, /* enc_puts, */
52 NULL, /* enc_gets, */
53 enc_ctrl,
54 enc_new,
55 enc_free,
56 enc_callback_ctrl,
57};
58
59const BIO_METHOD *BIO_f_cipher(void)
60{
61 return &methods_enc;
62}
63
64static int enc_new(BIO *bi)
65{
66 BIO_ENC_CTX *ctx;
67
68 if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL) {
69 EVPerr(EVP_F_ENC_NEW, ERR_R_MALLOC_FAILURE);
70 return 0;
71 }
72
73 ctx->cipher = EVP_CIPHER_CTX_new();
74 if (ctx->cipher == NULL) {
75 OPENSSL_free(ctx);
76 return 0;
77 }
78 ctx->cont = 1;
79 ctx->ok = 1;
80 ctx->read_end = ctx->read_start = &(ctx->buf[BUF_OFFSET]);
81 BIO_set_data(bi, ctx);
82 BIO_set_init(bi, 1);
83
84 return 1;
85}
86
87static int enc_free(BIO *a)
88{
89 BIO_ENC_CTX *b;
90
91 if (a == NULL)
92 return 0;
93
94 b = BIO_get_data(a);
95 if (b == NULL)
96 return 0;
97
98 EVP_CIPHER_CTX_free(b->cipher);
99 OPENSSL_clear_free(b, sizeof(BIO_ENC_CTX));
100 BIO_set_data(a, NULL);
101 BIO_set_init(a, 0);
102
103 return 1;
104}
105
106static int enc_read(BIO *b, char *out, int outl)
107{
108 int ret = 0, i, blocksize;
109 BIO_ENC_CTX *ctx;
110 BIO *next;
111
112 if (out == NULL)
113 return 0;
114 ctx = BIO_get_data(b);
115
116 next = BIO_next(b);
117 if ((ctx == NULL) || (next == NULL))
118 return 0;
119
120 /* First check if there are bytes decoded/encoded */
121 if (ctx->buf_len > 0) {
122 i = ctx->buf_len - ctx->buf_off;
123 if (i > outl)
124 i = outl;
125 memcpy(out, &(ctx->buf[ctx->buf_off]), i);
126 ret = i;
127 out += i;
128 outl -= i;
129 ctx->buf_off += i;
130 if (ctx->buf_len == ctx->buf_off) {
131 ctx->buf_len = 0;
132 ctx->buf_off = 0;
133 }
134 }
135
136 blocksize = EVP_CIPHER_CTX_block_size(ctx->cipher);
137 if (blocksize == 1)
138 blocksize = 0;
139
140 /*
141 * At this point, we have room of outl bytes and an empty buffer, so we
142 * should read in some more.
143 */
144
145 while (outl > 0) {
146 if (ctx->cont <= 0)
147 break;
148
149 if (ctx->read_start == ctx->read_end) { /* time to read more data */
150 ctx->read_end = ctx->read_start = &(ctx->buf[BUF_OFFSET]);
151 i = BIO_read(next, ctx->read_start, ENC_BLOCK_SIZE);
152 if (i > 0)
153 ctx->read_end += i;
154 } else {
155 i = ctx->read_end - ctx->read_start;
156 }
157
158 if (i <= 0) {
159 /* Should be continue next time we are called? */
160 if (!BIO_should_retry(next)) {
161 ctx->cont = i;
162 i = EVP_CipherFinal_ex(ctx->cipher,
163 ctx->buf, &(ctx->buf_len));
164 ctx->ok = i;
165 ctx->buf_off = 0;
166 } else {
167 ret = (ret == 0) ? i : ret;
168 break;
169 }
170 } else {
171 if (outl > ENC_MIN_CHUNK) {
172 /*
173 * Depending on flags block cipher decrypt can write
174 * one extra block and then back off, i.e. output buffer
175 * has to accommodate extra block...
176 */
177 int j = outl - blocksize, buf_len;
178
179 if (!EVP_CipherUpdate(ctx->cipher,
180 (unsigned char *)out, &buf_len,
181 ctx->read_start, i > j ? j : i)) {
182 BIO_clear_retry_flags(b);
183 return 0;
184 }
185 ret += buf_len;
186 out += buf_len;
187 outl -= buf_len;
188
189 if ((i -= j) <= 0) {
190 ctx->read_start = ctx->read_end;
191 continue;
192 }
193 ctx->read_start += j;
194 }
195 if (i > ENC_MIN_CHUNK)
196 i = ENC_MIN_CHUNK;
197 if (!EVP_CipherUpdate(ctx->cipher,
198 ctx->buf, &ctx->buf_len,
199 ctx->read_start, i)) {
200 BIO_clear_retry_flags(b);
201 ctx->ok = 0;
202 return 0;
203 }
204 ctx->read_start += i;
205 ctx->cont = 1;
206 /*
207 * Note: it is possible for EVP_CipherUpdate to decrypt zero
208 * bytes because this is or looks like the final block: if this
209 * happens we should retry and either read more data or decrypt
210 * the final 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
234static int enc_write(BIO *b, const char *in, int inl)
235{
236 int ret = 0, n, i;
237 BIO_ENC_CTX *ctx;
238 BIO *next;
239
240 ctx = BIO_get_data(b);
241 next = BIO_next(b);
242 if ((ctx == NULL) || (next == NULL))
243 return 0;
244
245 ret = inl;
246
247 BIO_clear_retry_flags(b);
248 n = ctx->buf_len - ctx->buf_off;
249 while (n > 0) {
250 i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
251 if (i <= 0) {
252 BIO_copy_next_retry(b);
253 return i;
254 }
255 ctx->buf_off += i;
256 n -= i;
257 }
258 /* at this point all pending data has been written */
259
260 if ((in == NULL) || (inl <= 0))
261 return 0;
262
263 ctx->buf_off = 0;
264 while (inl > 0) {
265 n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl;
266 if (!EVP_CipherUpdate(ctx->cipher,
267 ctx->buf, &ctx->buf_len,
268 (const unsigned char *)in, n)) {
269 BIO_clear_retry_flags(b);
270 ctx->ok = 0;
271 return 0;
272 }
273 inl -= n;
274 in += n;
275
276 ctx->buf_off = 0;
277 n = ctx->buf_len;
278 while (n > 0) {
279 i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
280 if (i <= 0) {
281 BIO_copy_next_retry(b);
282 return (ret == inl) ? i : ret - inl;
283 }
284 n -= i;
285 ctx->buf_off += i;
286 }
287 ctx->buf_len = 0;
288 ctx->buf_off = 0;
289 }
290 BIO_copy_next_retry(b);
291 return ret;
292}
293
294static long enc_ctrl(BIO *b, int cmd, long num, void *ptr)
295{
296 BIO *dbio;
297 BIO_ENC_CTX *ctx, *dctx;
298 long ret = 1;
299 int i;
300 EVP_CIPHER_CTX **c_ctx;
301 BIO *next;
302
303 ctx = BIO_get_data(b);
304 next = BIO_next(b);
305 if (ctx == NULL)
306 return 0;
307
308 switch (cmd) {
309 case BIO_CTRL_RESET:
310 ctx->ok = 1;
311 ctx->finished = 0;
312 if (!EVP_CipherInit_ex(ctx->cipher, NULL, NULL, NULL, NULL,
313 EVP_CIPHER_CTX_encrypting(ctx->cipher)))
314 return 0;
315 ret = BIO_ctrl(next, cmd, num, ptr);
316 break;
317 case BIO_CTRL_EOF: /* More to read */
318 if (ctx->cont <= 0)
319 ret = 1;
320 else
321 ret = BIO_ctrl(next, cmd, num, ptr);
322 break;
323 case BIO_CTRL_WPENDING:
324 ret = ctx->buf_len - ctx->buf_off;
325 if (ret <= 0)
326 ret = BIO_ctrl(next, cmd, num, ptr);
327 break;
328 case BIO_CTRL_PENDING: /* More to read in buffer */
329 ret = ctx->buf_len - ctx->buf_off;
330 if (ret <= 0)
331 ret = BIO_ctrl(next, cmd, num, ptr);
332 break;
333 case BIO_CTRL_FLUSH:
334 /* do a final write */
335 again:
336 while (ctx->buf_len != ctx->buf_off) {
337 i = enc_write(b, NULL, 0);
338 if (i < 0)
339 return i;
340 }
341
342 if (!ctx->finished) {
343 ctx->finished = 1;
344 ctx->buf_off = 0;
345 ret = EVP_CipherFinal_ex(ctx->cipher,
346 (unsigned char *)ctx->buf,
347 &(ctx->buf_len));
348 ctx->ok = (int)ret;
349 if (ret <= 0)
350 break;
351
352 /* push out the bytes */
353 goto again;
354 }
355
356 /* Finally flush the underlying BIO */
357 ret = BIO_ctrl(next, cmd, num, ptr);
358 break;
359 case BIO_C_GET_CIPHER_STATUS:
360 ret = (long)ctx->ok;
361 break;
362 case BIO_C_DO_STATE_MACHINE:
363 BIO_clear_retry_flags(b);
364 ret = BIO_ctrl(next, cmd, num, ptr);
365 BIO_copy_next_retry(b);
366 break;
367 case BIO_C_GET_CIPHER_CTX:
368 c_ctx = (EVP_CIPHER_CTX **)ptr;
369 *c_ctx = ctx->cipher;
370 BIO_set_init(b, 1);
371 break;
372 case BIO_CTRL_DUP:
373 dbio = (BIO *)ptr;
374 dctx = BIO_get_data(dbio);
375 dctx->cipher = EVP_CIPHER_CTX_new();
376 if (dctx->cipher == NULL)
377 return 0;
378 ret = EVP_CIPHER_CTX_copy(dctx->cipher, ctx->cipher);
379 if (ret)
380 BIO_set_init(dbio, 1);
381 break;
382 default:
383 ret = BIO_ctrl(next, cmd, num, ptr);
384 break;
385 }
386 return ret;
387}
388
389static long enc_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
390{
391 long ret = 1;
392 BIO *next = BIO_next(b);
393
394 if (next == NULL)
395 return 0;
396 switch (cmd) {
397 default:
398 ret = BIO_callback_ctrl(next, cmd, fp);
399 break;
400 }
401 return ret;
402}
403
404int BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k,
405 const unsigned char *i, int e)
406{
407 BIO_ENC_CTX *ctx;
408 long (*callback) (struct bio_st *, int, const char *, int, long, long);
409
410 ctx = BIO_get_data(b);
411 if (ctx == NULL)
412 return 0;
413
414 callback = BIO_get_callback(b);
415
416 if ((callback != NULL) &&
417 (callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e,
418 0L) <= 0))
419 return 0;
420
421 BIO_set_init(b, 1);
422
423 if (!EVP_CipherInit_ex(ctx->cipher, c, NULL, k, i, e))
424 return 0;
425
426 if (callback != NULL)
427 return callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);
428 return 1;
429}
430