2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (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
12 #include "internal/cryptlib.h"
13 #include <openssl/buffer.h>
14 #include <openssl/evp.h>
15 #include "internal/bio.h"
17 static int enc_write(BIO *h, const char *buf, int num);
18 static int enc_read(BIO *h, char *buf, int size);
19 static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);
20 static int enc_new(BIO *h);
21 static int enc_free(BIO *data);
22 static 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)
27 typedef struct enc_struct {
30 int cont; /* <= 0 when finished */
32 int ok; /* bad decrypt */
33 EVP_CIPHER_CTX *cipher;
34 unsigned char *read_start, *read_end;
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
39 unsigned char buf[BUF_OFFSET + ENC_BLOCK_SIZE];
42 static const BIO_METHOD methods_enc = {
43 BIO_TYPE_CIPHER, "cipher",
44 /* TODO: Convert to new style write function */
47 /* TODO: Convert to new style read function */
58 const BIO_METHOD *BIO_f_cipher(void)
60 return (&methods_enc);
63 static int enc_new(BIO *bi)
67 ctx = OPENSSL_zalloc(sizeof(*ctx));
71 ctx->cipher = EVP_CIPHER_CTX_new();
72 if (ctx->cipher == NULL) {
78 ctx->read_end = ctx->read_start = &(ctx->buf[BUF_OFFSET]);
79 BIO_set_data(bi, ctx);
85 static int enc_free(BIO *a)
96 EVP_CIPHER_CTX_free(b->cipher);
97 OPENSSL_clear_free(b, sizeof(BIO_ENC_CTX));
98 BIO_set_data(a, NULL);
104 static int enc_read(BIO *b, char *out, int outl)
106 int ret = 0, i, blocksize;
112 ctx = BIO_get_data(b);
115 if ((ctx == NULL) || (next == NULL))
118 /* First check if there are bytes decoded/encoded */
119 if (ctx->buf_len > 0) {
120 i = ctx->buf_len - ctx->buf_off;
123 memcpy(out, &(ctx->buf[ctx->buf_off]), i);
128 if (ctx->buf_len == ctx->buf_off) {
134 blocksize = EVP_CIPHER_CTX_block_size(ctx->cipher);
139 * At this point, we have room of outl bytes and an empty buffer, so we
140 * should read in some more.
147 if (ctx->read_start == ctx->read_end) { /* time to read more data */
148 ctx->read_end = ctx->read_start = &(ctx->buf[BUF_OFFSET]);
149 i = BIO_read(next, ctx->read_start, ENC_BLOCK_SIZE);
153 i = ctx->read_end - ctx->read_start;
157 /* Should be continue next time we are called? */
158 if (!BIO_should_retry(next)) {
160 i = EVP_CipherFinal_ex(ctx->cipher,
161 ctx->buf, &(ctx->buf_len));
165 ret = (ret == 0) ? i : ret;
169 if (outl > ENC_MIN_CHUNK) {
171 * Depending on flags block cipher decrypt can write
172 * one extra block and then back off, i.e. output buffer
173 * has to accommodate extra block...
175 int j = outl - blocksize, buf_len;
177 if (!EVP_CipherUpdate(ctx->cipher,
178 (unsigned char *)out, &buf_len,
179 ctx->read_start, i > j ? j : i)) {
180 BIO_clear_retry_flags(b);
188 ctx->read_start = ctx->read_end;
191 ctx->read_start += j;
193 if (i > ENC_MIN_CHUNK)
195 if (!EVP_CipherUpdate(ctx->cipher,
196 ctx->buf, &ctx->buf_len,
197 ctx->read_start, i)) {
198 BIO_clear_retry_flags(b);
202 ctx->read_start += i;
205 * Note: it is possible for EVP_CipherUpdate to decrypt zero
206 * bytes because this is or looks like the final block: if this
207 * happens we should retry and either read more data or decrypt
210 if (ctx->buf_len == 0)
214 if (ctx->buf_len <= outl)
220 memcpy(out, ctx->buf, i);
227 BIO_clear_retry_flags(b);
228 BIO_copy_next_retry(b);
229 return ((ret == 0) ? ctx->cont : ret);
232 static int enc_write(BIO *b, const char *in, int inl)
238 ctx = BIO_get_data(b);
240 if ((ctx == NULL) || (next == NULL))
245 BIO_clear_retry_flags(b);
246 n = ctx->buf_len - ctx->buf_off;
248 i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
250 BIO_copy_next_retry(b);
256 /* at this point all pending data has been written */
258 if ((in == NULL) || (inl <= 0))
263 n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl;
264 if (!EVP_CipherUpdate(ctx->cipher,
265 ctx->buf, &ctx->buf_len,
266 (const unsigned char *)in, n)) {
267 BIO_clear_retry_flags(b);
277 i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
279 BIO_copy_next_retry(b);
280 return (ret == inl) ? i : ret - inl;
288 BIO_copy_next_retry(b);
292 static long enc_ctrl(BIO *b, int cmd, long num, void *ptr)
295 BIO_ENC_CTX *ctx, *dctx;
298 EVP_CIPHER_CTX **c_ctx;
301 ctx = BIO_get_data(b);
310 if (!EVP_CipherInit_ex(ctx->cipher, NULL, NULL, NULL, NULL,
311 EVP_CIPHER_CTX_encrypting(ctx->cipher)))
313 ret = BIO_ctrl(next, cmd, num, ptr);
315 case BIO_CTRL_EOF: /* More to read */
319 ret = BIO_ctrl(next, cmd, num, ptr);
321 case BIO_CTRL_WPENDING:
322 ret = ctx->buf_len - ctx->buf_off;
324 ret = BIO_ctrl(next, cmd, num, ptr);
326 case BIO_CTRL_PENDING: /* More to read in buffer */
327 ret = ctx->buf_len - ctx->buf_off;
329 ret = BIO_ctrl(next, cmd, num, ptr);
332 /* do a final write */
334 while (ctx->buf_len != ctx->buf_off) {
335 i = enc_write(b, NULL, 0);
340 if (!ctx->finished) {
343 ret = EVP_CipherFinal_ex(ctx->cipher,
344 (unsigned char *)ctx->buf,
350 /* push out the bytes */
354 /* Finally flush the underlying BIO */
355 ret = BIO_ctrl(next, cmd, num, ptr);
357 case BIO_C_GET_CIPHER_STATUS:
360 case BIO_C_DO_STATE_MACHINE:
361 BIO_clear_retry_flags(b);
362 ret = BIO_ctrl(next, cmd, num, ptr);
363 BIO_copy_next_retry(b);
365 case BIO_C_GET_CIPHER_CTX:
366 c_ctx = (EVP_CIPHER_CTX **)ptr;
367 *c_ctx = ctx->cipher;
372 dctx = BIO_get_data(dbio);
373 dctx->cipher = EVP_CIPHER_CTX_new();
374 if (dctx->cipher == NULL)
376 ret = EVP_CIPHER_CTX_copy(dctx->cipher, ctx->cipher);
378 BIO_set_init(dbio, 1);
381 ret = BIO_ctrl(next, cmd, num, ptr);
387 static long enc_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
390 BIO *next = BIO_next(b);
396 ret = BIO_callback_ctrl(next, cmd, fp);
402 int BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k,
403 const unsigned char *i, int e)
406 long (*callback) (struct bio_st *, int, const char *, int, long, long);
408 ctx = BIO_get_data(b);
412 callback = BIO_get_callback(b);
414 if ((callback != NULL) &&
415 (callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e,
421 if (!EVP_CipherInit_ex(ctx->cipher, c, NULL, k, i, e))
424 if (callback != NULL)
425 return callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);