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 = {
45 /* TODO: Convert to new style write function */
48 /* TODO: Convert to new style read function */
59 const BIO_METHOD *BIO_f_cipher(void)
64 static int enc_new(BIO *bi)
68 ctx = OPENSSL_zalloc(sizeof(*ctx));
72 ctx->cipher = EVP_CIPHER_CTX_new();
73 if (ctx->cipher == NULL) {
79 ctx->read_end = ctx->read_start = &(ctx->buf[BUF_OFFSET]);
80 BIO_set_data(bi, ctx);
86 static int enc_free(BIO *a)
97 EVP_CIPHER_CTX_free(b->cipher);
98 OPENSSL_clear_free(b, sizeof(BIO_ENC_CTX));
99 BIO_set_data(a, NULL);
105 static int enc_read(BIO *b, char *out, int outl)
107 int ret = 0, i, blocksize;
113 ctx = BIO_get_data(b);
116 if ((ctx == NULL) || (next == NULL))
119 /* First check if there are bytes decoded/encoded */
120 if (ctx->buf_len > 0) {
121 i = ctx->buf_len - ctx->buf_off;
124 memcpy(out, &(ctx->buf[ctx->buf_off]), i);
129 if (ctx->buf_len == ctx->buf_off) {
135 blocksize = EVP_CIPHER_CTX_block_size(ctx->cipher);
140 * At this point, we have room of outl bytes and an empty buffer, so we
141 * should read in some more.
148 if (ctx->read_start == ctx->read_end) { /* time to read more data */
149 ctx->read_end = ctx->read_start = &(ctx->buf[BUF_OFFSET]);
150 i = BIO_read(next, ctx->read_start, ENC_BLOCK_SIZE);
154 i = ctx->read_end - ctx->read_start;
158 /* Should be continue next time we are called? */
159 if (!BIO_should_retry(next)) {
161 i = EVP_CipherFinal_ex(ctx->cipher,
162 ctx->buf, &(ctx->buf_len));
166 ret = (ret == 0) ? i : ret;
170 if (outl > ENC_MIN_CHUNK) {
172 * Depending on flags block cipher decrypt can write
173 * one extra block and then back off, i.e. output buffer
174 * has to accommodate extra block...
176 int j = outl - blocksize, buf_len;
178 if (!EVP_CipherUpdate(ctx->cipher,
179 (unsigned char *)out, &buf_len,
180 ctx->read_start, i > j ? j : i)) {
181 BIO_clear_retry_flags(b);
189 ctx->read_start = ctx->read_end;
192 ctx->read_start += j;
194 if (i > ENC_MIN_CHUNK)
196 if (!EVP_CipherUpdate(ctx->cipher,
197 ctx->buf, &ctx->buf_len,
198 ctx->read_start, i)) {
199 BIO_clear_retry_flags(b);
203 ctx->read_start += i;
206 * Note: it is possible for EVP_CipherUpdate to decrypt zero
207 * bytes because this is or looks like the final block: if this
208 * happens we should retry and either read more data or decrypt
211 if (ctx->buf_len == 0)
215 if (ctx->buf_len <= outl)
221 memcpy(out, ctx->buf, i);
228 BIO_clear_retry_flags(b);
229 BIO_copy_next_retry(b);
230 return ((ret == 0) ? ctx->cont : ret);
233 static int enc_write(BIO *b, const char *in, int inl)
239 ctx = BIO_get_data(b);
241 if ((ctx == NULL) || (next == NULL))
246 BIO_clear_retry_flags(b);
247 n = ctx->buf_len - ctx->buf_off;
249 i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
251 BIO_copy_next_retry(b);
257 /* at this point all pending data has been written */
259 if ((in == NULL) || (inl <= 0))
264 n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl;
265 if (!EVP_CipherUpdate(ctx->cipher,
266 ctx->buf, &ctx->buf_len,
267 (const unsigned char *)in, n)) {
268 BIO_clear_retry_flags(b);
278 i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
280 BIO_copy_next_retry(b);
281 return (ret == inl) ? i : ret - inl;
289 BIO_copy_next_retry(b);
293 static long enc_ctrl(BIO *b, int cmd, long num, void *ptr)
296 BIO_ENC_CTX *ctx, *dctx;
299 EVP_CIPHER_CTX **c_ctx;
302 ctx = BIO_get_data(b);
311 if (!EVP_CipherInit_ex(ctx->cipher, NULL, NULL, NULL, NULL,
312 EVP_CIPHER_CTX_encrypting(ctx->cipher)))
314 ret = BIO_ctrl(next, cmd, num, ptr);
316 case BIO_CTRL_EOF: /* More to read */
320 ret = BIO_ctrl(next, cmd, num, ptr);
322 case BIO_CTRL_WPENDING:
323 ret = ctx->buf_len - ctx->buf_off;
325 ret = BIO_ctrl(next, cmd, num, ptr);
327 case BIO_CTRL_PENDING: /* More to read in buffer */
328 ret = ctx->buf_len - ctx->buf_off;
330 ret = BIO_ctrl(next, cmd, num, ptr);
333 /* do a final write */
335 while (ctx->buf_len != ctx->buf_off) {
336 i = enc_write(b, NULL, 0);
341 if (!ctx->finished) {
344 ret = EVP_CipherFinal_ex(ctx->cipher,
345 (unsigned char *)ctx->buf,
351 /* push out the bytes */
355 /* Finally flush the underlying BIO */
356 ret = BIO_ctrl(next, cmd, num, ptr);
358 case BIO_C_GET_CIPHER_STATUS:
361 case BIO_C_DO_STATE_MACHINE:
362 BIO_clear_retry_flags(b);
363 ret = BIO_ctrl(next, cmd, num, ptr);
364 BIO_copy_next_retry(b);
366 case BIO_C_GET_CIPHER_CTX:
367 c_ctx = (EVP_CIPHER_CTX **)ptr;
368 *c_ctx = ctx->cipher;
373 dctx = BIO_get_data(dbio);
374 dctx->cipher = EVP_CIPHER_CTX_new();
375 if (dctx->cipher == NULL)
377 ret = EVP_CIPHER_CTX_copy(dctx->cipher, ctx->cipher);
379 BIO_set_init(dbio, 1);
382 ret = BIO_ctrl(next, cmd, num, ptr);
388 static long enc_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
391 BIO *next = BIO_next(b);
397 ret = BIO_callback_ctrl(next, cmd, fp);
403 int BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k,
404 const unsigned char *i, int e)
407 long (*callback) (struct bio_st *, int, const char *, int, long, long);
409 ctx = BIO_get_data(b);
413 callback = BIO_get_callback(b);
415 if ((callback != NULL) &&
416 (callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e,
422 if (!EVP_CipherInit_ex(ctx->cipher, c, NULL, k, i, e))
425 if (callback != NULL)
426 return callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);