2 * Copyright 1995-2023 The OpenSSL Project Authors. All Rights Reserved.
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
10 #define OPENSSL_SUPPRESS_DEPRECATED /* for BIO_get_callback */
14 #include "internal/cryptlib.h"
15 #include <openssl/buffer.h>
16 #include <openssl/evp.h>
17 #include "internal/bio.h"
19 static int enc_write(BIO *h, const char *buf, int num);
20 static int enc_read(BIO *h, char *buf, int size);
21 static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);
22 static int enc_new(BIO *h);
23 static int enc_free(BIO *data);
24 static long enc_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fps);
25 #define ENC_BLOCK_SIZE (1024*4)
26 #define ENC_MIN_CHUNK (256)
27 #define BUF_OFFSET (ENC_MIN_CHUNK + EVP_MAX_BLOCK_LENGTH)
29 typedef struct enc_struct {
32 int cont; /* <= 0 when finished */
34 int ok; /* bad decrypt */
35 EVP_CIPHER_CTX *cipher;
36 unsigned char *read_start, *read_end;
38 * buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate can return
39 * up to a block more data than is presented to it
41 unsigned char buf[BUF_OFFSET + ENC_BLOCK_SIZE];
44 static const BIO_METHOD methods_enc = {
59 const BIO_METHOD *BIO_f_cipher(void)
64 static int enc_new(BIO *bi)
68 if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
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_get_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;
302 ctx = BIO_get_data(b);
311 if (!EVP_CipherInit_ex(ctx->cipher, NULL, NULL, NULL, NULL,
312 EVP_CIPHER_CTX_is_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 pend = ctx->buf_len - ctx->buf_off;
337 i = enc_write(b, NULL, 0);
339 * i should never be > 0 here because we didn't ask to write any
340 * new data. We stop if we get an error or we failed to make any
341 * progress writing pending data.
343 if (i < 0 || (ctx->buf_len - ctx->buf_off) == pend)
347 if (!ctx->finished) {
350 ret = EVP_CipherFinal_ex(ctx->cipher,
351 (unsigned char *)ctx->buf,
357 /* push out the bytes */
361 /* Finally flush the underlying BIO */
362 ret = BIO_ctrl(next, cmd, num, ptr);
363 BIO_copy_next_retry(b);
365 case BIO_C_GET_CIPHER_STATUS:
368 case BIO_C_DO_STATE_MACHINE:
369 BIO_clear_retry_flags(b);
370 ret = BIO_ctrl(next, cmd, num, ptr);
371 BIO_copy_next_retry(b);
373 case BIO_C_GET_CIPHER_CTX:
374 c_ctx = (EVP_CIPHER_CTX **)ptr;
375 *c_ctx = ctx->cipher;
380 dctx = BIO_get_data(dbio);
381 dctx->cipher = EVP_CIPHER_CTX_new();
382 if (dctx->cipher == NULL)
384 ret = EVP_CIPHER_CTX_copy(dctx->cipher, ctx->cipher);
386 BIO_set_init(dbio, 1);
389 ret = BIO_ctrl(next, cmd, num, ptr);
395 static long enc_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
397 BIO *next = BIO_next(b);
402 return BIO_callback_ctrl(next, cmd, fp);
405 int BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k,
406 const unsigned char *i, int e)
409 BIO_callback_fn_ex callback_ex;
410 #ifndef OPENSSL_NO_DEPRECATED_3_0
411 long (*callback) (struct bio_st *, int, const char *, int, long, long) = NULL;
414 ctx = BIO_get_data(b);
418 if ((callback_ex = BIO_get_callback_ex(b)) != NULL) {
419 if (callback_ex(b, BIO_CB_CTRL, (const char *)c, 0, BIO_CTRL_SET,
423 #ifndef OPENSSL_NO_DEPRECATED_3_0
425 callback = BIO_get_callback(b);
427 if ((callback != NULL) &&
428 (callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e,
436 if (!EVP_CipherInit_ex(ctx->cipher, c, NULL, k, i, e))
439 if (callback_ex != NULL)
440 return callback_ex(b, BIO_CB_CTRL | BIO_CB_RETURN, (const char *)c, 0,
441 BIO_CTRL_SET, e, 1, NULL);
442 #ifndef OPENSSL_NO_DEPRECATED_3_0
443 else if (callback != NULL)
444 return callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);