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1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2  * All rights reserved.
3  *
4  * This package is an SSL implementation written
5  * by Eric Young (eay@cryptsoft.com).
6  * The implementation was written so as to conform with Netscapes SSL.
7  *
8  * This library is free for commercial and non-commercial use as long as
9  * the following conditions are aheared to.  The following conditions
10  * apply to all code found in this distribution, be it the RC4, RSA,
11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12  * included with this distribution is covered by the same copyright terms
13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14  *
15  * Copyright remains Eric Young's, and as such any Copyright notices in
16  * the code are not to be removed.
17  * If this package is used in a product, Eric Young should be given attribution
18  * as the author of the parts of the library used.
19  * This can be in the form of a textual message at program startup or
20  * in documentation (online or textual) provided with the package.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. All advertising materials mentioning features or use of this software
31  *    must display the following acknowledgement:
32  *    "This product includes cryptographic software written by
33  *     Eric Young (eay@cryptsoft.com)"
34  *    The word 'cryptographic' can be left out if the rouines from the library
35  *    being used are not cryptographic related :-).
36  * 4. If you include any Windows specific code (or a derivative thereof) from
37  *    the apps directory (application code) you must include an acknowledgement:
38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * The licence and distribution terms for any publically available version or
53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
54  * copied and put under another distribution licence
55  * [including the GNU Public Licence.] */
56 
57 #ifndef OPENSSL_HEADER_CIPHER_EXTRA_INTERNAL_H
58 #define OPENSSL_HEADER_CIPHER_EXTRA_INTERNAL_H
59 
60 #include <openssl/base.h>
61 
62 #include "../internal.h"
63 
64 #if defined(__cplusplus)
65 extern "C" {
66 #endif
67 
68 
69 // EVP_tls_cbc_get_padding determines the padding from the decrypted, TLS, CBC
70 // record in |in|. This decrypted record should not include any "decrypted"
71 // explicit IV. If the record is publicly invalid, it returns zero. Otherwise,
72 // it returns one and sets |*out_padding_ok| to all ones (0xfff..f) if the
73 // padding is valid and zero otherwise. It then sets |*out_len| to the length
74 // with the padding removed or |in_len| if invalid.
75 //
76 // If the function returns one, it runs in time independent of the contents of
77 // |in|. It is also guaranteed that |*out_len| >= |mac_size|, satisfying
78 // |EVP_tls_cbc_copy_mac|'s precondition.
79 int EVP_tls_cbc_remove_padding(crypto_word_t *out_padding_ok, size_t *out_len,
80                                const uint8_t *in, size_t in_len,
81                                size_t block_size, size_t mac_size);
82 
83 // EVP_tls_cbc_copy_mac copies |md_size| bytes from the end of the first
84 // |in_len| bytes of |in| to |out| in constant time (independent of the concrete
85 // value of |in_len|, which may vary within a 256-byte window). |in| must point
86 // to a buffer of |orig_len| bytes.
87 //
88 // On entry:
89 //   orig_len >= in_len >= md_size
90 //   md_size <= EVP_MAX_MD_SIZE
91 void EVP_tls_cbc_copy_mac(uint8_t *out, size_t md_size, const uint8_t *in,
92                           size_t in_len, size_t orig_len);
93 
94 // EVP_tls_cbc_record_digest_supported returns 1 iff |md| is a hash function
95 // which EVP_tls_cbc_digest_record supports.
96 int EVP_tls_cbc_record_digest_supported(const EVP_MD *md);
97 
98 // EVP_tls_cbc_digest_record computes the MAC of a decrypted, padded TLS
99 // record.
100 //
101 //   md: the hash function used in the HMAC.
102 //     EVP_tls_cbc_record_digest_supported must return true for this hash.
103 //   md_out: the digest output. At most EVP_MAX_MD_SIZE bytes will be written.
104 //   md_out_size: the number of output bytes is written here.
105 //   header: the 13-byte, TLS record header.
106 //   data: the record data itself
107 //   data_plus_mac_size: the secret, reported length of the data and MAC
108 //     once the padding has been removed.
109 //   data_plus_mac_plus_padding_size: the public length of the whole
110 //     record, including padding.
111 //
112 // On entry: by virtue of having been through one of the remove_padding
113 // functions, above, we know that data_plus_mac_size is large enough to contain
114 // a padding byte and MAC. (If the padding was invalid, it might contain the
115 // padding too. )
116 int EVP_tls_cbc_digest_record(const EVP_MD *md, uint8_t *md_out,
117                               size_t *md_out_size, const uint8_t header[13],
118                               const uint8_t *data, size_t data_plus_mac_size,
119                               size_t data_plus_mac_plus_padding_size,
120                               const uint8_t *mac_secret,
121                               unsigned mac_secret_length);
122 
123 
124 #if defined(__cplusplus)
125 }  // extern C
126 #endif
127 
128 #endif  // OPENSSL_HEADER_CIPHER_EXTRA_INTERNAL_H
129