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1.1 misho 1: /*
2: * Copyright (C) 2013 Tobias Brunner
3: * HSR Hochschule fuer Technik Rapperswil
4: *
5: * Copyright (C) 2010 Martin Willi
6: * Copyright (C) 2010 revosec AG
7: *
8: * This program is free software; you can redistribute it and/or modify it
9: * under the terms of the GNU General Public License as published by the
10: * Free Software Foundation; either version 2 of the License, or (at your
11: * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
12: *
13: * This program is distributed in the hope that it will be useful, but
14: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16: * for more details.
17: */
18:
19: #include "aead.h"
20:
21: #include <utils/debug.h>
22: #include <crypto/iv/iv_gen_rand.h>
23:
24: typedef struct private_aead_t private_aead_t;
25:
26: /**
27: * Private data of an aead_t object.
28: */
29: struct private_aead_t {
30:
31: /**
32: * Public aead_t interface.
33: */
34: aead_t public;
35:
36: /**
37: * traditional crypter
38: */
39: crypter_t *crypter;
40:
41: /**
42: * traditional signer
43: */
44: signer_t *signer;
45:
46: /**
47: * IV generator
48: */
49: iv_gen_t *iv_gen;
50: };
51:
52: METHOD(aead_t, encrypt, bool,
53: private_aead_t *this, chunk_t plain, chunk_t assoc, chunk_t iv,
54: chunk_t *encrypted)
55: {
56: chunk_t encr, sig;
57:
58: if (!this->signer->get_signature(this->signer, assoc, NULL) ||
59: !this->signer->get_signature(this->signer, iv, NULL))
60: {
61: return FALSE;
62: }
63:
64: if (encrypted)
65: {
66: if (!this->crypter->encrypt(this->crypter, plain, iv, &encr))
67: {
68: return FALSE;
69: }
70: if (!this->signer->allocate_signature(this->signer, encr, &sig))
71: {
72: free(encr.ptr);
73: return FALSE;
74: }
75: *encrypted = chunk_cat("cmm", iv, encr, sig);
76: }
77: else
78: {
79: if (!this->crypter->encrypt(this->crypter, plain, iv, NULL) ||
80: !this->signer->get_signature(this->signer,
81: plain, plain.ptr + plain.len))
82: {
83: return FALSE;
84: }
85: }
86: return TRUE;
87: }
88:
89: METHOD(aead_t, decrypt, bool,
90: private_aead_t *this, chunk_t encrypted, chunk_t assoc, chunk_t iv,
91: chunk_t *plain)
92: {
93: chunk_t sig;
94: size_t bs;
95:
96: bs = this->crypter->get_block_size(this->crypter);
97: sig.len = this->signer->get_block_size(this->signer);
98: if (sig.len > encrypted.len || (encrypted.len - sig.len) % bs)
99: {
100: DBG1(DBG_LIB, "invalid encrypted data length %d with block size %d",
101: encrypted.len - sig.len, bs);
102: return FALSE;
103: }
104: chunk_split(encrypted, "mm", encrypted.len - sig.len,
105: &encrypted, sig.len, &sig);
106:
107: if (!this->signer->get_signature(this->signer, assoc, NULL) ||
108: !this->signer->get_signature(this->signer, iv, NULL))
109: {
110: return FALSE;
111: }
112: if (!this->signer->verify_signature(this->signer, encrypted, sig))
113: {
114: DBG1(DBG_LIB, "MAC verification failed");
115: return FALSE;
116: }
117: return this->crypter->decrypt(this->crypter, encrypted, iv, plain);
118: }
119:
120: METHOD(aead_t, get_block_size, size_t,
121: private_aead_t *this)
122: {
123: return this->crypter->get_block_size(this->crypter);
124: }
125:
126: METHOD(aead_t, get_icv_size, size_t,
127: private_aead_t *this)
128: {
129: return this->signer->get_block_size(this->signer);
130: }
131:
132: METHOD(aead_t, get_iv_size, size_t,
133: private_aead_t *this)
134: {
135: return this->crypter->get_iv_size(this->crypter);
136: }
137:
138: METHOD(aead_t, get_iv_gen, iv_gen_t*,
139: private_aead_t *this)
140: {
141: return this->iv_gen;
142: }
143:
144: METHOD(aead_t, get_key_size, size_t,
145: private_aead_t *this)
146: {
147: return this->crypter->get_key_size(this->crypter) +
148: this->signer->get_key_size(this->signer);
149: }
150:
151: METHOD(aead_t, set_key, bool,
152: private_aead_t *this, chunk_t key)
153: {
154: chunk_t sig, enc;
155:
156: chunk_split(key, "mm", this->signer->get_key_size(this->signer), &sig,
157: this->crypter->get_key_size(this->crypter), &enc);
158:
159: return this->signer->set_key(this->signer, sig) &&
160: this->crypter->set_key(this->crypter, enc);
161: }
162:
163: METHOD(aead_t, destroy, void,
164: private_aead_t *this)
165: {
166: this->iv_gen->destroy(this->iv_gen);
167: this->crypter->destroy(this->crypter);
168: this->signer->destroy(this->signer);
169: free(this);
170: }
171:
172: /**
173: * See header
174: */
175: aead_t *aead_create(crypter_t *crypter, signer_t *signer, iv_gen_t *iv_gen)
176: {
177: private_aead_t *this;
178:
179: INIT(this,
180: .public = {
181: .encrypt = _encrypt,
182: .decrypt = _decrypt,
183: .get_block_size = _get_block_size,
184: .get_icv_size = _get_icv_size,
185: .get_iv_size = _get_iv_size,
186: .get_iv_gen = _get_iv_gen,
187: .get_key_size = _get_key_size,
188: .set_key = _set_key,
189: .destroy = _destroy,
190: },
191: .crypter = crypter,
192: .signer = signer,
193: .iv_gen = iv_gen,
194: );
195:
196: return &this->public;
197: }