[pci] Add support for PCI MSI-X interrupts
[ipxe.git] / src / crypto / aes_wrap.c
1 /*
2 * Copyright (c) 2009 Joshua Oreman <oremanj@rwcr.net>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 */
19
20 FILE_LICENCE ( GPL2_OR_LATER );
21
22 #include <stdlib.h>
23 #include <string.h>
24 #include <ipxe/crypto.h>
25 #include <ipxe/aes.h>
26
27 /**
28 * Wrap a key or other data using AES Key Wrap (RFC 3394)
29 *
30 * @v kek Key Encryption Key, 16 bytes
31 * @v src Data to encrypt
32 * @v nblk Number of 8-byte blocks in @a data
33 * @ret dest Encrypted data (8 bytes longer than input)
34 *
35 * The algorithm is implemented such that @a src and @a dest may point
36 * to the same buffer.
37 */
38 int aes_wrap ( const void *kek, const void *src, void *dest, int nblk )
39 {
40 u8 *A = dest;
41 u8 B[16];
42 u8 *R;
43 int i, j;
44 void *aes_ctx = malloc ( AES_CTX_SIZE );
45
46 if ( ! aes_ctx )
47 return -1;
48
49 cipher_setkey ( &aes_algorithm, aes_ctx, kek, 16 );
50
51 /* Set up */
52 memset ( A, 0xA6, 8 );
53 memmove ( dest + 8, src, nblk * 8 );
54
55 /* Wrap */
56 for ( j = 0; j < 6; j++ ) {
57 R = dest + 8;
58 for ( i = 1; i <= nblk; i++ ) {
59 memcpy ( B, A, 8 );
60 memcpy ( B + 8, R, 8 );
61 cipher_encrypt ( &aes_algorithm, aes_ctx, B, B, 16 );
62 memcpy ( A, B, 8 );
63 A[7] ^= ( nblk * j ) + i;
64 memcpy ( R, B + 8, 8 );
65 R += 8;
66 }
67 }
68
69 free ( aes_ctx );
70 return 0;
71 }
72
73 /**
74 * Unwrap a key or other data using AES Key Wrap (RFC 3394)
75 *
76 * @v kek Key Encryption Key, 16 bytes
77 * @v src Data to decrypt
78 * @v nblk Number of 8-byte blocks in @e plaintext key
79 * @ret dest Decrypted data (8 bytes shorter than input)
80 * @ret rc Zero on success, nonzero on IV mismatch
81 *
82 * The algorithm is implemented such that @a src and @a dest may point
83 * to the same buffer.
84 */
85 int aes_unwrap ( const void *kek, const void *src, void *dest, int nblk )
86 {
87 u8 A[8], B[16];
88 u8 *R;
89 int i, j;
90 void *aes_ctx = malloc ( AES_CTX_SIZE );
91
92 if ( ! aes_ctx )
93 return -1;
94
95 cipher_setkey ( &aes_algorithm, aes_ctx, kek, 16 );
96
97 /* Set up */
98 memcpy ( A, src, 8 );
99 memmove ( dest, src + 8, nblk * 8 );
100
101 /* Unwrap */
102 for ( j = 5; j >= 0; j-- ) {
103 R = dest + ( nblk - 1 ) * 8;
104 for ( i = nblk; i >= 1; i-- ) {
105 memcpy ( B, A, 8 );
106 memcpy ( B + 8, R, 8 );
107 B[7] ^= ( nblk * j ) + i;
108 cipher_decrypt ( &aes_algorithm, aes_ctx, B, B, 16 );
109 memcpy ( A, B, 8 );
110 memcpy ( R, B + 8, 8 );
111 R -= 8;
112 }
113 }
114
115 free ( aes_ctx );
116
117 /* Check IV */
118 for ( i = 0; i < 8; i++ ) {
119 if ( A[i] != 0xA6 )
120 return -1;
121 }
122
123 return 0;
124 }