1 /*
2 * Copyright (c) 2018-2019 iXsystems Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25 #include <sys/cdefs.h>
26 __FBSDID("$FreeBSD$");
27
28 #include <sys/types.h>
29 #include <sys/systm.h>
30 #include <sys/param.h>
31 #include <sys/endian.h>
32 #include <opencrypto/cbc_mac.h>
33 #include <opencrypto/xform_auth.h>
34
35 /*
36 * Given two CCM_CBC_BLOCK_LEN blocks, xor
37 * them into dst, and then encrypt dst.
38 */
39 static void
40 xor_and_encrypt(struct aes_cbc_mac_ctx *ctx,
41 const uint8_t *src, uint8_t *dst)
42 {
43 const uint64_t *b1;
44 uint64_t *b2;
45 uint64_t temp_block[CCM_CBC_BLOCK_LEN/sizeof(uint64_t)];
46
47 b1 = (const uint64_t*)src;
48 b2 = (uint64_t*)dst;
49
50 for (size_t count = 0;
51 count < CCM_CBC_BLOCK_LEN/sizeof(uint64_t);
52 count++) {
53 temp_block[count] = b1[count] ^ b2[count];
54 }
55 rijndaelEncrypt(ctx->keysched, ctx->rounds, (void*)temp_block, dst);
56 }
57
58 void
59 AES_CBC_MAC_Init(void *vctx)
60 {
61 struct aes_cbc_mac_ctx *ctx;
62
63 ctx = vctx;
64 bzero(ctx, sizeof(*ctx));
65 }
66
67 void
68 AES_CBC_MAC_Setkey(void *vctx, const uint8_t *key, u_int klen)
69 {
70 struct aes_cbc_mac_ctx *ctx;
71
72 ctx = vctx;
73 ctx->rounds = rijndaelKeySetupEnc(ctx->keysched, key, klen * 8);
74 }
75
76 /*
77 * This is called to set the nonce, aka IV.
78 * Before this call, the authDataLength and cryptDataLength fields
79 * MUST have been set. Sadly, there's no way to return an error.
80 *
81 * The CBC-MAC algorithm requires that the first block contain the
82 * nonce, as well as information about the sizes and lengths involved.
83 */
84 void
85 AES_CBC_MAC_Reinit(void *vctx, const uint8_t *nonce, u_int nonceLen)
86 {
87 struct aes_cbc_mac_ctx *ctx = vctx;
88 uint8_t b0[CCM_CBC_BLOCK_LEN];
89 uint8_t *bp = b0, flags = 0;
90 uint8_t L = 0;
91 uint64_t dataLength = ctx->cryptDataLength;
92
93 KASSERT(nonceLen >= 7 && nonceLen <= 13,
94 ("nonceLen must be between 7 and 13 bytes"));
95
96 ctx->nonce = nonce;
97 ctx->nonceLength = nonceLen;
98
99 ctx->authDataCount = 0;
100 ctx->blockIndex = 0;
101 explicit_bzero(ctx->staging_block, sizeof(ctx->staging_block));
102
103 /*
104 * Need to determine the L field value. This is the number of
105 * bytes needed to specify the length of the message; the length
106 * is whatever is left in the 16 bytes after specifying flags and
107 * the nonce.
108 */
109 L = 15 - nonceLen;
110
111 flags = ((ctx->authDataLength > 0) << 6) +
112 (((AES_CBC_MAC_HASH_LEN - 2) / 2) << 3) +
113 L - 1;
114 /*
115 * Now we need to set up the first block, which has flags, nonce,
116 * and the message length.
117 */
118 b0[0] = flags;
119 bcopy(nonce, b0 + 1, nonceLen);
120 bp = b0 + 1 + nonceLen;
121
122 /* Need to copy L' [aka L-1] bytes of cryptDataLength */
123 for (uint8_t *dst = b0 + sizeof(b0) - 1; dst >= bp; dst--) {
124 *dst = dataLength;
125 dataLength >>= 8;
126 }
127 /* Now need to encrypt b0 */
128 rijndaelEncrypt(ctx->keysched, ctx->rounds, b0, ctx->block);
129 /* If there is auth data, we need to set up the staging block */
130 if (ctx->authDataLength) {
131 size_t addLength;
132 if (ctx->authDataLength < ((1<<16) - (1<<8))) {
133 uint16_t sizeVal = htobe16(ctx->authDataLength);
134 bcopy(&sizeVal, ctx->staging_block, sizeof(sizeVal));
135 addLength = sizeof(sizeVal);
136 } else if (ctx->authDataLength < (1ULL<<32)) {
137 uint32_t sizeVal = htobe32(ctx->authDataLength);
138 ctx->staging_block[0] = 0xff;
139 ctx->staging_block[1] = 0xfe;
140 bcopy(&sizeVal, ctx->staging_block+2, sizeof(sizeVal));
141 addLength = 2 + sizeof(sizeVal);
142 } else {
143 uint64_t sizeVal = htobe64(ctx->authDataLength);
144 ctx->staging_block[0] = 0xff;
145 ctx->staging_block[1] = 0xff;
146 bcopy(&sizeVal, ctx->staging_block+2, sizeof(sizeVal));
147 addLength = 2 + sizeof(sizeVal);
148 }
149 ctx->blockIndex = addLength;
150 /*
151 * The length descriptor goes into the AAD buffer, so we
152 * need to account for it.
153 */
154 ctx->authDataLength += addLength;
155 ctx->authDataCount = addLength;
156 }
157 }
158
159 int
160 AES_CBC_MAC_Update(void *vctx, const void *vdata, u_int length)
161 {
162 struct aes_cbc_mac_ctx *ctx;
163 const uint8_t *data;
164 size_t copy_amt;
165
166 ctx = vctx;
167 data = vdata;
168
169 /*
170 * This will be called in one of two phases:
171 * (1) Applying authentication data, or
172 * (2) Applying the payload data.
173 *
174 * Because CBC-MAC puts the authentication data size before the
175 * data, subsequent calls won't be block-size-aligned. Which
176 * complicates things a fair bit.
177 *
178 * The payload data doesn't have that problem.
179 */
180
181 if (ctx->authDataCount < ctx->authDataLength) {
182 /*
183 * We need to process data as authentication data.
184 * Since we may be out of sync, we may also need
185 * to pad out the staging block.
186 */
187 const uint8_t *ptr = data;
188 while (length > 0) {
189
190 copy_amt = MIN(length,
191 sizeof(ctx->staging_block) - ctx->blockIndex);
192
193 bcopy(ptr, ctx->staging_block + ctx->blockIndex,
194 copy_amt);
195 ptr += copy_amt;
196 length -= copy_amt;
197 ctx->authDataCount += copy_amt;
198 ctx->blockIndex += copy_amt;
199 ctx->blockIndex %= sizeof(ctx->staging_block);
200
201 if (ctx->blockIndex == 0 ||
202 ctx->authDataCount == ctx->authDataLength) {
203 /*
204 * We're done with this block, so we
205 * xor staging_block with block, and then
206 * encrypt it.
207 */
208 xor_and_encrypt(ctx, ctx->staging_block, ctx->block);
209 bzero(ctx->staging_block, sizeof(ctx->staging_block));
210 ctx->blockIndex = 0;
211 if (ctx->authDataCount >= ctx->authDataLength)
212 break;
213 }
214 }
215 /*
216 * We'd like to be able to check length == 0 and return
217 * here, but the way OCF calls us, length is always
218 * blksize (16, in this case). So we have to count on
219 * the fact that OCF calls us separately for the AAD and
220 * for the real data.
221 */
222 return (0);
223 }
224 /*
225 * If we're here, then we're encoding payload data.
226 * This is marginally easier, except that _Update can
227 * be called with non-aligned update lengths. As a result,
228 * we still need to use the staging block.
229 */
230 KASSERT((length + ctx->cryptDataCount) <= ctx->cryptDataLength,
231 ("More encryption data than allowed"));
232
233 while (length) {
234 uint8_t *ptr;
235
236 copy_amt = MIN(sizeof(ctx->staging_block) - ctx->blockIndex,
237 length);
238 ptr = ctx->staging_block + ctx->blockIndex;
239 bcopy(data, ptr, copy_amt);
240 data += copy_amt;
241 ctx->blockIndex += copy_amt;
242 ctx->cryptDataCount += copy_amt;
243 length -= copy_amt;
244 if (ctx->blockIndex == sizeof(ctx->staging_block)) {
245 /* We've got a full block */
246 xor_and_encrypt(ctx, ctx->staging_block, ctx->block);
247 ctx->blockIndex = 0;
248 bzero(ctx->staging_block, sizeof(ctx->staging_block));
249 }
250 }
251 return (0);
252 }
253
254 void
255 AES_CBC_MAC_Final(uint8_t *buf, void *vctx)
256 {
257 struct aes_cbc_mac_ctx *ctx;
258 uint8_t s0[CCM_CBC_BLOCK_LEN];
259
260 ctx = vctx;
261
262 /*
263 * We first need to check to see if we've got any data
264 * left over to encrypt.
265 */
266 if (ctx->blockIndex != 0) {
267 xor_and_encrypt(ctx, ctx->staging_block, ctx->block);
268 ctx->cryptDataCount += ctx->blockIndex;
269 ctx->blockIndex = 0;
270 explicit_bzero(ctx->staging_block, sizeof(ctx->staging_block));
271 }
272 bzero(s0, sizeof(s0));
273 s0[0] = (15 - ctx->nonceLength) - 1;
274 bcopy(ctx->nonce, s0 + 1, ctx->nonceLength);
275 rijndaelEncrypt(ctx->keysched, ctx->rounds, s0, s0);
276 for (size_t indx = 0; indx < AES_CBC_MAC_HASH_LEN; indx++)
277 buf[indx] = ctx->block[indx] ^ s0[indx];
278 explicit_bzero(s0, sizeof(s0));
279 }
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