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1 : : /* ====================================================================
2 : : * Copyright (c) 2008 The OpenSSL Project. 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 : : *
8 : : * 1. Redistributions of source code must retain the above copyright
9 : : * notice, this list of conditions and the following disclaimer.
10 : : *
11 : : * 2. Redistributions in binary form must reproduce the above copyright
12 : : * notice, this list of conditions and the following disclaimer in
13 : : * the documentation and/or other materials provided with the
14 : : * distribution.
15 : : *
16 : : * 3. All advertising materials mentioning features or use of this
17 : : * software must display the following acknowledgment:
18 : : * "This product includes software developed by the OpenSSL Project
19 : : * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
20 : : *
21 : : * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 : : * endorse or promote products derived from this software without
23 : : * prior written permission. For written permission, please contact
24 : : * openssl-core@openssl.org.
25 : : *
26 : : * 5. Products derived from this software may not be called "OpenSSL"
27 : : * nor may "OpenSSL" appear in their names without prior written
28 : : * permission of the OpenSSL Project.
29 : : *
30 : : * 6. Redistributions of any form whatsoever must retain the following
31 : : * acknowledgment:
32 : : * "This product includes software developed by the OpenSSL Project
33 : : * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
34 : : *
35 : : * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 : : * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 : : * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 : : * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 : : * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 : : * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 : : * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 : : * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 : : * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 : : * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 : : * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 : : * OF THE POSSIBILITY OF SUCH DAMAGE.
47 : : * ====================================================================
48 : : *
49 : : */
50 : :
51 : : #include <openssl/crypto.h>
52 : : #include "modes_lcl.h"
53 : : #include <string.h>
54 : :
55 : : #ifndef MODES_DEBUG
56 : : # ifndef NDEBUG
57 : : # define NDEBUG
58 : : # endif
59 : : #endif
60 : : #include <assert.h>
61 : :
62 : : /* NOTE: the IV/counter CTR mode is big-endian. The code itself
63 : : * is endian-neutral. */
64 : :
65 : : /* increment counter (128-bit int) by 1 */
66 : 0 : static void ctr128_inc(unsigned char *counter) {
67 : 0 : u32 n=16;
68 : : u8 c;
69 : :
70 : : do {
71 : 0 : --n;
72 : 0 : c = counter[n];
73 : 0 : ++c;
74 : 0 : counter[n] = c;
75 [ # # ]: 0 : if (c) return;
76 [ # # ]: 0 : } while (n);
77 : : }
78 : :
79 : : #if !defined(OPENSSL_SMALL_FOOTPRINT)
80 : 0 : static void ctr128_inc_aligned(unsigned char *counter) {
81 : : size_t *data,c,n;
82 : : const union { long one; char little; } is_endian = {1};
83 : :
84 : : if (is_endian.little) {
85 : 0 : ctr128_inc(counter);
86 : : return;
87 : : }
88 : :
89 : : data = (size_t *)counter;
90 : : n = 16/sizeof(size_t);
91 : : do {
92 : : --n;
93 : : c = data[n];
94 : : ++c;
95 : : data[n] = c;
96 : : if (c) return;
97 : : } while (n);
98 : : }
99 : : #endif
100 : :
101 : : /* The input encrypted as though 128bit counter mode is being
102 : : * used. The extra state information to record how much of the
103 : : * 128bit block we have used is contained in *num, and the
104 : : * encrypted counter is kept in ecount_buf. Both *num and
105 : : * ecount_buf must be initialised with zeros before the first
106 : : * call to CRYPTO_ctr128_encrypt().
107 : : *
108 : : * This algorithm assumes that the counter is in the x lower bits
109 : : * of the IV (ivec), and that the application has full control over
110 : : * overflow and the rest of the IV. This implementation takes NO
111 : : * responsability for checking that the counter doesn't overflow
112 : : * into the rest of the IV when incremented.
113 : : */
114 : 0 : void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out,
115 : : size_t len, const void *key,
116 : : unsigned char ivec[16], unsigned char ecount_buf[16],
117 : : unsigned int *num, block128_f block)
118 : : {
119 : : unsigned int n;
120 : 0 : size_t l=0;
121 : :
122 : : assert(in && out && key && ecount_buf && num);
123 : : assert(*num < 16);
124 : :
125 : 0 : n = *num;
126 : :
127 : : #if !defined(OPENSSL_SMALL_FOOTPRINT)
128 : : if (16%sizeof(size_t) == 0) do { /* always true actually */
129 [ # # ]: 0 : while (n && len) {
130 : 0 : *(out++) = *(in++) ^ ecount_buf[n];
131 : 0 : --len;
132 : 0 : n = (n+1) % 16;
133 : : }
134 : :
135 : : #if defined(STRICT_ALIGNMENT)
136 : : if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
137 : : break;
138 : : #endif
139 [ # # ]: 0 : while (len>=16) {
140 : 0 : (*block)(ivec, ecount_buf, key);
141 : 0 : ctr128_inc_aligned(ivec);
142 [ # # ]: 0 : for (; n<16; n+=sizeof(size_t))
143 : 0 : *(size_t *)(out+n) =
144 : 0 : *(size_t *)(in+n) ^ *(size_t *)(ecount_buf+n);
145 : 0 : len -= 16;
146 : 0 : out += 16;
147 : 0 : in += 16;
148 : 0 : n = 0;
149 : : }
150 [ # # ]: 0 : if (len) {
151 : 0 : (*block)(ivec, ecount_buf, key);
152 : 0 : ctr128_inc_aligned(ivec);
153 [ # # ]: 0 : while (len--) {
154 : 0 : out[n] = in[n] ^ ecount_buf[n];
155 : 0 : ++n;
156 : : }
157 : : }
158 : 0 : *num = n;
159 : 0 : return;
160 : : } while(0);
161 : : /* the rest would be commonly eliminated by x86* compiler */
162 : : #endif
163 : : while (l<len) {
164 : : if (n==0) {
165 : : (*block)(ivec, ecount_buf, key);
166 : : ctr128_inc(ivec);
167 : : }
168 : : out[l] = in[l] ^ ecount_buf[n];
169 : : ++l;
170 : : n = (n+1) % 16;
171 : : }
172 : :
173 : : *num=n;
174 : : }
175 : :
176 : : /* increment upper 96 bits of 128-bit counter by 1 */
177 : 0 : static void ctr96_inc(unsigned char *counter) {
178 : 0 : u32 n=12;
179 : : u8 c;
180 : :
181 : : do {
182 : 0 : --n;
183 : 0 : c = counter[n];
184 : 0 : ++c;
185 : 0 : counter[n] = c;
186 [ # # ]: 0 : if (c) return;
187 [ # # ]: 0 : } while (n);
188 : : }
189 : :
190 : 9 : void CRYPTO_ctr128_encrypt_ctr32(const unsigned char *in, unsigned char *out,
191 : : size_t len, const void *key,
192 : : unsigned char ivec[16], unsigned char ecount_buf[16],
193 : : unsigned int *num, ctr128_f func)
194 : : {
195 : : unsigned int n,ctr32;
196 : :
197 : : assert(in && out && key && ecount_buf && num);
198 : : assert(*num < 16);
199 : :
200 : 9 : n = *num;
201 : :
202 [ - + ]: 9 : while (n && len) {
203 : 0 : *(out++) = *(in++) ^ ecount_buf[n];
204 : 0 : --len;
205 : 0 : n = (n+1) % 16;
206 : : }
207 : :
208 : 9 : ctr32 = GETU32(ivec+12);
209 [ + + ]: 18 : while (len>=16) {
210 : 9 : size_t blocks = len/16;
211 : : /*
212 : : * 1<<28 is just a not-so-small yet not-so-large number...
213 : : * Below condition is practically never met, but it has to
214 : : * be checked for code correctness.
215 : : */
216 [ - + ]: 9 : if (sizeof(size_t)>sizeof(unsigned int) && blocks>(1U<<28))
217 : 0 : blocks = (1U<<28);
218 : : /*
219 : : * As (*func) operates on 32-bit counter, caller
220 : : * has to handle overflow. 'if' below detects the
221 : : * overflow, which is then handled by limiting the
222 : : * amount of blocks to the exact overflow point...
223 : : */
224 : 9 : ctr32 += (u32)blocks;
225 [ - + ]: 9 : if (ctr32 < blocks) {
226 : 0 : blocks -= ctr32;
227 : 0 : ctr32 = 0;
228 : : }
229 : 9 : (*func)(in,out,blocks,key,ivec);
230 : : /* (*ctr) does not update ivec, caller does: */
231 : 9 : PUTU32(ivec+12,ctr32);
232 : : /* ... overflow was detected, propogate carry. */
233 [ - + ]: 9 : if (ctr32 == 0) ctr96_inc(ivec);
234 : 9 : blocks *= 16;
235 : 9 : len -= blocks;
236 : 9 : out += blocks;
237 : 9 : in += blocks;
238 : : }
239 [ + + ]: 9 : if (len) {
240 : : memset(ecount_buf,0,16);
241 : 3 : (*func)(ecount_buf,ecount_buf,1,key,ivec);
242 : 3 : ++ctr32;
243 : 3 : PUTU32(ivec+12,ctr32);
244 [ - + ]: 3 : if (ctr32 == 0) ctr96_inc(ivec);
245 [ + + ]: 15 : while (len--) {
246 : 12 : out[n] = in[n] ^ ecount_buf[n];
247 : 12 : ++n;
248 : : }
249 : : }
250 : :
251 : 9 : *num=n;
252 : 9 : }
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