1 /* ====================================================================
2 * Copyright (c) 2008 The OpenSSL Project. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
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
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/)"
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.
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.
30 * 6. Redistributions of any form whatsoever must retain the following
32 * "This product includes software developed by the OpenSSL Project
33 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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 * ====================================================================
61 typedef unsigned int u32;
62 typedef unsigned char u8;
64 #define STRICT_ALIGNMENT
65 #if defined(__i386) || defined(__i386__) || \
66 defined(__x86_64) || defined(__x86_64__) || \
67 defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \
68 defined(__s390__) || defined(__s390x__)
69 # undef STRICT_ALIGNMENT
72 /* NOTE: the IV/counter CTR mode is big-endian. The code itself
73 * is endian-neutral. */
75 /* increment counter (128-bit int) by 1 */
76 static void ctr128_inc(unsigned char *counter) {
89 #if !defined(OPENSSL_SMALL_FOOTPRINT)
90 static void ctr128_inc_aligned(unsigned char *counter) {
92 const union { long one; char little; } is_endian = {1};
94 if (is_endian.little) {
99 data = (size_t *)counter;
100 n = 16/sizeof(size_t);
111 /* The input encrypted as though 128bit counter mode is being
112 * used. The extra state information to record how much of the
113 * 128bit block we have used is contained in *num, and the
114 * encrypted counter is kept in ecount_buf. Both *num and
115 * ecount_buf must be initialised with zeros before the first
116 * call to CRYPTO_ctr128_encrypt().
118 * This algorithm assumes that the counter is in the x lower bits
119 * of the IV (ivec), and that the application has full control over
120 * overflow and the rest of the IV. This implementation takes NO
121 * responsability for checking that the counter doesn't overflow
122 * into the rest of the IV when incremented.
124 void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out,
125 size_t len, const void *key,
126 unsigned char ivec[16], unsigned char ecount_buf[16],
127 unsigned int *num, block128_f block)
132 assert(in && out && key && ecount_buf && num);
137 #if !defined(OPENSSL_SMALL_FOOTPRINT)
138 if (16%sizeof(size_t) == 0) do { /* always true actually */
140 *(out++) = *(in++) ^ ecount_buf[n];
145 #if defined(STRICT_ALIGNMENT)
146 if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
150 (*block)(ivec, ecount_buf, key);
151 ctr128_inc_aligned(ivec);
152 for (; n<16; n+=sizeof(size_t))
154 *(size_t *)(in+n) ^ *(size_t *)(ecount_buf+n);
161 (*block)(ivec, ecount_buf, key);
162 ctr128_inc_aligned(ivec);
164 out[n] = in[n] ^ ecount_buf[n];
171 /* the rest would be commonly eliminated by x86* compiler */
175 (*block)(ivec, ecount_buf, key);
178 out[l] = in[l] ^ ecount_buf[n];
186 #define GETU32(p) ((u32)(p)[0]<<24|(u32)(p)[1]<<16|(u32)(p)[2]<<8|(u32)(p)[3])
187 #define PUTU32(p,v) ((p)[0]=(u8)((v)>>24),(p)[1]=(u8)((v)>>16),(p)[2]=(u8)((v)>>8),(p)[3]=(u8)(v))
189 /* increment upper 96 bits of 128-bit counter by 1 */
190 static void ctr96_inc(unsigned char *counter) {
203 void CRYPTO_ctr128_encrypt_ctr32(const unsigned char *in, unsigned char *out,
204 size_t len, const void *key,
205 unsigned char ivec[16], unsigned char ecount_buf[16],
206 unsigned int *num, ctr128_f func)
208 unsigned int n,ctr32;
210 assert(in && out && key && ecount_buf && num);
216 *(out++) = *(in++) ^ ecount_buf[n];
221 ctr32 = GETU32(ivec+12);
223 size_t blocks = len/16;
225 * 1<<28 is just a not-so-small yet not-so-large number...
226 * Below condition is practically never met, but it has to
227 * be checked for code correctness.
229 if (sizeof(size_t)>sizeof(unsigned int) && blocks>(1U<<28))
232 * As (*func) operates on 32-bit counter, caller
233 * has to handle overflow. 'if' below detects the
234 * overflow, which is then handled by limiting the
235 * amount of blocks to the exact overflow point...
237 ctr32 += (u32)blocks;
238 if (ctr32 < blocks) {
242 (*func)(in,out,blocks,key,ivec);
243 /* (*ctr) does not update ivec, caller does: */
244 PUTU32(ivec+12,ctr32);
245 /* ... overflow was detected, propogate carry. */
246 if (ctr32 == 0) ctr96_inc(ivec);
253 memset(ecount_buf,0,16);
254 (*func)(ecount_buf,ecount_buf,1,key,ivec);
256 PUTU32(ivec+12,ctr32);
257 if (ctr32 == 0) ctr96_inc(ivec);
259 out[n] = in[n] ^ ecount_buf[n];