--- /dev/null
+/* ====================================================================
+ * Copyright (c) 2008 The OpenSSL Project. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ * software must display the following acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ * endorse or promote products derived from this software without
+ * prior written permission. For written permission, please contact
+ * openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ * nor may "OpenSSL" appear in their names without prior written
+ * permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ * acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ */
+
+#include <openssl/crypto.h>
+#include "modes_lcl.h"
+#include <string.h>
+
+#ifndef MODES_DEBUG
+# ifndef NDEBUG
+# define NDEBUG
+# endif
+#endif
+#include <assert.h>
+
+/* NOTE: the IV/counter CTR mode is big-endian. The code itself
+ * is endian-neutral. */
+
+/* increment counter (128-bit int) by 1 */
+static void ctr128_inc(unsigned char *counter) {
+ u32 n=16;
+ u8 c;
+
+ do {
+ --n;
+ c = counter[n];
+ ++c;
+ counter[n] = c;
+ if (c) return;
+ } while (n);
+}
+
+#if !defined(OPENSSL_SMALL_FOOTPRINT)
+static void ctr128_inc_aligned(unsigned char *counter) {
+ size_t *data,c,n;
+ const union { long one; char little; } is_endian = {1};
+
+ if (is_endian.little) {
+ ctr128_inc(counter);
+ return;
+ }
+
+ data = (size_t *)counter;
+ n = 16/sizeof(size_t);
+ do {
+ --n;
+ c = data[n];
+ ++c;
+ data[n] = c;
+ if (c) return;
+ } while (n);
+}
+#endif
+
+/* The input encrypted as though 128bit counter mode is being
+ * used. The extra state information to record how much of the
+ * 128bit block we have used is contained in *num, and the
+ * encrypted counter is kept in ecount_buf. Both *num and
+ * ecount_buf must be initialised with zeros before the first
+ * call to CRYPTO_ctr128_encrypt().
+ *
+ * This algorithm assumes that the counter is in the x lower bits
+ * of the IV (ivec), and that the application has full control over
+ * overflow and the rest of the IV. This implementation takes NO
+ * responsability for checking that the counter doesn't overflow
+ * into the rest of the IV when incremented.
+ */
+void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out,
+ size_t len, const void *key,
+ unsigned char ivec[16], unsigned char ecount_buf[16],
+ unsigned int *num, block128_f block)
+{
+ unsigned int n;
+ size_t l=0;
+
+ assert(in && out && key && ecount_buf && num);
+ assert(*num < 16);
+
+ n = *num;
+
+#if !defined(OPENSSL_SMALL_FOOTPRINT)
+ if (16%sizeof(size_t) == 0) do { /* always true actually */
+ while (n && len) {
+ *(out++) = *(in++) ^ ecount_buf[n];
+ --len;
+ n = (n+1) % 16;
+ }
+
+#if defined(STRICT_ALIGNMENT)
+ if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0)
+ break;
+#endif
+ while (len>=16) {
+ (*block)(ivec, ecount_buf, key);
+ ctr128_inc_aligned(ivec);
+ for (; n<16; n+=sizeof(size_t))
+ *(size_t *)(out+n) =
+ *(size_t *)(in+n) ^ *(size_t *)(ecount_buf+n);
+ len -= 16;
+ out += 16;
+ in += 16;
+ n = 0;
+ }
+ if (len) {
+ (*block)(ivec, ecount_buf, key);
+ ctr128_inc_aligned(ivec);
+ while (len--) {
+ out[n] = in[n] ^ ecount_buf[n];
+ ++n;
+ }
+ }
+ *num = n;
+ return;
+ } while(0);
+ /* the rest would be commonly eliminated by x86* compiler */
+#endif
+ while (l<len) {
+ if (n==0) {
+ (*block)(ivec, ecount_buf, key);
+ ctr128_inc(ivec);
+ }
+ out[l] = in[l] ^ ecount_buf[n];
+ ++l;
+ n = (n+1) % 16;
+ }
+
+ *num=n;
+}
+
+/* increment upper 96 bits of 128-bit counter by 1 */
+static void ctr96_inc(unsigned char *counter) {
+ u32 n=12;
+ u8 c;
+
+ do {
+ --n;
+ c = counter[n];
+ ++c;
+ counter[n] = c;
+ if (c) return;
+ } while (n);
+}
+
+void CRYPTO_ctr128_encrypt_ctr32(const unsigned char *in, unsigned char *out,
+ size_t len, const void *key,
+ unsigned char ivec[16], unsigned char ecount_buf[16],
+ unsigned int *num, ctr128_f func)
+{
+ unsigned int n,ctr32;
+
+ assert(in && out && key && ecount_buf && num);
+ assert(*num < 16);
+
+ n = *num;
+
+ while (n && len) {
+ *(out++) = *(in++) ^ ecount_buf[n];
+ --len;
+ n = (n+1) % 16;
+ }
+
+ ctr32 = GETU32(ivec+12);
+ while (len>=16) {
+ size_t blocks = len/16;
+ /*
+ * 1<<28 is just a not-so-small yet not-so-large number...
+ * Below condition is practically never met, but it has to
+ * be checked for code correctness.
+ */
+ if (sizeof(size_t)>sizeof(unsigned int) && blocks>(1U<<28))
+ blocks = (1U<<28);
+ /*
+ * As (*func) operates on 32-bit counter, caller
+ * has to handle overflow. 'if' below detects the
+ * overflow, which is then handled by limiting the
+ * amount of blocks to the exact overflow point...
+ */
+ ctr32 += (u32)blocks;
+ if (ctr32 < blocks) {
+ blocks -= ctr32;
+ ctr32 = 0;
+ }
+ (*func)(in,out,blocks,key,ivec);
+ /* (*ctr) does not update ivec, caller does: */
+ PUTU32(ivec+12,ctr32);
+ /* ... overflow was detected, propogate carry. */
+ if (ctr32 == 0) ctr96_inc(ivec);
+ blocks *= 16;
+ len -= blocks;
+ out += blocks;
+ in += blocks;
+ }
+ if (len) {
+ memset(ecount_buf,0,16);
+ (*func)(ecount_buf,ecount_buf,1,key,ivec);
+ ++ctr32;
+ PUTU32(ivec+12,ctr32);
+ if (ctr32 == 0) ctr96_inc(ivec);
+ while (len--) {
+ out[n] = in[n] ^ ecount_buf[n];
+ ++n;
+ }
+ }
+
+ *num=n;
+}
projects / cassiopeia.git / blobdiff