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-rw-r--r--crypto/modes/ctr128.c354
1 files changed, 186 insertions, 168 deletions
diff --git a/crypto/modes/ctr128.c b/crypto/modes/ctr128.c
index ee642c5863cd..f3bbcbf72376 100644
--- a/crypto/modes/ctr128.c
+++ b/crypto/modes/ctr128.c
@@ -6,7 +6,7 @@
* are met:
*
* 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
+ * 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
@@ -59,194 +59,212 @@
#endif
#include <assert.h>
-/* NOTE: the IV/counter CTR mode is big-endian. The code itself
- * is endian-neutral. */
+/*
+ * 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);
+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);
+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.
+/*
+ * 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)
+ 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;
+ unsigned int n;
+ size_t l = 0;
- assert(in && out && key && ecount_buf && num);
- assert(*num < 16);
+ assert(in && out && key && ecount_buf && num);
+ assert(*num < 16);
- n = *num;
+ 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 */
+ if (16 % sizeof(size_t) == 0) { /* always true actually */
+ do {
+ 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;
+ 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);
+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)
+ 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;
+ 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;
}