X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fmodes%2Fctr128.c;h=181614a98c2d522f8fc54ed98ce4061fe3d67c0b;hp=db79c76d392f20242084cf8cc5bdfc1802e7f3b8;hb=fbe2e28911070a8556ad05bdfd6b6871d4a82244;hpb=85b2c0ce7fdf597d60d8c366e8f7de24f674fc5a

diff --git a/crypto/modes/ctr128.c b/crypto/modes/ctr128.c
index db79c76d39..181614a98c 100644
--- a/crypto/modes/ctr128.c
+++ b/crypto/modes/ctr128.c
@@ -48,7 +48,7 @@
  *
  */
 
-#include <stddef.h>
+#include "modes.h"
 #include <string.h>
 
 #ifndef MODES_DEBUG
@@ -58,19 +58,14 @@
 #endif
 #include <assert.h>
 
-#include "modes.h"
-
 typedef unsigned int u32;
 typedef unsigned char u8;
 
-# define GETU32(pt) (((u32)(pt)[0] << 24) ^ ((u32)(pt)[1] << 16) ^ ((u32)(pt)[2] <<  8) ^ ((u32)(pt)[3]))
-# define PUTU32(ct, st) { (ct)[0] = (u8)((st) >> 24); (ct)[1] = (u8)((st) >> 16); (ct)[2] = (u8)((st) >>  8); (ct)[3] = (u8)(st); }
-
 #define STRICT_ALIGNMENT
-#if defined(__i386) || defined(__i386__) || \
-    defined(__x86_64) || defined(__x86_64__) || \
-    defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \
-    defined(__s390__) || defined(__s390x__)
+#if defined(__i386)    || defined(__i386__)    || \
+    defined(__x86_64)  || defined(__x86_64__)  || \
+    defined(_M_IX86)   || defined(_M_AMD64)    || defined(_M_X64) || \
+    defined(__s390__)  || defined(__s390x__)
 #  undef STRICT_ALIGNMENT
 #endif
 
@@ -79,18 +74,19 @@ typedef unsigned char u8;
 
 /* increment counter (128-bit int) by 1 */
 static void ctr128_inc(unsigned char *counter) {
-	u32 c,n=16;
+	u32 n=16;
+	u8  c;
 
 	do {
-		n -= 4;
-		c = GETU32(counter+n);
-		++c;	c &= 0xFFFFFFFF;
-		PUTU32(counter + n, c);
+		--n;
+		c = counter[n];
+		++c;
+		counter[n] = c;
 		if (c) return;
 	} while (n);
 }
 
-#if !defined(OPENSSL_SMALL_FOORPRINT)
+#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};
@@ -128,7 +124,7 @@ static void ctr128_inc_aligned(unsigned char *counter) {
 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, block_f block)
+			unsigned int *num, block128_f block)
 {
 	unsigned int n;
 	size_t l=0;
@@ -153,14 +149,14 @@ void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out,
 		while (len>=16) {
 			(*block)(ivec, ecount_buf, key);
 			ctr128_inc_aligned(ivec);
-			for (n=0; n<16; n+=sizeof(size_t))
+			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;
 		}
-		n = 0;
 		if (len) {
 			(*block)(ivec, ecount_buf, key);
  			ctr128_inc_aligned(ivec);
@@ -186,3 +182,84 @@ void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out,
 
 	*num=n;
 }
+
+#define GETU32(p)	((u32)(p)[0]<<24|(u32)(p)[1]<<16|(u32)(p)[2]<<8|(u32)(p)[3])
+#define PUTU32(p,v)	((p)[0]=(u8)((v)>>24),(p)[1]=(u8)((v)>>16),(p)[2]=(u8)((v)>>8),(p)[3]=(u8)(v))
+
+/* 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;
+}