cmac.c: optimize make_kn and move zero_iv to const segment.

[openssl.git] / crypto / cmac / cmac.c

diff --git a/crypto/cmac/cmac.c b/crypto/cmac/cmac.c
index 5807e30ddd4cf460c3f6e1452789b7de5206b91c..064b67d073262b526cf3c2f7d3866c2e0164923f 100644 (file)
--- a/crypto/cmac/cmac.c
+++ b/crypto/cmac/cmac.c
@@ -77,19 +77,17 @@ struct CMAC_CTX_st
 
 /* Make temporary keys K1 and K2 */
 
-static void make_kn(unsigned char *k1, unsigned char *l, int bl)
+static void make_kn(unsigned char *k1, const unsigned char *l, int bl)
        {
        int i;
+       unsigned char c = l[0], carry = c>>7, cnext;
+
        /* Shift block to left, including carry */
-       for (i = 0; i < bl; i++)
-               {
-               k1[i] = l[i] << 1;
-               if (i < bl - 1 && l[i + 1] & 0x80)
-                       k1[i] |= 1;
-               }
+       for (i = 0; i < bl-1; i++, c = cnext)
+               k1[i] = (c << 1) | ((cnext=l[i+1]) >> 7);
+
        /* If MSB set fixup with R */
-       if (l[0] & 0x80)
-               k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b;
+       k1[i] = (c << 1) ^ ((0-carry)&(bl==16?0x87:0x1b));
        }
 
 CMAC_CTX *CMAC_CTX_new(void)
@@ -143,7 +141,8 @@ int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
 int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen, 
                        const EVP_CIPHER *cipher, ENGINE *impl)
        {
-       static unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH];
+       __fips_constseg
+       static const unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH] = {0};
        /* All zeros means restart */
        if (!key && !cipher && !impl && keylen == 0)
                {