gosthash2012: Simplify `pad'

[openssl-gost/engine.git] / gosthash2012.c

diff --git a/gosthash2012.c b/gosthash2012.c
index bbe7dcbf83d1cb8932bf24d34b10c5f9540e04dd..201fe317ec23fb954e023c6b7a9fc48b5b0993eb 100644 (file)
--- a/gosthash2012.c
+++ b/gosthash2012.c
@@ -35,24 +35,22 @@ void init_gost2012_hash_ctx(gost2012_hash_ctx * CTX,
     memset(CTX, 0, sizeof(gost2012_hash_ctx));
 
     CTX->digest_size = digest_size;
+    /*
+     * IV for 512-bit hash should be 0^512
+     * IV for 256-bit hash should be (00000001)^64
+     *
+     * It's already zeroed when CTX is cleared above, so we only
+     * need to set it to 0x01-s for 256-bit hash.
+     */
     if (digest_size == 256)
         memset(&CTX->h, 0x01, sizeof(uint512_u));
-    else
-        memset(&CTX->h, 0x00, sizeof(uint512_u));
 }
 
 static INLINE void pad(gost2012_hash_ctx * CTX)
 {
-    unsigned char buf[64];
-
-    if (CTX->bufsize > 63)
-        return;
-
-    memset(&buf, 0x00, sizeof buf);
-    memcpy(&buf, CTX->buffer, CTX->bufsize);
+    memset(&(CTX->buffer[CTX->bufsize]), 0, sizeof(CTX->buffer) - CTX->bufsize);
+    CTX->buffer[CTX->bufsize] = 1;
 
-    buf[CTX->bufsize] = 0x01;
-    memcpy(CTX->buffer, &buf, sizeof buf);
 }
 
 static INLINE void add512(const union uint512_u *x,
@@ -192,7 +190,6 @@ static INLINE void stage3(gost2012_hash_ctx * CTX)
     g(&(CTX->h), &buffer0, (const unsigned char *)&(CTX->N));
 
     g(&(CTX->h), &buffer0, (const unsigned char *)&(CTX->Sigma));
-    memcpy(&(CTX->hash), &(CTX->h), sizeof(uint512_u));
 }
 
 /*
@@ -242,7 +239,7 @@ void gost2012_finish_hash(gost2012_hash_ctx * CTX, unsigned char *digest)
     CTX->bufsize = 0;
 
     if (CTX->digest_size == 256)
-        memcpy(digest, &(CTX->hash.QWORD[4]), 32);
+        memcpy(digest, &(CTX->h.QWORD[4]), 32);
     else
-        memcpy(digest, &(CTX->hash.QWORD[0]), 64);
+        memcpy(digest, &(CTX->h.QWORD[0]), 64);
 }