Final SHA-256/-512 touches. Extra md_len field in SHA[256|512]_CTX

reserves for truncated hash function output mode and makes SHA224
thread-safe. Next stop is integration with EVP and we're done...

crypto/sha/sha.h

@@ -130,18 +130,13 @@ typedef struct SHA256state_st
 	SHA_LONG h[8];
 	SHA_LONG Nl,Nh;
 	SHA_LONG data[SHA_LBLOCK];
-	int num;
+	unsigned int num,md_len;
 	} SHA256_CTX;
 
 #ifndef OPENSSL_NO_SHA256
 int SHA224_Init(SHA256_CTX *c);
-#if 0
 int SHA224_Update(SHA256_CTX *c, const void *data, size_t len);
 int SHA224_Final(unsigned char *md, SHA256_CTX *c);
-#else
-#define SHA224_Update(c,data,len)	SHA256_Update((c),(data),(len))
-#define SHA224_Final(md,c)	SHA256_Final((md),(c))
-#endif
 unsigned char *SHA224(const unsigned char *d, size_t n,unsigned char *md);
 int SHA256_Init(SHA256_CTX *c);
 int SHA256_Update(SHA256_CTX *c, const void *data, size_t len);
@@ -177,7 +172,7 @@ typedef struct SHA512state_st
 		SHA_LONG64	d[SHA_LBLOCK];
 		unsigned char	p[SHA512_CBLOCK];
 	} u;
-	int num;
+	unsigned int num,md_len;
 	} SHA512_CTX;
 
 #ifndef OPENSSL_NO_SHA512

crypto/sha/sha256.c

@@ -20,9 +20,9 @@ int SHA224_Init (SHA256_CTX *c)
 	c->h[2]=0x3070dd17UL;	c->h[3]=0xf70e5939UL;
 	c->h[4]=0xffc00b31UL;	c->h[5]=0x68581511UL;
 	c->h[6]=0x64f98fa7UL;	c->h[7]=0xbefa4fa4UL;
-        c->Nl=0;        c->Nh=0;
-        c->num=0;
-        return 1;
+	c->Nl=0;	c->Nh=0;
+	c->num=0;	c->md_len=SHA224_DIGEST_LENGTH;
+	return 1;
 	}
 
 int SHA256_Init (SHA256_CTX *c)
@@ -31,23 +31,20 @@ int SHA256_Init (SHA256_CTX *c)
 	c->h[2]=0x3c6ef372UL;	c->h[3]=0xa54ff53aUL;
 	c->h[4]=0x510e527fUL;	c->h[5]=0x9b05688cUL;
 	c->h[6]=0x1f83d9abUL;	c->h[7]=0x5be0cd19UL;
-        c->Nl=0;        c->Nh=0;
-        c->num=0;
-        return 1;
+	c->Nl=0;	c->Nh=0;
+	c->num=0;	c->md_len=SHA256_DIGEST_LENGTH;
+	return 1;
 	}
 
 unsigned char *SHA224(const unsigned char *d, size_t n, unsigned char *md)
 	{
 	SHA256_CTX c;
-	static unsigned char m[SHA256_DIGEST_LENGTH];
+	static unsigned char m[SHA224_DIGEST_LENGTH];
 
+	if (md == NULL) md=m;
 	SHA224_Init(&c);
 	SHA256_Update(&c,d,n);
-	SHA256_Final(m,&c);
-	if (md != NULL) memcpy (md,m,SHA224_DIGEST_LENGTH),
-			memset (m,0,sizeof(m));
-	else		md=m,
-			memset (m+SHA224_DIGEST_LENGTH,0,sizeof(m)-SHA256_DIGEST_LENGTH);
+	SHA256_Final(md,&c);
 	OPENSSL_cleanse(&c,sizeof(c));
 	return(md);
 	}
@@ -65,6 +62,11 @@ unsigned char *SHA256(const unsigned char *d, size_t n, unsigned char *md)
 	return(md);
 	}
 
+int SHA224_Update(SHA256_CTX *c, const void *data, size_t len)
+{   return SHA256_Update (c,data,len);   }
+int SHA224_Final (unsigned char *md, SHA256_CTX *c)
+{   return SHA256_Final (md,c);   }
+
 #ifndef	SHA_LONG_LOG2
 #define	SHA_LONG_LOG2	2	/* default to 32 bits */
 #endif
@@ -76,12 +78,33 @@ unsigned char *SHA256(const unsigned char *d, size_t n, unsigned char *md)
 #define	HASH_CTX		SHA256_CTX
 #define	HASH_CBLOCK		SHA_CBLOCK
 #define	HASH_LBLOCK		SHA_LBLOCK
+/*
+ * Note that FIPS180-2 discusses "Truncation of the Hash Function Output."
+ * default: case below covers for it. It's not clear however if it's
+ * permitted to truncate at amount of bits not divisable by 4. I bet not,
+ * but if it is, then default: case shall be extended. For reference.
+ * Idea behind separate cases for pre-defined lenghts is to let the
+ * compiler decide if it's appropriate to unroll small loops.
+ */
 #define	HASH_MAKE_STRING(c,s)	do {	\
 	unsigned long ll;		\
-	ll=(c)->h[0]; HOST_l2c(ll,(s));	ll=(c)->h[1]; HOST_l2c(ll,(s));	\
-	ll=(c)->h[2]; HOST_l2c(ll,(s));	ll=(c)->h[3]; HOST_l2c(ll,(s));	\
-	ll=(c)->h[4]; HOST_l2c(ll,(s));	ll=(c)->h[5]; HOST_l2c(ll,(s));	\
-	ll=(c)->h[6]; HOST_l2c(ll,(s));	ll=(c)->h[7]; HOST_l2c(ll,(s));	\
+	unsigned int  n;		\
+	switch ((c)->md_len)		\
+	{   case SHA224_DIGEST_LENGTH:	\
+		for (n=0;n<SHA224_DIGEST_LENGTH/4;n++)	\
+		{   ll=(c)->h[n]; HOST_l2c(ll,(s));   }	\
+		break;			\
+	    case SHA256_DIGEST_LENGTH:	\
+		for (n=0;n<SHA256_DIGEST_LENGTH/4;n++)	\
+		{   ll=(c)->h[n]; HOST_l2c(ll,(s));   }	\
+		break;			\
+	    default:			\
+		if ((c)->md_len > SHA256_DIGEST_LENGTH)	\
+		    return 0;				\
+		for (n=0;n<(c)->md_len/4;n++)		\
+		{   ll=(c)->h[n]; HOST_l2c(ll,(s));   }	\
+		break;			\
+	}				\
 	} while (0)
 
 #define	HASH_UPDATE		SHA256_Update

crypto/sha/sha512.c

@@ -64,7 +64,7 @@ int SHA384_Init (SHA512_CTX *c)
 	c->h[6]=U64(0xdb0c2e0d64f98fa7);
 	c->h[7]=U64(0x47b5481dbefa4fa4);
         c->Nl=0;        c->Nh=0;
-        c->num=0;
+        c->num=0;       c->md_len=SHA384_DIGEST_LENGTH;
         return 1;
 	}
 
@@ -79,18 +79,18 @@ int SHA512_Init (SHA512_CTX *c)
 	c->h[6]=U64(0x1f83d9abfb41bd6b);
 	c->h[7]=U64(0x5be0cd19137e2179);
         c->Nl=0;        c->Nh=0;
-        c->num=0;
+        c->num=0;       c->md_len=SHA512_DIGEST_LENGTH;
         return 1;
 	}
 
 static void sha512_block (SHA512_CTX *ctx, const void *in, size_t num);
 
-static int sha512_final (unsigned char *md, SHA512_CTX *c, size_t msz)
+int SHA512_Final (unsigned char *md, SHA512_CTX *c)
 	{
 	unsigned char *p=(unsigned char *)c->u.p;
 	size_t n=c->num;
 
-	p[n]=0x80;
+	p[n]=0x80;	/* There always is a room for one */
 	n++;
 	if (n > (sizeof(c->u)-16))
 		memset (p+n,0,sizeof(c->u)-n), n=0,
@@ -123,23 +123,40 @@ static int sha512_final (unsigned char *md, SHA512_CTX *c, size_t msz)
 
 	if (md==0) return 0;
 
-	for (n=0;msz>0;n++,msz-=8)
+	switch (c->md_len)
 		{
-		SHA_LONG64 t = c->h[n];
-
-		*(md++)	= (t>>56)&0xFF;	*(md++)	= (t>>48)&0xFF;
-		*(md++)	= (t>>40)&0xFF;	*(md++)	= (t>>32)&0xFF;
-		*(md++)	= (t>>24)&0xFF;	*(md++)	= (t>>16)&0xFF;
-		*(md++)	= (t>>8)&0xFF;	*(md++)	= (t)&0xFF;
+		/* Let compiler decide if it's appropriate to unroll... */
+		case SHA384_DIGEST_LENGTH:
+			for (n=0;n<SHA384_DIGEST_LENGTH/8;n++)
+				{
+				SHA_LONG64 t = c->h[n];
+
+				*(md++)	= (t>>56)&0xFF;	*(md++)	= (t>>48)&0xFF;
+				*(md++)	= (t>>40)&0xFF;	*(md++)	= (t>>32)&0xFF;
+				*(md++)	= (t>>24)&0xFF;	*(md++)	= (t>>16)&0xFF;
+				*(md++)	= (t>>8)&0xFF;	*(md++)	= (t)&0xFF;
+				}
+			break;
+		case SHA512_DIGEST_LENGTH:
+			for (n=0;n<SHA512_DIGEST_LENGTH/8;n++)
+				{
+				SHA_LONG64 t = c->h[n];
+
+				*(md++)	= (t>>56)&0xFF;	*(md++)	= (t>>48)&0xFF;
+				*(md++)	= (t>>40)&0xFF;	*(md++)	= (t>>32)&0xFF;
+				*(md++)	= (t>>24)&0xFF;	*(md++)	= (t>>16)&0xFF;
+				*(md++)	= (t>>8)&0xFF;	*(md++)	= (t)&0xFF;
+				}
+			break;
+		/* ... as well as make sure md_len is not abused. */
+		default:	return 0;
 		}
 
 	return 1;
 	}
 
 int SHA384_Final (unsigned char *md,SHA512_CTX *c)
-{   return sha512_final (md,c,SHA384_DIGEST_LENGTH);   }
-int SHA512_Final (unsigned char *md,SHA512_CTX *c)
-{   return sha512_final (md,c,SHA512_DIGEST_LENGTH);   }
+{   return SHA512_Final (md,c);   }
 
 int SHA512_Update (SHA512_CTX *c, const void *_data, size_t len)
 	{
@@ -206,7 +223,7 @@ unsigned char *SHA384(const unsigned char *d, size_t n, unsigned char *md)
 	if (md == NULL) md=m;
 	SHA384_Init(&c);
 	SHA512_Update(&c,d,n);
-	sha512_final(md,&c,sizeof(m));
+	SHA512_Final(md,&c);
 	OPENSSL_cleanse(&c,sizeof(c));
 	return(md);
 	}
@@ -219,7 +236,7 @@ unsigned char *SHA512(const unsigned char *d, size_t n, unsigned char *md)
 	if (md == NULL) md=m;
 	SHA512_Init(&c);
 	SHA512_Update(&c,d,n);
-	sha512_final(md,&c,sizeof(m));
+	SHA512_Final(md,&c);
 	OPENSSL_cleanse(&c,sizeof(c));
 	return(md);
 	}