a

libsec/md5.c

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+#include "os.h"
+#include <libsec.h>
+
+/*
+ *  rfc1321 requires that I include this.  The code is new.  The constants
+ *  all come from the rfc (hence the copyright).  We trade a table for the
+ *  macros in rfc.  The total size is a lot less. -- presotto
+ *
+ *	Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
+ *	rights reserved.
+ *
+ *	License to copy and use this software is granted provided that it
+ *	is identified as the "RSA Data Security, Inc. MD5 Message-Digest
+ *	Algorithm" in all material mentioning or referencing this software
+ *	or this function.
+ *
+ *	License is also granted to make and use derivative works provided
+ *	that such works are identified as "derived from the RSA Data
+ *	Security, Inc. MD5 Message-Digest Algorithm" in all material
+ *	mentioning or referencing the derived work.
+ *
+ *	RSA Data Security, Inc. makes no representations concerning either
+ *	the merchantability of this software or the suitability of this
+ *	software forany particular purpose. It is provided "as is"
+ *	without express or implied warranty of any kind.
+ *	These notices must be retained in any copies of any part of this
+ *	documentation and/or software.
+ */
+
+static void encode(uchar*, u32int*, ulong);
+static void decode(u32int*, uchar*, ulong);
+
+extern void _md5block(uchar*, ulong, u32int*);
+
+MD5state*
+md5(uchar *p, ulong len, uchar *digest, MD5state *s)
+{
+	u32int x[16];
+	uchar buf[128];
+	int i;
+	uchar *e;
+
+	if(s == nil){
+		s = malloc(sizeof(*s));
+		if(s == nil)
+			return nil;
+		memset(s, 0, sizeof(*s));
+		s->malloced = 1;
+	}
+
+	if(s->seeded == 0){
+		/* seed the state, these constants would look nicer big-endian */
+		s->state[0] = 0x67452301;
+		s->state[1] = 0xefcdab89;
+		s->state[2] = 0x98badcfe;
+		s->state[3] = 0x10325476;
+		s->seeded = 1;
+	}
+
+	/* fill out the partial 64 byte block from previous calls */
+	if(s->blen){
+		i = 64 - s->blen;
+		if(len < i)
+			i = len;
+		memmove(s->buf + s->blen, p, i);
+		len -= i;
+		s->blen += i;
+		p += i;
+		if(s->blen == 64){
+			_md5block(s->buf, s->blen, s->state);
+			s->len += s->blen;
+			s->blen = 0;
+		}
+	}
+
+	/* do 64 byte blocks */
+	i = len & ~0x3f;
+	if(i){
+		_md5block(p, i, s->state);
+		s->len += i;
+		len -= i;
+		p += i;
+	}
+
+	/* save the left overs if not last call */
+	if(digest == 0){
+		if(len){
+			memmove(s->buf, p, len);
+			s->blen += len;
+		}
+		return s;
+	}
+
+	/*
+	 *  this is the last time through, pad what's left with 0x80,
+	 *  0's, and the input count to create a multiple of 64 bytes
+	 */
+	if(s->blen){
+		p = s->buf;
+		len = s->blen;
+	} else {
+		memmove(buf, p, len);
+		p = buf;
+	}
+	s->len += len;
+	e = p + len;
+	if(len < 56)
+		i = 56 - len;
+	else
+		i = 120 - len;
+	memset(e, 0, i);
+	*e = 0x80;
+	len += i;
+
+	/* append the count */
+	x[0] = s->len<<3;
+	x[1] = s->len>>29;
+	encode(p+len, x, 8);
+
+	/* digest the last part */
+	_md5block(p, len+8, s->state);
+	s->len += len;
+
+	/* return result and free state */
+	encode(digest, s->state, MD5dlen);
+	if(s->malloced == 1)
+		free(s);
+	return nil;
+}
+
+/*
+ *	encodes input (u32int) into output (uchar). Assumes len is
+ *	a multiple of 4.
+ */
+static void
+encode(uchar *output, u32int *input, ulong len)
+{
+	u32int x;
+	uchar *e;
+
+	for(e = output + len; output < e;) {
+		x = *input++;
+		*output++ = x;
+		*output++ = x >> 8;
+		*output++ = x >> 16;
+		*output++ = x >> 24;
+	}
+}