From ef27c0cca3ad4f65005f669c6fd98e1e9e57cfb3 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sun, 17 Dec 1995 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1995-12-17

---
 port/devssl.c  | 414 +++++++++++++++++++++++--------------------------
 port/portfns.h |   1 +
 port/qio.c     |  51 ++++++
 3 files changed, 245 insertions(+), 221 deletions(-)

diff --git a/port/devssl.c b/port/devssl.c
index 98ce6247c8fcffbebd07a569d0dfeccf179f811c..a89a8d895ce9278f8edae020c7d802f2d1539ea5 100644
--- a/port/devssl.c
+++ b/port/devssl.c
@@ -49,7 +49,7 @@ struct Dstate
 	DigestState *(*hf)(uchar*, ulong, uchar*, DigestState*);	/* hash func */
 
 	int	max;		/* maximum unpadded data per msg */
-	int	maxpad;	/* maximum padded data per msg */
+	int	maxpad;		/* maximum padded data per msg */
 
 	/* input side */
 	OneWay	in;
@@ -86,6 +86,17 @@ Randq randq;
 
 void producerand(void);
 
+static void	ensure(Dstate*, Block**, int);
+static void	consume(Block**, uchar*, int);
+static void	setsecret(OneWay*, uchar*, int);
+static Block*	encryptb(Dstate*, Block*, int);
+static Block*	decryptb(Dstate*, Block*);
+static Block*	digestb(Dstate*, Block*, int);
+static void	checkdigestb(Dstate*, Block*);
+static Chan*	buftochan(char*, long);
+static void	dighangup(Dstate*);
+
+
 void
 sslreset(void)
 {
@@ -203,24 +214,83 @@ sslread(Chan *c, void *a, long n, ulong offset)
 	return n;
 }
 
-static void
-setsecret(OneWay *w, uchar *secret, int n)
+Block*
+sslbread(Chan *c, long n, ulong offset)
 {
-	w->secret = smalloc(n);
-	memmove(w->secret, secret, n);
-	w->slen = n;
-	w->mid = 0;
+	Block *bp, **l;
+	uchar count[2];
+	int len;
+	int pad;
 
-	switch(s->encryptalg){
-	case DESCBC:
-		w->state = smalloc(sizeof(DESstate));
-		setupDESstate(w->state, secret, 0);
-		break;
-	case DESCBC:
-		w->state = smalloc(sizeof(DESstate));
-		setupDESstate(w->state, secret, secret+8);
-		break;
+	USED(offset);
+
+	s = c->aux;
+	if(s == 0 || s->state != Established)
+		error(Ebadusefd);
+
+	if(waserror()){
+		qunlock(&s->in);
+		dighangup(s);
+		nexterror();
+	}
+	qlock(&s->in);
+
+	if(s->processed == 0){
+	
+		/* read in the whole message */
+		s->processed = s->unprocessed;
+		s->unprocessed =- 0;
+		ensure(s, &s->processed, 2);
+		consume(&s->processed, count, 2);
+		if(count[0] & 0x80){
+			len = ((count[0] & 0x7f)<<8) | count[1];
+			pad = 0;
+		} else {
+			len = ((count[0] & 0x3f)<<8) | count[1];
+			ensure(s, &s->processed, 1);
+			consume(&s->processed, count, 1);
+			pad = count[0];
+		}
+		ensure(s, &s->processed, len);
+
+		/* trade memory bandwidth for less processing complexity */
+		b = s->processed = pullupblock(s->processed, len);
+
+		/* put remainder on unprocessed queue */
+		i = BLEN(b);
+		if(i > len){
+			i -= len;
+			s->unprocessed = allocb(i);
+			memmove(s->unprocessed->wp, b->rp+len, i);
+			s->unprocessed->wp += i;
+			b->wp -= i;
+		}
+
+		if(s->encrypalg)
+			b = decryptb(s, b);
+		else
+			checkdigestb(s, b);
+
+		/* remove pad */
+		if(b->wp - b->rp > pad)
+			panic("sslbread");
+		b->wp -= pad;
+		s->processed = b;
 	}
+
+	b = s->processed;
+	if(BLEN(b) > n){
+		b = allocb(n);
+		memmove(b->wp, s->processed->rp, n);
+		b->wp += n;
+		s->processed->rp += n;
+	} else 
+		s->processed = b->next;
+
+	qunlock(&s->in);
+	poperror();
+
+	return b;
 }
 
 long
@@ -326,6 +396,7 @@ sslbwrite(Chan *c, Block *b, ulong offset)
 	Dstate *s;
 	Block *nb;
 	int h, n, m, pad, rv;
+	uchar *p;
 
 	s = c->aux;
 	if(s == 0 || s->state != Established)
@@ -379,19 +450,26 @@ sslbwrite(Chan *c, Block *b, ulong offset)
 		m += s->diglen;
 
 		/* SSL style count */
+		p = np->rp;
 		if(pad){
 			memset(nb->wp, 0, pad);
 			m += pad;
 			nb->wp += pad;
-		} else
+			p[0] = (m>>8);
+			p[1] = m;
+			p[2] = pad;
+			offset = 3;
+		} else {
 			m |= 0x8000;
-		np->rp[0] = (m>>8);
-		np->rp[1] = m;
+			p[0] = (m>>8);
+			p[1] = m;
+			offset = 2;
+		}
 
 		if(encryptalg)
-			encryptb(s, nb);
+			nb = encryptb(s, nb, offset);
 		else
-			digestb(s, nb);
+			nb = digestb(s, nb, ofsetf);
 
 		(*devtab[s->c->type].bwrite)(s->c, nb, offset);
 
@@ -402,113 +480,6 @@ sslbwrite(Chan *c, Block *b, ulong offset)
 	return rv;
 }
 
-Block*
-sslbread(Chan *c, long n, ulong offset)
-{
-	Block *bp, **l;
-	uchar count[2];
-	int len;
-	int pad;
-
-	USED(offset);
-
-	s = c->aux;
-	if(s == 0 || s->state != Established)
-		error(Ebadusefd);
-
-	if(waserror()){
-		qunlock(&s->in);
-		dighangup(s);
-		nexterror();
-	}
-	qlock(&s->in);
-
-	if(s->processed == 0){
-	
-		/* read in the whole message */
-		s->processed = s->unprocessed;
-		s->unprocessed =- 0;
-		ensure(s, &s->processed, 2);
-		consume(&s->processed, count, 2);
-		if(count[0] & 0x80){
-			len = ((count[0] & 0x7f)<<8) | count[1];
-			pad = 0;
-		} else {
-			len = ((count[0] & 0x3f)<<8) | count[1];
-			ensure(s, &s->processed, 1);
-			consume(&s->processed, count, 1);
-			pad = count[0];
-		}
-		ensure(s, &s->processed, len);
-
-		/* put remainder on unprocessed */
-		i = 0;
-		for(b = s->processed; b; b = b->next){
-			i = BLEN(b);
-			if(i >= len)
-				break;
-			(*s->func)(b->rp, i, 0, &ss);
-			len -= i;
-		}
-		if(b == 0)
-			panic("digestbread");
-		if(i > len){
-			i -= len;
-			s->unprocessed = allocb(i);
-			memmove(s->unprocessed->wp, b->rp+len, i);
-			s->unprocessed->wp += i;
-			b->wp -= i;
-		}
-			
-		if(s->encrypalg)
-			decryptb(s, len);
-		else
-			checkdigestb(s, len);
-
-		if(pad){
-			for(b = s->processed; b; b = b->next){
-	}
-
-	b = s->processed;
-	if(BLEN(b) > n){
-		b = allocb(n);
-		memmove(b->wp, s->processed->rp, n);
-		b->wp += n;
-		s->processed->rp += n;
-	} else 
-		s->processed = b->next;
-
-	qunlock(&s->in);
-	poperror();
-
-	return b;
-}
-
-Block*
-decryptb(Dstate *s, Block *b, int len)
-{
-	ulong n, h;
-	uchar *p, *ep;
-	DESstate *ds;
-
-	h = s->diglen + 2;
-
-	switch(s->encryptalg){
-	case DESEBC:
-		ds = s->in.state;
-		ep = b->rp + BLEN(b);
-		for(p = b->rp + h; p < ep; p += 8)
-			block_cipher(ds->expanded, p, 1);
-		break;
-	case DESCBC:
-		ds = s->in.state;
-		ep = b->rp + BLEN(b);
-		for(p = b->rp + h; p < ep; p += 8)
-			bCBCDecrypt(p, ds->ivec, ds->expanded, 8);
-		break;
-	}
-}
-
 /*
  *  make sure we have at least 'n' bytes in list 'l'
  */
@@ -566,86 +537,78 @@ consume(Block **l, uchar *p, int n)
 	}
 }
 
-static Block*
-digestbread(Dstate *s, long n)
+static void
+setsecret(OneWay *w, uchar *secret, int n)
 {
-	Block *b;
-	int i, m, len;
-	uchar *p;
-	uchar *dp;
-	uchar digestin[32];
-	uchar digest[32];
-	DigestState ss;
-
-	memset(&ss, 0, sizeof(ss));
+	w->secret = smalloc(n);
+	memmove(w->secret, secret, n);
+	w->slen = n;
+	w->mid = 0;
 
-	ensure(s, &s->unprocessed, s->diglen);
-		len = 0;
-		for(i = 0; i < 4; i++){
-			consume(&s->unprocessed, digestin+i, 1);
-			m = digestin[i];
-			if((m & 0x80) == 0)
-				break;
-			len = (len<<7) | (m & 0x7f);
-		}
-	
-		/* digest count */
-		p = &digestin[s->diglen];
-		(*s->func)(p, i, 0, &ss);
-		ensure(s, &s->unprocessed, s->diglen);
+	switch(s->encryptalg){
+	case DESCBC:
+		w->state = smalloc(sizeof(DESstate));
+		setupDESstate(w->state, secret, 0);
+		break;
+	case DESCBC:
+		w->state = smalloc(sizeof(DESstate));
+		setupDESstate(w->state, secret, secret+8);
+		break;
+	}
+}
 
-		/* get message */
-		s->processed = s->unprocessed;
-		s->unprocessed = 0;
-		ensure(s, &s->processed, len);
+static Block*
+encryptb(Dstate *s, Block *b, int offset)
+{
+	ulong n;
+	int j;
+	uchar *p, *ep;
+	DESstate *ds;
 
-		/* digest message */
-		i = 0;
-		for(b = s->processed; b; b = b->next){
-			i = BLEN(b);
-			if(i >= len)
-				break;
-			(*s->func)(b->rp, i, 0, &ss);
-			len -= i;
-		}
-		if(b == 0)
-			panic("digestbread");
-		if(i > len){
-			i -= len;
-			s->unprocessed = allocb(i);
-			memmove(s->unprocessed->wp, b->rp+len, i);
-			s->unprocessed->wp += i;
-			b->wp -= i;
-		}
-		(*s->func)(b->rp, len, 0, &ss);
-
-		/* digest secret & message id */
-		p = s->in.secret;
-		m = s->in.mid++;
-		*p++ = m>>24;
-		*p++ = m>>16;
-		*p++ = m>>8;
-		*p = m;
-		(*s->func)(s->in.secret, s->in.slen, digest, &ss);
-
-		if(memcmp(digest, digestin, s->diglen) != 0)
-			error("bad digest");
+	switch(s->encryptalg){
+	case DESEBC:
+		ds = s->out.state;
+		ep = b->rp + BLEN(b);
+		for(p = b->rp + offset; p < ep; p += 8)
+			block_cipher(ds->expanded, p, 0);
+		break;
+	case DESCBC:
+		ds = s->out.state;
+		ep = b->rp + BLEN(b);
+		for(p = b->rp + offset; p < ep; p += 8)
+			bCBCEncrypt(p, ds->ivec, ds->expanded, 8);
+		break;
 	}
+	return b;
+}
 
-	b = s->processed;
-	if(BLEN(b) > n){
-		b = allocb(n);
-		memmove(b->wp, s->processed->rp, n);
-		b->wp += n;
-		s->processed->rp += n;
-	} else 
-		s->processed = b->next;
+static Block*
+decryptb(Dstate *s, Block *b)
+{
+	ulong n, h;
+	int j;
+	uchar *p, *ep;
+	DESstate *ds;
 
+	switch(s->encryptalg){
+	case DESEBC:
+		ds = s->out.state;
+		ep = b->rp + BLEN(b);
+		for(p = b->rp + s->diglen; p < ep; p += 8)
+			block_cipher(ds->expanded, p, 1);
+		break;
+	case DESCBC:
+		ds = s->out.state;
+		ep = b->rp + BLEN(b);
+		for(p = b->rp + s->diglen; p < ep; p += 8)
+			bCBCDecrypt(p, ds->ivec, ds->expanded, 8);
+		break;
+	}
 	return b;
 }
 
-void
-digestb(Dstate *s, Block *b)
+static Block*
+digestb(Dstate *s, Block *b, int offset)
 {
 	Block *nb;
 	uchar *p;
@@ -657,7 +620,7 @@ digestb(Dstate *s, Block *b)
 	w = &s->out;
 
 	memset(&ss, 0, sizeof(ss));
-	h = s->diglen + 2;
+	h = s->diglen + offset;
 	n = BLEN(b) - h;
 
 	/* hash secret + message */
@@ -671,34 +634,43 @@ digestb(Dstate *s, Block *b)
 	*p++ = n>>16;
 	*p++ = n>>8;
 	*p = n;
-	(*s->func)(msgid, 4, nb->rp + 2, &ss);
+	(*s->func)(msgid, 4, nb->rp+offset, &ss);
+
+	retrn b;
 }
 
-long
-encryptb(Dstate *s, Block *b)
+static void
+checkdigestb(Dstate *s, Block *b)
 {
+	Block *nb;
+	uchar *p;
+	DigestState ss;
+	uchar msgid[4];
 	ulong n, h;
-	int j;
-	uchar *p, *ep, *ip;
-	DESstate *ds;
+	OneWay *w;
+	uchar digest[128];
 
-	h = s->diglen + 2;
+	w = &s->in;
 
-	switch(s->encryptalg){
-	case DESEBC:
-		ds = s->out.state;
-		ep = b->rp + BLEN(b);
-		for(p = b->rp + h; p < ep; p += 8)
-			block_cipher(ds->expanded, p, 0);
-		break;
-	case DESCBC:
-		ds = s->out.state;
-		ep = b->rp + BLEN(b);
-		for(p = b->rp + h; p < ep; p += 8)
-			bCBCEncrypt(p, ds->ivec, ds->expanded, 8);
-		break;
-	}
-	
+	memset(&ss, 0, sizeof(ss));
+	h = s->diglen;
+	n = BLEN(b) - h;
+
+	/* hash secret + message */
+	(*s->hf)(w->secret, w->slen, 0, &ss);
+	(*s->hf)(nb->rp + h, n, 0, &ss);
+
+	/* hash message id */
+	p = msgid;
+	n = w->mid++;
+	*p++ = n>>24;
+	*p++ = n>>16;
+	*p++ = n>>8;
+	*p = n;
+	(*s->func)(msgid, 4, digest, &ss);
+
+	if(memcmp(digest, nb->rp, s->diglen) != 0)
+		error("bad digest");
 }
 
 /* get channel associated with an fd */
diff --git a/port/portfns.h b/port/portfns.h
index 5ab08f43963fb066b5388538a90fe3bc5f52603c..fc9124387134d919eadb7a11c9a65527ec748cf9 100644
--- a/port/portfns.h
+++ b/port/portfns.h
@@ -189,6 +189,7 @@ Pte*		ptealloc(void);
 Pte*		ptecpy(Pte*);
 Path*		ptenter(Pthash*, Path*, char*);
 int		ptpath(Path*, char*, int);
+Block*		pullupblock(Block*, int);
 void		putimage(Image*);
 void		putmmu(ulong, ulong, Page*);
 void		putpage(Page*);
diff --git a/port/qio.c b/port/qio.c
index 2c3684a841b27a4bb551392002791d571e5fe589..71650e8f5be66dbe2a3b588c566831e104bab9df 100644
--- a/port/qio.c
+++ b/port/qio.c
@@ -773,3 +773,54 @@ qstate(Queue *q)
 {
 	return q->state;
 }
+
+/*
+ *  make sure the first block has at least n bytes
+ */
+Block*
+pullupblock(Block *bp, int n)
+{
+	int i;
+	Block *nbp;
+
+	/*
+	 *  this should almost always be true, the rest it
+	 *  just to avoid every caller checking.
+	 */
+	if(BLEN(bp) >= n)
+		return bp;
+
+	/*
+	 *  if not enough room in the first block,
+	 *  add another to the front of the list.
+	 */
+	if(bp->lim - bp->rp < n){
+		nbp = allocb(n);
+		nbp->next = bp;
+		bp = nbp;
+	}
+
+	/*
+	 *  copy bytes from the trailing blocks into the first
+	 */
+	n -= BLEN(bp);
+	while(nbp = bp->next){
+		i = BLEN(nbp);
+		if(i >= n) {
+			memmove(bp->wp, nbp->rp, n);
+			bp->wp += n;
+			nbp->rp += n;
+			return bp;
+		}
+		else {
+			memmove(bp->wp, nbp->rp, i);
+			bp->wp += i;
+			bp->next = nbp->next;
+			nbp->next = 0;
+			freeb(nbp);
+			n -= i;
+		}
+	}
+	freeb(bp);
+	return 0;
+}