add ssh-agent via factotum

7 files changed, 216 insertions, 51 deletions

diff --git a/src/cmd/auth/factotum/ctl.c b/src/cmd/auth/factotum/ctl.c
index df44b97d..85fbe5d8 100644
--- a/src/cmd/auth/factotum/ctl.c
+++ b/src/cmd/auth/factotum/ctl.c
@@ -40,6 +40,9 @@ ctlwrite(char *a)
 	Key *k;
 	Proto *proto;
 
+	while(*a == ' ' || *a == '\t' || *a == '\n')
+		a++;
+
 	if(a[0] == '#' || a[0] == '\0')
 		return 0;
 
@@ -63,7 +66,7 @@ ctlwrite(char *a)
 		*p++ = '\0';
 	switch(classify(a)){
 	default:
-		werrstr("unknown verb");
+		werrstr("unknown verb %s", a);
 		return -1;
 	case 0:	/* key */
 		attr = parseattr(p);
diff --git a/src/cmd/auth/factotum/dat.h b/src/cmd/auth/factotum/dat.h
index 11648328..678594a2 100644
--- a/src/cmd/auth/factotum/dat.h
+++ b/src/cmd/auth/factotum/dat.h
@@ -9,6 +9,8 @@ enum
 	RpcRead,
 	RpcStart,
 	RpcWrite,
+	RpcReadHex,
+	RpcWriteHex,
 
 	/* thread stack size - big buffers for printing */
 	STACK = 65536,
@@ -27,6 +29,7 @@ struct Rpc
 	int op;
 	void *data;
 	int count;
+	int hex;	/* should result of read be turned into hex? */
 };
 
 struct Conv
@@ -214,9 +217,10 @@ extern int		xiowrite(int, void*, int);
 extern int		xioasrdresp(int, void*, int);
 extern int		xioasgetticket(int, char*, char*);
 
-/* pkcs1.c */
+/* pkcs1.c - maybe should be in libsec */
 typedef DigestState *DigestAlg(uchar*, ulong, uchar*, DigestState*);
 int	rsasign(RSApriv*, DigestAlg*, uchar*, uint, uchar*, uint);
+int	rsaverify(RSApub*, DigestAlg*, uchar*, uint, uchar*, uint);
 void	mptoberjust(mpint*, uchar*, uint);
 
 
diff --git a/src/cmd/auth/factotum/dsa.c b/src/cmd/auth/factotum/dsa.c
index 73f8d296..c0d199e4 100644
--- a/src/cmd/auth/factotum/dsa.c
+++ b/src/cmd/auth/factotum/dsa.c
@@ -23,7 +23,7 @@ xdsasign(Conv *c)
 {
 	int n;
 	mpint *m;
-	uchar digest[SHA1dlen];
+	uchar digest[SHA1dlen], sigblob[20+20];
 	DSAsig *sig;
 	Key *k;
 
@@ -46,7 +46,13 @@ xdsasign(Conv *c)
 	mpfree(m);
 	if(sig == nil)
 		return -1;
-	convprint(c, "%B %B", sig->r, sig->s);
+	if(mpsignif(sig->r) > 20*8 || mpsignif(sig->s) > 20*8){
+		werrstr("signature too long");
+		return -1;
+	}
+	mptoberjust(sig->r, sigblob, 20);
+	mptoberjust(sig->s, sigblob+20, 20);
+	convwrite(c, sigblob, sizeof sigblob);
 	dsasigfree(sig);
 	return 0;
 }
@@ -80,11 +86,11 @@ readdsapriv(Key *k)
 	|| (priv->pub.q=strtomp(a, nil, 16, nil))==nil)
 		goto Error;
 	strlwr(a);
-	if((a=strfindattr(k->privattr, "alpha"))==nil 
+	if((a=strfindattr(k->attr, "alpha"))==nil 
 	|| (priv->pub.alpha=strtomp(a, nil, 16, nil))==nil)
 		goto Error;
 	strlwr(a);
-	if((a=strfindattr(k->privattr, "key"))==nil 
+	if((a=strfindattr(k->attr, "key"))==nil 
 	|| (priv->pub.key=strtomp(a, nil, 16, nil))==nil)
 		goto Error;
 	strlwr(a);
diff --git a/src/cmd/auth/factotum/fs.c b/src/cmd/auth/factotum/fs.c
index f9ad785b..88bbfd8b 100644
--- a/src/cmd/auth/factotum/fs.c
+++ b/src/cmd/auth/factotum/fs.c
@@ -166,7 +166,7 @@ static int
 keylist(int i, char *a, uint nn)
 {
 	int n;
-	char buf[512];
+	char buf[4096];
 	Key *k;
 
 	if(i >= ring.nkey)
diff --git a/src/cmd/auth/factotum/pkcs1.c b/src/cmd/auth/factotum/pkcs1.c
index fb35ce83..f3278454 100644
--- a/src/cmd/auth/factotum/pkcs1.c
+++ b/src/cmd/auth/factotum/pkcs1.c
@@ -36,7 +36,7 @@ rsasign(RSApriv *key, DigestAlg *hash, uchar *digest, uint dlen,
 	/*
 	 * Create number to sign.
 	 */
-	len = (mpsignif(key->pub.n)+7)/8;
+	len = (mpsignif(key->pub.n)+7)/8 - 1;
 	if(len < n+2){
 		werrstr("rsa key too short");
 		return -1;
@@ -65,9 +65,41 @@ rsasign(RSApriv *key, DigestAlg *hash, uchar *digest, uint dlen,
 	mpfree(m);
 	if(s == nil)
 		return -1;
-	mptoberjust(s, sig, len);
+	mptoberjust(s, sig, len+1);
 	mpfree(s);
-	return len;
+	return len+1;
+}
+
+int
+rsaverify(RSApub *key, DigestAlg *hash, uchar *digest, uint dlen,
+	uchar *sig, uint siglen)
+{
+	uchar asn1[64], xasn1[64];
+	int n, nn;
+	mpint *m, *s;
+
+	/*
+	 * Create ASN.1
+	 */
+	n = mkasn1(asn1, hash, digest, dlen);
+
+	/*
+	 * Extract plaintext of signature.
+	 */
+	s = betomp(sig, siglen, nil);
+	if(s == nil)
+		return -1;
+	m = rsaencrypt(key, s, nil);
+	mpfree(s);
+	if(m == nil)
+		return -1;
+	nn = mptobe(m, xasn1, sizeof xasn1, nil);
+	mpfree(m);
+	if(n != nn || memcmp(asn1, xasn1, n) != 0){
+		werrstr("signature did not verify");
+		return -1;
+	}
+	return 0;
 }
 
 /*
@@ -116,6 +148,15 @@ uchar oidmd5[] = { O0(1, 2), O2(840), O3(113549), 2, 5 };
  *		digestAlgorithm AlgorithmIdentifier,
  *		digest OCTET STRING
  *	}
+ *
+ * except that OpenSSL seems to sign
+ *
+ *	DigestInfo ::= SEQUENCE {
+ *		SEQUENCE{ digestAlgorithm AlgorithmIdentifier, NULL }
+ *		digest OCTET STRING
+ *	}
+ *
+ * instead.  Sigh.
  */
 static int
 mkasn1(uchar *asn1, DigestAlg *alg, uchar *d, uint dlen)
@@ -138,17 +179,25 @@ mkasn1(uchar *asn1, DigestAlg *alg, uchar *d, uint dlen)
 	*p++ = 0x30;	/* sequence */
 	p++;
 	
+	*p++ = 0x30;	/* another sequence */
+	p++;
+
 	*p++ = 0x06;	/* object id */
 	*p++ = olen;
 	memmove(p, obj, olen);
 	p += olen;
 	
+	*p++ = 0x05;	/* null */
+	*p++ = 0;
+	
+	asn1[3] = p - (asn1+4);	/* end of inner sequence */
+	
 	*p++ = 0x04;	/* octet string */
 	*p++ = dlen;
 	memmove(p, d, dlen);
 	p += dlen;
 
-	asn1[1] = p - (asn1+2);
+	asn1[1] = p - (asn1+2);	/* end of outer sequence */
 	return p-asn1;
 }
 
diff --git a/src/cmd/auth/factotum/rpc.c b/src/cmd/auth/factotum/rpc.c
index e9c163aa..8e2b17a0 100644
--- a/src/cmd/auth/factotum/rpc.c
+++ b/src/cmd/auth/factotum/rpc.c
@@ -40,6 +40,8 @@ char *rpcname[] =
 	"read",
 	"start",
 	"write",
+	"readhex",
+	"writehex",
 };
 
 static int
@@ -153,7 +155,20 @@ rpcexec(Conv *c)
 {
 	uchar *p;
 
+	c->rpc.hex = 0;
 	switch(c->rpc.op){
+	case RpcWriteHex:
+		c->rpc.op = RpcWrite;
+		if(dec16(c->rpc.data, c->rpc.count, c->rpc.data, c->rpc.count) != c->rpc.count/2){
+			rpcrespond(c, "bad hex");
+			break;
+		}
+		c->rpc.count /= 2;
+		goto Default;
+	case RpcReadHex:
+		c->rpc.hex = 1;
+		c->rpc.op = RpcRead;
+		/* fall through */
 	case RpcRead:
 		if(c->rpc.count > 0){
 			rpcrespond(c, "error read takes no parameters");
@@ -161,6 +176,7 @@ rpcexec(Conv *c)
 		}
 		/* fall through */
 	default:
+	Default:
 		if(!c->active){
 			if(c->done)
 				rpcrespond(c, "done");
@@ -224,11 +240,18 @@ void
 rpcrespondn(Conv *c, char *verb, void *data, int count)
 {
 	char *p;
+	int need, hex;
 
 	if(c->hangup)
 		return;
 
-	if(strlen(verb)+1+count > sizeof c->reply){
+	need = strlen(verb)+1+count;
+	hex = 0;
+	if(c->rpc.hex && strcmp(verb, "ok") == 0){
+		need += count;
+		hex = 1;
+	}
+	if(need > sizeof c->reply){
 		print("RPC response too large; caller %#lux", getcallerpc(&c));
 		return;
 	}
@@ -236,8 +259,14 @@ rpcrespondn(Conv *c, char *verb, void *data, int count)
 	strcpy(c->reply, verb);
 	p = c->reply + strlen(c->reply);
 	*p++ = ' ';
-	memmove(p, data, count);
-	c->nreply = count + (p - c->reply);
+	if(hex){
+		enc16(p, 2*count, data, count);
+		p += 2*count;
+	}else{
+		memmove(p, data, count);
+		p += count;
+	}
+	c->nreply = p - c->reply;
 	(*c->kickreply)(c);
 	c->rpc.op = RpcUnknown;
 }
diff --git a/src/cmd/auth/factotum/rsa.c b/src/cmd/auth/factotum/rsa.c
index 327dbc5b..34ddb784 100644
--- a/src/cmd/auth/factotum/rsa.c
+++ b/src/cmd/auth/factotum/rsa.c
@@ -4,65 +4,116 @@
 /*
  * RSA authentication.
  * 
- * Client:
+ * Encrypt/Decrypt:
  *	start n=xxx ek=xxx
  *	write msg
- *	read decrypt(msg)
+ *	read encrypt/decrypt(msg)
  *
  * Sign (PKCS #1 using hash=sha1 or hash=md5)
  *	start n=xxx ek=xxx
  *	write hash(msg)
  *	read signature(hash(msg))
  * 
+ * Verify:
+ *	start n=xxx ek=xxx
+ *	write hash(msg)
+ *	write signature(hash(msg))
+ *	read ok or fail
+ *
  * all numbers are hexadecimal biginits parsable with strtomp.
  * must be lower case for attribute matching in start.
  */
 
 static int
-rsaclient(Conv *c)
+xrsadecrypt(Conv *c)
 {
-	char *chal;
-	mpint *m;
+	char *txt, buf[4096], *role;
+	int n, ret;
+	mpint *m, *mm;
 	Key *k;
+	RSApriv *key;
+
+	ret = -1;
+	txt = nil;
+	m = nil;
+	mm = nil;
 
+	/* fetch key */
+	c->state = "keylookup";
 	k = keylookup("%A", c->attr);
 	if(k == nil)
-		return -1;
-	c->state = "read challenge";
-	if(convreadm(c, &chal) < 0){
-		keyclose(k);
-		return -1;
+		goto out;
+	key = k->priv;
+	
+	/* make sure have private half if needed */
+	role = strfindattr(c->attr, "role");
+	if(strcmp(role, "decrypt") == 0 && !key->c2){
+		werrstr("missing private half of key -- cannot decrypt");
+		goto out;
 	}
-	if(strlen(chal) < 32){
-	badchal:
-		free(chal);
-		convprint(c, "bad challenge");
-		keyclose(k);
-		return -1;
+	
+	/* read text */
+	c->state = "read";
+	if((n=convreadm(c, &txt)) < 0)
+		goto out;
+	if(n < 32){
+		convprint(c, "data too short");
+		goto out;
 	}
-	m = strtomp(chal, nil, 16, nil);
+	
+	/* encrypt/decrypt */
+	m = betomp(txt, n, nil);
 	if(m == nil)
-		goto badchal;
-	free(chal);
-	m = rsadecrypt(k->priv, m, m);
-	convprint(c, "%B", m);
+		goto out;
+	if(strcmp(role, "decrypt") == 0)
+		mm = rsadecrypt(key, m, m);
+	else
+		mm = rsaencrypt(&key->pub, m, nil);
+	if(mm == nil)
+		goto out;
+	n = mptobe(m, buf, sizeof buf, nil);
+	
+	/* send response */
+	c->state = "write";
+	convwrite(c, buf, n);
+	ret = 0;
+
+out:
 	mpfree(m);
+	mpfree(mm);
 	keyclose(k);
-	return 0;
+	free(txt);
+	return ret;
 }
 
 static int
 xrsasign(Conv *c)
 {
-	char *hash;
-	int dlen, n;
+	char *hash, *role;
+	int dlen, n, ret;
 	DigestAlg *hashfn;
 	Key *k;
+	RSApriv *key;
 	uchar sig[1024], digest[64];
+	char *sig2;
 
+	ret = -1;
+	
+	/* fetch key */
+	c->state = "keylookup";
 	k = keylookup("%A", c->attr);
 	if(k == nil)
-		return -1;
+		goto out;
+
+	/* make sure have private half if needed */
+	key = k->priv;
+	role = strfindattr(c->attr, "role");
+	if(strcmp(role, "sign") == 0 && !key->c2){
+		werrstr("missing private half of key -- cannot sign");
+		goto out;
+	}
+	
+	/* get hash type from key */
 	hash = strfindattr(k->attr, "hash");
 	if(hash == nil)
 		hash = "sha1";
@@ -74,20 +125,38 @@ xrsasign(Conv *c)
 		dlen = MD5dlen;
 	}else{
 		werrstr("unknown hash function %s", hash);
-		return -1;
+		goto out;
 	}
-	c->state = "read data";
-	if((n=convread(c, digest, dlen)) < 0){
-		keyclose(k);
-		return -1;
+
+	/* read hash */
+	c->state = "read hash";
+	if((n=convread(c, digest, dlen)) < 0)
+		goto out;
+
+	if(strcmp(role, "sign") == 0){
+		/* sign */
+		if((n=rsasign(key, hashfn, digest, dlen, sig, sizeof sig)) < 0)
+			goto out;
+
+		/* write */
+		convwrite(c, sig, n);
+	}else{
+		/* read signature */
+		if((n = convreadm(c, &sig2)) < 0)
+			goto out;
+			
+		/* verify */
+		if(rsaverify(&key->pub, hashfn, digest, dlen, (uchar*)sig2, n) == 0)
+			convprint(c, "ok");
+		else
+			convprint(c, "signature does not verify");
+		free(sig2);
 	}
-	memset(sig, 0xAA, sizeof sig);
-	n = rsasign(k->priv, hashfn, digest, dlen, sig, sizeof sig);
+	ret = 0;
+
+out:
 	keyclose(k);
-	if(n < 0)
-		return -1;	
-	convwrite(c, sig, n);
-	return 0;
+	return ret;
 }
 
 /*
@@ -119,6 +188,9 @@ readrsapriv(Key *k)
 	|| (priv->pub.n=strtomp(a, nil, 16, nil))==nil)
 		goto Error;
 	strlwr(a);
+	if(k->privattr == nil)	/* only public half */
+		return priv;
+
 	if((a=strfindattr(k->privattr, "!p"))==nil 
 	|| (priv->p=strtomp(a, nil, 16, nil))==nil)
 		goto Error;
@@ -177,8 +249,10 @@ rsaclose(Key *k)
 static Role
 rsaroles[] = 
 {
-	"client",	rsaclient,
 	"sign",	xrsasign,
+	"verify",	xrsasign,	/* public operation */
+	"decrypt",	xrsadecrypt,
+	"encrypt",	xrsadecrypt,	/* public operation */
 	0
 };