1 files changed, 140 insertions, 0 deletions
diff --git a/src/cmd/auth/factotum/dsa.c b/src/cmd/auth/factotum/dsa.c
new file mode 100644
index 00000000..73f8d296
--- /dev/null
+++ b/src/cmd/auth/factotum/dsa.c
@@ -0,0 +1,140 @@
+#include "std.h"
+#include "dat.h"
+
+/*
+ * DSA signing and verification
+ * 
+ * Sign:
+ *	start p=xxx q=xxx alpha=xxx key=xxx
+ *	write msg
+ *	read signature(msg)
+ *
+ * Verify: (not implemented)
+ *	start p=xxx q=xxx alpha=xxx key=xxx
+ *	write msg
+ *	write signature(msg)
+ *	read ok or fail
+ * 
+ * all numbers are hexadecimal bigints parsable with strtomp.
+ */
+ 
+static int
+xdsasign(Conv *c)
+{
+	int n;
+	mpint *m;
+	uchar digest[SHA1dlen];
+	DSAsig *sig;
+	Key *k;
+
+	k = keylookup("%A", c->attr);
+	if(k == nil)
+		return -1;
+
+	c->state = "read data";
+	if((n=convread(c, digest, SHA1dlen)) < 0){
+		keyclose(k);
+		return -1;
+	}
+	m = betomp(digest, SHA1dlen, nil);
+	if(m == nil){
+		keyclose(k);
+		return -1;
+	}
+	sig = dsasign(k->priv, m);
+	keyclose(k);
+	mpfree(m);
+	if(sig == nil)
+		return -1;
+	convprint(c, "%B %B", sig->r, sig->s);
+	dsasigfree(sig);
+	return 0;
+}
+
+/*
+ * convert to canonical form (lower case) 
+ * for use in attribute matches.
+ */
+static void
+strlwr(char *a)
+{
+	for(; *a; a++){
+		if('A' <= *a && *a <= 'Z')
+			*a += 'a' - 'A';
+	}
+}
+
+static DSApriv*
+readdsapriv(Key *k)
+{
+	char *a;
+	DSApriv *priv;
+
+	priv = dsaprivalloc();
+
+	if((a=strfindattr(k->attr, "p"))==nil 
+	|| (priv->pub.p=strtomp(a, nil, 16, nil))==nil)
+		goto Error;
+	strlwr(a);
+	if((a=strfindattr(k->attr, "q"))==nil 
+	|| (priv->pub.q=strtomp(a, nil, 16, nil))==nil)
+		goto Error;
+	strlwr(a);
+	if((a=strfindattr(k->privattr, "alpha"))==nil 
+	|| (priv->pub.alpha=strtomp(a, nil, 16, nil))==nil)
+		goto Error;
+	strlwr(a);
+	if((a=strfindattr(k->privattr, "key"))==nil 
+	|| (priv->pub.key=strtomp(a, nil, 16, nil))==nil)
+		goto Error;
+	strlwr(a);
+	if((a=strfindattr(k->privattr, "!secret"))==nil 
+	|| (priv->secret=strtomp(a, nil, 16, nil))==nil)
+		goto Error;
+	strlwr(a);
+	return priv;
+
+Error:
+	dsaprivfree(priv);
+	return nil;
+}
+
+static int
+dsacheck(Key *k)
+{
+	static int first = 1;
+	
+	if(first){
+		fmtinstall('B', mpfmt);
+		first = 0;
+	}
+
+	if((k->priv = readdsapriv(k)) == nil){
+		werrstr("malformed key data");
+		return -1;
+	}
+	return 0;
+}
+
+static void
+dsaclose(Key *k)
+{
+	dsaprivfree(k->priv);
+	k->priv = nil;
+}
+
+static Role
+dsaroles[] = 
+{
+	"sign",	xdsasign,
+	0
+};
+
+Proto dsa = {
+	"dsa",
+	dsaroles,
+	nil,
+	dsacheck,
+	dsaclose
+};
+