new

src/cmd/auth/factotum/httpdigest.c

@@ -0,0 +1,119 @@
+/*
+ * HTTPDIGEST - MD5 challenge/response authentication (RFC 2617)
+ *
+ * Client protocol:
+ *	write challenge: nonce method uri 
+ *	read response: 2*MD5dlen hex digits
+ *
+ * Server protocol:
+ *	unimplemented
+ */
+#include "std.h"
+#include "dat.h"
+
+static void
+digest(char *user, char *realm, char *passwd,
+	char *nonce, char *method, char *uri,
+	char *dig);
+
+static int
+hdclient(Conv *c)
+{
+	char *realm, *passwd, *user, *f[4], *s, resp[MD5dlen*2+1];
+	int ret;
+	Key *k;
+	
+	ret = -1;
+	s = nil;
+	
+	c->state = "keylookup";
+	k = keyfetch(c, "%A", c->attr);
+	if(k == nil)
+		goto out;
+
+	user = strfindattr(k->attr, "user");
+	realm = strfindattr(k->attr, "realm");
+	passwd = strfindattr(k->attr, "!password");
+
+	if(convreadm(c, &s) < 0)
+		goto out;
+	if(tokenize(s, f, 4) != 3){
+		werrstr("bad challenge -- want nonce method uri");
+		goto out;
+	}
+
+	digest(user, realm, passwd, f[0], f[1], f[2], resp);
+	convwrite(c, resp, strlen(resp));
+	ret = 0;
+	
+out:
+	free(s);
+	keyclose(k);
+	return ret;
+}
+
+static void
+strtolower(char *s)
+{
+	while(*s){
+		*s = tolower(*s);
+		s++;
+	}
+}
+
+static void
+digest(char *user, char *realm, char *passwd,
+	char *nonce, char *method, char *uri,
+	char *dig)
+{
+	uchar b[MD5dlen];
+	char ha1[MD5dlen*2+1];
+	char ha2[MD5dlen*2+1];
+	DigestState *s;
+
+	/*
+	 *  H(A1) = MD5(uid + ":" + realm ":" + passwd)
+	 */
+	s = md5((uchar*)user, strlen(user), nil, nil);
+	md5((uchar*)":", 1, nil, s);
+	md5((uchar*)realm, strlen(realm), nil, s);
+	md5((uchar*)":", 1, nil, s);
+	md5((uchar*)passwd, strlen(passwd), b, s);
+	enc16(ha1, sizeof(ha1), b, MD5dlen);
+	strtolower(ha1);
+
+	/*
+	 *  H(A2) = MD5(method + ":" + uri)
+	 */
+	s = md5((uchar*)method, strlen(method), nil, nil);
+	md5((uchar*)":", 1, nil, s);
+	md5((uchar*)uri, strlen(uri), b, s);
+	enc16(ha2, sizeof(ha2), b, MD5dlen);
+	strtolower(ha2);
+
+	/*
+	 *  digest = MD5(H(A1) + ":" + nonce + ":" + H(A2))
+	 */
+	s = md5((uchar*)ha1, MD5dlen*2, nil, nil);
+	md5((uchar*)":", 1, nil, s);
+	md5((uchar*)nonce, strlen(nonce), nil, s);
+	md5((uchar*)":", 1, nil, s);
+	md5((uchar*)ha2, MD5dlen*2, b, s);
+	enc16(dig, MD5dlen*2+1, b, MD5dlen);
+	strtolower(dig);
+}
+
+static Role hdroles[] = 
+{
+	"client",	hdclient,
+	0
+};
+
+Proto httpdigest =
+{
+	"httpdigest",
+	hdroles,
+	"user? realm? !password?",
+	nil,
+	nil
+};