1 files changed, 107 insertions, 0 deletions
diff --git a/lib/libgssapi/gss_decapsulate_token.c b/lib/libgssapi/gss_decapsulate_token.c
new file mode 100644
index 0000000..65ff46a
--- /dev/null
+++ b/lib/libgssapi/gss_decapsulate_token.c
@@ -0,0 +1,107 @@
+/*-
+ * Copyright (c) 2008 Doug Rabson
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <gssapi/gssapi.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "utils.h"
+
+OM_uint32
+gss_decapsulate_token(const gss_buffer_t input_token, gss_OID oid,
+    gss_buffer_t output_token)
+{
+	unsigned char *p = input_token->value;
+	size_t len = input_token->length;
+	size_t a, b;
+	gss_OID_desc mech_oid;
+
+	_gss_buffer_zero(output_token);
+
+	/*
+	 * Token must start with [APPLICATION 0] SEQUENCE.
+	 */
+	if (len == 0 || *p != 0x60)
+		return (GSS_S_DEFECTIVE_TOKEN);
+	p++;
+	len--;
+
+	/*
+	 * Decode the length and make sure it agrees with the
+	 * token length.
+	 */
+	if (len == 0)
+		return (GSS_S_DEFECTIVE_TOKEN);
+	if ((*p & 0x80) == 0) {
+		a = *p;
+		p++;
+		len--;
+	} else {
+		b = *p & 0x7f;
+		p++;
+		len--;
+		if (len < b)
+			return (GSS_S_DEFECTIVE_TOKEN);
+		a = 0;
+		while (b) {
+			a = (a << 8) | *p;
+			p++;
+			len--;
+			b--;
+		}
+	}
+	if (a != len)
+		return (GSS_S_DEFECTIVE_TOKEN);
+
+	/*
+	 * Decode the OID for the mechanism. Simplify life by
+	 * assuming that the OID length is less than 128 bytes.
+	 */
+	if (len < 2 || *p != 0x06)
+		return (GSS_S_DEFECTIVE_TOKEN);
+	if ((p[1] & 0x80) || p[1] > (len - 2))
+		return (GSS_S_DEFECTIVE_TOKEN);
+	mech_oid.length = p[1];
+	p += 2;
+	len -= 2;
+	mech_oid.elements = p;
+
+	if (!gss_oid_equal(&mech_oid, oid))
+		return (GSS_S_FAILURE);
+
+	p += mech_oid.length;
+	len -= mech_oid.length;
+
+	output_token->length = len;
+	output_token->value = malloc(len);
+	if (!output_token->value)
+		return (GSS_S_DEFECTIVE_TOKEN);
+	memcpy(output_token->value, p, len);
+
+	return (GSS_S_COMPLETE);
+}