--- /dev/null
+/*
+ * Copyright 1993 by OpenVision Technologies, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without fee,
+ * provided that the above copyright notice appears in all copies and
+ * that both that copyright notice and this permission notice appear in
+ * supporting documentation, and that the name of OpenVision not be used
+ * in advertising or publicity pertaining to distribution of the software
+ * without specific, written prior permission. OpenVision makes no
+ * representations about the suitability of this software for any
+ * purpose. It is provided "as is" without express or implied warranty.
+ *
+ * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
+ * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <string.h>
+#include <gssapi/gssapi.h>
+
+/*
+ * $Id: util_token.c 23457 2009-12-08 00:04:48Z tlyu $
+ */
+
+/* XXXX this code currently makes the assumption that a mech oid will
+ never be longer than 127 bytes. This assumption is not inherent in
+ the interfaces, so the code can be fixed if the OSI namespace
+ balloons unexpectedly. */
+
+#define g_OID_equal(o1, o2) \
+ (((o1)->length == (o2)->length) && \
+ (memcmp((o1)->elements, (o2)->elements, (o1)->length) == 0))
+
+/*
+ * Each token looks like this:
+ * 0x60 tag for APPLICATION 0, SEQUENCE
+ * (constructed, definite-length)
+ * <length> possible multiple bytes, need to parse/generate
+ * 0x06 tag for OBJECT IDENTIFIER
+ * <moid_length> compile-time constant string (assume 1 byte)
+ * <moid_bytes> compile-time constant string
+ * <inner_bytes> the ANY containing the application token
+ * bytes 0,1 are the token type
+ * bytes 2,n are the token data
+ *
+ * Note that the token type field is a feature of RFC 1964 mechanisms and
+ * is not used by other GSSAPI mechanisms. As such, a token type of -1
+ * is interpreted to mean that no token type should be expected or
+ * generated.
+ *
+ * For the purposes of this abstraction, the token "header" consists of
+ * the sequence tag and length octets, the mech OID DER encoding, and the
+ * first two inner bytes, which indicate the token type. The token
+ * "body" consists of everything else.
+ */
+
+static size_t
+der_length_size(size_t length)
+{
+ if (length < (1<<7))
+ return 1;
+ else if (length < (1<<8))
+ return 2;
+#if INT_MAX == 0x7fff
+ else
+ return 3;
+#else
+ else if (length < (1<<16))
+ return 3;
+ else if (length < (1<<24))
+ return 4;
+ else
+ return 5;
+#endif
+}
+
+static void
+der_write_length(unsigned char **buf, size_t length)
+{
+ if (length < (1<<7)) {
+ *(*buf)++ = (unsigned char)length;
+ } else {
+ *(*buf)++ = (unsigned char)(der_length_size(length)+127);
+#if INT_MAX > 0x7fff
+ if (length >= (1<<24))
+ *(*buf)++ = (unsigned char)(length>>24);
+ if (length >= (1<<16))
+ *(*buf)++ = (unsigned char)((length>>16)&0xff);
+#endif
+ if (length >= (1<<8))
+ *(*buf)++ = (unsigned char)((length>>8)&0xff);
+ *(*buf)++ = (unsigned char)(length&0xff);
+ }
+}
+
+/* returns decoded length, or < 0 on failure. Advances buf and
+ decrements bufsize */
+
+static int
+der_read_length(unsigned char **buf, ssize_t *bufsize)
+{
+ unsigned char sf;
+ int ret;
+
+ if (*bufsize < 1)
+ return -1;
+
+ sf = *(*buf)++;
+ (*bufsize)--;
+ if (sf & 0x80) {
+ if ((sf &= 0x7f) > ((*bufsize)-1))
+ return -1;
+ if (sf > sizeof(int))
+ return -1;
+ ret = 0;
+ for (; sf; sf--) {
+ ret = (ret<<8) + (*(*buf)++);
+ (*bufsize)--;
+ }
+ } else {
+ ret = sf;
+ }
+
+ return ret;
+}
+
+/* returns the length of a token, given the mech oid and the body size */
+
+size_t
+gs2_token_size(const gss_OID_desc *mech, size_t body_size)
+{
+ /* set body_size to sequence contents size */
+ body_size += 4 + (size_t) mech->length; /* NEED overflow check */
+ return 1 + der_length_size(body_size) + body_size;
+}
+
+/* fills in a buffer with the token header. The buffer is assumed to
+ be the right size. buf is advanced past the token header */
+
+void
+gs2_make_token_header(
+ const gss_OID_desc *mech,
+ size_t body_size,
+ unsigned char **buf)
+{
+ *(*buf)++ = 0x60;
+ der_write_length(buf, 2 + mech->length + body_size);
+ *(*buf)++ = 0x06;
+ *(*buf)++ = (unsigned char)mech->length;
+ memcpy(*buf, mech->elements, mech->length);
+ *buf += mech->length;
+}
+
+/*
+ * Given a buffer containing a token, reads and verifies the token,
+ * leaving buf advanced past the token header, and setting body_size
+ * to the number of remaining bytes. Returns 0 on success,
+ * G_BAD_TOK_HEADER for a variety of errors, and G_WRONG_MECH if the
+ * mechanism in the token does not match the mech argument. buf and
+ * *body_size are left unmodified on error.
+ */
+
+OM_uint32
+gs2_verify_token_header(OM_uint32 *minor,
+ gss_OID mech,
+ size_t *body_size,
+ unsigned char **buf_in,
+ size_t toksize_in)
+{
+ unsigned char *buf = *buf_in;
+ ssize_t seqsize;
+ gss_OID_desc toid;
+ ssize_t toksize = (ssize_t)toksize_in;
+
+ *minor = 0;
+
+ if ((toksize -= 1) < 0)
+ return GSS_S_DEFECTIVE_TOKEN;
+
+ if (*buf++ != 0x60)
+ return GSS_S_DEFECTIVE_TOKEN;
+
+ seqsize = der_read_length(&buf, &toksize);
+ if (seqsize < 0)
+ return GSS_S_DEFECTIVE_TOKEN;
+
+ if (seqsize != toksize)
+ return GSS_S_DEFECTIVE_TOKEN;
+
+ if ((toksize -= 1) < 0)
+ return GSS_S_DEFECTIVE_TOKEN;
+
+ if (*buf++ != 0x06)
+ return GSS_S_DEFECTIVE_TOKEN;
+
+ if ((toksize -= 1) < 0)
+ return GSS_S_DEFECTIVE_TOKEN;
+
+ toid.length = *buf++;
+
+ if ((toksize -= toid.length) < 0)
+ return GSS_S_DEFECTIVE_TOKEN;
+
+ toid.elements = buf;
+ buf += toid.length;
+
+ if (mech->elements == NULL) {
+ *mech = toid;
+ if (toid.length == 0)
+ return GSS_S_BAD_MECH;
+ } else if (!g_OID_equal(&toid, mech)) {
+ return GSS_S_BAD_MECH;
+ }
+
+ *buf_in = buf;
+ *body_size = toksize;
+
+ return GSS_S_COMPLETE;
+}
projects / cyrus-sasl.git / commitdiff