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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
* 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 "gssapiP_generic.h"
#ifdef HAVE_MEMORY_H
#include <memory.h>
#endif
#include <limits.h>
/*
* $Id$
*/
/* 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. */
/*
* 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 unsigned int
der_length_size(int 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, int 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, int *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 */
unsigned int
g_token_size(const gss_OID_desc * mech, unsigned int body_size)
{
/* set body_size to sequence contents size */
body_size += 4 + (unsigned int)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
g_make_token_header(
const gss_OID_desc * mech,
unsigned int body_size,
unsigned char **buf,
int tok_type)
{
*(*buf)++ = 0x60;
der_write_length(buf, ((tok_type == -1) ? 2 : 4) + mech->length + body_size);
*(*buf)++ = 0x06;
*(*buf)++ = (unsigned char) mech->length;
TWRITE_STR(*buf, mech->elements, mech->length);
if (tok_type != -1) {
*(*buf)++ = (unsigned char) ((tok_type>>8)&0xff);
*(*buf)++ = (unsigned char) (tok_type&0xff);
}
}
/*
* 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.
*/
gss_int32
g_verify_token_header(
const gss_OID_desc * mech,
unsigned int *body_size,
unsigned char **buf_in,
int tok_type,
unsigned int toksize_in,
int flags)
{
unsigned char *buf = *buf_in;
int seqsize;
gss_OID_desc toid;
int toksize = toksize_in;
if ((toksize-=1) < 0)
return(G_BAD_TOK_HEADER);
if (*buf++ != 0x60) {
if (flags & G_VFY_TOKEN_HDR_WRAPPER_REQUIRED)
return(G_BAD_TOK_HEADER);
buf--;
toksize++;
goto skip_wrapper;
}
if ((seqsize = der_read_length(&buf, &toksize)) < 0)
return(G_BAD_TOK_HEADER);
if (seqsize != toksize)
return(G_BAD_TOK_HEADER);
if ((toksize-=1) < 0)
return(G_BAD_TOK_HEADER);
if (*buf++ != 0x06)
return(G_BAD_TOK_HEADER);
if ((toksize-=1) < 0)
return(G_BAD_TOK_HEADER);
toid.length = *buf++;
if ((toksize-=toid.length) < 0)
return(G_BAD_TOK_HEADER);
toid.elements = buf;
buf+=toid.length;
if (! g_OID_equal(&toid, mech))
return G_WRONG_MECH;
skip_wrapper:
if (tok_type != -1) {
if ((toksize-=2) < 0)
return(G_BAD_TOK_HEADER);
if ((*buf++ != ((tok_type>>8)&0xff)) ||
(*buf++ != (tok_type&0xff)))
return(G_WRONG_TOKID);
}
*buf_in = buf;
*body_size = toksize;
return 0;
}
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