net/sunrpc/auth_gss/gss_spkm3_token.c - maze/linux - Git at Google

 /*
  *  linux/net/sunrpc/gss_spkm3_token.c
  *
  *  Copyright (c) 2003 The Regents of the University of Michigan.
  *  All rights reserved.
  *
  *  Andy Adamson <andros@umich.edu>
  *
  *  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.
  *  3. Neither the name of the University nor the names of its
  *     contributors may be used to endorse or promote products derived
  *     from this software without specific prior written permission.
  *
  *  THIS SOFTWARE IS PROVIDED ``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 REGENTS 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.
  *
  */

 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/jiffies.h>
 #include <linux/sunrpc/gss_spkm3.h>
 #include <linux/random.h>
 #include <linux/crypto.h>

 #ifdef RPC_DEBUG
 # define RPCDBG_FACILITY        RPCDBG_AUTH
 #endif

 /*
  * asn1_bitstring_len()
  *
  * calculate the asn1 bitstring length of the xdr_netobject
  */
 void
 asn1_bitstring_len(struct xdr_netobj *in, int *enclen, int *zerobits)
 {
 	int i, zbit = 0,elen = in->len;
 	char *ptr;

 	ptr = &in->data[in->len -1];

 	/* count trailing 0's */
 	for(i = in->len; i > 0; i--) {
 		if (*ptr == 0) {
 			ptr--;
 			elen--;
 		} else
 			break;
 	}

 	/* count number of 0 bits in final octet */
 	ptr = &in->data[elen - 1];
 	for(i = 0; i < 8; i++) {
 		short mask = 0x01;

 		if (!((mask << i) & *ptr))
 			zbit++;
 		else
 			break;
 	}
 	*enclen = elen;
 	*zerobits = zbit;
 }

 /*
  * decode_asn1_bitstring()
  *
  * decode a bitstring into a buffer of the expected length.
  * enclen = bit string length
  * explen = expected length (define in rfc)
  */
 int
 decode_asn1_bitstring(struct xdr_netobj *out, char *in, int enclen, int explen)
 {
 	if (!(out->data = kzalloc(explen,GFP_KERNEL)))
 		return 0;
 	out->len = explen;
 	memcpy(out->data, in, enclen);
 	return 1;
 }

 /*
  * SPKMInnerContextToken choice SPKM_MIC asn1 token layout
  *
  * contextid is always 16 bytes plain data. max asn1 bitstring len = 17.
  *
  * tokenlen = pos[0] to end of token (max pos[45] with MD5 cksum)
  *
  * pos  value
  * ----------
  * [0]	a4  SPKM-MIC tag
  * [1]	??  innertoken length  (max 44)
  *
  *
  * tok_hdr piece of checksum data starts here
  *
  * the maximum mic-header len = 9 + 17 = 26
  *	mic-header
  *	----------
  * [2]	30      SEQUENCE tag
  * [3]	??	mic-header length: (max 23) = TokenID + ContextID
  *
  *		TokenID  - all fields constant and can be hardcoded
  *		-------
  * [4]	  02	Type 2
  * [5]	  02	Length 2
  * [6][7] 01 01	TokenID (SPKM_MIC_TOK)
  *
  *		ContextID  - encoded length not constant, calculated
  *		---------
  * [8]	03	Type 3
  * [9]	??	encoded length
  * [10]	??	ctxzbit
  * [11]	 	contextid
  *
  * mic_header piece of checksum data ends here.
  *
  *	int-cksum - encoded length not constant, calculated
  *	---------
  * [??]	03	Type 3
  * [??]	??	encoded length
  * [??]	??	md5zbit
  * [??]	 	int-cksum (NID_md5 = 16)
  *
  * maximum SPKM-MIC innercontext token length =
  *	 10 + encoded contextid_size(17 max) + 2 + encoded
  *       cksum_size (17 maxfor NID_md5) = 46
  */

 /*
  * spkm3_mic_header()
  *
  * Prepare the SPKM_MIC_TOK mic-header for check-sum calculation
  * elen: 16 byte context id asn1 bitstring encoded length
  */
 void
 spkm3_mic_header(unsigned char **hdrbuf, unsigned int *hdrlen, unsigned char *ctxdata, int elen, int zbit)
 {
 	char *hptr = *hdrbuf;
 	char *top = *hdrbuf;

 	*(u8 *)hptr++ = 0x30;
 	*(u8 *)hptr++ = elen + 7;  /* on the wire header length */

 	/* tokenid */
 	*(u8 *)hptr++ = 0x02;
 	*(u8 *)hptr++ = 0x02;
 	*(u8 *)hptr++ = 0x01;
 	*(u8 *)hptr++ = 0x01;

 	/* coniextid */
 	*(u8 *)hptr++ = 0x03;
 	*(u8 *)hptr++ = elen + 1; /* add 1 to include zbit */
 	*(u8 *)hptr++ = zbit;
 	memcpy(hptr, ctxdata, elen);
 	hptr += elen;
 	*hdrlen = hptr - top;
 }

 /*
  * spkm3_mic_innercontext_token()
  *
  * *tokp points to the beginning of the SPKM_MIC token  described
  * in rfc 2025, section 3.2.1:
  *
  * toklen is the inner token length
  */
 void
 spkm3_make_mic_token(unsigned char **tokp, int toklen, struct xdr_netobj *mic_hdr, struct xdr_netobj *md5cksum, int md5elen, int md5zbit)
 {
 	unsigned char *ict = *tokp;

 	*(u8 *)ict++ = 0xa4;
 	*(u8 *)ict++ = toklen;
 	memcpy(ict, mic_hdr->data, mic_hdr->len);
 	ict += mic_hdr->len;

 	*(u8 *)ict++ = 0x03;
 	*(u8 *)ict++ = md5elen + 1; /* add 1 to include zbit */
 	*(u8 *)ict++ = md5zbit;
 	memcpy(ict, md5cksum->data, md5elen);
 }

 u32
 spkm3_verify_mic_token(unsigned char **tokp, int *mic_hdrlen, unsigned char **cksum)
 {
 	struct xdr_netobj       spkm3_ctx_id = {.len =0, .data = NULL};
 	unsigned char 		*ptr = *tokp;
 	int 			ctxelen;
 	u32     		ret = GSS_S_DEFECTIVE_TOKEN;

 	/* spkm3 innercontext token preamble */
 	if ((ptr[0] != 0xa4) || (ptr[2] != 0x30)) {
 		dprintk("RPC: BAD SPKM ictoken preamble\n");
 		goto out;
 	}

 	*mic_hdrlen = ptr[3];

 	/* token type */
 	if ((ptr[4] != 0x02) || (ptr[5] != 0x02)) {
 		dprintk("RPC: BAD asn1 SPKM3 token type\n");
 		goto out;
 	}

 	/* only support SPKM_MIC_TOK */
 	if((ptr[6] != 0x01) || (ptr[7] != 0x01)) {
 		dprintk("RPC: ERROR unsupported SPKM3 token \n");
 		goto out;
 	}

 	/* contextid */
 	if (ptr[8] != 0x03) {
 		dprintk("RPC: BAD SPKM3 asn1 context-id type\n");
 		goto out;
 	}

 	ctxelen = ptr[9];
 	if (ctxelen > 17) {  /* length includes asn1 zbit octet */
 		dprintk("RPC: BAD SPKM3 contextid len %d\n", ctxelen);
 		goto out;
 	}

 	/* ignore ptr[10] */

 	if(!decode_asn1_bitstring(&spkm3_ctx_id, &ptr[11], ctxelen - 1, 16))
 		goto out;

 	/*
 	* in the current implementation: the optional int-alg is not present
 	* so the default int-alg (md5) is used the optional snd-seq field is
 	* also not present
 	*/

 	if (*mic_hdrlen != 6 + ctxelen) {
 		dprintk("RPC: BAD SPKM_ MIC_TOK header len %d: we only support default int-alg (should be absent) and do not support snd-seq\n", *mic_hdrlen);
 		goto out;
 	}
 	/* checksum */
         *cksum = (&ptr[10] + ctxelen); /* ctxelen includes ptr[10] */

 	ret = GSS_S_COMPLETE;
 out:
 	kfree(spkm3_ctx_id.data);
 	return ret;
 }
	/*
	* linux/net/sunrpc/gss_spkm3_token.c
	*
	* Copyright (c) 2003 The Regents of the University of Michigan.
	* All rights reserved.
	*
	* Andy Adamson <andros@umich.edu>
	*
	* 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.
	* 3. Neither the name of the University nor the names of its
	* contributors may be used to endorse or promote products derived
	* from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED ``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 REGENTS 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.
	*
	*/

	#include <linux/types.h>
	#include <linux/slab.h>
	#include <linux/jiffies.h>
	#include <linux/sunrpc/gss_spkm3.h>
	#include <linux/random.h>
	#include <linux/crypto.h>

	#ifdef RPC_DEBUG
	# define RPCDBG_FACILITY RPCDBG_AUTH
	#endif

	/*
	* asn1_bitstring_len()
	*
	* calculate the asn1 bitstring length of the xdr_netobject
	*/
	void
	asn1_bitstring_len(struct xdr_netobj in, int enclen, int *zerobits)
	{
	int i, zbit = 0,elen = in->len;
	char *ptr;

	ptr = &in->data[in->len -1];

	/* count trailing 0's */
	for(i = in->len; i > 0; i--) {
	if (*ptr == 0) {
	ptr--;
	elen--;
	} else
	break;
	}

	/* count number of 0 bits in final octet */
	ptr = &in->data[elen - 1];
	for(i = 0; i < 8; i++) {
	short mask = 0x01;

	if (!((mask << i) & *ptr))
	zbit++;
	else
	break;
	}
	*enclen = elen;
	*zerobits = zbit;
	}

	/*
	* decode_asn1_bitstring()
	*
	* decode a bitstring into a buffer of the expected length.
	* enclen = bit string length
	* explen = expected length (define in rfc)
	*/
	int
	decode_asn1_bitstring(struct xdr_netobj out, char in, int enclen, int explen)
	{
	if (!(out->data = kzalloc(explen,GFP_KERNEL)))
	return 0;
	out->len = explen;
	memcpy(out->data, in, enclen);
	return 1;
	}

	/*
	* SPKMInnerContextToken choice SPKM_MIC asn1 token layout
	*
	* contextid is always 16 bytes plain data. max asn1 bitstring len = 17.
	*
	* tokenlen = pos[0] to end of token (max pos[45] with MD5 cksum)
	*
	* pos value
	* ----------
	* [0] a4 SPKM-MIC tag
	* [1] ?? innertoken length (max 44)
	*
	*
	* tok_hdr piece of checksum data starts here
	*
	* the maximum mic-header len = 9 + 17 = 26
	* mic-header
	* ----------
	* [2] 30 SEQUENCE tag
	* [3] ?? mic-header length: (max 23) = TokenID + ContextID
	*
	* TokenID - all fields constant and can be hardcoded
	* -------
	* [4] 02 Type 2
	* [5] 02 Length 2
	* [6][7] 01 01 TokenID (SPKM_MIC_TOK)
	*
	* ContextID - encoded length not constant, calculated
	* ---------
	* [8] 03 Type 3
	* [9] ?? encoded length
	* [10] ?? ctxzbit
	* [11] contextid
	*
	* mic_header piece of checksum data ends here.
	*
	* int-cksum - encoded length not constant, calculated
	* ---------
	* [??] 03 Type 3
	* [??] ?? encoded length
	* [??] ?? md5zbit
	* [??] int-cksum (NID_md5 = 16)
	*
	* maximum SPKM-MIC innercontext token length =
	* 10 + encoded contextid_size(17 max) + 2 + encoded
	* cksum_size (17 maxfor NID_md5) = 46
	*/

	/*
	* spkm3_mic_header()
	*
	* Prepare the SPKM_MIC_TOK mic-header for check-sum calculation
	* elen: 16 byte context id asn1 bitstring encoded length
	*/
	void
	spkm3_mic_header(unsigned char *hdrbuf, unsigned int hdrlen, unsigned char *ctxdata, int elen, int zbit)
	{
	char hptr = hdrbuf;
	char top = hdrbuf;

	(u8 )hptr++ = 0x30;
	(u8 )hptr++ = elen + 7; /* on the wire header length */

	/* tokenid */
	(u8 )hptr++ = 0x02;
	(u8 )hptr++ = 0x02;
	(u8 )hptr++ = 0x01;
	(u8 )hptr++ = 0x01;

	/* coniextid */
	(u8 )hptr++ = 0x03;
	(u8 )hptr++ = elen + 1; /* add 1 to include zbit */
	(u8 )hptr++ = zbit;
	memcpy(hptr, ctxdata, elen);
	hptr += elen;
	*hdrlen = hptr - top;
	}

	/*
	* spkm3_mic_innercontext_token()
	*
	* *tokp points to the beginning of the SPKM_MIC token described
	* in rfc 2025, section 3.2.1:
	*
	* toklen is the inner token length
	*/
	void
	spkm3_make_mic_token(unsigned char *tokp, int toklen, struct xdr_netobj mic_hdr, struct xdr_netobj *md5cksum, int md5elen, int md5zbit)
	{
	unsigned char ict = tokp;

	(u8 )ict++ = 0xa4;
	(u8 )ict++ = toklen;
	memcpy(ict, mic_hdr->data, mic_hdr->len);
	ict += mic_hdr->len;

	(u8 )ict++ = 0x03;
	(u8 )ict++ = md5elen + 1; /* add 1 to include zbit */
	(u8 )ict++ = md5zbit;
	memcpy(ict, md5cksum->data, md5elen);
	}

	u32
	spkm3_verify_mic_token(unsigned char *tokp, int mic_hdrlen, unsigned char **cksum)
	{
	struct xdr_netobj spkm3_ctx_id = {.len =0, .data = NULL};
	unsigned char ptr = tokp;
	int ctxelen;
	u32 ret = GSS_S_DEFECTIVE_TOKEN;

	/* spkm3 innercontext token preamble */
	if ((ptr[0] != 0xa4) \|\| (ptr[2] != 0x30)) {
	dprintk("RPC: BAD SPKM ictoken preamble\n");
	goto out;
	}

	*mic_hdrlen = ptr[3];

	/* token type */
	if ((ptr[4] != 0x02) \|\| (ptr[5] != 0x02)) {
	dprintk("RPC: BAD asn1 SPKM3 token type\n");
	goto out;
	}

	/* only support SPKM_MIC_TOK */
	if((ptr[6] != 0x01) \|\| (ptr[7] != 0x01)) {
	dprintk("RPC: ERROR unsupported SPKM3 token \n");
	goto out;
	}

	/* contextid */
	if (ptr[8] != 0x03) {
	dprintk("RPC: BAD SPKM3 asn1 context-id type\n");
	goto out;
	}

	ctxelen = ptr[9];
	if (ctxelen > 17) { /* length includes asn1 zbit octet */
	dprintk("RPC: BAD SPKM3 contextid len %d\n", ctxelen);
	goto out;
	}

	/* ignore ptr[10] */

	if(!decode_asn1_bitstring(&spkm3_ctx_id, &ptr[11], ctxelen - 1, 16))
	goto out;

	/*
	* in the current implementation: the optional int-alg is not present
	* so the default int-alg (md5) is used the optional snd-seq field is
	* also not present
	*/

	if (*mic_hdrlen != 6 + ctxelen) {
	dprintk("RPC: BAD SPKM_ MIC_TOK header len %d: we only support default int-alg (should be absent) and do not support snd-seq\n", *mic_hdrlen);
	goto out;
	}
	/* checksum */
	cksum = (&ptr[10] + ctxelen); / ctxelen includes ptr[10] */

	ret = GSS_S_COMPLETE;
	out:
	kfree(spkm3_ctx_id.data);
	return ret;
	}