/* *  linux/net/sunrpc/gss_krb5_unseal.c * *  Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/k5unseal.c * *  Copyright (c) 2000 The Regents of the University of Michigan. *  All rights reserved. * *  Andy Adamson   <andros@umich.edu> *//* * 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. *//* * Copyright (C) 1998 by the FundsXpress, INC. * * All rights reserved. * * Export of this software from the United States of America may require * a specific license from the United States Government.  It is the * responsibility of any person or organization contemplating export to * obtain such a license before exporting. * * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and * distribute this software and its documentation for any purpose and * without fee is hereby granted, provided that the above copyright * notice appear in all copies and that both that copyright notice and * this permission notice appear in supporting documentation, and that * the name of FundsXpress. not be used in advertising or publicity pertaining * to distribution of the software without specific, written prior * permission.  FundsXpress makes no representations about the suitability of * this software for any purpose.  It is provided "as is" without express * or implied warranty. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. */#include <linux/types.h>#include <linux/slab.h>#include <linux/jiffies.h>#include <linux/sunrpc/gss_krb5.h>#include <linux/crypto.h>#ifdef RPC_DEBUG# define RPCDBG_FACILITY        RPCDBG_AUTH#endif/* message_buffer is an input if toktype is MIC and an output if it is WRAP: * If toktype is MIC: read_token is a mic token, and message_buffer is the *   data that the mic was supposedly taken over. * If toktype is WRAP: read_token is a wrap token, and message_buffer is used *   to return the decrypted data. *//* XXX will need to change prototype and/or just split into a separate function * when we add privacy (because read_token will be in pages too). */u32krb5_read_token(struct krb5_ctx *ctx,		struct xdr_netobj *read_token,		struct xdr_buf *message_buffer,		int *qop_state, int toktype){	int			signalg;	int			sealalg;	s32			checksum_type;	struct xdr_netobj	md5cksum = {.len = 0, .data = NULL};	s32			now;	int			direction;	s32			seqnum;	unsigned char		*ptr = (unsigned char *)read_token->data;	int			bodysize;	u32			ret = GSS_S_DEFECTIVE_TOKEN;	dprintk("RPC:      krb5_read_token\n");	if (g_verify_token_header(&ctx->mech_used, &bodysize, &ptr, toktype,					read_token->len))		goto out;	if ((*ptr++ != ((toktype>>8)&0xff)) || (*ptr++ != (toktype&0xff)))		goto out;	/* XXX sanity-check bodysize?? */	if (toktype == KG_TOK_WRAP_MSG) {		/* XXX gone */		goto out;	}	/* get the sign and seal algorithms */	signalg = ptr[0] + (ptr[1] << 8);	sealalg = ptr[2] + (ptr[3] << 8);	/* Sanity checks */	if ((ptr[4] != 0xff) || (ptr[5] != 0xff))		goto out;	if (((toktype != KG_TOK_WRAP_MSG) && (sealalg != 0xffff)) ||	    ((toktype == KG_TOK_WRAP_MSG) && (sealalg == 0xffff)))		goto out;	/* in the current spec, there is only one valid seal algorithm per	   key type, so a simple comparison is ok */	if ((toktype == KG_TOK_WRAP_MSG) && !(sealalg == ctx->sealalg))		goto out;	/* there are several mappings of seal algorithms to sign algorithms,	   but few enough that we can try them all. */	if ((ctx->sealalg == SEAL_ALG_NONE && signalg > 1) ||	    (ctx->sealalg == SEAL_ALG_1 && signalg != SGN_ALG_3) ||	    (ctx->sealalg == SEAL_ALG_DES3KD &&	     signalg != SGN_ALG_HMAC_SHA1_DES3_KD))		goto out;	/* compute the checksum of the message */	/* initialize the the cksum */	switch (signalg) {	case SGN_ALG_DES_MAC_MD5:		checksum_type = CKSUMTYPE_RSA_MD5;		break;	default:		ret = GSS_S_DEFECTIVE_TOKEN;		goto out;	}	switch (signalg) {	case SGN_ALG_DES_MAC_MD5:		ret = make_checksum(checksum_type, ptr - 2, 8,					 message_buffer, &md5cksum);		if (ret)			goto out;		ret = krb5_encrypt(ctx->seq, NULL, md5cksum.data,				   md5cksum.data, 16);		if (ret)			goto out;		if (memcmp(md5cksum.data + 8, ptr + 14, 8)) {			ret = GSS_S_BAD_SIG;			goto out;		}		break;	default:		ret = GSS_S_DEFECTIVE_TOKEN;		goto out;	}	/* it got through unscathed.  Make sure the context is unexpired */	if (qop_state)		*qop_state = GSS_C_QOP_DEFAULT;	now = get_seconds();	ret = GSS_S_CONTEXT_EXPIRED;	if (now > ctx->endtime)		goto out;	/* do sequencing checks */	ret = GSS_S_BAD_SIG;	if ((ret = krb5_get_seq_num(ctx->seq, ptr + 14, ptr + 6, &direction,				    &seqnum)))		goto out;	if ((ctx->initiate && direction != 0xff) ||	    (!ctx->initiate && direction != 0))		goto out;	ret = GSS_S_COMPLETE;out:	if (md5cksum.data) kfree(md5cksum.data);	return ret;}