net/sunrpc/auth_gss/gss_krb5_unseal.c - linux - Git at Google

 /*
  *  linux/net/sunrpc/gss_krb5_unseal.c
  *
  *  Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/k5unseal.c
  *
  *  Copyright (c) 2000-2008 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/jiffies.h>
 #include <linux/sunrpc/gss_krb5.h>
 #include <linux/crypto.h>

 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 # define RPCDBG_FACILITY        RPCDBG_AUTH
 #endif


 /* read_token is a mic token, and message_buffer is the data that the mic was
  * supposedly taken over. */

 static u32
 gss_verify_mic_v1(struct krb5_ctx *ctx,
 		struct xdr_buf *message_buffer, struct xdr_netobj *read_token)
 {
 	int			signalg;
 	int			sealalg;
 	char			cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
 	struct xdr_netobj	md5cksum = {.len = sizeof(cksumdata),
 					    .data = cksumdata};
 	s32			now;
 	int			direction;
 	u32			seqnum;
 	unsigned char		*ptr = (unsigned char *)read_token->data;
 	int			bodysize;
 	u8			*cksumkey;

 	dprintk("RPC:       krb5_read_token\n");

 	if (g_verify_token_header(&ctx->mech_used, &bodysize, &ptr,
 					read_token->len))
 		return GSS_S_DEFECTIVE_TOKEN;

 	if ((ptr[0] != ((KG_TOK_MIC_MSG >> 8) & 0xff)) ||
 	    (ptr[1] !=  (KG_TOK_MIC_MSG & 0xff)))
 		return GSS_S_DEFECTIVE_TOKEN;

 	/* XXX sanity-check bodysize?? */

 	signalg = ptr[2] + (ptr[3] << 8);
 	if (signalg != ctx->gk5e->signalg)
 		return GSS_S_DEFECTIVE_TOKEN;

 	sealalg = ptr[4] + (ptr[5] << 8);
 	if (sealalg != SEAL_ALG_NONE)
 		return GSS_S_DEFECTIVE_TOKEN;

 	if ((ptr[6] != 0xff) || (ptr[7] != 0xff))
 		return GSS_S_DEFECTIVE_TOKEN;

 	if (ctx->gk5e->keyed_cksum)
 		cksumkey = ctx->cksum;
 	else
 		cksumkey = NULL;

 	if (make_checksum(ctx, ptr, 8, message_buffer, 0,
 			  cksumkey, KG_USAGE_SIGN, &md5cksum))
 		return GSS_S_FAILURE;

 	if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN,
 					ctx->gk5e->cksumlength))
 		return GSS_S_BAD_SIG;

 	/* it got through unscathed.  Make sure the context is unexpired */

 	now = ktime_get_real_seconds();

 	if (now > ctx->endtime)
 		return GSS_S_CONTEXT_EXPIRED;

 	/* do sequencing checks */

 	if (krb5_get_seq_num(ctx, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8,
 			     &direction, &seqnum))
 		return GSS_S_FAILURE;

 	if ((ctx->initiate && direction != 0xff) ||
 	    (!ctx->initiate && direction != 0))
 		return GSS_S_BAD_SIG;

 	return GSS_S_COMPLETE;
 }

 static u32
 gss_verify_mic_v2(struct krb5_ctx *ctx,
 		struct xdr_buf *message_buffer, struct xdr_netobj *read_token)
 {
 	char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
 	struct xdr_netobj cksumobj = {.len = sizeof(cksumdata),
 				      .data = cksumdata};
 	time64_t now;
 	u8 *ptr = read_token->data;
 	u8 *cksumkey;
 	u8 flags;
 	int i;
 	unsigned int cksum_usage;
 	__be16 be16_ptr;

 	dprintk("RPC:       %s\n", __func__);

 	memcpy(&be16_ptr, (char *) ptr, 2);
 	if (be16_to_cpu(be16_ptr) != KG2_TOK_MIC)
 		return GSS_S_DEFECTIVE_TOKEN;

 	flags = ptr[2];
 	if ((!ctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) ||
 	    (ctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
 		return GSS_S_BAD_SIG;

 	if (flags & KG2_TOKEN_FLAG_SEALED) {
 		dprintk("%s: token has unexpected sealed flag\n", __func__);
 		return GSS_S_FAILURE;
 	}

 	for (i = 3; i < 8; i++)
 		if (ptr[i] != 0xff)
 			return GSS_S_DEFECTIVE_TOKEN;

 	if (ctx->initiate) {
 		cksumkey = ctx->acceptor_sign;
 		cksum_usage = KG_USAGE_ACCEPTOR_SIGN;
 	} else {
 		cksumkey = ctx->initiator_sign;
 		cksum_usage = KG_USAGE_INITIATOR_SIGN;
 	}

 	if (make_checksum_v2(ctx, ptr, GSS_KRB5_TOK_HDR_LEN, message_buffer, 0,
 			     cksumkey, cksum_usage, &cksumobj))
 		return GSS_S_FAILURE;

 	if (memcmp(cksumobj.data, ptr + GSS_KRB5_TOK_HDR_LEN,
 				ctx->gk5e->cksumlength))
 		return GSS_S_BAD_SIG;

 	/* it got through unscathed.  Make sure the context is unexpired */
 	now = ktime_get_real_seconds();
 	if (now > ctx->endtime)
 		return GSS_S_CONTEXT_EXPIRED;

 	/*
 	 * NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss
 	 * doesn't want it checked; see page 6 of rfc 2203.
 	 */

 	return GSS_S_COMPLETE;
 }

 u32
 gss_verify_mic_kerberos(struct gss_ctx *gss_ctx,
 			struct xdr_buf *message_buffer,
 			struct xdr_netobj *read_token)
 {
 	struct krb5_ctx *ctx = gss_ctx->internal_ctx_id;

 	switch (ctx->enctype) {
 	default:
 		BUG();
 	case ENCTYPE_DES_CBC_RAW:
 	case ENCTYPE_DES3_CBC_RAW:
 	case ENCTYPE_ARCFOUR_HMAC:
 		return gss_verify_mic_v1(ctx, message_buffer, read_token);
 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
 		return gss_verify_mic_v2(ctx, message_buffer, read_token);
 	}
 }
	/*
	* linux/net/sunrpc/gss_krb5_unseal.c
	*
	* Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/k5unseal.c
	*
	* Copyright (c) 2000-2008 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/jiffies.h>
	#include <linux/sunrpc/gss_krb5.h>
	#include <linux/crypto.h>

	#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
	# define RPCDBG_FACILITY RPCDBG_AUTH
	#endif


	/* read_token is a mic token, and message_buffer is the data that the mic was
	* supposedly taken over. */

	static u32
	gss_verify_mic_v1(struct krb5_ctx *ctx,
	struct xdr_buf message_buffer, struct xdr_netobj read_token)
	{
	int signalg;
	int sealalg;
	char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
	struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
	.data = cksumdata};
	s32 now;
	int direction;
	u32 seqnum;
	unsigned char ptr = (unsigned char )read_token->data;
	int bodysize;
	u8 *cksumkey;

	dprintk("RPC: krb5_read_token\n");

	if (g_verify_token_header(&ctx->mech_used, &bodysize, &ptr,
	read_token->len))
	return GSS_S_DEFECTIVE_TOKEN;

	if ((ptr[0] != ((KG_TOK_MIC_MSG >> 8) & 0xff)) \|\|
	(ptr[1] != (KG_TOK_MIC_MSG & 0xff)))
	return GSS_S_DEFECTIVE_TOKEN;

	/* XXX sanity-check bodysize?? */

	signalg = ptr[2] + (ptr[3] << 8);
	if (signalg != ctx->gk5e->signalg)
	return GSS_S_DEFECTIVE_TOKEN;

	sealalg = ptr[4] + (ptr[5] << 8);
	if (sealalg != SEAL_ALG_NONE)
	return GSS_S_DEFECTIVE_TOKEN;

	if ((ptr[6] != 0xff) \|\| (ptr[7] != 0xff))
	return GSS_S_DEFECTIVE_TOKEN;

	if (ctx->gk5e->keyed_cksum)
	cksumkey = ctx->cksum;
	else
	cksumkey = NULL;

	if (make_checksum(ctx, ptr, 8, message_buffer, 0,
	cksumkey, KG_USAGE_SIGN, &md5cksum))
	return GSS_S_FAILURE;

	if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN,
	ctx->gk5e->cksumlength))
	return GSS_S_BAD_SIG;

	/* it got through unscathed. Make sure the context is unexpired */

	now = ktime_get_real_seconds();

	if (now > ctx->endtime)
	return GSS_S_CONTEXT_EXPIRED;

	/* do sequencing checks */

	if (krb5_get_seq_num(ctx, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8,
	&direction, &seqnum))
	return GSS_S_FAILURE;

	if ((ctx->initiate && direction != 0xff) \|\|
	(!ctx->initiate && direction != 0))
	return GSS_S_BAD_SIG;

	return GSS_S_COMPLETE;
	}

	static u32
	gss_verify_mic_v2(struct krb5_ctx *ctx,
	struct xdr_buf message_buffer, struct xdr_netobj read_token)
	{
	char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
	struct xdr_netobj cksumobj = {.len = sizeof(cksumdata),
	.data = cksumdata};
	time64_t now;
	u8 *ptr = read_token->data;
	u8 *cksumkey;
	u8 flags;
	int i;
	unsigned int cksum_usage;
	__be16 be16_ptr;

	dprintk("RPC: %s\n", __func__);

	memcpy(&be16_ptr, (char *) ptr, 2);
	if (be16_to_cpu(be16_ptr) != KG2_TOK_MIC)
	return GSS_S_DEFECTIVE_TOKEN;

	flags = ptr[2];
	if ((!ctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) \|\|
	(ctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
	return GSS_S_BAD_SIG;

	if (flags & KG2_TOKEN_FLAG_SEALED) {
	dprintk("%s: token has unexpected sealed flag\n", __func__);
	return GSS_S_FAILURE;
	}

	for (i = 3; i < 8; i++)
	if (ptr[i] != 0xff)
	return GSS_S_DEFECTIVE_TOKEN;

	if (ctx->initiate) {
	cksumkey = ctx->acceptor_sign;
	cksum_usage = KG_USAGE_ACCEPTOR_SIGN;
	} else {
	cksumkey = ctx->initiator_sign;
	cksum_usage = KG_USAGE_INITIATOR_SIGN;
	}

	if (make_checksum_v2(ctx, ptr, GSS_KRB5_TOK_HDR_LEN, message_buffer, 0,
	cksumkey, cksum_usage, &cksumobj))
	return GSS_S_FAILURE;

	if (memcmp(cksumobj.data, ptr + GSS_KRB5_TOK_HDR_LEN,
	ctx->gk5e->cksumlength))
	return GSS_S_BAD_SIG;

	/* it got through unscathed. Make sure the context is unexpired */
	now = ktime_get_real_seconds();
	if (now > ctx->endtime)
	return GSS_S_CONTEXT_EXPIRED;

	/*
	* NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss
	* doesn't want it checked; see page 6 of rfc 2203.
	*/

	return GSS_S_COMPLETE;
	}

	u32
	gss_verify_mic_kerberos(struct gss_ctx *gss_ctx,
	struct xdr_buf *message_buffer,
	struct xdr_netobj *read_token)
	{
	struct krb5_ctx *ctx = gss_ctx->internal_ctx_id;

	switch (ctx->enctype) {
	default:
	BUG();
	case ENCTYPE_DES_CBC_RAW:
	case ENCTYPE_DES3_CBC_RAW:
	case ENCTYPE_ARCFOUR_HMAC:
	return gss_verify_mic_v1(ctx, message_buffer, read_token);
	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
	return gss_verify_mic_v2(ctx, message_buffer, read_token);
	}
	}