228 lines
6.7 KiB
C
228 lines
6.7 KiB
C
/*
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* linux/net/sunrpc/gss_krb5_unseal.c
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*
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* Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/k5unseal.c
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*
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* Copyright (c) 2000-2008 The Regents of the University of Michigan.
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* All rights reserved.
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*
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* Andy Adamson <andros@umich.edu>
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*/
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/*
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* Copyright 1993 by OpenVision Technologies, Inc.
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*
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* Permission to use, copy, modify, distribute, and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appears in all copies and
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* that both that copyright notice and this permission notice appear in
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* supporting documentation, and that the name of OpenVision not be used
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* in advertising or publicity pertaining to distribution of the software
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* without specific, written prior permission. OpenVision makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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* OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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* EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
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* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* Copyright (C) 1998 by the FundsXpress, INC.
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*
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* All rights reserved.
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*
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* Export of this software from the United States of America may require
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* a specific license from the United States Government. It is the
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* responsibility of any person or organization contemplating export to
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* obtain such a license before exporting.
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*
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* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
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* distribute this software and its documentation for any purpose and
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* without fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright notice and
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* this permission notice appear in supporting documentation, and that
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* the name of FundsXpress. not be used in advertising or publicity pertaining
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* to distribution of the software without specific, written prior
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* permission. FundsXpress makes no representations about the suitability of
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* this software for any purpose. It is provided "as is" without express
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* or implied warranty.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#include <linux/types.h>
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#include <linux/jiffies.h>
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#include <linux/sunrpc/gss_krb5.h>
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#include <linux/crypto.h>
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#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
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# define RPCDBG_FACILITY RPCDBG_AUTH
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#endif
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/* read_token is a mic token, and message_buffer is the data that the mic was
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* supposedly taken over. */
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static u32
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gss_verify_mic_v1(struct krb5_ctx *ctx,
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struct xdr_buf *message_buffer, struct xdr_netobj *read_token)
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{
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int signalg;
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int sealalg;
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char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
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struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
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.data = cksumdata};
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s32 now;
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int direction;
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u32 seqnum;
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unsigned char *ptr = (unsigned char *)read_token->data;
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int bodysize;
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u8 *cksumkey;
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dprintk("RPC: krb5_read_token\n");
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if (g_verify_token_header(&ctx->mech_used, &bodysize, &ptr,
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read_token->len))
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return GSS_S_DEFECTIVE_TOKEN;
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if ((ptr[0] != ((KG_TOK_MIC_MSG >> 8) & 0xff)) ||
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(ptr[1] != (KG_TOK_MIC_MSG & 0xff)))
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return GSS_S_DEFECTIVE_TOKEN;
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/* XXX sanity-check bodysize?? */
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signalg = ptr[2] + (ptr[3] << 8);
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if (signalg != ctx->gk5e->signalg)
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return GSS_S_DEFECTIVE_TOKEN;
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sealalg = ptr[4] + (ptr[5] << 8);
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if (sealalg != SEAL_ALG_NONE)
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return GSS_S_DEFECTIVE_TOKEN;
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if ((ptr[6] != 0xff) || (ptr[7] != 0xff))
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return GSS_S_DEFECTIVE_TOKEN;
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if (ctx->gk5e->keyed_cksum)
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cksumkey = ctx->cksum;
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else
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cksumkey = NULL;
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if (make_checksum(ctx, ptr, 8, message_buffer, 0,
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cksumkey, KG_USAGE_SIGN, &md5cksum))
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return GSS_S_FAILURE;
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if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN,
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ctx->gk5e->cksumlength))
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return GSS_S_BAD_SIG;
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/* it got through unscathed. Make sure the context is unexpired */
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now = get_seconds();
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if (now > ctx->endtime)
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return GSS_S_CONTEXT_EXPIRED;
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/* do sequencing checks */
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if (krb5_get_seq_num(ctx, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8,
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&direction, &seqnum))
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return GSS_S_FAILURE;
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if ((ctx->initiate && direction != 0xff) ||
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(!ctx->initiate && direction != 0))
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return GSS_S_BAD_SIG;
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return GSS_S_COMPLETE;
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}
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static u32
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gss_verify_mic_v2(struct krb5_ctx *ctx,
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struct xdr_buf *message_buffer, struct xdr_netobj *read_token)
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{
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char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
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struct xdr_netobj cksumobj = {.len = sizeof(cksumdata),
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.data = cksumdata};
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s32 now;
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u8 *ptr = read_token->data;
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u8 *cksumkey;
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u8 flags;
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int i;
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unsigned int cksum_usage;
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__be16 be16_ptr;
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dprintk("RPC: %s\n", __func__);
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memcpy(&be16_ptr, (char *) ptr, 2);
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if (be16_to_cpu(be16_ptr) != KG2_TOK_MIC)
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return GSS_S_DEFECTIVE_TOKEN;
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flags = ptr[2];
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if ((!ctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) ||
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(ctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
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return GSS_S_BAD_SIG;
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if (flags & KG2_TOKEN_FLAG_SEALED) {
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dprintk("%s: token has unexpected sealed flag\n", __func__);
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return GSS_S_FAILURE;
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}
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for (i = 3; i < 8; i++)
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if (ptr[i] != 0xff)
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return GSS_S_DEFECTIVE_TOKEN;
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if (ctx->initiate) {
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cksumkey = ctx->acceptor_sign;
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cksum_usage = KG_USAGE_ACCEPTOR_SIGN;
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} else {
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cksumkey = ctx->initiator_sign;
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cksum_usage = KG_USAGE_INITIATOR_SIGN;
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}
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if (make_checksum_v2(ctx, ptr, GSS_KRB5_TOK_HDR_LEN, message_buffer, 0,
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cksumkey, cksum_usage, &cksumobj))
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return GSS_S_FAILURE;
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if (memcmp(cksumobj.data, ptr + GSS_KRB5_TOK_HDR_LEN,
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ctx->gk5e->cksumlength))
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return GSS_S_BAD_SIG;
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/* it got through unscathed. Make sure the context is unexpired */
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now = get_seconds();
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if (now > ctx->endtime)
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return GSS_S_CONTEXT_EXPIRED;
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/*
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* NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss
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* doesn't want it checked; see page 6 of rfc 2203.
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*/
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return GSS_S_COMPLETE;
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}
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u32
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gss_verify_mic_kerberos(struct gss_ctx *gss_ctx,
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struct xdr_buf *message_buffer,
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struct xdr_netobj *read_token)
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{
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struct krb5_ctx *ctx = gss_ctx->internal_ctx_id;
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switch (ctx->enctype) {
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default:
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BUG();
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case ENCTYPE_DES_CBC_RAW:
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case ENCTYPE_DES3_CBC_RAW:
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case ENCTYPE_ARCFOUR_HMAC:
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return gss_verify_mic_v1(ctx, message_buffer, read_token);
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case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
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case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
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return gss_verify_mic_v2(ctx, message_buffer, read_token);
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}
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}
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