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/*
* linux/net/sunrpc/gss_spkm3_unseal.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/crypto.h>
#ifdef RPC_DEBUG
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
/*
* spkm3_read_token()
*
* only SPKM_MIC_TOK with md5 intg-alg is supported
*/
u32
spkm3_read_token(struct spkm3_ctx *ctx,
struct xdr_netobj *read_token, /* checksum */
struct xdr_buf *message_buffer, /* signbuf */
int toktype)
{
s32 checksum_type;
s32 code;
struct xdr_netobj wire_cksum = {.len =0, .data = NULL};
char cksumdata[16];
struct xdr_netobj md5cksum = {.len = 0, .data = cksumdata};
unsigned char *ptr = (unsigned char *)read_token->data;
unsigned char *cksum;
int bodysize, md5elen;
int mic_hdrlen;
u32 ret = GSS_S_DEFECTIVE_TOKEN;
if (g_verify_token_header((struct xdr_netobj *) &ctx->mech_used,
&bodysize, &ptr, read_token->len))
goto out;
/* decode the token */
if (toktype != SPKM_MIC_TOK) {
dprintk("RPC: BAD SPKM3 token type: %d\n", toktype);
goto out;
}
if ((ret = spkm3_verify_mic_token(&ptr, &mic_hdrlen, &cksum)))
goto out;
if (*cksum++ != 0x03) {
dprintk("RPC: spkm3_read_token BAD checksum type\n");
goto out;
}
md5elen = *cksum++;
cksum++; /* move past the zbit */
if (!decode_asn1_bitstring(&wire_cksum, cksum, md5elen - 1, 16))
goto out;
/* HARD CODED FOR MD5 */
/* compute the checksum of the message.
* ptr + 2 = start of header piece of checksum
* mic_hdrlen + 2 = length of header piece of checksum
*/
ret = GSS_S_DEFECTIVE_TOKEN;
if (!g_OID_equal(&ctx->intg_alg, &hmac_md5_oid)) {
dprintk("RPC: gss_spkm3_seal: unsupported I-ALG "
"algorithm\n");
goto out;
}
checksum_type = CKSUMTYPE_HMAC_MD5;
code = make_spkm3_checksum(checksum_type,
&ctx->derived_integ_key, ptr + 2, mic_hdrlen + 2,
message_buffer, 0, &md5cksum);
if (code)
goto out;
ret = GSS_S_BAD_SIG;
code = memcmp(md5cksum.data, wire_cksum.data, wire_cksum.len);
if (code) {
dprintk("RPC: bad MIC checksum\n");
goto out;
}
/* XXX: need to add expiration and sequencing */
ret = GSS_S_COMPLETE;
out:
kfree(wire_cksum.data);
return ret;
}
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