128 lines
3.8 KiB
C
128 lines
3.8 KiB
C
/*
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* linux/net/sunrpc/gss_spkm3_unseal.c
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*
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* Copyright (c) 2003 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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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/jiffies.h>
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#include <linux/sunrpc/gss_spkm3.h>
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#include <linux/crypto.h>
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#ifdef RPC_DEBUG
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# define RPCDBG_FACILITY RPCDBG_AUTH
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#endif
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/*
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* spkm3_read_token()
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*
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* only SPKM_MIC_TOK with md5 intg-alg is supported
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*/
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u32
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spkm3_read_token(struct spkm3_ctx *ctx,
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struct xdr_netobj *read_token, /* checksum */
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struct xdr_buf *message_buffer, /* signbuf */
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int toktype)
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{
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s32 checksum_type;
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s32 code;
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struct xdr_netobj wire_cksum = {.len =0, .data = NULL};
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char cksumdata[16];
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struct xdr_netobj md5cksum = {.len = 0, .data = cksumdata};
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unsigned char *ptr = (unsigned char *)read_token->data;
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unsigned char *cksum;
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int bodysize, md5elen;
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int mic_hdrlen;
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u32 ret = GSS_S_DEFECTIVE_TOKEN;
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if (g_verify_token_header((struct xdr_netobj *) &ctx->mech_used,
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&bodysize, &ptr, read_token->len))
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goto out;
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/* decode the token */
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if (toktype != SPKM_MIC_TOK) {
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dprintk("RPC: BAD SPKM3 token type: %d\n", toktype);
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goto out;
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}
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if ((ret = spkm3_verify_mic_token(&ptr, &mic_hdrlen, &cksum)))
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goto out;
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if (*cksum++ != 0x03) {
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dprintk("RPC: spkm3_read_token BAD checksum type\n");
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goto out;
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}
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md5elen = *cksum++;
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cksum++; /* move past the zbit */
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if (!decode_asn1_bitstring(&wire_cksum, cksum, md5elen - 1, 16))
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goto out;
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/* HARD CODED FOR MD5 */
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/* compute the checksum of the message.
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* ptr + 2 = start of header piece of checksum
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* mic_hdrlen + 2 = length of header piece of checksum
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*/
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ret = GSS_S_DEFECTIVE_TOKEN;
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if (!g_OID_equal(&ctx->intg_alg, &hmac_md5_oid)) {
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dprintk("RPC: gss_spkm3_seal: unsupported I-ALG "
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"algorithm\n");
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goto out;
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}
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checksum_type = CKSUMTYPE_HMAC_MD5;
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code = make_spkm3_checksum(checksum_type,
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&ctx->derived_integ_key, ptr + 2, mic_hdrlen + 2,
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message_buffer, 0, &md5cksum);
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if (code)
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goto out;
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ret = GSS_S_BAD_SIG;
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code = memcmp(md5cksum.data, wire_cksum.data, wire_cksum.len);
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if (code) {
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dprintk("RPC: bad MIC checksum\n");
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goto out;
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}
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/* XXX: need to add expiration and sequencing */
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ret = GSS_S_COMPLETE;
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out:
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kfree(wire_cksum.data);
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return ret;
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}
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