1/* 2 * linux/net/sunrpc/gss_spkm3_unseal.c 3 * 4 * Copyright (c) 2003 The Regents of the University of Michigan. 5 * All rights reserved. 6 * 7 * Andy Adamson <andros@umich.edu> 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its 19 * contributors may be used to endorse or promote products derived 20 * from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 25 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 29 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 30 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 31 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 32 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 * 34 */ 35 36#include <linux/types.h> 37#include <linux/slab.h> 38#include <linux/jiffies.h> 39#include <linux/sunrpc/gss_spkm3.h> 40#include <linux/crypto.h> 41 42#ifdef RPC_DEBUG 43# define RPCDBG_FACILITY RPCDBG_AUTH 44#endif 45 46/* 47 * spkm3_read_token() 48 * 49 * only SPKM_MIC_TOK with md5 intg-alg is supported 50 */ 51u32 52spkm3_read_token(struct spkm3_ctx *ctx, 53 struct xdr_netobj *read_token, /* checksum */ 54 struct xdr_buf *message_buffer, /* signbuf */ 55 int toktype) 56{ 57 s32 checksum_type; 58 s32 code; 59 struct xdr_netobj wire_cksum = {.len =0, .data = NULL}; 60 char cksumdata[16]; 61 struct xdr_netobj md5cksum = {.len = 0, .data = cksumdata}; 62 unsigned char *ptr = (unsigned char *)read_token->data; 63 unsigned char *cksum; 64 int bodysize, md5elen; 65 int mic_hdrlen; 66 u32 ret = GSS_S_DEFECTIVE_TOKEN; 67 68 if (g_verify_token_header((struct xdr_netobj *) &ctx->mech_used, 69 &bodysize, &ptr, read_token->len)) 70 goto out; 71 72 /* decode the token */ 73 74 if (toktype != SPKM_MIC_TOK) { 75 dprintk("RPC: BAD SPKM3 token type: %d\n", toktype); 76 goto out; 77 } 78 79 if ((ret = spkm3_verify_mic_token(&ptr, &mic_hdrlen, &cksum))) 80 goto out; 81 82 if (*cksum++ != 0x03) { 83 dprintk("RPC: spkm3_read_token BAD checksum type\n"); 84 goto out; 85 } 86 md5elen = *cksum++; 87 cksum++; /* move past the zbit */ 88 89 if (!decode_asn1_bitstring(&wire_cksum, cksum, md5elen - 1, 16)) 90 goto out; 91 92 /* HARD CODED FOR MD5 */ 93 94 /* compute the checksum of the message. 95 * ptr + 2 = start of header piece of checksum 96 * mic_hdrlen + 2 = length of header piece of checksum 97 */ 98 ret = GSS_S_DEFECTIVE_TOKEN; 99 if (!g_OID_equal(&ctx->intg_alg, &hmac_md5_oid)) { 100 dprintk("RPC: gss_spkm3_seal: unsupported I-ALG " 101 "algorithm\n"); 102 goto out; 103 } 104 105 checksum_type = CKSUMTYPE_HMAC_MD5; 106 107 code = make_spkm3_checksum(checksum_type, 108 &ctx->derived_integ_key, ptr + 2, mic_hdrlen + 2, 109 message_buffer, 0, &md5cksum); 110 111 if (code) 112 goto out; 113 114 ret = GSS_S_BAD_SIG; 115 code = memcmp(md5cksum.data, wire_cksum.data, wire_cksum.len); 116 if (code) { 117 dprintk("RPC: bad MIC checksum\n"); 118 goto out; 119 } 120 121 122 ret = GSS_S_COMPLETE; 123out: 124 kfree(wire_cksum.data); 125 return ret; 126} 127