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1da177e4 LT |
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() | |
cca5172a | 48 | * |
1da177e4 LT |
49 | * only SPKM_MIC_TOK with md5 intg-alg is supported |
50 | */ | |
51 | u32 | |
52 | spkm3_read_token(struct spkm3_ctx *ctx, | |
53 | struct xdr_netobj *read_token, /* checksum */ | |
54 | struct xdr_buf *message_buffer, /* signbuf */ | |
00fd6e14 | 55 | int toktype) |
1da177e4 | 56 | { |
adeb8133 | 57 | s32 checksum_type; |
1da177e4 LT |
58 | s32 code; |
59 | struct xdr_netobj wire_cksum = {.len =0, .data = NULL}; | |
9e57b302 BF |
60 | char cksumdata[16]; |
61 | struct xdr_netobj md5cksum = {.len = 0, .data = cksumdata}; | |
1da177e4 | 62 | unsigned char *ptr = (unsigned char *)read_token->data; |
adeb8133 | 63 | unsigned char *cksum; |
1da177e4 LT |
64 | int bodysize, md5elen; |
65 | int mic_hdrlen; | |
66 | u32 ret = GSS_S_DEFECTIVE_TOKEN; | |
67 | ||
1da177e4 LT |
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 | ||
adeb8133 | 74 | if (toktype != SPKM_MIC_TOK) { |
8885cb36 | 75 | dprintk("RPC: BAD SPKM3 token type: %d\n", toktype); |
adeb8133 OK |
76 | goto out; |
77 | } | |
78 | ||
79 | if ((ret = spkm3_verify_mic_token(&ptr, &mic_hdrlen, &cksum))) | |
80 | goto out; | |
81 | ||
82 | if (*cksum++ != 0x03) { | |
8885cb36 | 83 | dprintk("RPC: spkm3_read_token BAD checksum type\n"); |
adeb8133 OK |
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)) { | |
8885cb36 CL |
100 | dprintk("RPC: gss_spkm3_seal: unsupported I-ALG " |
101 | "algorithm\n"); | |
adeb8133 OK |
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) { | |
8885cb36 | 117 | dprintk("RPC: bad MIC checksum\n"); |
1da177e4 LT |
118 | goto out; |
119 | } | |
120 | ||
adeb8133 | 121 | |
1da177e4 LT |
122 | /* XXX: need to add expiration and sequencing */ |
123 | ret = GSS_S_COMPLETE; | |
124 | out: | |
a51482bd | 125 | kfree(wire_cksum.data); |
1da177e4 LT |
126 | return ret; |
127 | } |