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1da177e4 LT |
1 | /* |
2 | * linux/net/sunrpc/gss_generic_token.c | |
3 | * | |
4 | * Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/generic/util_token.c | |
5 | * | |
6 | * Copyright (c) 2000 The Regents of the University of Michigan. | |
7 | * All rights reserved. | |
8 | * | |
9 | * Andy Adamson <andros@umich.edu> | |
10 | */ | |
11 | ||
12 | /* | |
13 | * Copyright 1993 by OpenVision Technologies, Inc. | |
cca5172a | 14 | * |
1da177e4 LT |
15 | * Permission to use, copy, modify, distribute, and sell this software |
16 | * and its documentation for any purpose is hereby granted without fee, | |
17 | * provided that the above copyright notice appears in all copies and | |
18 | * that both that copyright notice and this permission notice appear in | |
19 | * supporting documentation, and that the name of OpenVision not be used | |
20 | * in advertising or publicity pertaining to distribution of the software | |
21 | * without specific, written prior permission. OpenVision makes no | |
22 | * representations about the suitability of this software for any | |
23 | * purpose. It is provided "as is" without express or implied warranty. | |
cca5172a | 24 | * |
1da177e4 LT |
25 | * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, |
26 | * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO | |
27 | * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR | |
28 | * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF | |
29 | * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR | |
30 | * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR | |
31 | * PERFORMANCE OF THIS SOFTWARE. | |
32 | */ | |
33 | ||
34 | #include <linux/types.h> | |
35 | #include <linux/module.h> | |
1da177e4 LT |
36 | #include <linux/string.h> |
37 | #include <linux/sunrpc/sched.h> | |
38 | #include <linux/sunrpc/gss_asn1.h> | |
39 | ||
40 | ||
41 | #ifdef RPC_DEBUG | |
42 | # define RPCDBG_FACILITY RPCDBG_AUTH | |
43 | #endif | |
44 | ||
45 | ||
46 | /* TWRITE_STR from gssapiP_generic.h */ | |
47 | #define TWRITE_STR(ptr, str, len) \ | |
48 | memcpy((ptr), (char *) (str), (len)); \ | |
49 | (ptr) += (len); | |
50 | ||
51 | /* XXXX this code currently makes the assumption that a mech oid will | |
52 | never be longer than 127 bytes. This assumption is not inherent in | |
53 | the interfaces, so the code can be fixed if the OSI namespace | |
54 | balloons unexpectedly. */ | |
55 | ||
56 | /* Each token looks like this: | |
57 | ||
58 | 0x60 tag for APPLICATION 0, SEQUENCE | |
59 | (constructed, definite-length) | |
60 | <length> possible multiple bytes, need to parse/generate | |
61 | 0x06 tag for OBJECT IDENTIFIER | |
62 | <moid_length> compile-time constant string (assume 1 byte) | |
63 | <moid_bytes> compile-time constant string | |
64 | <inner_bytes> the ANY containing the application token | |
65 | bytes 0,1 are the token type | |
66 | bytes 2,n are the token data | |
67 | ||
68 | For the purposes of this abstraction, the token "header" consists of | |
69 | the sequence tag and length octets, the mech OID DER encoding, and the | |
70 | first two inner bytes, which indicate the token type. The token | |
71 | "body" consists of everything else. | |
72 | ||
73 | */ | |
74 | ||
75 | static int | |
76 | der_length_size( int length) | |
77 | { | |
78 | if (length < (1<<7)) | |
a02cec21 | 79 | return 1; |
1da177e4 | 80 | else if (length < (1<<8)) |
a02cec21 | 81 | return 2; |
1da177e4 LT |
82 | #if (SIZEOF_INT == 2) |
83 | else | |
a02cec21 | 84 | return 3; |
1da177e4 LT |
85 | #else |
86 | else if (length < (1<<16)) | |
a02cec21 | 87 | return 3; |
1da177e4 | 88 | else if (length < (1<<24)) |
a02cec21 | 89 | return 4; |
1da177e4 | 90 | else |
a02cec21 | 91 | return 5; |
1da177e4 LT |
92 | #endif |
93 | } | |
94 | ||
95 | static void | |
96 | der_write_length(unsigned char **buf, int length) | |
97 | { | |
98 | if (length < (1<<7)) { | |
99 | *(*buf)++ = (unsigned char) length; | |
100 | } else { | |
101 | *(*buf)++ = (unsigned char) (der_length_size(length)+127); | |
102 | #if (SIZEOF_INT > 2) | |
103 | if (length >= (1<<24)) | |
104 | *(*buf)++ = (unsigned char) (length>>24); | |
105 | if (length >= (1<<16)) | |
106 | *(*buf)++ = (unsigned char) ((length>>16)&0xff); | |
107 | #endif | |
108 | if (length >= (1<<8)) | |
109 | *(*buf)++ = (unsigned char) ((length>>8)&0xff); | |
110 | *(*buf)++ = (unsigned char) (length&0xff); | |
111 | } | |
112 | } | |
113 | ||
114 | /* returns decoded length, or < 0 on failure. Advances buf and | |
115 | decrements bufsize */ | |
116 | ||
117 | static int | |
118 | der_read_length(unsigned char **buf, int *bufsize) | |
119 | { | |
120 | unsigned char sf; | |
121 | int ret; | |
122 | ||
123 | if (*bufsize < 1) | |
a02cec21 | 124 | return -1; |
1da177e4 LT |
125 | sf = *(*buf)++; |
126 | (*bufsize)--; | |
127 | if (sf & 0x80) { | |
128 | if ((sf &= 0x7f) > ((*bufsize)-1)) | |
a02cec21 | 129 | return -1; |
1da177e4 | 130 | if (sf > SIZEOF_INT) |
a02cec21 | 131 | return -1; |
1da177e4 LT |
132 | ret = 0; |
133 | for (; sf; sf--) { | |
134 | ret = (ret<<8) + (*(*buf)++); | |
135 | (*bufsize)--; | |
136 | } | |
137 | } else { | |
138 | ret = sf; | |
139 | } | |
140 | ||
a02cec21 | 141 | return ret; |
1da177e4 LT |
142 | } |
143 | ||
144 | /* returns the length of a token, given the mech oid and the body size */ | |
145 | ||
146 | int | |
147 | g_token_size(struct xdr_netobj *mech, unsigned int body_size) | |
148 | { | |
149 | /* set body_size to sequence contents size */ | |
4ab4b0be | 150 | body_size += 2 + (int) mech->len; /* NEED overflow check */ |
a02cec21 | 151 | return 1 + der_length_size(body_size) + body_size; |
1da177e4 LT |
152 | } |
153 | ||
7bd88269 | 154 | EXPORT_SYMBOL_GPL(g_token_size); |
1da177e4 LT |
155 | |
156 | /* fills in a buffer with the token header. The buffer is assumed to | |
157 | be the right size. buf is advanced past the token header */ | |
158 | ||
159 | void | |
160 | g_make_token_header(struct xdr_netobj *mech, int body_size, unsigned char **buf) | |
161 | { | |
162 | *(*buf)++ = 0x60; | |
4ab4b0be | 163 | der_write_length(buf, 2 + mech->len + body_size); |
1da177e4 LT |
164 | *(*buf)++ = 0x06; |
165 | *(*buf)++ = (unsigned char) mech->len; | |
166 | TWRITE_STR(*buf, mech->data, ((int) mech->len)); | |
167 | } | |
168 | ||
7bd88269 | 169 | EXPORT_SYMBOL_GPL(g_make_token_header); |
1da177e4 LT |
170 | |
171 | /* | |
172 | * Given a buffer containing a token, reads and verifies the token, | |
173 | * leaving buf advanced past the token header, and setting body_size | |
174 | * to the number of remaining bytes. Returns 0 on success, | |
175 | * G_BAD_TOK_HEADER for a variety of errors, and G_WRONG_MECH if the | |
176 | * mechanism in the token does not match the mech argument. buf and | |
177 | * *body_size are left unmodified on error. | |
178 | */ | |
179 | u32 | |
180 | g_verify_token_header(struct xdr_netobj *mech, int *body_size, | |
181 | unsigned char **buf_in, int toksize) | |
182 | { | |
183 | unsigned char *buf = *buf_in; | |
184 | int seqsize; | |
185 | struct xdr_netobj toid; | |
186 | int ret = 0; | |
187 | ||
188 | if ((toksize-=1) < 0) | |
a02cec21 | 189 | return G_BAD_TOK_HEADER; |
1da177e4 | 190 | if (*buf++ != 0x60) |
a02cec21 | 191 | return G_BAD_TOK_HEADER; |
1da177e4 LT |
192 | |
193 | if ((seqsize = der_read_length(&buf, &toksize)) < 0) | |
a02cec21 | 194 | return G_BAD_TOK_HEADER; |
1da177e4 LT |
195 | |
196 | if (seqsize != toksize) | |
a02cec21 | 197 | return G_BAD_TOK_HEADER; |
1da177e4 LT |
198 | |
199 | if ((toksize-=1) < 0) | |
a02cec21 | 200 | return G_BAD_TOK_HEADER; |
1da177e4 | 201 | if (*buf++ != 0x06) |
a02cec21 | 202 | return G_BAD_TOK_HEADER; |
cca5172a | 203 | |
1da177e4 | 204 | if ((toksize-=1) < 0) |
a02cec21 | 205 | return G_BAD_TOK_HEADER; |
1da177e4 LT |
206 | toid.len = *buf++; |
207 | ||
208 | if ((toksize-=toid.len) < 0) | |
a02cec21 | 209 | return G_BAD_TOK_HEADER; |
1da177e4 LT |
210 | toid.data = buf; |
211 | buf+=toid.len; | |
212 | ||
cca5172a | 213 | if (! g_OID_equal(&toid, mech)) |
1da177e4 | 214 | ret = G_WRONG_MECH; |
cca5172a | 215 | |
1da177e4 LT |
216 | /* G_WRONG_MECH is not returned immediately because it's more important |
217 | to return G_BAD_TOK_HEADER if the token header is in fact bad */ | |
218 | ||
219 | if ((toksize-=2) < 0) | |
a02cec21 | 220 | return G_BAD_TOK_HEADER; |
1da177e4 LT |
221 | |
222 | if (ret) | |
a02cec21 | 223 | return ret; |
1da177e4 LT |
224 | |
225 | if (!ret) { | |
226 | *buf_in = buf; | |
227 | *body_size = toksize; | |
228 | } | |
229 | ||
a02cec21 | 230 | return ret; |
1da177e4 LT |
231 | } |
232 | ||
7bd88269 | 233 | EXPORT_SYMBOL_GPL(g_verify_token_header); |
1da177e4 | 234 |