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54 #include "gssapiP_eap.h"
57 * $Id: util_token.c 23457 2009-12-08 00:04:48Z tlyu $
60 /* XXXX this code currently makes the assumption that a mech oid will
61 never be longer than 127 bytes. This assumption is not inherent in
62 the interfaces, so the code can be fixed if the OSI namespace
63 balloons unexpectedly. */
66 * Each token looks like this:
67 * 0x60 tag for APPLICATION 0, SEQUENCE
68 * (constructed, definite-length)
69 * <length> possible multiple bytes, need to parse/generate
70 * 0x06 tag for OBJECT IDENTIFIER
71 * <moid_length> compile-time constant string (assume 1 byte)
72 * <moid_bytes> compile-time constant string
73 * <inner_bytes> the ANY containing the application token
74 * bytes 0,1 are the token type
75 * bytes 2,n are the token data
77 * Note that the token type field is a feature of RFC 1964 mechanisms and
78 * is not used by other GSSAPI mechanisms. As such, a token type of -1
79 * is interpreted to mean that no token type should be expected or
82 * For the purposes of this abstraction, the token "header" consists of
83 * the sequence tag and length octets, the mech OID DER encoding, and the
84 * first two inner bytes, which indicate the token type. The token
85 * "body" consists of everything else.
89 der_length_size(size_t length)
93 else if (length < (1<<8))
99 else if (length < (1<<16))
101 else if (length < (1<<24))
109 der_write_length(unsigned char **buf, size_t length)
111 if (length < (1<<7)) {
112 *(*buf)++ = (unsigned char)length;
114 *(*buf)++ = (unsigned char)(der_length_size(length)+127);
116 if (length >= (1<<24))
117 *(*buf)++ = (unsigned char)(length>>24);
118 if (length >= (1<<16))
119 *(*buf)++ = (unsigned char)((length>>16)&0xff);
121 if (length >= (1<<8))
122 *(*buf)++ = (unsigned char)((length>>8)&0xff);
123 *(*buf)++ = (unsigned char)(length&0xff);
127 /* returns decoded length, or < 0 on failure. Advances buf and
128 decrements bufsize */
131 der_read_length(unsigned char **buf, ssize_t *bufsize)
142 if ((sf &= 0x7f) > ((*bufsize)-1))
144 if (sf > sizeof(int))
148 ret = (ret<<8) + (*(*buf)++);
158 /* returns the length of a token, given the mech oid and the body size */
161 tokenSize(const gss_OID_desc *mech, size_t body_size)
163 /* set body_size to sequence contents size */
164 body_size += 4 + (size_t) mech->length; /* NEED overflow check */
165 return 1 + der_length_size(body_size) + body_size;
168 /* fills in a buffer with the token header. The buffer is assumed to
169 be the right size. buf is advanced past the token header */
173 const gss_OID_desc *mech,
176 enum gss_eap_token_type tok_type)
179 der_write_length(buf, (tok_type == -1) ?2:4 + mech->length + body_size);
181 *(*buf)++ = (unsigned char)mech->length;
182 memcpy(*buf, mech->elements, mech->length);
183 *buf += mech->length;
184 if (tok_type != TOK_TYPE_NONE) {
185 *(*buf)++ = (unsigned char)((tok_type>>8) & 0xff);
186 *(*buf)++ = (unsigned char)(tok_type & 0xff);
191 * Given a buffer containing a token, reads and verifies the token,
192 * leaving buf advanced past the token header, and setting body_size
193 * to the number of remaining bytes. Returns 0 on success,
194 * G_BAD_TOK_HEADER for a variety of errors, and G_WRONG_MECH if the
195 * mechanism in the token does not match the mech argument. buf and
196 * *body_size are left unmodified on error.
200 verifyTokenHeader(OM_uint32 *minor,
203 unsigned char **buf_in,
205 enum gss_eap_token_type tok_type)
207 unsigned char *buf = *buf_in;
210 ssize_t toksize = (ssize_t)toksize_in;
214 if ((toksize -= 1) < 0)
215 return GSS_S_DEFECTIVE_TOKEN;
218 return GSS_S_DEFECTIVE_TOKEN;
220 seqsize = der_read_length(&buf, &toksize);
222 return GSS_S_DEFECTIVE_TOKEN;
224 if (seqsize != toksize)
225 return GSS_S_DEFECTIVE_TOKEN;
227 if ((toksize -= 1) < 0)
228 return GSS_S_DEFECTIVE_TOKEN;
231 return GSS_S_DEFECTIVE_TOKEN;
233 if ((toksize -= 1) < 0)
234 return GSS_S_DEFECTIVE_TOKEN;
236 toid.length = *buf++;
238 if ((toksize -= toid.length) < 0)
239 return GSS_S_DEFECTIVE_TOKEN;
244 if (mech->elements == NULL) {
246 if (toid.length == 0)
247 return GSS_S_BAD_MECH;
248 } else if (!oidEqual(&toid, mech)) {
249 return GSS_S_BAD_MECH;
252 if (tok_type != TOK_TYPE_NONE) {
253 if ((toksize -= 2) < 0)
254 return GSS_S_DEFECTIVE_TOKEN;
256 if ((*buf++ != ((tok_type >> 8) & 0xff)) ||
257 (*buf++ != (tok_type & 0xff)))
258 return GSS_S_DEFECTIVE_TOKEN;
261 *body_size = toksize;
263 return GSS_S_COMPLETE;