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37 #include "gssapiP_eap.h"
39 static GSSEAP_THREAD_ONCE krbContextKeyOnce = GSSEAP_ONCE_INITIALIZER;
40 static GSSEAP_THREAD_KEY krbContextKey;
43 destroyKrbContext(void *arg)
45 krb5_context context = (krb5_context)arg;
48 krb5_free_context(context);
52 createKrbContextKey(void)
54 GSSEAP_KEY_CREATE(&krbContextKey, destroyKrbContext);
58 gssEapKerberosInit(OM_uint32 *minor, krb5_context *context)
62 GSSEAP_ONCE(&krbContextKeyOnce, createKrbContextKey);
64 *context = GSSEAP_GETSPECIFIC(krbContextKey);
65 if (*context == NULL) {
66 *minor = krb5_init_context(context);
68 if (GSSEAP_SETSPECIFIC(krbContextKey, *context) != 0) {
70 krb5_free_context(*context);
76 return *minor == 0 ? GSS_S_COMPLETE : GSS_S_FAILURE;
80 * Derive a key K for RFC 4121 use by using the following
81 * derivation function (based on RFC 4402);
83 * KMSK = random-to-key(MSK)
84 * Tn = pseudo-random(KMSK, n || "rfc4121-gss-eap")
86 * K = truncate(L, T1 || T2 || .. || Tn)
89 gssEapDeriveRfc3961Key(OM_uint32 *minor,
90 const unsigned char *inputKey,
91 size_t inputKeyLength,
92 krb5_enctype encryptionType,
95 krb5_context krbContext;
96 krb5_data data, ns, t, prfOut;
99 size_t randomLength, keyLength, prfLength;
100 unsigned char constant[4 + sizeof("rfc4121-gss-eap") - 1], *p;
103 assert(encryptionType != ENCTYPE_NULL);
105 memset(pKey, 0, sizeof(*pKey));
107 GSSEAP_KRB_INIT(&krbContext);
110 KRB_KEY_TYPE(&kd) = encryptionType;
118 code = krb5_c_keylengths(krbContext, encryptionType,
119 &randomLength, &keyLength);
123 data.length = MIN(inputKeyLength, randomLength);
124 data.data = (char *)inputKey;
126 KRB_KEY_DATA(&kd) = GSSEAP_MALLOC(keyLength);
127 if (KRB_KEY_DATA(&kd) == NULL) {
131 KRB_KEY_LENGTH(&kd) = keyLength;
133 /* Convert MSK into a Kerberos key */
134 code = krb5_c_random_to_key(krbContext, encryptionType, &data, &kd);
138 memset(&constant[0], 0, 4);
139 memcpy(&constant[4], "rfc4121-gss-eap", sizeof("rfc4121-gss-eap") - 1);
141 ns.length = sizeof(constant);
142 ns.data = (char *)constant;
144 /* Plug derivation constant and key into PRF */
145 code = krb5_c_prf_length(krbContext, encryptionType, &prfLength);
149 t.length = prfLength;
150 t.data = GSSEAP_MALLOC(t.length);
151 if (t.data == NULL) {
156 prfOut.length = randomLength;
157 prfOut.data = GSSEAP_MALLOC(prfOut.length);
158 if (prfOut.data == NULL) {
163 for (i = 0, p = (unsigned char *)prfOut.data, remain = randomLength;
165 p += t.length, remain -= t.length, i++)
167 store_uint32_be(i, ns.data);
169 code = krb5_c_prf(krbContext, &kd, &ns, &t);
173 memcpy(p, t.data, MIN(t.length, remain));
176 /* Finally, convert PRF output into a new key which we will return */
177 code = krb5_c_random_to_key(krbContext, encryptionType, &prfOut, &kd);
182 KRB_KEY_DATA(&kd) = NULL;
185 if (KRB_KEY_DATA(&kd) != NULL) {
186 memset(KRB_KEY_DATA(&kd), 0, KRB_KEY_LENGTH(&kd));
187 GSSEAP_FREE(KRB_KEY_DATA(&kd));
189 if (t.data != NULL) {
190 memset(t.data, 0, t.length);
193 if (prfOut.data != NULL) {
194 memset(prfOut.data, 0, prfOut.length);
195 GSSEAP_FREE(prfOut.data);
198 return (code == 0) ? GSS_S_COMPLETE : GSS_S_FAILURE;
201 #ifdef HAVE_KRB5INT_C_MANDATORY_CKSUMTYPE
202 extern krb5_error_code
203 krb5int_c_mandatory_cksumtype(krb5_context, krb5_enctype, krb5_cksumtype *);
207 rfc3961ChecksumTypeForKey(OM_uint32 *minor,
209 krb5_cksumtype *cksumtype)
211 krb5_context krbContext;
212 #ifndef HAVE_KRB5INT_C_MANDATORY_CKSUMTYPE
217 GSSEAP_KRB_INIT(&krbContext);
219 #ifdef HAVE_KRB5INT_C_MANDATORY_CKSUMTYPE
220 *minor = krb5int_c_mandatory_cksumtype(krbContext, KRB_KEY_TYPE(key),
223 return GSS_S_FAILURE;
228 memset(&cksum, 0, sizeof(cksum));
231 * This is a complete hack but it's the only way to work with
232 * MIT Kerberos pre-1.9 without using private API, as it does
233 * not support passing in zero as the checksum type.
235 *minor = krb5_c_make_checksum(krbContext, 0, key, 0, &data, &cksum);
237 return GSS_S_FAILURE;
239 *cksumtype = cksum.checksum_type;
241 krb5_free_checksum_contents(krbContext, &cksum);
242 #endif /* HAVE_KRB5INT_C_MANDATORY_CKSUMTYPE */
244 return GSS_S_COMPLETE;