1 /* 2 * lib/gssapi/krb5/set_allowable_enctypes.c 3 * 4 * Copyright 2004 by the Massachusetts Institute of Technology. 5 * All Rights Reserved. 6 * 7 * Export of this software from the United States of America may 8 * require a specific license from the United States Government. 9 * It is the responsibility of any person or organization contemplating 10 * export to obtain such a license before exporting. 11 * 12 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and 13 * distribute this software and its documentation for any purpose and 14 * without fee is hereby granted, provided that the above copyright 15 * notice appear in all copies and that both that copyright notice and 16 * this permission notice appear in supporting documentation, and that 17 * the name of M.I.T. not be used in advertising or publicity pertaining 18 * to distribution of the software without specific, written prior 19 * permission. Furthermore if you modify this software you must label 20 * your software as modified software and not distribute it in such a 21 * fashion that it might be confused with the original M.I.T. software. 22 * M.I.T. makes no representations about the suitability of 23 * this software for any purpose. It is provided "as is" without express 24 * or implied warranty. 25 * 26 * krb5_gss_set_allowable_enctypes() 27 */ 28 29 /* 30 * gss_krb5_set_allowable_enctypes 31 * 32 * This function may be called by a context initiator after calling 33 * gss_acquire_cred(), but before calling gss_init_sec_context(), 34 * to restrict the set of enctypes which will be negotiated during 35 * context establishment to those in the provided array. 36 * 37 * 'cred_handle' must be a valid credential handle obtained via 38 * gss_acquire_cred(). It may not be GSS_C_NO_CREDENTIAL. 39 * gss_acquire_cred() may be called with GSS_C_NO_CREDENTIAL 40 * to get a handle to the default credential. 41 * 42 * The purpose of this function is to limit the keys that may 43 * be exported via gss_krb5_export_lucid_sec_context(); thus it 44 * should limit the enctypes of all keys that will be needed 45 * after the security context has been established. 46 * (i.e. context establishment may use a session key with a 47 * stronger enctype than in the provided array, however a 48 * subkey must be established within the enctype limits 49 * established by this function.) 50 * 51 */ 52 53 #include "gssapiP_krb5.h" 54 #ifdef HAVE_STRING_H 55 #include <string.h> 56 #else 57 #include <strings.h> 58 #endif 59 #include "gssapi_krb5.h" 60 61 OM_uint32 KRB5_CALLCONV 62 gss_krb5int_set_allowable_enctypes(OM_uint32 *minor_status, 63 gss_cred_id_t cred_handle, 64 OM_uint32 num_ktypes, 65 krb5_enctype *ktypes) 66 { 67 int i; 68 krb5_enctype * new_ktypes; 69 OM_uint32 major_status; 70 krb5_gss_cred_id_t cred; 71 krb5_error_code kerr = 0; 72 OM_uint32 temp_status; 73 74 /* Assume a failure */ 75 *minor_status = 0; 76 major_status = GSS_S_FAILURE; 77 78 /* verify and valildate cred handle */ 79 if (cred_handle == GSS_C_NO_CREDENTIAL) { 80 kerr = KRB5_NOCREDS_SUPPLIED; 81 goto error_out; 82 } 83 major_status = krb5_gss_validate_cred(&temp_status, cred_handle); 84 if (GSS_ERROR(major_status)) { 85 kerr = temp_status; 86 goto error_out; 87 } 88 cred = (krb5_gss_cred_id_t) cred_handle; 89 90 if (ktypes) { 91 for (i = 0; i < num_ktypes && ktypes[i]; i++) { 92 if (!krb5_c_valid_enctype(ktypes[i])) { 93 kerr = KRB5_PROG_ETYPE_NOSUPP; 94 goto error_out; 95 } 96 } 97 } else { 98 kerr = k5_mutex_lock(&cred->lock); 99 if (kerr) 100 goto error_out; 101 if (cred->req_enctypes) 102 free(cred->req_enctypes); 103 cred->req_enctypes = NULL; 104 k5_mutex_unlock(&cred->lock); 105 return GSS_S_COMPLETE; 106 } 107 108 /* Copy the requested ktypes into the cred structure */ 109 if ((new_ktypes = (krb5_enctype *)malloc(sizeof(krb5_enctype) * (i + 1)))) { 110 memcpy(new_ktypes, ktypes, sizeof(krb5_enctype) * i); 111 new_ktypes[i] = 0; /* "null-terminate" the list */ 112 } 113 else { 114 kerr = ENOMEM; 115 goto error_out; 116 } 117 kerr = k5_mutex_lock(&cred->lock); 118 if (kerr) { 119 free(new_ktypes); 120 goto error_out; 121 } 122 if (cred->req_enctypes) 123 free(cred->req_enctypes); 124 cred->req_enctypes = new_ktypes; 125 k5_mutex_unlock(&cred->lock); 126 127 /* Success! */ 128 return GSS_S_COMPLETE; 129 130 error_out: 131 *minor_status = kerr; 132 return(major_status); 133 } 134