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      1 #pragma ident	"%Z%%M%	%I%	%E% SMI"
      2 
      3 /*
      4  * lib/gssapi/krb5/set_allowable_enctypes.c
      5  *
      6  * Copyright 2004  by the Massachusetts Institute of Technology.
      7  * All Rights Reserved.
      8  *
      9  * Export of this software from the United States of America may
     10  *   require a specific license from the United States Government.
     11  *   It is the responsibility of any person or organization contemplating
     12  *   export to obtain such a license before exporting.
     13  *
     14  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
     15  * distribute this software and its documentation for any purpose and
     16  * without fee is hereby granted, provided that the above copyright
     17  * notice appear in all copies and that both that copyright notice and
     18  * this permission notice appear in supporting documentation, and that
     19  * the name of M.I.T. not be used in advertising or publicity pertaining
     20  * to distribution of the software without specific, written prior
     21  * permission.  Furthermore if you modify this software you must label
     22  * your software as modified software and not distribute it in such a
     23  * fashion that it might be confused with the original M.I.T. software.
     24  * M.I.T. makes no representations about the suitability of
     25  * this software for any purpose.  It is provided "as is" without express
     26  * or implied warranty.
     27  *
     28  * krb5_gss_set_allowable_enctypes()
     29  */
     30 
     31 /*
     32  * gss_krb5_set_allowable_enctypes
     33  *
     34  * This function may be called by a context initiator after calling
     35  * gss_acquire_cred(), but before calling gss_init_sec_context(),
     36  * to restrict the set of enctypes which will be negotiated during
     37  * context establishment to those in the provided array.
     38  *
     39  * 'cred_handle' must be a valid credential handle obtained via
     40  * gss_acquire_cred().  It may not be GSS_C_NO_CREDENTIAL.
     41  * gss_acquire_cred() may be called with GSS_C_NO_CREDENTIAL
     42  * to get a handle to the default credential.
     43  *
     44  * The purpose of this function is to limit the keys that may
     45  * be exported via gss_krb5_export_lucid_sec_context(); thus it
     46  * should limit the enctypes of all keys that will be needed
     47  * after the security context has been established.
     48  * (i.e. context establishment may use a session key with a
     49  * stronger enctype than in the provided array, however a
     50  * subkey must be established within the enctype limits
     51  * established by this function.)
     52  *
     53  */
     54 
     55 #include "gssapiP_krb5.h"
     56 #ifdef HAVE_STRING_H
     57 #include <string.h>
     58 #else
     59 #include <strings.h>
     60 #endif
     61 #include "gssapi_krb5.h"
     62 
     63 OM_uint32 KRB5_CALLCONV
     64 gss_krb5int_set_allowable_enctypes(OM_uint32 *minor_status,
     65 				   gss_cred_id_t cred_handle,
     66 				   OM_uint32 num_ktypes,
     67 				   krb5_enctype *ktypes)
     68 {
     69     int i;
     70     krb5_enctype * new_ktypes;
     71     OM_uint32 major_status;
     72     krb5_gss_cred_id_t cred;
     73     krb5_error_code kerr = 0;
     74     OM_uint32 temp_status;
     75 
     76     /* Assume a failure */
     77     *minor_status = 0;
     78     major_status = GSS_S_FAILURE;
     79 
     80     /* verify and valildate cred handle */
     81     if (cred_handle == GSS_C_NO_CREDENTIAL) {
     82 	kerr = KRB5_NOCREDS_SUPPLIED;
     83 	goto error_out;
     84     }
     85     major_status = krb5_gss_validate_cred(&temp_status, cred_handle);
     86     if (GSS_ERROR(major_status)) {
     87 	kerr = temp_status;
     88 	goto error_out;
     89     }
     90     cred = (krb5_gss_cred_id_t) cred_handle;
     91 
     92     if (ktypes) {
     93 	for (i = 0; i < num_ktypes && ktypes[i]; i++) {
     94 	    if (!krb5_c_valid_enctype(ktypes[i])) {
     95 		kerr = KRB5_PROG_ETYPE_NOSUPP;
     96 		goto error_out;
     97 	    }
     98 	}
     99     } else {
    100 	kerr = k5_mutex_lock(&cred->lock);
    101 	if (kerr)
    102 	    goto error_out;
    103 	if (cred->req_enctypes)
    104 	    free(cred->req_enctypes);
    105 	cred->req_enctypes = NULL;
    106 	k5_mutex_unlock(&cred->lock);
    107 	return GSS_S_COMPLETE;
    108     }
    109 
    110     /* Copy the requested ktypes into the cred structure */
    111     if ((new_ktypes = (krb5_enctype *)malloc(sizeof(krb5_enctype) * (i + 1)))) {
    112 	memcpy(new_ktypes, ktypes, sizeof(krb5_enctype) * i);
    113 	new_ktypes[i] = 0;	/* "null-terminate" the list */
    114     }
    115     else {
    116 	kerr = ENOMEM;
    117 	goto error_out;
    118     }
    119     kerr = k5_mutex_lock(&cred->lock);
    120     if (kerr) {
    121 	free(new_ktypes);
    122 	goto error_out;
    123     }
    124     if (cred->req_enctypes)
    125 	free(cred->req_enctypes);
    126     cred->req_enctypes = new_ktypes;
    127     k5_mutex_unlock(&cred->lock);
    128 
    129     /* Success! */
    130     return GSS_S_COMPLETE;
    131 
    132 error_out:
    133     *minor_status = kerr;
    134     return(major_status);
    135 }
    136