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freeipa/ipa-client/ipa-getkeytab.c
Rob Crittenden 4d8a255c06 Fix segfault in ipa-getkeytab 
463548
2008-09-24 18:04:28 -04:00

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/* Authors: Simo Sorce <ssorce@redhat.com>
*
* Copyright (C) 2007 Red Hat
* see file 'COPYING' for use and warranty information
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; version 2 only
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/time.h>
#include <unistd.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <time.h>
#define KRB5_PRIVATE 1
#include <krb5.h>
#ifdef WITH_MOZLDAP
#include <mozldap/ldap.h>
#else
#include <ldap.h>
#endif
#include <sasl/sasl.h>
#include <popt.h>
/* Salt types */
#define NO_SALT -1
#define KRB5_KDB_SALTTYPE_NORMAL 0
#define KRB5_KDB_SALTTYPE_V4 1
#define KRB5_KDB_SALTTYPE_NOREALM 2
#define KRB5_KDB_SALTTYPE_ONLYREALM 3
#define KRB5_KDB_SALTTYPE_SPECIAL 4
#define KRB5_KDB_SALTTYPE_AFS3 5
#define KEYTAB_SET_OID "2.16.840.1.113730.3.8.3.1"
#define KEYTAB_RET_OID "2.16.840.1.113730.3.8.3.2"
struct krb_key_salt {
krb5_enctype enctype;
krb5_int32 salttype;
krb5_keyblock key;
krb5_data salt;
};
struct keys_container {
krb5_int32 nkeys;
struct krb_key_salt *ksdata;
};
static int ldap_sasl_interact(LDAP *ld, unsigned flags, void *priv_data, void *sit)
{
sasl_interact_t *in = NULL;
int ret = LDAP_OTHER;
krb5_principal princ = (krb5_principal)priv_data;
if (!ld) return LDAP_PARAM_ERROR;
for (in = sit; in && in->id != SASL_CB_LIST_END; in++) {
switch(in->id) {
case SASL_CB_USER:
in->result = princ->data[0].data;
in->len = princ->data[0].length;
ret = LDAP_SUCCESS;
break;
case SASL_CB_GETREALM:
in->result = princ->realm.data;
in->len = princ->realm.length;
ret = LDAP_SUCCESS;
break;
default:
in->result = NULL;
in->len = 0;
ret = LDAP_OTHER;
}
}
return ret;
}
static void free_keys_contents(krb5_context krbctx, struct keys_container *keys)
{
struct krb_key_salt *ksdata;
int i;
ksdata = keys->ksdata;
for (i = 0; i < keys->nkeys; i++) {
krb5_free_keyblock_contents(krbctx, &ksdata[i].key);
krb5_free_data_contents(krbctx, &ksdata[i].salt);
}
free(ksdata);
keys->ksdata = NULL;
keys->nkeys = 0;
}
/* Determines Encryption and Salt types,
* allocates key_salt data storage,
* filters out equivalent encodings,
* returns 0 if no enctypes available, >0 if enctypes are available */
static int prep_ksdata(krb5_context krbctx, const char *str,
struct keys_container *keys)
{
struct krb_key_salt *ksdata;
krb5_error_code krberr;
int n, i, j, nkeys;
if (str == NULL) {
krb5_enctype *ktypes;
krberr = krb5_get_permitted_enctypes(krbctx, &ktypes);
if (krberr) {
fprintf(stderr, "No system preferred enctypes ?!\n");
return 0;
}
for (n = 0; ktypes[n]; n++) /* count */ ;
ksdata = calloc(n + 1, sizeof(struct krb_key_salt));
if (NULL == ksdata) {
fprintf(stderr, "Out of memory!?\n");
return 0;
}
for (i = 0; i < n; i++) {
ksdata[i].enctype = ktypes[i];
ksdata[i].salttype = KRB5_KDB_SALTTYPE_NORMAL;
}
krb5_free_ktypes(krbctx, ktypes);
nkeys = i;
} else {
char *tmp, *t, *p, *q;
t = tmp = strdup(str);
if (!tmp) {
fprintf(stderr, "Out of memory\n");
return 0;
}
/* count */
n = 0;
while ((p = strchr(t, ','))) {
t = p+1;
n++;
}
n++; /* count the last one that is 0 terminated instead */
/* at the end we will have at most n entries + 1 terminating */
ksdata = calloc(n + 1, sizeof(struct krb_key_salt));
if (!ksdata) {
fprintf(stderr, "Out of memory\n");
return 0;
}
for (i = 0, j = 0, t = tmp; i < n; i++) {
p = strchr(t, ',');
if (p) *p = '\0';
q = strchr(t, ':');
if (q) *q++ = '\0';
krberr = krb5_string_to_enctype(t, &ksdata[j].enctype);
if (krberr != 0) {
fprintf(stderr,
"Warning unrecognized encryption type: [%s]\n", t);
t = p+1;
continue;
}
t = p+1;
if (!q) {
ksdata[j].salttype = KRB5_KDB_SALTTYPE_NORMAL;
j++;
continue;
}
krberr = krb5_string_to_salttype(q, &ksdata[j].salttype);
if (krberr != 0) {
fprintf(stderr, "Warning unrecognized salt type: [%s]\n", q);
continue;
}
j++;
}
nkeys = j;
free(tmp);
}
/* Check we don't already have a key with a similar encoding,
* it would just produce redundant data and this is what the
* MIT code do anyway */
for (i = 0, n = 0; i < nkeys; i++ ) {
int similar = 0;
for (j = 0; j < i; j++) {
krberr = krb5_c_enctype_compare(krbctx,
ksdata[j].enctype,
ksdata[i].enctype,
&similar);
if (krberr) {
free_keys_contents(krbctx, keys);
fprintf(stderr, "Enctype comparison failed!\n");
return 0;
}
if (similar &&
(ksdata[j].salttype == ksdata[i].salttype)) {
break;
}
}
if (j < i) {
/* redundant encoding, remove it, and shift others */
int x;
for (x = i; x < nkeys-1; x++) {
ksdata[x].enctype = ksdata[x+1].enctype;
ksdata[x].salttype = ksdata[x+1].salttype;
}
continue;
}
/* count only confirmed enc/salt tuples */
n++;
}
keys->nkeys = n;
keys->ksdata = ksdata;
return n;
}
static int create_keys(krb5_context krbctx,
krb5_principal princ,
char *password,
const char *enctypes_string,
struct keys_container *keys)
{
struct krb_key_salt *ksdata;
krb5_error_code krberr;
krb5_data key_password;
krb5_data *realm;
int i, j, nkeys;
int ret;
ret = prep_ksdata(krbctx, enctypes_string, keys);
if (ret == 0) return 0;
ksdata = keys->ksdata;
nkeys = keys->nkeys;
if (password) {
key_password.data = password;
key_password.length = strlen(password);
realm = krb5_princ_realm(krbctx, princ);
}
for (i = 0; i < nkeys; i++) {
krb5_data *salt;
if (!password) {
/* cool, random keys */
krberr = krb5_c_make_random_key(krbctx,
ksdata[i].enctype,
&ksdata[i].key);
if (krberr) {
fprintf(stderr, "Failed to create random key!\n");
return 0;
}
/* set the salt to NO_SALT as the key was random */
ksdata[i].salttype = NO_SALT;
continue;
}
/* Make keys using password and required salt */
switch (ksdata[i].salttype) {
case KRB5_KDB_SALTTYPE_ONLYREALM:
krberr = krb5_copy_data(krbctx, realm, &salt);
if (krberr) {
fprintf(stderr, "Failed to create key!\n");
return 0;
}
ksdata[i].salt.length = salt->length;
ksdata[i].salt.data = malloc(salt->length);
if (!ksdata[i].salt.data) {
fprintf(stderr, "Out of memory!\n");
return 0;
}
memcpy(ksdata[i].salt.data, salt->data, salt->length);
krb5_free_data(krbctx, salt);
break;
case KRB5_KDB_SALTTYPE_NOREALM:
krberr = krb5_principal2salt_norealm(krbctx, princ, &ksdata[i].salt);
if (krberr) {
fprintf(stderr, "Failed to create key!\n");
return 0;
}
break;
case KRB5_KDB_SALTTYPE_NORMAL:
krberr = krb5_principal2salt(krbctx, princ, &ksdata[i].salt);
if (krberr) {
fprintf(stderr, "Failed to create key!\n");
return 0;
}
break;
/* no KRB5_KDB_SALTTYPE_V4, we do not support krb v4 */
case KRB5_KDB_SALTTYPE_AFS3:
/* Comment from MIT sources:
* * Why do we do this? Well, the afs_mit_string_to_key
* * needs to use strlen, and the realm is not NULL
* * terminated....
*/
ksdata[i].salt.data = (char *)malloc(realm->length + 1);
if (NULL == ksdata[i].salt.data) {
fprintf(stderr, "Out of memory!\n");
return 0;
}
memcpy((char *)ksdata[i].salt.data,
(char *)realm->data, realm->length);
ksdata[i].salt.data[realm->length] = '\0';
/* AFS uses a special length (UGLY) */
ksdata[i].salt.length = SALT_TYPE_AFS_LENGTH;
break;
default:
fprintf(stderr, "Bad or unsupported salt type (%d)!\n",
ksdata[i].salttype);
return 0;
}
krberr = krb5_c_string_to_key(krbctx,
ksdata[i].enctype,
&key_password,
&ksdata[i].salt,
&ksdata[i].key);
if (krberr) {
fprintf(stderr, "Failed to create key!\n");
return 0;
}
/* set back salt length to real value if AFS3 */
if (ksdata[i].salttype == KRB5_KDB_SALTTYPE_AFS3) {
ksdata[i].salt.length = realm->length;
}
}
return nkeys;
}
static struct berval *create_key_control(struct keys_container *keys,
const char *principalName)
{
struct krb_key_salt *ksdata;
struct berval *bval;
BerElement *be;
int ret, i;
be = ber_alloc_t(LBER_USE_DER);
if (!be) {
return NULL;
}
ret = ber_printf(be, "{s{", principalName);
if (ret == -1) {
ber_free(be, 1);
return NULL;
}
ksdata = keys->ksdata;
for (i = 0; i < keys->nkeys; i++) {
/* we set only the EncryptionKey and salt, no s2kparams */
ret = ber_printf(be, "{t[{t[i]t[o]}]",
(ber_tag_t)(LBER_CONSTRUCTED | LBER_CLASS_CONTEXT | 0),
(ber_tag_t)(LBER_CONSTRUCTED | LBER_CLASS_CONTEXT | 0),
(ber_int_t)ksdata[i].enctype,
(ber_tag_t)(LBER_CONSTRUCTED | LBER_CLASS_CONTEXT | 1),
(char *)ksdata[i].key.contents, (ber_len_t)ksdata[i].key.length);
if (ret == -1) {
ber_free(be, 1);
return NULL;
}
if (ksdata[i].salttype == NO_SALT) {
ret = ber_printf(be, "}");
continue;
}
/* we have to pass a salt structure */
ret = ber_printf(be, "t[{t[i]t[o]}]}",
(ber_tag_t)(LBER_CONSTRUCTED | LBER_CLASS_CONTEXT | 1),
(ber_tag_t)(LBER_CONSTRUCTED | LBER_CLASS_CONTEXT | 0),
(ber_int_t)ksdata[i].salttype,
(ber_tag_t)(LBER_CONSTRUCTED | LBER_CLASS_CONTEXT | 1),
(char *)ksdata[i].salt.data, (ber_len_t)ksdata[i].salt.length);
if (ret == -1) {
ber_free(be, 1);
return NULL;
}
}
ret = ber_printf(be, "}}");
if (ret == -1) {
ber_free(be, 1);
return NULL;
}
ret = ber_flatten(be, &bval);
if (ret == -1) {
ber_free(be, 1);
return NULL;
}
ber_free(be, 1);
return bval;
}
int filter_keys(krb5_context krbctx, struct keys_container *keys,
ber_int_t *enctypes)
{
struct krb_key_salt *ksdata;
int i, j, n;
n = keys->nkeys;
ksdata = keys->ksdata;
for (i = 0; i < n; i++) {
if (ksdata[i].enctype == enctypes[i]) continue;
if (enctypes[i] == 0) {
/* remove unsupported one */
krb5_free_keyblock_contents(krbctx, &ksdata[i].key);
krb5_free_data_contents(krbctx, &ksdata[i].salt);
for (j = i; j < n-1; j++) {
keys[j] = keys[j + 1];
}
n--;
/* new key has been moved to this position, make sure
* we do not skip it, by neutralizing next i increment */
i--;
}
}
if (n == 0) {
fprintf(stderr, "No keys accepted by KDC\n");
return 0;
}
keys->nkeys = n;
return n;
}
static int ldap_set_keytab(krb5_context krbctx,
const char *servername,
const char *principal_name,
krb5_principal princ,
struct keys_container *keys)
{
int version;
LDAP *ld = NULL;
BerElement *sctrl = NULL;
struct berval *control = NULL;
char *retoid = NULL;
struct berval *retdata = NULL;
struct timeval tv;
LDAPMessage *res = NULL;
LDAPControl **srvctrl = NULL;
LDAPControl *pprc = NULL;
char *err = NULL;
int msgid;
int ret, rc;
int kvno, i;
ber_tag_t rtag;
ber_int_t *encs = NULL;
/* cant' return more than nkeys, sometimes less */
encs = calloc(keys->nkeys + 1, sizeof(ber_int_t));
if (!encs) {
fprintf(stderr, "Out of Memory!\n");
return 0;
}
/* build password change control */
control = create_key_control(keys, principal_name);
if (!control) {
fprintf(stderr, "Failed to create control!\n");
goto error_out;
}
/* TODO: support referrals ? */
ld = ldap_init(servername, 389);
if(ld == NULL) {
fprintf(stderr, "Unable to initialize ldap library!\n");
goto error_out;
}
version = LDAP_VERSION3;
ret = ldap_set_option(ld, LDAP_OPT_PROTOCOL_VERSION, &version);
if (ret != LDAP_SUCCESS) {
fprintf(stderr, "Unable to set ldap options!\n");
goto error_out;
}
ret = ldap_sasl_interactive_bind_s(ld,
NULL, "GSSAPI",
NULL, NULL,
LDAP_SASL_QUIET,
ldap_sasl_interact, princ);
if (ret != LDAP_SUCCESS) {
fprintf(stderr, "SASL Bind failed!\n");
goto error_out;
}
/* find base dn */
/* TODO: address the case where we have multiple naming contexts */
tv.tv_sec = 10;
tv.tv_usec = 0;
/* perform password change */
ret = ldap_extended_operation(ld,
KEYTAB_SET_OID,
control, NULL, NULL,
&msgid);
if (ret != LDAP_SUCCESS) {
fprintf(stderr, "Operation failed! %s\n", ldap_err2string(ret));
goto error_out;
}
ber_bvfree(control);
control = NULL;
tv.tv_sec = 10;
tv.tv_usec = 0;
ret = ldap_result(ld, msgid, 1, &tv, &res);
if (ret == -1) {
fprintf(stderr, "Operation failed! %s\n", ldap_err2string(ret));
goto error_out;
}
ret = ldap_parse_extended_result(ld, res, &retoid, &retdata, 0);
if(ret != LDAP_SUCCESS) {
fprintf(stderr, "Operation failed! %s\n", ldap_err2string(ret));
goto error_out;
}
ret = ldap_parse_result(ld, res, &rc, NULL, &err, NULL, &srvctrl, 0);
if(ret != LDAP_SUCCESS || rc != LDAP_SUCCESS) {
fprintf(stderr, "Operation failed! %s\n", err?err:ldap_err2string(ret));
goto error_out;
}
if (!srvctrl) {
fprintf(stderr, "Missing reply control!\n");
goto error_out;
}
for (i = 0; srvctrl[i]; i++) {
if (0 == strcmp(srvctrl[i]->ldctl_oid, KEYTAB_RET_OID)) {
pprc = srvctrl[i];
}
}
if (!pprc) {
fprintf(stderr, "Missing reply control!\n");
goto error_out;
}
sctrl = ber_init(&pprc->ldctl_value);
if (!sctrl) {
fprintf(stderr, "ber_init() failed, Invalid control ?!\n");
goto error_out;
}
/* Format of response
*
* KeytabGetRequest ::= SEQUENCE {
* new_kvno Int32
* SEQUENCE OF KeyTypes
* }
*
* * List of accepted enctypes *
* KeyTypes ::= SEQUENCE {
* enctype Int32
* }
*/
rtag = ber_scanf(sctrl, "{i{", &kvno);
if (rtag == LBER_ERROR) {
fprintf(stderr, "ber_scanf() failed, Invalid control ?!\n");
goto error_out;
}
for (i = 0; i < keys->nkeys; i++) {
ret = ber_scanf(sctrl, "{i}", &encs[i]);
if (ret == LBER_ERROR) break;
}
ret = filter_keys(krbctx, keys, encs);
if (ret == 0) goto error_out;
if (err) ldap_memfree(err);
ber_free(sctrl, 1);
ldap_controls_free(srvctrl);
ldap_msgfree(res);
ldap_unbind_ext(ld, NULL, NULL);
return kvno;
error_out:
if (sctrl) ber_free(sctrl, 1);
if (srvctrl) ldap_controls_free(srvctrl);
if (err) ldap_memfree(err);
if (res) ldap_msgfree(res);
if (ld) ldap_unbind_ext(ld, NULL, NULL);
if (control) ber_bvfree(control);
free(encs);
return 0;
}
static char *ask_password(krb5_context krbctx)
{
krb5_prompt ap_prompts[2];
krb5_data k5d_pw0;
krb5_data k5d_pw1;
char pw0[256];
char pw1[256];
char *password;
k5d_pw0.length = sizeof(pw0);
k5d_pw0.data = pw0;
ap_prompts[0].prompt = "New Principal Password";
ap_prompts[0].hidden = 1;
ap_prompts[0].reply = &k5d_pw0;
k5d_pw1.length = sizeof(pw1);
k5d_pw1.data = pw1;
ap_prompts[1].prompt = "Verify Principal Password";
ap_prompts[1].hidden = 1;
ap_prompts[1].reply = &k5d_pw1;
krb5_prompter_posix(krbctx, NULL,
NULL, NULL,
2, ap_prompts);
if (strcmp(pw0, pw1)) {
fprintf(stderr, "Passwords do not match!");
return NULL;
}
password = malloc(k5d_pw0.length + 1);
if (!password) return NULL;
memcpy(password, pw0, k5d_pw0.length);
password[k5d_pw0.length] = '\0';
return password;
}
int main(int argc, char *argv[])
{
static const char *server = NULL;
static const char *principal = NULL;
static const char *keytab = NULL;
static const char *enctypes_string = NULL;
int quiet = 0;
int askpass = 0;
int permitted_enctypes = 0;
struct poptOption options[] = {
{ "quiet", 'q', POPT_ARG_NONE, &quiet, 0, "Print as little as possible", "Output only on errors"},
{ "server", 's', POPT_ARG_STRING, &server, 0, "Contact this specific KDC Server", "Server Name" },
{ "principal", 'p', POPT_ARG_STRING, &principal, 0, "The principal to get a keytab for (ex: ftp/ftp.example.com@EXAMPLE.COM)", "Kerberos Service Principal Name" },
{ "keytab", 'k', POPT_ARG_STRING, &keytab, 0, "File were to store the keytab information", "Keytab File Name" },
{ "enctypes", 'e', POPT_ARG_STRING, &enctypes_string, 0, "Encryption types to request", "Comma separated encryption types list" },
{ "permitted-enctypes", 0, POPT_ARG_NONE, &permitted_enctypes, 0, "Show the list of permitted encryption types and exit", "Permitted Encryption Types"},
{ "password", 'P', POPT_ARG_NONE, &askpass, 0, "Asks for a non-random password to use for the principal" },
{ NULL, 0, POPT_ARG_NONE, NULL, 0, NULL, NULL }
};
poptContext pc;
char *ktname;
char *password = NULL;
krb5_context krbctx;
krb5_ccache ccache;
krb5_principal uprinc;
krb5_principal sprinc;
krb5_error_code krberr;
ber_int_t *enctypes;
struct keys_container keys;
krb5_keytab kt;
int kvno;
int i, ret;
krberr = krb5_init_context(&krbctx);
if (krberr) {
fprintf(stderr, "Kerberos context initialization failed\n");
exit(1);
}
pc = poptGetContext("ipa-getkeytab", argc, (const char **)argv, options, 0);
ret = poptGetNextOpt(pc);
if (ret == -1 && permitted_enctypes &&
!(server || principal || keytab || quiet)) {
krb5_enctype *ktypes;
char enc[79]; /* fit std terminal or truncate */
krberr = krb5_get_permitted_enctypes(krbctx, &ktypes);
if (krberr) {
fprintf(stderr, "No system preferred enctypes ?!\n");
exit(1);
}
fprintf(stdout, "Supported encryption types:\n");
for (i = 0; ktypes[i]; i++) {
krberr = krb5_enctype_to_string(ktypes[i], enc, 79);
if (krberr) {
fprintf(stderr, "Warning: failed to convert type (#%d)\n", i);
continue;
}
fprintf(stdout, "%s\n", enc);
}
krb5_free_ktypes(krbctx, ktypes);
exit (0);
}
if (ret != -1 || !server || !principal || !keytab || permitted_enctypes) {
if (!quiet) {
poptPrintUsage(pc, stderr, 0);
}
exit(2);
}
if (askpass) {
password = ask_password(krbctx);
if (!password) {
exit(2);
}
} else if (enctypes_string && strchr(enctypes_string, ':')) {
if (!quiet) {
fprintf(stderr, "Warning: salt types are not honored with randomized passwords (see opt. -P)\n");
}
}
ret = asprintf(&ktname, "WRFILE:%s", keytab);
if (ret == -1) {
exit(3);
}
krberr = krb5_parse_name(krbctx, principal, &sprinc);
if (krberr) {
fprintf(stderr, "Invalid Service Principal Name\n");
exit(4);
}
krberr = krb5_cc_default(krbctx, &ccache);
if (krberr) {
fprintf(stderr, "Kerberos Credential Cache not found\n"
"Do you have a Kerberos Ticket?\n");
exit(5);
}
krberr = krb5_cc_get_principal(krbctx, ccache, &uprinc);
if (krberr) {
fprintf(stderr, "Kerberos User Principal not found\n"
"Do you have a valid Credential Cache?\n");
exit(6);
}
krberr = krb5_kt_resolve(krbctx, ktname, &kt);
if (krberr) {
fprintf(stderr, "Failed to open Keytab\n");
exit(7);
}
/* create key material */
ret = create_keys(krbctx, sprinc, password, enctypes_string, &keys);
if (!ret) {
fprintf(stderr, "Failed to create key material\n");
exit(8);
}
kvno = ldap_set_keytab(krbctx, server, principal, uprinc, &keys);
if (!kvno) {
exit(9);
}
for (i = 0; i < keys.nkeys; i++) {
krb5_keytab_entry kt_entry;
memset((char *)&kt_entry, 0, sizeof(kt_entry));
kt_entry.principal = sprinc;
kt_entry.key = keys.ksdata[i].key;
kt_entry.vno = kvno;
krberr = krb5_kt_add_entry(krbctx, kt, &kt_entry);
if (krberr) {
fprintf(stderr, "Failed to add key to the keytab\n");
exit (11);
}
}
free_keys_contents(krbctx, &keys);
krberr = krb5_kt_close(krbctx, kt);
if (krberr) {
fprintf(stderr, "Failed to close the keytab\n");
exit (12);
}
if (!quiet) {
fprintf(stderr,
"Keytab successfully retrieved and stored in: %s\n",
keytab);
}
exit(0);
}
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