sin/samba-mirror
1
0
Fork 0
mirror of https://github.com/samba-team/samba.git synced 2025-02-25 17:57:42 +03:00
Code

s4-auth-krb: Move keytab functions in a separate file.

Browse Source 
Confine ldb dependency.

Signed-off-by: Andreas Schneider <asn@samba.org>
This commit is contained in:
Simo Sorce 2012-03-30 19:33:53 -04:00 committed by Andreas Schneider
parent 7d203f70ae
commit b226955587
8 changed files with 754 additions and 710 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
auth/credentials/credentials_krb5.c
View File

@ -28,6 +28,7 @@
#include "auth/credentials/credentials_proto.h"
#include "auth/credentials/credentials_krb5.h"
#include "auth/kerberos/kerberos_credentials.h"
#include "auth/kerberos/kerberos_srv_keytab.h"
#include "auth/kerberos/kerberos_util.h"
#include "param/param.h"

4
auth/credentials/wscript_build Normal file → Executable file
View File

@ -11,13 +11,13 @@ bld.SAMBA_LIBRARY('samba-credentials',
bld.SAMBA_SUBSYSTEM('CREDENTIALS_KRB5',
source='credentials_krb5.c',
deps='KERBEROS_UTIL gssapi samba-credentials',
deps='KERBEROS_SRV_KEYTAB KERBEROS_UTIL gssapi samba-credentials',
public_deps='com_err authkrb5',
)
bld.SAMBA_SUBSYSTEM('CREDENTIALS_SECRETS',
source='credentials_secrets.c',
deps='CREDENTIALS_KRB5 CREDENTIALS_NTLM ldb samdb-common',
deps='CREDENTIALS_KRB5 CREDENTIALS_NTLM ldb SECRETS samdb-common',
)
bld.SAMBA_SUBSYSTEM('CREDENTIALS_NTLM',

6
source4/auth/kerberos/kerberos.h
View File

@ -40,6 +40,12 @@ struct keytab_container {
krb5_keytab keytab;
};
struct principal_container {
struct smb_krb5_context *smb_krb5_context;
krb5_principal principal;
const char *string_form; /* Optional */
};
/* not really ASN.1, but RFC 1964 */
#define TOK_ID_KRB_AP_REQ ((const uint8_t *)"\x01\x00")
#define TOK_ID_KRB_AP_REP ((const uint8_t *)"\x02\x00")

717
source4/auth/kerberos/kerberos_util.c
View File

@ -28,16 +28,8 @@
#include "auth/credentials/credentials_krb5.h"
#include "auth/kerberos/kerberos_credentials.h"
#include "auth/kerberos/kerberos_util.h"
#include <ldb.h>
#include "param/secrets.h"
struct principal_container {
struct smb_krb5_context *smb_krb5_context;
krb5_principal principal;
const char *string_form; /* Optional */
};
static krb5_error_code free_principal(struct principal_container *pc)
krb5_error_code free_principal(struct principal_container *pc)
{
/* current heimdal - 0.6.3, which we need anyway, fixes segfaults here */
krb5_free_principal(pc->smb_krb5_context->krb5_context, pc->principal);
@ -46,7 +38,7 @@ static krb5_error_code free_principal(struct principal_container *pc)
}
static krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
const char *princ_string,
struct smb_krb5_context *smb_krb5_context,
krb5_principal *princ,
@ -84,235 +76,6 @@ static krb5_error_code parse_principal(TALLOC_CTX *parent_ctx,
return 0;
}
static krb5_error_code principals_from_msg(TALLOC_CTX *parent_ctx,
struct ldb_message *msg,
struct smb_krb5_context *smb_krb5_context,
struct principal_container ***principals_out,
const char **error_string)
{
unsigned int i;
krb5_error_code ret;
char *upper_realm;
const char *realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);
const char *samAccountName = ldb_msg_find_attr_as_string(msg,
"samAccountName", NULL);
struct ldb_message_element *spn_el = ldb_msg_find_element(msg,
"servicePrincipalName");
TALLOC_CTX *tmp_ctx;
struct principal_container **principals;
tmp_ctx = talloc_new(parent_ctx);
if (!tmp_ctx) {
*error_string = "Cannot allocate tmp_ctx";
return ENOMEM;
}
if (!realm) {
*error_string = "Cannot have a kerberos secret in "
"secrets.ldb without a realm";
return EINVAL;
}
upper_realm = strupper_talloc(tmp_ctx, realm);
if (!upper_realm) {
talloc_free(tmp_ctx);
*error_string = "Cannot allocate full upper case realm";
return ENOMEM;
}
principals = talloc_array(tmp_ctx, struct principal_container *,
spn_el ? (spn_el->num_values + 2) : 2);
spn_el = ldb_msg_find_element(msg, "servicePrincipalName");
for (i=0; spn_el && i < spn_el->num_values; i++) {
principals[i] = talloc(principals, struct principal_container);
if (!principals[i]) {
talloc_free(tmp_ctx);
*error_string = "Cannot allocate mem_ctx";
return ENOMEM;
}
principals[i]->smb_krb5_context =
talloc_reference(principals[i], smb_krb5_context);
principals[i]->string_form =
talloc_asprintf(principals[i], "%*.*s@%s",
(int)spn_el->values[i].length,
(int)spn_el->values[i].length,
(const char *)spn_el->values[i].data,
upper_realm);
if (!principals[i]->string_form) {
talloc_free(tmp_ctx);
*error_string = "Cannot allocate full samAccountName";
return ENOMEM;
}
ret = krb5_parse_name(smb_krb5_context->krb5_context,
principals[i]->string_form,
&principals[i]->principal);
if (ret) {
talloc_free(tmp_ctx);
(*error_string) = smb_get_krb5_error_message(
smb_krb5_context->krb5_context,
ret, parent_ctx);
return ret;
}
/* This song-and-dance effectivly puts the principal
* into talloc, so we can't loose it. */
talloc_set_destructor(principals[i], free_principal);
}
if (samAccountName) {
principals[i] = talloc(principals, struct principal_container);
if (!principals[i]) {
talloc_free(tmp_ctx);
*error_string = "Cannot allocate mem_ctx";
return ENOMEM;
}
principals[i]->smb_krb5_context =
talloc_reference(principals[i], smb_krb5_context);
principals[i]->string_form =
talloc_asprintf(parent_ctx, "%s@%s",
samAccountName, upper_realm);
if (!principals[i]->string_form) {
talloc_free(tmp_ctx);
*error_string = "Cannot allocate full samAccountName";
return ENOMEM;
}
ret = krb5_make_principal(smb_krb5_context->krb5_context,
&principals[i]->principal,
upper_realm, samAccountName,
NULL);
if (ret) {
talloc_free(tmp_ctx);
(*error_string) = smb_get_krb5_error_message(
smb_krb5_context->krb5_context,
ret, parent_ctx);
return ret;
}
/* This song-and-dance effectively puts the principal
* into talloc, so we can't loose it. */
talloc_set_destructor(principals[i], free_principal);
i++;
}
principals[i] = NULL;
*principals_out = talloc_steal(parent_ctx, principals);
talloc_free(tmp_ctx);
return ret;
}
static krb5_error_code salt_principal_from_msg(TALLOC_CTX *parent_ctx,
struct ldb_message *msg,
struct smb_krb5_context *smb_krb5_context,
krb5_principal *salt_princ,
const char **error_string)
{
const char *salt_principal = ldb_msg_find_attr_as_string(msg,
"saltPrincipal", NULL);
const char *samAccountName = ldb_msg_find_attr_as_string(msg,
"samAccountName", NULL);
const char *realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);
struct principal_container *mem_ctx;
krb5_error_code ret;
char *machine_username;
char *salt_body;
char *lower_realm;
char *upper_realm;
TALLOC_CTX *tmp_ctx;
if (salt_principal) {
return parse_principal(parent_ctx, salt_principal,
smb_krb5_context, salt_princ,
error_string);
}
if (!samAccountName) {
(*error_string) = "Cannot determine salt principal, no "
"saltPrincipal or samAccountName specified";
return EINVAL;
}
mem_ctx = talloc(parent_ctx, struct principal_container);
if (!mem_ctx) {
*error_string = "Cannot allocate mem_ctx";
return ENOMEM;
}
tmp_ctx = talloc_new(mem_ctx);
if (!tmp_ctx) {
talloc_free(mem_ctx);
*error_string = "Cannot allocate tmp_ctx";
return ENOMEM;
}
if (!realm) {
*error_string = "Cannot have a kerberos secret in "
"secrets.ldb without a realm";
return EINVAL;
}
machine_username = talloc_strdup(tmp_ctx, samAccountName);
if (!machine_username) {
talloc_free(mem_ctx);
*error_string = "Cannot duplicate samAccountName";
return ENOMEM;
}
if (machine_username[strlen(machine_username)-1] == '$') {
machine_username[strlen(machine_username)-1] = '\0';
}
lower_realm = strlower_talloc(tmp_ctx, realm);
if (!lower_realm) {
talloc_free(mem_ctx);
*error_string = "Cannot allocate to lower case realm";
return ENOMEM;
}
upper_realm = strupper_talloc(tmp_ctx, realm);
if (!upper_realm) {
talloc_free(mem_ctx);
*error_string = "Cannot allocate to upper case realm";
return ENOMEM;
}
salt_body = talloc_asprintf(tmp_ctx, "%s.%s", machine_username,
lower_realm);
talloc_free(lower_realm);
talloc_free(machine_username);
if (!salt_body) {
talloc_free(mem_ctx);
*error_string = "Cannot form salt principal body";
return ENOMEM;
}
ret = krb5_make_principal(smb_krb5_context->krb5_context, salt_princ,
upper_realm,
"host", salt_body, NULL);
if (ret == 0) {
/* This song-and-dance effectively puts the principal
* into talloc, so we can't loose it. */
mem_ctx->smb_krb5_context = talloc_reference(mem_ctx,
smb_krb5_context);
mem_ctx->principal = *salt_princ;
talloc_set_destructor(mem_ctx, free_principal);
} else {
(*error_string) = smb_get_krb5_error_message(
smb_krb5_context->krb5_context,
ret, parent_ctx);
}
talloc_free(tmp_ctx);
return ret;
}
/* Obtain the principal set on this context. Requires a
* smb_krb5_context because we are doing krb5 principal parsing with
* the library routines. The returned princ is placed in the talloc
@ -557,16 +320,19 @@ static krb5_error_code free_keytab_container(struct keytab_container *ktc)
}
krb5_error_code smb_krb5_get_keytab_container(TALLOC_CTX *mem_ctx,
struct smb_krb5_context *smb_krb5_context,
const char *keytab_name, struct keytab_container **ktc)
struct smb_krb5_context *smb_krb5_context,
const char *keytab_name,
struct keytab_container **ktc)
{
krb5_keytab keytab;
krb5_error_code ret;
ret = krb5_kt_resolve(smb_krb5_context->krb5_context, keytab_name, &keytab);
ret = krb5_kt_resolve(smb_krb5_context->krb5_context,
keytab_name, &keytab);
if (ret) {
DEBUG(1,("failed to open krb5 keytab: %s\n",
smb_get_krb5_error_message(smb_krb5_context->krb5_context,
ret, mem_ctx)));
DEBUG(1,("failed to open krb5 keytab: %s\n",
smb_get_krb5_error_message(
smb_krb5_context->krb5_context,
ret, mem_ctx)));
return ret;
}
@ -582,423 +348,6 @@ krb5_error_code smb_krb5_get_keytab_container(TALLOC_CTX *mem_ctx,
return 0;
}
static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
struct principal_container **principals,
krb5_principal salt_princ,
int kvno,
const char *password_s,
krb5_context krb5_context,
krb5_enctype *enctypes,
krb5_keytab keytab,
const char **error_string)
{
unsigned int i, p;
krb5_error_code ret;
krb5_data password;
password.data = discard_const_p(char *, password_s);
password.length = strlen(password_s);
for (i = 0; enctypes[i]; i++) {
krb5_keytab_entry entry;
ZERO_STRUCT(entry);
ret = create_kerberos_key_from_string_direct(krb5_context,
salt_princ, &password,
&entry.keyblock, enctypes[i]);
if (ret != 0) {
return ret;
}
entry.vno = kvno;
for (p = 0; principals[p]; p++) {
entry.principal = principals[p]->principal;
ret = krb5_kt_add_entry(krb5_context,
keytab, &entry);
if (ret != 0) {
char *k5_error_string =
smb_get_krb5_error_message(
krb5_context, ret, NULL);
*error_string = talloc_asprintf(parent_ctx,
"Failed to add enctype %d entry for "
"%s(kvno %d) to keytab: %s\n",
(int)enctypes[i],
principals[p]->string_form,
kvno, k5_error_string);
talloc_free(k5_error_string);
krb5_free_keyblock_contents(krb5_context,
&entry.keyblock);
return ret;
}
DEBUG(5, ("Added %s(kvno %d) to keytab (enctype %d)\n",
principals[p]->string_form, kvno,
(int)enctypes[i]));
}
krb5_free_keyblock_contents(krb5_context, &entry.keyblock);
}
return 0;
}
static krb5_error_code ms_suptypes_to_ietf_enctypes(TALLOC_CTX *mem_ctx,
uint32_t enctype_bitmap,
krb5_enctype **enctypes);
static krb5_error_code create_keytab(TALLOC_CTX *parent_ctx,
struct ldb_message *msg,
struct principal_container **principals,
struct smb_krb5_context *smb_krb5_context,
krb5_keytab keytab,
bool add_old,
const char **error_string)
{
krb5_error_code ret;
const char *password_s;
const char *old_secret;
int kvno;
uint32_t enctype_bitmap;
krb5_principal salt_princ;
krb5_enctype *enctypes;
TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
if (!mem_ctx) {
*error_string = "unable to allocate tmp_ctx for create_keytab";
return ENOMEM;
}
/* The salt used to generate these entries may be different however,
* fetch that */
ret = salt_principal_from_msg(mem_ctx, msg,
smb_krb5_context,
&salt_princ, error_string);
if (ret) {
talloc_free(mem_ctx);
return ret;
}
kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
/* Finally, do the dance to get the password to put in the entry */
password_s = ldb_msg_find_attr_as_string(msg, "secret", NULL);
if (!password_s) {
/* There is no password here, so nothing to do */
talloc_free(mem_ctx);
return 0;
}
if (add_old && kvno != 0) {
old_secret = ldb_msg_find_attr_as_string(msg,
"priorSecret", NULL);
} else {
old_secret = NULL;
}
enctype_bitmap = (uint32_t)ldb_msg_find_attr_as_int(msg,
"msDS-SupportedEncryptionTypes",
ENC_ALL_TYPES);
ret = ms_suptypes_to_ietf_enctypes(mem_ctx, enctype_bitmap, &enctypes);
if (ret) {
*error_string = talloc_asprintf(parent_ctx,
"create_keytab: generating list of "
"encryption types failed (%s)\n",
smb_get_krb5_error_message(
smb_krb5_context->krb5_context,
ret, mem_ctx));
talloc_free(mem_ctx);
return ret;
}
ret = keytab_add_keys(mem_ctx, principals,
salt_princ, kvno, password_s,
smb_krb5_context->krb5_context,
enctypes, keytab, error_string);
if (ret) {
talloc_free(mem_ctx);
return ret;
}
if (old_secret) {
ret = keytab_add_keys(mem_ctx, principals,
salt_princ, kvno - 1, old_secret,
smb_krb5_context->krb5_context,
enctypes, keytab, error_string);
if (ret) {
talloc_free(mem_ctx);
return ret;
}
}
talloc_free(mem_ctx);
return ret;
}
/*
* Walk the keytab, looking for entries of this principal name,
* with KVNO other than current kvno -1.
*
* These entries are now stale,
* we only keep the current and previous entries around.
*
* Inspired by the code in Samba3 for 'use kerberos keytab'.
*/
static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
struct ldb_message *msg,
struct principal_container **principals,
bool delete_all_kvno,
krb5_context krb5_context,
krb5_keytab keytab,
bool *found_previous,
const char **error_string)
{
krb5_error_code ret, ret2;
krb5_kt_cursor cursor;
int kvno;
TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
if (!mem_ctx) {
return ENOMEM;
}
*found_previous = false;
kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
/* for each entry in the keytab */
ret = krb5_kt_start_seq_get(krb5_context, keytab, &cursor);
switch (ret) {
case 0:
break;
case HEIM_ERR_OPNOTSUPP:
case ENOENT:
case KRB5_KT_END:
/* no point enumerating if there isn't anything here */
talloc_free(mem_ctx);
return 0;
default:
*error_string = talloc_asprintf(parent_ctx,
"failed to open keytab for read of old entries: %s\n",
smb_get_krb5_error_message(krb5_context,
ret, mem_ctx));
talloc_free(mem_ctx);
return ret;
}
while (!ret) {
unsigned int i;
bool matched = false;
krb5_keytab_entry entry;
ret = krb5_kt_next_entry(krb5_context, keytab,
&entry, &cursor);
if (ret) {
break;
}
for (i = 0; principals[i]; i++) {
/* if it matches our principal */
if (krb5_kt_compare(krb5_context, &entry,
principals[i]->principal, 0, 0)) {
matched = true;
break;
}
}
if (!matched) {
/* Free the entry,
* it wasn't the one we were looking for anyway */
krb5_kt_free_entry(krb5_context, &entry);
continue;
}
/* delete it, if it is not kvno -1 */
if (entry.vno != (kvno - 1 )) {
/* Release the enumeration. We are going to
* have to start this from the top again,
* because deletes during enumeration may not
* always be consistent.
*
* Also, the enumeration locks a FILE: keytab
*/
krb5_kt_end_seq_get(krb5_context, keytab, &cursor);
ret = krb5_kt_remove_entry(krb5_context, keytab, &entry);
krb5_kt_free_entry(krb5_context, &entry);
/* Deleted: Restart from the top */
ret2 = krb5_kt_start_seq_get(krb5_context,
keytab, &cursor);
if (ret2) {
krb5_kt_free_entry(krb5_context, &entry);
DEBUG(1, ("failed to restart enumeration of keytab: %s\n",
smb_get_krb5_error_message(krb5_context,
ret, mem_ctx)));
talloc_free(mem_ctx);
return ret2;
}
if (ret) {
break;
}
} else {
*found_previous = true;
}
/* Free the entry, we don't need it any more */
krb5_kt_free_entry(krb5_context, &entry);
}
krb5_kt_end_seq_get(krb5_context, keytab, &cursor);
switch (ret) {
case 0:
break;
case ENOENT:
case KRB5_KT_END:
ret = 0;
break;
default:
*error_string = talloc_asprintf(parent_ctx,
"failed in deleting old entries for principal: %s\n",
smb_get_krb5_error_message(krb5_context,
ret, mem_ctx));
}
talloc_free(mem_ctx);
return ret;
}
krb5_error_code smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
struct smb_krb5_context *smb_krb5_context,
struct ldb_context *ldb,
struct ldb_message *msg,
bool delete_all_kvno,
const char **error_string)
{
krb5_error_code ret;
bool found_previous;
TALLOC_CTX *mem_ctx = talloc_new(NULL);
struct keytab_container *keytab_container;
struct principal_container **principals;
const char *keytab_name;
if (!mem_ctx) {
return ENOMEM;
}
keytab_name = keytab_name_from_msg(mem_ctx, ldb, msg);
if (!keytab_name) {
return ENOENT;
}
ret = smb_krb5_get_keytab_container(mem_ctx, smb_krb5_context,
keytab_name, &keytab_container);
if (ret != 0) {
talloc_free(mem_ctx);
return ret;
}
DEBUG(5, ("Opened keytab %s\n", keytab_name));
/* Get the principal we will store the new keytab entries under */
ret = principals_from_msg(mem_ctx, msg, smb_krb5_context,
&principals, error_string);
if (ret != 0) {
*error_string = talloc_asprintf(parent_ctx,
"Failed to load principals from ldb message: %s\n",
*error_string);
talloc_free(mem_ctx);
return ret;
}
ret = remove_old_entries(mem_ctx, msg, principals, delete_all_kvno,
smb_krb5_context->krb5_context,
keytab_container->keytab,
&found_previous, error_string);
if (ret != 0) {
*error_string = talloc_asprintf(parent_ctx,
"Failed to remove old principals from keytab: %s\n",
*error_string);
talloc_free(mem_ctx);
return ret;
}
if (!delete_all_kvno) {
/* Create a new keytab. If during the cleanout we found
* entires for kvno -1, then don't try and duplicate them.
* Otherwise, add kvno, and kvno -1 */
ret = create_keytab(mem_ctx, msg, principals,
smb_krb5_context,
keytab_container->keytab,
found_previous ? false : true,
error_string);
}
talloc_free(mem_ctx);
return ret;
}
krb5_error_code smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
struct cli_credentials *machine_account,
struct smb_krb5_context *smb_krb5_context,
struct keytab_container **keytab_container)
{
krb5_error_code ret;
TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
const char *rand_string;
const char *keytab_name;
struct ldb_message *msg;
const char *error_string;
if (!mem_ctx) {
return ENOMEM;
}
*keytab_container = talloc(mem_ctx, struct keytab_container);
rand_string = generate_random_str(mem_ctx, 16);
if (!rand_string) {
talloc_free(mem_ctx);
return ENOMEM;
}
keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s",
rand_string);
if (!keytab_name) {
talloc_free(mem_ctx);
return ENOMEM;
}
ret = smb_krb5_get_keytab_container(mem_ctx, smb_krb5_context, keytab_name, keytab_container);
if (ret) {
return ret;
}
msg = ldb_msg_new(mem_ctx);
if (!msg) {
talloc_free(mem_ctx);
return ENOMEM;
}
ldb_msg_add_string(msg, "krb5Keytab", keytab_name);
ldb_msg_add_string(msg, "secret", cli_credentials_get_password(machine_account));
ldb_msg_add_string(msg, "samAccountName", cli_credentials_get_username(machine_account));
ldb_msg_add_string(msg, "realm", cli_credentials_get_realm(machine_account));
ldb_msg_add_fmt(msg, "msDS-KeyVersionNumber", "%d", (int)cli_credentials_get_kvno(machine_account));
ret = smb_krb5_update_keytab(mem_ctx, smb_krb5_context, NULL, msg, false, &error_string);
if (ret == 0) {
talloc_steal(parent_ctx, *keytab_container);
} else {
DEBUG(0, ("Failed to create in-memory keytab: %s\n", error_string));
*keytab_container = NULL;
}
talloc_free(mem_ctx);
return ret;
}
/* Translate between the IETF encryption type values and the Microsoft msDS-SupportedEncryptionTypes values */
uint32_t kerberos_enctype_to_bitmap(krb5_enctype enc_type_enum)
{
@ -1017,47 +366,3 @@ uint32_t kerberos_enctype_to_bitmap(krb5_enctype enc_type_enum)
return 0;
}
}
/* Translate between the Microsoft msDS-SupportedEncryptionTypes values
* and the IETF encryption type values */
static krb5_enctype ms_suptype_to_ietf_enctype(uint32_t enctype_bitmap)
{
switch (enctype_bitmap) {
case ENC_CRC32:
return ENCTYPE_DES_CBC_CRC;
case ENC_RSA_MD5:
return ENCTYPE_DES_CBC_MD5;
case ENC_RC4_HMAC_MD5:
return ENCTYPE_ARCFOUR_HMAC_MD5;
case ENC_HMAC_SHA1_96_AES128:
return ENCTYPE_AES128_CTS_HMAC_SHA1_96;
case ENC_HMAC_SHA1_96_AES256:
return ENCTYPE_AES256_CTS_HMAC_SHA1_96;
default:
return 0;
}
}
/* Return an array of krb5_enctype values */
static krb5_error_code ms_suptypes_to_ietf_enctypes(TALLOC_CTX *mem_ctx,
uint32_t enctype_bitmap,
krb5_enctype **enctypes)
{
unsigned int i, j = 0;
*enctypes = talloc_zero_array(mem_ctx, krb5_enctype,
(8 * sizeof(enctype_bitmap)) + 1);
if (!*enctypes) {
return ENOMEM;
}
for (i = 0; i < (8 * sizeof(enctype_bitmap)); i++) {
uint32_t bit_value = (1 << i) & enctype_bitmap;
if (bit_value & enctype_bitmap) {
(*enctypes)[j] = ms_suptype_to_ietf_enctype(bit_value);
if (!(*enctypes)[j]) {
continue;
}
j++;
}
}
(*enctypes)[j] = 0;
return 0;
}

726
source4/auth/kerberos/srv_keytab.c Normal file
View File

@ -0,0 +1,726 @@
/*
Unix SMB/CIFS implementation.
Kerberos utility functions
Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
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; either version 3 of the License, or
(at your option) any later version.
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, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "auth/credentials/credentials.h"
#include "system/kerberos.h"
#include "auth/kerberos/kerberos.h"
#include "auth/kerberos/kerberos_srv_keytab.h"
#include "auth/kerberos/kerberos_util.h"
#include <ldb.h>
#include "param/secrets.h"
static krb5_error_code principals_from_msg(TALLOC_CTX *parent_ctx,
struct ldb_message *msg,
struct smb_krb5_context *smb_krb5_context,
struct principal_container ***principals_out,
const char **error_string)
{
unsigned int i;
krb5_error_code ret;
char *upper_realm;
const char *realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);
const char *samAccountName = ldb_msg_find_attr_as_string(msg,
"samAccountName", NULL);
struct ldb_message_element *spn_el = ldb_msg_find_element(msg,
"servicePrincipalName");
TALLOC_CTX *tmp_ctx;
struct principal_container **principals;
tmp_ctx = talloc_new(parent_ctx);
if (!tmp_ctx) {
*error_string = "Cannot allocate tmp_ctx";
return ENOMEM;
}
if (!realm) {
*error_string = "Cannot have a kerberos secret in "
"secrets.ldb without a realm";
return EINVAL;
}
upper_realm = strupper_talloc(tmp_ctx, realm);
if (!upper_realm) {
talloc_free(tmp_ctx);
*error_string = "Cannot allocate full upper case realm";
return ENOMEM;
}
principals = talloc_array(tmp_ctx, struct principal_container *,
spn_el ? (spn_el->num_values + 2) : 2);
spn_el = ldb_msg_find_element(msg, "servicePrincipalName");
for (i=0; spn_el && i < spn_el->num_values; i++) {
principals[i] = talloc(principals, struct principal_container);
if (!principals[i]) {
talloc_free(tmp_ctx);
*error_string = "Cannot allocate mem_ctx";
return ENOMEM;
}
principals[i]->smb_krb5_context =
talloc_reference(principals[i], smb_krb5_context);
principals[i]->string_form =
talloc_asprintf(principals[i], "%*.*s@%s",
(int)spn_el->values[i].length,
(int)spn_el->values[i].length,
(const char *)spn_el->values[i].data,
upper_realm);
if (!principals[i]->string_form) {
talloc_free(tmp_ctx);
*error_string = "Cannot allocate full samAccountName";
return ENOMEM;
}
ret = krb5_parse_name(smb_krb5_context->krb5_context,
principals[i]->string_form,
&principals[i]->principal);
if (ret) {
talloc_free(tmp_ctx);
(*error_string) = smb_get_krb5_error_message(
smb_krb5_context->krb5_context,
ret, parent_ctx);
return ret;
}
/* This song-and-dance effectivly puts the principal
* into talloc, so we can't loose it. */
talloc_set_destructor(principals[i], free_principal);
}
if (samAccountName) {
principals[i] = talloc(principals, struct principal_container);
if (!principals[i]) {
talloc_free(tmp_ctx);
*error_string = "Cannot allocate mem_ctx";
return ENOMEM;
}
principals[i]->smb_krb5_context =
talloc_reference(principals[i], smb_krb5_context);
principals[i]->string_form =
talloc_asprintf(parent_ctx, "%s@%s",
samAccountName, upper_realm);
if (!principals[i]->string_form) {
talloc_free(tmp_ctx);
*error_string = "Cannot allocate full samAccountName";
return ENOMEM;
}
ret = krb5_make_principal(smb_krb5_context->krb5_context,
&principals[i]->principal,
upper_realm, samAccountName,
NULL);
if (ret) {
talloc_free(tmp_ctx);
(*error_string) = smb_get_krb5_error_message(
smb_krb5_context->krb5_context,
ret, parent_ctx);
return ret;
}
/* This song-and-dance effectively puts the principal
* into talloc, so we can't loose it. */
talloc_set_destructor(principals[i], free_principal);
i++;
}
principals[i] = NULL;
*principals_out = talloc_steal(parent_ctx, principals);
talloc_free(tmp_ctx);
return ret;
}
static krb5_error_code salt_principal_from_msg(TALLOC_CTX *parent_ctx,
struct ldb_message *msg,
struct smb_krb5_context *smb_krb5_context,
krb5_principal *salt_princ,
const char **error_string)
{
const char *salt_principal = ldb_msg_find_attr_as_string(msg,
"saltPrincipal", NULL);
const char *samAccountName = ldb_msg_find_attr_as_string(msg,
"samAccountName", NULL);
const char *realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);
struct principal_container *mem_ctx;
krb5_error_code ret;
char *machine_username;
char *salt_body;
char *lower_realm;
char *upper_realm;
TALLOC_CTX *tmp_ctx;
if (salt_principal) {
return parse_principal(parent_ctx, salt_principal,
smb_krb5_context, salt_princ,
error_string);
}
if (!samAccountName) {
(*error_string) = "Cannot determine salt principal, no "
"saltPrincipal or samAccountName specified";
return EINVAL;
}
mem_ctx = talloc(parent_ctx, struct principal_container);
if (!mem_ctx) {
*error_string = "Cannot allocate mem_ctx";
return ENOMEM;
}
tmp_ctx = talloc_new(mem_ctx);
if (!tmp_ctx) {
talloc_free(mem_ctx);
*error_string = "Cannot allocate tmp_ctx";
return ENOMEM;
}
if (!realm) {
*error_string = "Cannot have a kerberos secret in "
"secrets.ldb without a realm";
return EINVAL;
}
machine_username = talloc_strdup(tmp_ctx, samAccountName);
if (!machine_username) {
talloc_free(mem_ctx);
*error_string = "Cannot duplicate samAccountName";
return ENOMEM;
}
if (machine_username[strlen(machine_username)-1] == '$') {
machine_username[strlen(machine_username)-1] = '\0';
}
lower_realm = strlower_talloc(tmp_ctx, realm);
if (!lower_realm) {
talloc_free(mem_ctx);
*error_string = "Cannot allocate to lower case realm";
return ENOMEM;
}
upper_realm = strupper_talloc(tmp_ctx, realm);
if (!upper_realm) {
talloc_free(mem_ctx);
*error_string = "Cannot allocate to upper case realm";
return ENOMEM;
}
salt_body = talloc_asprintf(tmp_ctx, "%s.%s", machine_username,
lower_realm);
talloc_free(lower_realm);
talloc_free(machine_username);
if (!salt_body) {
talloc_free(mem_ctx);
*error_string = "Cannot form salt principal body";
return ENOMEM;
}
ret = krb5_make_principal(smb_krb5_context->krb5_context, salt_princ,
upper_realm,
"host", salt_body, NULL);
if (ret == 0) {
/* This song-and-dance effectively puts the principal
* into talloc, so we can't loose it. */
mem_ctx->smb_krb5_context = talloc_reference(mem_ctx,
smb_krb5_context);
mem_ctx->principal = *salt_princ;
talloc_set_destructor(mem_ctx, free_principal);
} else {
(*error_string) = smb_get_krb5_error_message(
smb_krb5_context->krb5_context,
ret, parent_ctx);
}
talloc_free(tmp_ctx);
return ret;
}
/* Translate between the Microsoft msDS-SupportedEncryptionTypes values
* and the IETF encryption type values */
static krb5_enctype ms_suptype_to_ietf_enctype(uint32_t enctype_bitmap)
{
switch (enctype_bitmap) {
case ENC_CRC32:
return ENCTYPE_DES_CBC_CRC;
case ENC_RSA_MD5:
return ENCTYPE_DES_CBC_MD5;
case ENC_RC4_HMAC_MD5:
return ENCTYPE_ARCFOUR_HMAC_MD5;
case ENC_HMAC_SHA1_96_AES128:
return ENCTYPE_AES128_CTS_HMAC_SHA1_96;
case ENC_HMAC_SHA1_96_AES256:
return ENCTYPE_AES256_CTS_HMAC_SHA1_96;
default:
return 0;
}
}
/* Return an array of krb5_enctype values */
static krb5_error_code ms_suptypes_to_ietf_enctypes(TALLOC_CTX *mem_ctx,
uint32_t enctype_bitmap,
krb5_enctype **enctypes)
{
unsigned int i, j = 0;
*enctypes = talloc_zero_array(mem_ctx, krb5_enctype,
(8 * sizeof(enctype_bitmap)) + 1);
if (!*enctypes) {
return ENOMEM;
}
for (i = 0; i < (8 * sizeof(enctype_bitmap)); i++) {
uint32_t bit_value = (1 << i) & enctype_bitmap;
if (bit_value & enctype_bitmap) {
(*enctypes)[j] = ms_suptype_to_ietf_enctype(bit_value);
if (!(*enctypes)[j]) {
continue;
}
j++;
}
}
(*enctypes)[j] = 0;
return 0;
}
static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx,
struct principal_container **principals,
krb5_principal salt_princ,
int kvno,
const char *password_s,
krb5_context krb5_context,
krb5_enctype *enctypes,
krb5_keytab keytab,
const char **error_string)
{
unsigned int i, p;
krb5_error_code ret;
krb5_data password;
password.data = discard_const_p(char *, password_s);
password.length = strlen(password_s);
for (i = 0; enctypes[i]; i++) {
krb5_keytab_entry entry;
ZERO_STRUCT(entry);
ret = create_kerberos_key_from_string_direct(krb5_context,
salt_princ, &password,
&entry.keyblock, enctypes[i]);
if (ret != 0) {
return ret;
}
entry.vno = kvno;
for (p = 0; principals[p]; p++) {
entry.principal = principals[p]->principal;
ret = krb5_kt_add_entry(krb5_context,
keytab, &entry);
if (ret != 0) {
char *k5_error_string =
smb_get_krb5_error_message(
krb5_context, ret, NULL);
*error_string = talloc_asprintf(parent_ctx,
"Failed to add enctype %d entry for "
"%s(kvno %d) to keytab: %s\n",
(int)enctypes[i],
principals[p]->string_form,
kvno, k5_error_string);
talloc_free(k5_error_string);
krb5_free_keyblock_contents(krb5_context,
&entry.keyblock);
return ret;
}
DEBUG(5, ("Added %s(kvno %d) to keytab (enctype %d)\n",
principals[p]->string_form, kvno,
(int)enctypes[i]));
}
krb5_free_keyblock_contents(krb5_context, &entry.keyblock);
}
return 0;
}
static krb5_error_code create_keytab(TALLOC_CTX *parent_ctx,
struct ldb_message *msg,
struct principal_container **principals,
struct smb_krb5_context *smb_krb5_context,
krb5_keytab keytab,
bool add_old,
const char **error_string)
{
krb5_error_code ret;
const char *password_s;
const char *old_secret;
int kvno;
uint32_t enctype_bitmap;
krb5_principal salt_princ;
krb5_enctype *enctypes;
TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
if (!mem_ctx) {
*error_string = "unable to allocate tmp_ctx for create_keytab";
return ENOMEM;
}
/* The salt used to generate these entries may be different however,
* fetch that */
ret = salt_principal_from_msg(mem_ctx, msg,
smb_krb5_context,
&salt_princ, error_string);
if (ret) {
talloc_free(mem_ctx);
return ret;
}
kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
/* Finally, do the dance to get the password to put in the entry */
password_s = ldb_msg_find_attr_as_string(msg, "secret", NULL);
if (!password_s) {
/* There is no password here, so nothing to do */
talloc_free(mem_ctx);
return 0;
}
if (add_old && kvno != 0) {
old_secret = ldb_msg_find_attr_as_string(msg,
"priorSecret", NULL);
} else {
old_secret = NULL;
}
enctype_bitmap = (uint32_t)ldb_msg_find_attr_as_int(msg,
"msDS-SupportedEncryptionTypes",
ENC_ALL_TYPES);
ret = ms_suptypes_to_ietf_enctypes(mem_ctx, enctype_bitmap, &enctypes);
if (ret) {
*error_string = talloc_asprintf(parent_ctx,
"create_keytab: generating list of "
"encryption types failed (%s)\n",
smb_get_krb5_error_message(
smb_krb5_context->krb5_context,
ret, mem_ctx));
talloc_free(mem_ctx);
return ret;
}
ret = keytab_add_keys(mem_ctx, principals,
salt_princ, kvno, password_s,
smb_krb5_context->krb5_context,
enctypes, keytab, error_string);
if (ret) {
talloc_free(mem_ctx);
return ret;
}
if (old_secret) {
ret = keytab_add_keys(mem_ctx, principals,
salt_princ, kvno - 1, old_secret,
smb_krb5_context->krb5_context,
enctypes, keytab, error_string);
if (ret) {
talloc_free(mem_ctx);
return ret;
}
}
talloc_free(mem_ctx);
return ret;
}
/*
* Walk the keytab, looking for entries of this principal name,
* with KVNO other than current kvno -1.
*
* These entries are now stale,
* we only keep the current and previous entries around.
*
* Inspired by the code in Samba3 for 'use kerberos keytab'.
*/
static krb5_error_code remove_old_entries(TALLOC_CTX *parent_ctx,
struct ldb_message *msg,
struct principal_container **principals,
bool delete_all_kvno,
krb5_context krb5_context,
krb5_keytab keytab,
bool *found_previous,
const char **error_string)
{
krb5_error_code ret, ret2;
krb5_kt_cursor cursor;
int kvno;
TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
if (!mem_ctx) {
return ENOMEM;
}
*found_previous = false;
kvno = ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0);
/* for each entry in the keytab */
ret = krb5_kt_start_seq_get(krb5_context, keytab, &cursor);
switch (ret) {
case 0:
break;
case HEIM_ERR_OPNOTSUPP:
case ENOENT:
case KRB5_KT_END:
/* no point enumerating if there isn't anything here */
talloc_free(mem_ctx);
return 0;
default:
*error_string = talloc_asprintf(parent_ctx,
"failed to open keytab for read of old entries: %s\n",
smb_get_krb5_error_message(krb5_context,
ret, mem_ctx));
talloc_free(mem_ctx);
return ret;
}
while (!ret) {
unsigned int i;
bool matched = false;
krb5_keytab_entry entry;
ret = krb5_kt_next_entry(krb5_context, keytab,
&entry, &cursor);
if (ret) {
break;
}
for (i = 0; principals[i]; i++) {
/* if it matches our principal */
if (krb5_kt_compare(krb5_context, &entry,
principals[i]->principal, 0, 0)) {
matched = true;
break;
}
}
if (!matched) {
/* Free the entry,
* it wasn't the one we were looking for anyway */
krb5_kt_free_entry(krb5_context, &entry);
continue;
}
/* delete it, if it is not kvno -1 */
if (entry.vno != (kvno - 1 )) {
/* Release the enumeration. We are going to
* have to start this from the top again,
* because deletes during enumeration may not
* always be consistent.
*
* Also, the enumeration locks a FILE: keytab
*/
krb5_kt_end_seq_get(krb5_context, keytab, &cursor);
ret = krb5_kt_remove_entry(krb5_context, keytab, &entry);
krb5_kt_free_entry(krb5_context, &entry);
/* Deleted: Restart from the top */
ret2 = krb5_kt_start_seq_get(krb5_context,
keytab, &cursor);
if (ret2) {
krb5_kt_free_entry(krb5_context, &entry);
DEBUG(1, ("failed to restart enumeration of keytab: %s\n",
smb_get_krb5_error_message(krb5_context,
ret, mem_ctx)));
talloc_free(mem_ctx);
return ret2;
}
if (ret) {
break;
}
} else {
*found_previous = true;
}
/* Free the entry, we don't need it any more */
krb5_kt_free_entry(krb5_context, &entry);
}
krb5_kt_end_seq_get(krb5_context, keytab, &cursor);
switch (ret) {
case 0:
break;
case ENOENT:
case KRB5_KT_END:
ret = 0;
break;
default:
*error_string = talloc_asprintf(parent_ctx,
"failed in deleting old entries for principal: %s\n",
smb_get_krb5_error_message(krb5_context,
ret, mem_ctx));
}
talloc_free(mem_ctx);
return ret;
}
krb5_error_code smb_krb5_update_keytab(TALLOC_CTX *parent_ctx,
struct smb_krb5_context *smb_krb5_context,
struct ldb_context *ldb,
struct ldb_message *msg,
bool delete_all_kvno,
const char **error_string)
{
krb5_error_code ret;
bool found_previous;
TALLOC_CTX *mem_ctx = talloc_new(NULL);
struct keytab_container *keytab_container;
struct principal_container **principals;
const char *keytab_name;
if (!mem_ctx) {
return ENOMEM;
}
keytab_name = keytab_name_from_msg(mem_ctx, ldb, msg);
if (!keytab_name) {
return ENOENT;
}
ret = smb_krb5_get_keytab_container(mem_ctx, smb_krb5_context,
keytab_name, &keytab_container);
if (ret != 0) {
talloc_free(mem_ctx);
return ret;
}
DEBUG(5, ("Opened keytab %s\n", keytab_name));
/* Get the principal we will store the new keytab entries under */
ret = principals_from_msg(mem_ctx, msg, smb_krb5_context,
&principals, error_string);
if (ret != 0) {
*error_string = talloc_asprintf(parent_ctx,
"Failed to load principals from ldb message: %s\n",
*error_string);
talloc_free(mem_ctx);
return ret;
}
ret = remove_old_entries(mem_ctx, msg, principals, delete_all_kvno,
smb_krb5_context->krb5_context,
keytab_container->keytab,
&found_previous, error_string);
if (ret != 0) {
*error_string = talloc_asprintf(parent_ctx,
"Failed to remove old principals from keytab: %s\n",
*error_string);
talloc_free(mem_ctx);
return ret;
}
if (!delete_all_kvno) {
/* Create a new keytab. If during the cleanout we found
* entires for kvno -1, then don't try and duplicate them.
* Otherwise, add kvno, and kvno -1 */
ret = create_keytab(mem_ctx, msg, principals,
smb_krb5_context,
keytab_container->keytab,
found_previous ? false : true,
error_string);
}
talloc_free(mem_ctx);
return ret;
}
krb5_error_code smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx,
struct cli_credentials *machine_account,
struct smb_krb5_context *smb_krb5_context,
struct keytab_container **keytab_container)
{
krb5_error_code ret;
TALLOC_CTX *mem_ctx = talloc_new(parent_ctx);
const char *rand_string;
const char *keytab_name;
struct ldb_message *msg;
const char *error_string;
if (!mem_ctx) {
return ENOMEM;
}
*keytab_container = talloc(mem_ctx, struct keytab_container);
rand_string = generate_random_str(mem_ctx, 16);
if (!rand_string) {
talloc_free(mem_ctx);
return ENOMEM;
}
keytab_name = talloc_asprintf(mem_ctx, "MEMORY:%s",
rand_string);
if (!keytab_name) {
talloc_free(mem_ctx);
return ENOMEM;
}
ret = smb_krb5_get_keytab_container(mem_ctx, smb_krb5_context,
keytab_name, keytab_container);
if (ret) {
return ret;
}
msg = ldb_msg_new(mem_ctx);
if (!msg) {
talloc_free(mem_ctx);
return ENOMEM;
}
ldb_msg_add_string(msg, "krb5Keytab", keytab_name);
ldb_msg_add_string(msg, "secret",
cli_credentials_get_password(machine_account));
ldb_msg_add_string(msg, "samAccountName",
cli_credentials_get_username(machine_account));
ldb_msg_add_string(msg, "realm",
cli_credentials_get_realm(machine_account));
ldb_msg_add_fmt(msg, "msDS-KeyVersionNumber", "%d",
(int)cli_credentials_get_kvno(machine_account));
ret = smb_krb5_update_keytab(mem_ctx, smb_krb5_context, NULL,
msg, false, &error_string);
if (ret == 0) {
talloc_steal(parent_ctx, *keytab_container);
} else {
DEBUG(0, ("Failed to create in-memory keytab: %s\n",
error_string));
*keytab_container = NULL;
}
talloc_free(mem_ctx);
return ret;
}

7
source4/auth/kerberos/wscript_build Normal file → Executable file
View File

@ -11,6 +11,11 @@ bld.SAMBA_LIBRARY('authkrb5',
bld.SAMBA_SUBSYSTEM('KERBEROS_UTIL',
autoproto='kerberos_util.h',
source='kerberos_util.c',
deps='authkrb5 com_err ldb CREDENTIALS_KRB5 SECRETS',
deps='authkrb5 com_err CREDENTIALS_KRB5',
)
bld.SAMBA_SUBSYSTEM('KERBEROS_SRV_KEYTAB',
autoproto='kerberos_srv_keytab.h',
source='srv_keytab.c',
deps='authkrb5 ldb samba-credentials SECRETS KERBEROS_UTIL',
)

1
source4/dsdb/samdb/ldb_modules/update_keytab.c
View File

@ -34,6 +34,7 @@
#include "auth/credentials/credentials_krb5.h"
#include "system/kerberos.h"
#include "auth/kerberos/kerberos.h"
#include "auth/kerberos/kerberos_srv_keytab.h"
#include "dsdb/samdb/ldb_modules/util.h"
struct dn_list {

2
source4/dsdb/samdb/ldb_modules/wscript_build Normal file → Executable file
View File

@ -214,7 +214,7 @@ bld.SAMBA_MODULE('ldb_update_keytab',
init_function='ldb_update_keytab_module_init',
module_init_name='ldb_init_module',
internal_module=False,
deps='talloc samba-credentials ldb com_err KERBEROS_UTIL DSDB_MODULE_HELPERS'
deps='talloc samba-credentials ldb com_err KERBEROS_SRV_KEYTAB DSDB_MODULE_HELPERS'
)