diff options
Diffstat (limited to 'source4/auth/kerberos/srv_keytab.c')
| -rw-r--r-- | source4/auth/kerberos/srv_keytab.c | 406 |
1 files changed, 406 insertions, 0 deletions
diff --git a/source4/auth/kerberos/srv_keytab.c b/source4/auth/kerberos/srv_keytab.c new file mode 100644 index 0000000..52e1e22 --- /dev/null +++ b/source4/auth/kerberos/srv_keytab.c @@ -0,0 +1,406 @@ +/* + 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/>. +*/ + +/** + * @file srv_keytab.c + * + * @brief Kerberos keytab utility functions + * + */ + +#include "includes.h" +#include "system/kerberos.h" +#include "auth/credentials/credentials.h" +#include "auth/kerberos/kerberos.h" +#include "auth/kerberos/kerberos_util.h" +#include "auth/kerberos/kerberos_srv_keytab.h" + +static void keytab_principals_free(krb5_context context, + uint32_t num_principals, + krb5_principal *set) +{ + uint32_t i; + + for (i = 0; i < num_principals; i++) { + krb5_free_principal(context, set[i]); + } +} + +static krb5_error_code keytab_add_keys(TALLOC_CTX *parent_ctx, + uint32_t num_principals, + krb5_principal *principals, + krb5_principal salt_princ, + int kvno, + const char *password_s, + krb5_context context, + krb5_enctype *enctypes, + krb5_keytab keytab, + const char **error_string) +{ + unsigned int i, p; + krb5_error_code ret; + krb5_data password; + char *unparsed; + + 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 = smb_krb5_create_key_from_string(context, + salt_princ, + NULL, + &password, + enctypes[i], + KRB5_KT_KEY(&entry)); + if (ret != 0) { + *error_string = talloc_strdup(parent_ctx, + "Failed to create key from string"); + return ret; + } + + entry.vno = kvno; + + for (p = 0; p < num_principals; p++) { + unparsed = NULL; + entry.principal = principals[p]; + ret = krb5_kt_add_entry(context, keytab, &entry); + if (ret != 0) { + char *k5_error_string = + smb_get_krb5_error_message(context, + ret, NULL); + krb5_unparse_name(context, + principals[p], &unparsed); + *error_string = talloc_asprintf(parent_ctx, + "Failed to add enctype %d entry for " + "%s(kvno %d) to keytab: %s\n", + (int)enctypes[i], unparsed, + kvno, k5_error_string); + + free(unparsed); + talloc_free(k5_error_string); + krb5_free_keyblock_contents(context, + KRB5_KT_KEY(&entry)); + return ret; + } + + DEBUG(5, ("Added key (kvno %d) to keytab (enctype %d)\n", + kvno, (int)enctypes[i])); + } + krb5_free_keyblock_contents(context, KRB5_KT_KEY(&entry)); + } + return 0; +} + +static krb5_error_code create_keytab(TALLOC_CTX *parent_ctx, + const char *samAccountName, + const char *realm, + const char *saltPrincipal, + int kvno, + const char *new_secret, + const char *old_secret, + uint32_t supp_enctypes, + uint32_t num_principals, + krb5_principal *principals, + krb5_context context, + krb5_keytab keytab, + bool add_old, + const char **perror_string) +{ + krb5_error_code ret; + krb5_principal salt_princ = NULL; + krb5_enctype *enctypes; + TALLOC_CTX *mem_ctx; + const char *error_string = NULL; + + if (!new_secret) { + /* There is no password here, so nothing to do */ + return 0; + } + + mem_ctx = talloc_new(parent_ctx); + if (!mem_ctx) { + *perror_string = talloc_strdup(parent_ctx, + "unable to allocate tmp_ctx for create_keytab"); + return ENOMEM; + } + + /* The salt used to generate these entries may be different however, + * fetch that */ + ret = krb5_parse_name(context, saltPrincipal, &salt_princ); + if (ret) { + *perror_string = smb_get_krb5_error_message(context, + ret, + parent_ctx); + talloc_free(mem_ctx); + return ret; + } + + ret = ms_suptypes_to_ietf_enctypes(mem_ctx, supp_enctypes, &enctypes); + if (ret) { + *perror_string = talloc_asprintf(parent_ctx, + "create_keytab: generating list of " + "encryption types failed (%s)\n", + smb_get_krb5_error_message(context, + ret, mem_ctx)); + goto done; + } + + ret = keytab_add_keys(mem_ctx, + num_principals, + principals, + salt_princ, kvno, new_secret, + context, enctypes, keytab, &error_string); + if (ret) { + *perror_string = talloc_steal(parent_ctx, error_string); + goto done; + } + + if (old_secret && add_old && kvno != 0) { + ret = keytab_add_keys(mem_ctx, + num_principals, + principals, + salt_princ, kvno - 1, old_secret, + context, enctypes, keytab, &error_string); + if (ret) { + *perror_string = talloc_steal(parent_ctx, error_string); + } + } + +done: + krb5_free_principal(context, salt_princ); + talloc_free(mem_ctx); + return ret; +} + +/** + * @brief Update a Kerberos keytab and removes any obsolete keytab entries. + * + * If the keytab does not exist, this function will create one. + * + * @param[in] parent_ctx Talloc memory context + * @param[in] context Kerberos context + * @param[in] keytab_name Keytab to open + * @param[in] samAccountName User account to update + * @param[in] realm Kerberos realm + * @param[in] SPNs Service principal names to update + * @param[in] num_SPNs Length of SPNs + * @param[in] saltPrincipal Salt used for AES encryption. + * Required, unless delete_all_kvno is set. + * @param[in] old_secret Old password + * @param[in] new_secret New password + * @param[in] kvno Current key version number + * @param[in] supp_enctypes msDS-SupportedEncryptionTypes bit-field + * @param[in] delete_all_kvno Removes all obsolete entries, without + * recreating the keytab. + * @param[out] _keytab If supplied, returns the keytab + * @param[out] perror_string Error string on failure + * + * @return 0 on success, errno on failure + */ +krb5_error_code smb_krb5_update_keytab(TALLOC_CTX *parent_ctx, + krb5_context context, + const char *keytab_name, + const char *samAccountName, + const char *realm, + const char **SPNs, + int num_SPNs, + const char *saltPrincipal, + const char *new_secret, + const char *old_secret, + int kvno, + uint32_t supp_enctypes, + bool delete_all_kvno, + krb5_keytab *_keytab, + const char **perror_string) +{ + krb5_keytab keytab; + krb5_error_code ret; + bool found_previous = false; + TALLOC_CTX *tmp_ctx; + krb5_principal *principals = NULL; + uint32_t num_principals = 0; + char *upper_realm; + const char *error_string = NULL; + + if (keytab_name == NULL) { + return ENOENT; + } + + ret = krb5_kt_resolve(context, keytab_name, &keytab); + if (ret) { + *perror_string = smb_get_krb5_error_message(context, + ret, parent_ctx); + return ret; + } + + DEBUG(5, ("Opened keytab %s\n", keytab_name)); + + tmp_ctx = talloc_new(parent_ctx); + if (!tmp_ctx) { + *perror_string = talloc_strdup(parent_ctx, + "Failed to allocate memory context"); + return ENOMEM; + } + + upper_realm = strupper_talloc(tmp_ctx, realm); + if (upper_realm == NULL) { + *perror_string = talloc_strdup(parent_ctx, + "Cannot allocate memory to upper case realm"); + talloc_free(tmp_ctx); + return ENOMEM; + } + + ret = smb_krb5_create_principals_array(tmp_ctx, + context, + samAccountName, + upper_realm, + num_SPNs, + SPNs, + &num_principals, + &principals, + &error_string); + if (ret != 0) { + *perror_string = talloc_asprintf(parent_ctx, + "Failed to load principals from ldb message: %s\n", + error_string); + goto done; + } + + ret = smb_krb5_remove_obsolete_keytab_entries(tmp_ctx, + context, + keytab, + num_principals, + principals, + kvno, + &found_previous, + &error_string); + if (ret != 0) { + *perror_string = talloc_asprintf(parent_ctx, + "Failed to remove old principals from keytab: %s\n", + error_string); + goto done; + } + + if (!delete_all_kvno) { + /* Create a new keytab. If during the cleanout we found + * entries for kvno -1, then don't try and duplicate them. + * Otherwise, add kvno, and kvno -1 */ + if (saltPrincipal == NULL) { + *perror_string = talloc_strdup(parent_ctx, + "No saltPrincipal provided"); + ret = EINVAL; + goto done; + } + + ret = create_keytab(tmp_ctx, + samAccountName, upper_realm, saltPrincipal, + kvno, new_secret, old_secret, + supp_enctypes, + num_principals, + principals, + context, keytab, + found_previous ? false : true, + &error_string); + if (ret) { + *perror_string = talloc_steal(parent_ctx, error_string); + } + } + + if (ret == 0 && _keytab != NULL) { + /* caller wants the keytab handle back */ + *_keytab = keytab; + } + +done: + keytab_principals_free(context, num_principals, principals); + if (ret != 0 || _keytab == NULL) { + krb5_kt_close(context, keytab); + } + talloc_free(tmp_ctx); + return ret; +} + +/** + * @brief Wrapper around smb_krb5_update_keytab() for creating an in-memory keytab + * + * @param[in] parent_ctx Talloc memory context + * @param[in] context Kerberos context + * @param[in] new_secret New password + * @param[in] samAccountName User account to update + * @param[in] realm Kerberos realm + * @param[in] salt_principal Salt used for AES encryption. + * Required, unless delete_all_kvno is set. + * @param[in] kvno Current key version number + * @param[out] keytab If supplied, returns the keytab + * @param[out] keytab_name Returns the created keytab name + * + * @return 0 on success, errno on failure + */ +krb5_error_code smb_krb5_create_memory_keytab(TALLOC_CTX *parent_ctx, + krb5_context context, + const char *new_secret, + const char *samAccountName, + const char *realm, + const char *salt_principal, + int kvno, + krb5_keytab *keytab, + const char **keytab_name) +{ + krb5_error_code ret; + TALLOC_CTX *mem_ctx = talloc_new(parent_ctx); + const char *rand_string; + const char *error_string = NULL; + if (!mem_ctx) { + return ENOMEM; + } + + 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 == NULL) { + talloc_free(mem_ctx); + return ENOMEM; + } + + ret = smb_krb5_update_keytab(mem_ctx, context, + *keytab_name, samAccountName, realm, + NULL, 0, salt_principal, new_secret, NULL, + kvno, ENC_ALL_TYPES, + false, keytab, &error_string); + if (ret == 0) { + talloc_steal(parent_ctx, *keytab_name); + } else { + DEBUG(0, ("Failed to create in-memory keytab: %s\n", + error_string)); + *keytab_name = NULL; + } + talloc_free(mem_ctx); + return ret; +} |