krb5-samba: interdomain trust uses different salt principal
[samba.git] / lib / krb5_wrap / krb5_samba.c
index 307be93..a6ff976 100644 (file)
@@ -23,6 +23,8 @@
 #include "includes.h"
 #include "system/filesys.h"
 #include "krb5_samba.h"
+#include "lib/crypto/crypto.h"
+#include "../libds/common/flags.h"
 
 #ifdef HAVE_COM_ERR_H
 #include <com_err.h>
@@ -143,13 +145,13 @@ const krb5_data *krb5_princ_component(krb5_context context,
  *
  * @param[out] pkaddr   A Kerberos address to store tha address in.
  *
- * @return True on success, false if an error occured.
+ * @return True on success, false if an error occurred.
  */
 bool smb_krb5_sockaddr_to_kaddr(struct sockaddr_storage *paddr,
                                krb5_address *pkaddr)
 {
        memset(pkaddr, '\0', sizeof(krb5_address));
-#if defined(HAVE_IPV6) && defined(KRB5_ADDRESS_INET6)
+#ifdef HAVE_IPV6
        if (paddr->ss_family == AF_INET6) {
                pkaddr->addr_type = KRB5_ADDRESS_INET6;
                pkaddr->address.length = sizeof(((struct sockaddr_in6 *)paddr)->sin6_addr);
@@ -176,13 +178,13 @@ bool smb_krb5_sockaddr_to_kaddr(struct sockaddr_storage *paddr,
  *
  * @param[in]  pkaddr A Kerberos address to store tha address in.
  *
- * @return True on success, false if an error occured.
+ * @return True on success, false if an error occurred.
  */
 bool smb_krb5_sockaddr_to_kaddr(struct sockaddr_storage *paddr,
                                krb5_address *pkaddr)
 {
        memset(pkaddr, '\0', sizeof(krb5_address));
-#if defined(HAVE_IPV6) && defined(ADDRTYPE_INET6)
+#ifdef HAVE_IPV6
        if (paddr->ss_family == AF_INET6) {
                pkaddr->addrtype = ADDRTYPE_INET6;
                pkaddr->length = sizeof(((struct sockaddr_in6 *)paddr)->sin6_addr);
@@ -300,6 +302,42 @@ int smb_krb5_create_key_from_string(krb5_context context,
                return -1;
        }
 
+       if ((int)enctype == (int)ENCTYPE_ARCFOUR_HMAC) {
+               TALLOC_CTX *frame = talloc_stackframe();
+               uint8_t *utf16 = NULL;
+               size_t utf16_size = 0;
+               uint8_t nt_hash[16];
+               bool ok;
+
+               ok = convert_string_talloc(frame, CH_UNIX, CH_UTF16LE,
+                                          password->data, password->length,
+                                          (void **)&utf16, &utf16_size);
+               if (!ok) {
+                       if (errno == 0) {
+                               errno = EINVAL;
+                       }
+                       ret = errno;
+                       TALLOC_FREE(frame);
+                       return ret;
+               }
+
+               mdfour(nt_hash, utf16, utf16_size);
+               memset(utf16, 0, utf16_size);
+               ret = smb_krb5_keyblock_init_contents(context,
+                                                     ENCTYPE_ARCFOUR_HMAC,
+                                                     nt_hash,
+                                                     sizeof(nt_hash),
+                                                     key);
+               ZERO_STRUCT(nt_hash);
+               if (ret != 0) {
+                       TALLOC_FREE(frame);
+                       return ret;
+               }
+
+               TALLOC_FREE(frame);
+               return 0;
+       }
+
 #if defined(HAVE_KRB5_PRINCIPAL2SALT) && defined(HAVE_KRB5_C_STRING_TO_KEY)
 {/* MIT */
        krb5_data _salt;
@@ -385,6 +423,221 @@ int smb_krb5_get_pw_salt(krb5_context context,
 #error UNKNOWN_SALT_FUNCTIONS
 #endif
 
+/**
+ * @brief This constructs the salt principal used by active directory
+ *
+ * Most Kerberos encryption types require a salt in order to
+ * calculate the long term private key for user/computer object
+ * based on a password.
+ *
+ * The returned _salt_principal is a string in forms like this:
+ * - host/somehost.example.com@EXAMPLE.COM
+ * - SomeAccount@EXAMPLE.COM
+ * - SomePrincipal@EXAMPLE.COM
+ *
+ * This is not the form that's used as salt, it's just
+ * the human readable form. It needs to be converted by
+ * smb_krb5_salt_principal2data().
+ *
+ * @param[in]  realm              The realm the user/computer is added too.
+ *
+ * @param[in]  sAMAccountName     The sAMAccountName attribute of the object.
+ *
+ * @param[in]  userPrincipalName  The userPrincipalName attribute of the object
+ *                                or NULL is not available.
+ *
+ * @param[in]  uac_flags          UF_ACCOUNT_TYPE_MASKed userAccountControl field
+ *
+ * @param[in]  mem_ctx            The TALLOC_CTX to allocate _salt_principal.
+ *
+ * @param[out]  _salt_principal   The resulting principal as string.
+ *
+ * @retval 0 Success; otherwise - Kerberos error codes
+ *
+ * @see smb_krb5_salt_principal2data
+ */
+int smb_krb5_salt_principal(const char *realm,
+                           const char *sAMAccountName,
+                           const char *userPrincipalName,
+                           uint32_t uac_flags,
+                           TALLOC_CTX *mem_ctx,
+                           char **_salt_principal)
+{
+       TALLOC_CTX *frame = talloc_stackframe();
+       char *upper_realm = NULL;
+       const char *principal = NULL;
+       int principal_len = 0;
+
+       *_salt_principal = NULL;
+
+       if (sAMAccountName == NULL) {
+               TALLOC_FREE(frame);
+               return EINVAL;
+       }
+
+       if (realm == NULL) {
+               TALLOC_FREE(frame);
+               return EINVAL;
+       }
+
+       if (uac_flags & ~UF_ACCOUNT_TYPE_MASK) {
+               /*
+                * catch callers which still
+                * pass 'true'.
+                */
+               TALLOC_FREE(frame);
+               return EINVAL;
+       }
+       if (uac_flags == 0) {
+               /*
+                * catch callers which still
+                * pass 'false'.
+                */
+               TALLOC_FREE(frame);
+               return EINVAL;
+       }
+
+       upper_realm = strupper_talloc(frame, realm);
+       if (upper_realm == NULL) {
+               TALLOC_FREE(frame);
+               return ENOMEM;
+       }
+
+       /* Many, many thanks to lukeh@padl.com for this
+        * algorithm, described in his Nov 10 2004 mail to
+        * samba-technical@lists.samba.org */
+
+       /*
+        * Determine a salting principal
+        */
+       if (uac_flags & UF_TRUST_ACCOUNT_MASK) {
+               int computer_len = 0;
+               char *tmp = NULL;
+
+               computer_len = strlen(sAMAccountName);
+               if (sAMAccountName[computer_len-1] == '$') {
+                       computer_len -= 1;
+               }
+
+               if (uac_flags & UF_INTERDOMAIN_TRUST_ACCOUNT) {
+                       principal = talloc_asprintf(frame, "krbtgt/%*.*s",
+                                                   computer_len, computer_len,
+                                                   sAMAccountName);
+                       if (principal == NULL) {
+                               TALLOC_FREE(frame);
+                               return ENOMEM;
+                       }
+               } else {
+
+                       tmp = talloc_asprintf(frame, "host/%*.*s.%s",
+                                             computer_len, computer_len,
+                                             sAMAccountName, realm);
+                       if (tmp == NULL) {
+                               TALLOC_FREE(frame);
+                               return ENOMEM;
+                       }
+
+                       principal = strlower_talloc(frame, tmp);
+                       TALLOC_FREE(tmp);
+                       if (principal == NULL) {
+                               TALLOC_FREE(frame);
+                               return ENOMEM;
+                       }
+               }
+
+               principal_len = strlen(principal);
+
+       } else if (userPrincipalName != NULL) {
+               char *p;
+
+               principal = userPrincipalName;
+               p = strchr(principal, '@');
+               if (p != NULL) {
+                       principal_len = PTR_DIFF(p, principal);
+               } else {
+                       principal_len = strlen(principal);
+               }
+       } else {
+               principal = sAMAccountName;
+               principal_len = strlen(principal);
+       }
+
+       *_salt_principal = talloc_asprintf(mem_ctx, "%*.*s@%s",
+                                          principal_len, principal_len,
+                                          principal, upper_realm);
+       if (*_salt_principal == NULL) {
+               TALLOC_FREE(frame);
+               return ENOMEM;
+       }
+
+       TALLOC_FREE(frame);
+       return 0;
+}
+
+/**
+ * @brief Converts the salt principal string into the salt data blob
+ *
+ * This function takes a salt_principal as string in forms like this:
+ * - host/somehost.example.com@EXAMPLE.COM
+ * - SomeAccount@EXAMPLE.COM
+ * - SomePrincipal@EXAMPLE.COM
+ *
+ * It generates values like:
+ * - EXAMPLE.COMhost/somehost.example.com
+ * - EXAMPLE.COMSomeAccount
+ * - EXAMPLE.COMSomePrincipal
+ *
+ * @param[in]  realm              The realm the user/computer is added too.
+ *
+ * @param[in]  sAMAccountName     The sAMAccountName attribute of the object.
+ *
+ * @param[in]  userPrincipalName  The userPrincipalName attribute of the object
+ *                                or NULL is not available.
+ *
+ * @param[in]  is_computer        The indication of the object includes
+ *                                objectClass=computer.
+ *
+ * @param[in]  mem_ctx            The TALLOC_CTX to allocate _salt_principal.
+ *
+ * @param[out]  _salt_principal   The resulting principal as string.
+ *
+ * @retval 0 Success; otherwise - Kerberos error codes
+ *
+ * @see smb_krb5_salt_principal
+ */
+int smb_krb5_salt_principal2data(krb5_context context,
+                                const char *salt_principal,
+                                TALLOC_CTX *mem_ctx,
+                                char **_salt_data)
+{
+       krb5_error_code ret;
+       krb5_principal salt_princ = NULL;
+       krb5_data salt;
+
+       *_salt_data = NULL;
+
+       ret = krb5_parse_name(context, salt_principal, &salt_princ);
+       if (ret != 0) {
+               return ret;
+       }
+
+       ret = smb_krb5_get_pw_salt(context, salt_princ, &salt);
+       krb5_free_principal(context, salt_princ);
+       if (ret != 0) {
+               return ret;
+       }
+
+       *_salt_data = talloc_strndup(mem_ctx,
+                                    (char *)salt.data,
+                                    salt.length);
+       smb_krb5_free_data_contents(context, &salt);
+       if (*_salt_data == NULL) {
+               return ENOMEM;
+       }
+
+       return 0;
+}
+
 #if defined(HAVE_KRB5_GET_PERMITTED_ENCTYPES)
 /**
  * @brief Get a list of encryption types allowed for session keys
@@ -863,7 +1116,7 @@ krb5_error_code smb_krb5_gen_netbios_krb5_address(smb_krb5_addresses **kerb_addr
                addrs->val = (krb5_address *)SMB_MALLOC(sizeof(krb5_address));
                if (addrs->val == NULL) {
                        SAFE_FREE(addrs);
-                       SAFE_FREE(kerb_addr);
+                       SAFE_FREE(*kerb_addr);
                        return ENOMEM;
                }
 
@@ -972,7 +1225,7 @@ krb5_error_code smb_krb5_enctype_to_string(krb5_context context,
 /**
  * @brief Open a key table readonly or with readwrite access.
  *
- * Allows to use a different keytab than the default one using a relative
+ * Allows one to use a different keytab than the default one using a relative
  * path to the keytab.
  *
  * @param[in]  context  The library context
@@ -1110,7 +1363,7 @@ out:
 /**
  * @brief Open a key table readonly or with readwrite access.
  *
- * Allows to use a different keytab than the default one. The path needs to be
+ * Allows one to use a different keytab than the default one. The path needs to be
  * an absolute path or an error will be returned.
  *
  * @param[in]  context  The library context
@@ -1150,6 +1403,8 @@ krb5_error_code smb_krb5_kt_open(krb5_context context,
                goto open_keytab;
        }
 
+       DBG_WARNING("ERROR: Invalid keytab name: %s\n", keytab_name_req);
+
        return KRB5_KT_BADNAME;
 
 open_keytab:
@@ -1229,17 +1484,13 @@ krb5_error_code smb_krb5_kt_seek_and_delete_old_entries(krb5_context context,
 {
        krb5_error_code ret;
        krb5_kt_cursor cursor;
-       krb5_kt_cursor zero_csr;
        krb5_keytab_entry kt_entry;
-       krb5_keytab_entry zero_kt_entry;
        char *ktprinc = NULL;
        krb5_kvno old_kvno = kvno - 1;
        TALLOC_CTX *tmp_ctx;
 
        ZERO_STRUCT(cursor);
-       ZERO_STRUCT(zero_csr);
        ZERO_STRUCT(kt_entry);
-       ZERO_STRUCT(zero_kt_entry);
 
        ret = krb5_kt_start_seq_get(context, keytab, &cursor);
        if (ret == KRB5_KT_END || ret == ENOENT ) {
@@ -1327,7 +1578,7 @@ krb5_error_code smb_krb5_kt_seek_and_delete_old_entries(krb5_context context,
                }
 
                if (!flush &&
-                   (kt_entry.vno == kvno) &&
+                   ((kt_entry.vno & 0xff) == (kvno & 0xff)) &&
                    (kt_entry_enctype != enctype))
                {
                        DEBUG(5, (__location__ ": Saving entry with kvno [%d] "
@@ -1374,10 +1625,10 @@ krb5_error_code smb_krb5_kt_seek_and_delete_old_entries(krb5_context context,
 
 out:
        talloc_free(tmp_ctx);
-       if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
+       if (!all_zero((uint8_t *)&kt_entry, sizeof(kt_entry))) {
                smb_krb5_kt_free_entry(context, &kt_entry);
        }
-       if (memcmp(&cursor, &zero_csr, sizeof(krb5_kt_cursor)) != 0) {
+       if (!all_zero((uint8_t *)&cursor, sizeof(cursor))) {
                krb5_kt_end_seq_get(context, keytab, &cursor);
        }
        return ret;
@@ -1946,6 +2197,7 @@ krb5_error_code smb_krb5_kinit_s4u2_ccache(krb5_context ctx,
        krb5_principal target_princ;
        krb5_ccache tmp_cc;
        const char *self_realm;
+       const char *client_realm = NULL;
        krb5_principal blacklist_principal = NULL;
        krb5_principal whitelist_principal = NULL;
 
@@ -2277,6 +2529,29 @@ krb5_error_code smb_krb5_kinit_s4u2_ccache(krb5_context ctx,
                return code;
        }
 
+       client_realm = krb5_principal_get_realm(ctx, store_creds.client);
+       if (client_realm != NULL) {
+               /*
+                * Because the CANON flag doesn't have any impact
+                * on the impersonate_principal => store_creds.client
+                * realm mapping. We need to store the credentials twice,
+                * once with the returned realm and once with the
+                * realm of impersonate_principal.
+                */
+               code = krb5_principal_set_realm(ctx, store_creds.server,
+                                               client_realm);
+               if (code != 0) {
+                       krb5_free_cred_contents(ctx, &store_creds);
+                       return code;
+               }
+
+               code = krb5_cc_store_cred(ctx, store_cc, &store_creds);
+               if (code != 0) {
+                       krb5_free_cred_contents(ctx, &store_creds);
+                       return code;
+               }
+       }
+
        if (expire_time) {
                *expire_time = (time_t) store_creds.times.endtime;
        }
@@ -2509,7 +2784,7 @@ krb5_error_code smb_krb5_make_pac_checksum(TALLOC_CTX *mem_ctx,
  *
  * @param[in] principal The principal to get the realm from.
  *
- * @return An allocated string with the realm or NULL if an error occured.
+ * @return An allocated string with the realm or NULL if an error occurred.
  *
  * The caller must free the realm string with free() if not needed anymore.
  */
@@ -2571,67 +2846,27 @@ krb5_error_code smb_krb5_principal_set_realm(krb5_context context,
 }
 
 
-/************************************************************************
- Routine to get the default realm from the kerberos credentials cache.
- Caller must free if the return value is not NULL.
-************************************************************************/
-
-static char *smb_krb5_get_default_realm_from_ccache(TALLOC_CTX *mem_ctx)
-{
-       char *realm = NULL;
-       krb5_context ctx = NULL;
-       krb5_ccache cc = NULL;
-       krb5_principal princ = NULL;
-
-       initialize_krb5_error_table();
-       if (krb5_init_context(&ctx)) {
-               return NULL;
-       }
-
-       DEBUG(5,("kerberos_get_default_realm_from_ccache: "
-               "Trying to read krb5 cache: %s\n",
-               krb5_cc_default_name(ctx)));
-       if (krb5_cc_default(ctx, &cc)) {
-               DEBUG(5,("kerberos_get_default_realm_from_ccache: "
-                       "failed to read default cache\n"));
-               goto out;
-       }
-       if (krb5_cc_get_principal(ctx, cc, &princ)) {
-               DEBUG(5,("kerberos_get_default_realm_from_ccache: "
-                       "failed to get default principal\n"));
-               goto out;
-       }
-
-#if defined(HAVE_KRB5_PRINCIPAL_GET_REALM)
-       realm = talloc_strdup(mem_ctx, krb5_principal_get_realm(ctx, princ));
-#elif defined(HAVE_KRB5_PRINC_REALM)
-       {
-               krb5_data *realm_data = krb5_princ_realm(ctx, princ);
-               realm = talloc_strndup(mem_ctx, realm_data->data, realm_data->length);
-       }
-#endif
-
-  out:
-
-       if (ctx) {
-               if (princ) {
-                       krb5_free_principal(ctx, princ);
-               }
-               if (cc) {
-                       krb5_cc_close(ctx, cc);
-               }
-               krb5_free_context(ctx);
-       }
-
-       return realm;
-}
-
-/************************************************************************
- Routine to get the realm from a given DNS name.
-************************************************************************/
-
-static char *smb_krb5_get_realm_from_hostname(TALLOC_CTX *mem_ctx,
-                                               const char *hostname)
+/**
+ * @brief Get the realm from the service hostname.
+ *
+ * This function will look for a domain realm mapping in the [domain_realm]
+ * section of the krb5.conf first and fallback to extract the realm from
+ * the provided service hostname. As a last resort it will return the
+ * provided client_realm.
+ *
+ * @param[in]  mem_ctx     The talloc context
+ *
+ * @param[in]  hostname    The service hostname
+ *
+ * @param[in]  client_realm  If we can not find a mapping, fall back to
+ *                           this realm.
+ *
+ * @return The realm to use for the service hostname, NULL if a fatal error
+ *         occured.
+ */
+char *smb_krb5_get_realm_from_hostname(TALLOC_CTX *mem_ctx,
+                                      const char *hostname,
+                                      const char *client_realm)
 {
 #if defined(HAVE_KRB5_REALM_TYPE)
        /* Heimdal. */
@@ -2650,6 +2885,10 @@ static char *smb_krb5_get_realm_from_hostname(TALLOC_CTX *mem_ctx,
        }
 
        kerr = krb5_get_host_realm(ctx, hostname, &realm_list);
+       if (kerr == KRB5_ERR_HOST_REALM_UNKNOWN) {
+               realm_list = NULL;
+               kerr = 0;
+       }
        if (kerr != 0) {
                DEBUG(3,("kerberos_get_realm_from_hostname %s: "
                        "failed %s\n",
@@ -2658,8 +2897,33 @@ static char *smb_krb5_get_realm_from_hostname(TALLOC_CTX *mem_ctx,
                goto out;
        }
 
-       if (realm_list && realm_list[0]) {
+       if (realm_list != NULL &&
+           realm_list[0] != NULL &&
+           realm_list[0][0] != '\0') {
                realm = talloc_strdup(mem_ctx, realm_list[0]);
+               if (realm == NULL) {
+                       goto out;
+               }
+       } else {
+               const char *p = NULL;
+
+               /*
+                * "dc6.samba2003.example.com"
+                * returns a realm of "SAMBA2003.EXAMPLE.COM"
+                *
+                * "dc6." returns realm as NULL
+                */
+               p = strchr_m(hostname, '.');
+               if (p != NULL && p[1] != '\0') {
+                       realm = talloc_strdup_upper(mem_ctx, p + 1);
+                       if (realm == NULL) {
+                               goto out;
+                       }
+               }
+       }
+
+       if (realm == NULL) {
+               realm = talloc_strdup(mem_ctx, client_realm);
        }
 
   out:
@@ -2675,61 +2939,6 @@ static char *smb_krb5_get_realm_from_hostname(TALLOC_CTX *mem_ctx,
        return realm;
 }
 
-/**
- * @brief Get the principal as a string from the service hostname.
- *
- * @param[in]  mem_ctx  The talloc context
- *
- * @param[in]  service  The service name
- *
- * @param[in]  remote_name The remote name
- *
- * @param[in]  default_realm The default_realm if we cannot get it from the
- *                           hostname or netbios name.
- *
- * @return A talloc'ed principal string or NULL if an error occured.
- *
- * The caller needs to free the principal with talloc_free() if it isn't needed
- * anymore.
- */
-char *smb_krb5_get_principal_from_service_hostname(TALLOC_CTX *mem_ctx,
-                                                  const char *service,
-                                                  const char *remote_name,
-                                                  const char *default_realm)
-{
-       char *realm = NULL;
-       char *host = NULL;
-       char *principal;
-       host = strchr_m(remote_name, '.');
-       if (host) {
-               /* DNS name. */
-               realm = smb_krb5_get_realm_from_hostname(talloc_tos(),
-                                                        remote_name);
-       } else {
-               /* NetBIOS name - use our realm. */
-               realm = smb_krb5_get_default_realm_from_ccache(talloc_tos());
-       }
-
-       if (realm == NULL || *realm == '\0') {
-               realm = talloc_strdup(talloc_tos(), default_realm);
-               if (!realm) {
-                       return NULL;
-               }
-               DEBUG(3,("Cannot get realm from, "
-                        "desthost %s or default ccache. Using default "
-                        "smb.conf realm %s\n",
-                        remote_name,
-                        realm));
-       }
-
-       principal = talloc_asprintf(mem_ctx,
-                                   "%s/%s@%s",
-                                   service, remote_name,
-                                   realm);
-       TALLOC_FREE(realm);
-       return principal;
-}
-
 /**
  * @brief Get an error string from a Kerberos error code.
  *
@@ -2739,7 +2948,7 @@ char *smb_krb5_get_principal_from_service_hostname(TALLOC_CTX *mem_ctx,
  *
  * @param[in]  mem_ctx  The talloc context to allocate the error string on.
  *
- * @return A talloc'ed error string or NULL if an error occured.
+ * @return A talloc'ed error string or NULL if an error occurred.
  *
  * The caller must free the returned error string with talloc_free() if not
  * needed anymore