krb5-samba: interdomain trust uses different salt principal
[samba.git] / lib / krb5_wrap / krb5_samba.c
index 5cd79ec..a6ff976 100644 (file)
@@ -23,7 +23,8 @@
 #include "includes.h"
 #include "system/filesys.h"
 #include "krb5_samba.h"
-#include "lib/util/asn1.h"
+#include "lib/crypto/crypto.h"
+#include "../libds/common/flags.h"
 
 #ifdef HAVE_COM_ERR_H
 #include <com_err.h>
@@ -144,13 +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);
@@ -177,13 +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);
@@ -207,6 +208,8 @@ krb5_error_code smb_krb5_mk_error(krb5_context context,
                                  krb5_error_code error_code,
                                  const char *e_text,
                                  krb5_data *e_data,
+                                 const krb5_principal client,
+                                 const krb5_principal server,
                                  krb5_data *enc_err)
 {
        krb5_error_code code = EINVAL;
@@ -215,27 +218,59 @@ krb5_error_code smb_krb5_mk_error(krb5_context context,
                             error_code,
                             e_text,
                             e_data,
-                            NULL, /* client */
-                            NULL, /* server */
+                            client,
+                            server,
                             NULL, /* client_time */
                             NULL, /* client_usec */
                             enc_err);
 #else
-       krb5_error dec_err = {
-               .error = error_code,
-       };
+       krb5_principal unspec_server = NULL;
+       krb5_error errpkt;
 
+       errpkt.ctime = 0;
+       errpkt.cusec = 0;
+
+       code = krb5_us_timeofday(context,
+                                &errpkt.stime,
+                                &errpkt.susec);
+       if (code != 0) {
+               return code;
+       }
+
+       errpkt.error = error_code;
+
+       errpkt.text.length = 0;
        if (e_text != NULL) {
-               dec_err.text.length = strlen(e_text);
-               dec_err.text.data = discard_const_p(char, e_text);
+               errpkt.text.length = strlen(e_text);
+               errpkt.text.data = discard_const_p(char, e_text);
        }
+
+       errpkt.e_data.magic = KV5M_DATA;
+       errpkt.e_data.length = 0;
+       errpkt.e_data.data = NULL;
        if (e_data != NULL) {
-               dec_err.e_data = *e_data;
+               errpkt.e_data = *e_data;
+       }
+
+       errpkt.client = client;
+
+       if (server != NULL) {
+               errpkt.server = server;
+       } else {
+               code = smb_krb5_make_principal(context,
+                                              &unspec_server,
+                                              "<unspecified realm>",
+                                              NULL);
+               if (code != 0) {
+                       return code;
+               }
+               errpkt.server = unspec_server;
        }
 
        code = krb5_mk_error(context,
-                            &dec_err,
+                            &errpkt,
                             enc_err);
+       krb5_free_principal(context, unspec_server);
 #endif
        return code;
 }
@@ -267,6 +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;
@@ -352,6 +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
@@ -386,61 +672,23 @@ krb5_error_code smb_krb5_get_allowed_etypes(krb5_context context,
 #error UNKNOWN_GET_ENCTYPES_FUNCTIONS
 #endif
 
-bool unwrap_edata_ntstatus(TALLOC_CTX *mem_ctx,
-                          DATA_BLOB *edata,
-                          DATA_BLOB *edata_out)
-{
-       DATA_BLOB edata_contents;
-       ASN1_DATA *data;
-       int edata_type;
-
-       if (!edata->length) {
-               return false;
-       }
-
-       data = asn1_init(mem_ctx);
-       if (data == NULL) {
-               return false;
-       }
-
-       if (!asn1_load(data, *edata)) goto err;
-       if (!asn1_start_tag(data, ASN1_SEQUENCE(0))) goto err;
-       if (!asn1_start_tag(data, ASN1_CONTEXT(1))) goto err;
-       if (!asn1_read_Integer(data, &edata_type)) goto err;
-
-       if (edata_type != KRB5_PADATA_PW_SALT) {
-               DEBUG(0,("edata is not of required type %d but of type %d\n",
-                       KRB5_PADATA_PW_SALT, edata_type));
-               goto err;
-       }
-
-       if (!asn1_start_tag(data, ASN1_CONTEXT(2))) goto err;
-       if (!asn1_read_OctetString(data, talloc_tos(), &edata_contents)) goto err;
-       if (!asn1_end_tag(data)) goto err;
-       if (!asn1_end_tag(data)) goto err;
-       if (!asn1_end_tag(data)) goto err;
-       asn1_free(data);
-
-       *edata_out = data_blob_talloc(mem_ctx, edata_contents.data, edata_contents.length);
-
-       data_blob_free(&edata_contents);
-
-       return true;
-
-  err:
-
-       asn1_free(data);
-       return false;
-}
-
-
-/**************************************************************
- krb5_parse_name that takes a UNIX charset.
-**************************************************************/
 
+/**
+ * @brief Convert a string principal name to a Kerberos principal.
+ *
+ * @param[in]  context  The library context
+ *
+ * @param[in]  name     The principal as a unix charset string.
+ *
+ * @param[out] principal The newly allocated principal.
+ *
+ * Use krb5_free_principal() to free a principal when it is no longer needed.
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
 krb5_error_code smb_krb5_parse_name(krb5_context context,
-                               const char *name, /* in unix charset */
-                               krb5_principal *principal)
+                                   const char *name,
+                                   krb5_principal *principal)
 {
        krb5_error_code ret;
        char *utf8_name;
@@ -457,11 +705,26 @@ krb5_error_code smb_krb5_parse_name(krb5_context context,
        return ret;
 }
 
-/**************************************************************
- krb5_parse_name that returns a UNIX charset name. Must
- be freed with talloc_free() call.
-**************************************************************/
-
+/**
+ * @brief Convert a Kerberos principal structure to a string representation.
+ *
+ * The resulting string representation will be a unix charset name and is
+ * talloc'ed.
+ *
+ * @param[in]  mem_ctx  The talloc context to allocate memory on.
+ *
+ * @param[in]  context  The library context.
+ *
+ * @param[in]  principal The principal.
+ *
+ * @param[out] unix_name A string representation of the princpial name as with
+ *                       unix charset.
+ *
+ * Use talloc_free() to free the string representation if it is no longer
+ * needed.
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
 krb5_error_code smb_krb5_unparse_name(TALLOC_CTX *mem_ctx,
                                      krb5_context context,
                                      krb5_const_principal principal,
@@ -485,25 +748,6 @@ krb5_error_code smb_krb5_unparse_name(TALLOC_CTX *mem_ctx,
        return 0;
 }
 
-krb5_error_code smb_krb5_parse_name_norealm(krb5_context context, 
-                                           const char *name, 
-                                           krb5_principal *principal)
-{
-       /* we are cheating here because parse_name will in fact set the realm.
-        * We don't care as the only caller of smb_krb5_parse_name_norealm
-        * ignores the realm anyway when calling
-        * smb_krb5_principal_compare_any_realm later - Guenther */
-
-       return smb_krb5_parse_name(context, name, principal);
-}
-
-bool smb_krb5_principal_compare_any_realm(krb5_context context, 
-                                         krb5_const_principal princ1, 
-                                         krb5_const_principal princ2)
-{
-       return krb5_principal_compare_any_realm(context, princ1, princ2);
-}
-
 /**
  * @brief Free the contents of a krb5_data structure and zero the data field.
  *
@@ -872,7 +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;
                }
 
@@ -896,18 +1140,29 @@ krb5_error_code smb_krb5_gen_netbios_krb5_address(smb_krb5_addresses **kerb_addr
        return ret;
 }
 
-void smb_krb5_get_init_creds_opt_free(krb5_context context,
-                               krb5_get_init_creds_opt *opt)
-{
-       /* Modern MIT or Heimdal version */
-       krb5_get_init_creds_opt_free(context, opt);
-}
-
-krb5_enctype smb_get_enctype_from_kt_entry(krb5_keytab_entry *kt_entry)
+/**
+ * @brief Get the enctype from a key table entry
+ *
+ * @param[in]  kt_entry Key table entry to get the enctype from.
+ *
+ * @return The enctype from the entry.
+ */
+krb5_enctype smb_krb5_kt_get_enctype_from_entry(krb5_keytab_entry *kt_entry)
 {
        return KRB5_KEY_TYPE(KRB5_KT_KEY(kt_entry));
 }
 
+/**
+ * @brief Free the contents of a key table entry.
+ *
+ * @param[in]  context The library context.
+ *
+ * @param[in]  kt_entry The key table entry to free the contents of.
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ *
+ * The pointer itself is not freed.
+ */
 krb5_error_code smb_krb5_kt_free_entry(krb5_context context,
                                        krb5_keytab_entry *kt_entry)
 {
@@ -926,7 +1181,20 @@ krb5_error_code smb_krb5_kt_free_entry(krb5_context context,
 }
 
 
-/* caller needs to free etype_s */
+/**
+ * @brief Convert an encryption type to a string.
+ *
+ * @param[in]  context The library context.
+ *
+ * @param[in]  enctype The encryption type.
+ *
+ * @param[in]  etype_s A pointer to store the allocated encryption type as a
+ *                     string.
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ *
+ * The caller needs to free the allocated string etype_s.
+ */
 krb5_error_code smb_krb5_enctype_to_string(krb5_context context,
                                           krb5_enctype enctype,
                                           char **etype_s)
@@ -949,25 +1217,33 @@ krb5_error_code smb_krb5_enctype_to_string(krb5_context context,
 #endif
 }
 
-/**********************************************************************
- * Open a krb5 keytab with flags, handles readonly or readwrite access and
- * allows one to process non-default keytab names.
- * @param context krb5_context
- * @param keytab_name_req string
- * @param write_access bool if writable keytab is required
- * @param krb5_keytab pointer to krb5_keytab (close with krb5_kt_close())
- * @return krb5_error_code
-**********************************************************************/
-
 /* This MAX_NAME_LEN is a constant defined in krb5.h */
 #ifndef MAX_KEYTAB_NAME_LEN
 #define MAX_KEYTAB_NAME_LEN 1100
 #endif
 
-krb5_error_code smb_krb5_open_keytab_relative(krb5_context context,
-                                             const char *keytab_name_req,
-                                             bool write_access,
-                                             krb5_keytab *keytab)
+/**
+ * @brief Open a key table readonly or with readwrite access.
+ *
+ * Allows one to use a different keytab than the default one using a relative
+ * path to the keytab.
+ *
+ * @param[in]  context  The library context
+ *
+ * @param[in]  keytab_name_req The path to the key table.
+ *
+ * @param[in]  write_access Open with readwrite access.
+ *
+ * @param[in]  keytab A pointer o the opended key table.
+ *
+ * The keytab pointer should be freed using krb5_kt_close().
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
+krb5_error_code smb_krb5_kt_open_relative(krb5_context context,
+                                         const char *keytab_name_req,
+                                         bool write_access,
+                                         krb5_keytab *keytab)
 {
        krb5_error_code ret = 0;
        TALLOC_CTX *mem_ctx;
@@ -1000,8 +1276,8 @@ krb5_error_code smb_krb5_open_keytab_relative(krb5_context context,
                        goto out;
                }
 
-               if ((strncmp(keytab_name_req, "WRFILE:/", 8) == 0) ||
-                   (strncmp(keytab_name_req, "FILE:/", 6) == 0)) {
+               if ((strncmp(keytab_name_req, "WRFILE:", 7) == 0) ||
+                   (strncmp(keytab_name_req, "FILE:", 5) == 0)) {
                        tmp = keytab_name_req;
                        goto resolve;
                }
@@ -1075,33 +1351,85 @@ krb5_error_code smb_krb5_open_keytab_relative(krb5_context context,
                goto out;
        }
 
- resolve:
+resolve:
        DEBUG(10,("smb_krb5_open_keytab: resolving: %s\n", tmp));
        ret = krb5_kt_resolve(context, tmp, keytab);
 
- out:
+out:
        TALLOC_FREE(mem_ctx);
        return ret;
 }
 
-krb5_error_code smb_krb5_open_keytab(krb5_context context,
-                                    const char *keytab_name_req,
-                                    bool write_access,
-                                    krb5_keytab *keytab)
+/**
+ * @brief Open a key table readonly or with readwrite access.
+ *
+ * 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
+ *
+ * @param[in]  keytab_name_req The path to the key table.
+ *
+ * @param[in]  write_access Open with readwrite access.
+ *
+ * @param[in]  keytab A pointer o the opended key table.
+ *
+ * The keytab pointer should be freed using krb5_kt_close().
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
+krb5_error_code smb_krb5_kt_open(krb5_context context,
+                                const char *keytab_name_req,
+                                bool write_access,
+                                krb5_keytab *keytab)
 {
-       if (keytab_name_req != NULL) {
-               if (keytab_name_req[0] != '/') {
-                       return KRB5_KT_BADNAME;
-               }
+       int cmp;
+
+       if (keytab_name_req == NULL) {
+               return KRB5_KT_BADNAME;
+       }
+
+       if (keytab_name_req[0] == '/') {
+               goto open_keytab;
        }
 
-       return smb_krb5_open_keytab_relative(context,
-                                            keytab_name_req,
-                                            write_access,
-                                            keytab);
+       cmp = strncmp(keytab_name_req, "FILE:/", 6);
+       if (cmp == 0) {
+               goto open_keytab;
+       }
+
+       cmp = strncmp(keytab_name_req, "WRFILE:/", 8);
+       if (cmp == 0) {
+               goto open_keytab;
+       }
+
+       DBG_WARNING("ERROR: Invalid keytab name: %s\n", keytab_name_req);
+
+       return KRB5_KT_BADNAME;
+
+open_keytab:
+       return smb_krb5_kt_open_relative(context,
+                                        keytab_name_req,
+                                        write_access,
+                                        keytab);
 }
 
-krb5_error_code smb_krb5_keytab_name(TALLOC_CTX *mem_ctx,
+/**
+ * @brief Get a key table name.
+ *
+ * @param[in]  mem_ctx The talloc context to use for allocation.
+ *
+ * @param[in]  context The library context.
+ *
+ * @param[in]  keytab The key table to get the name from.
+ *
+ * @param[in]  keytab_name A talloc'ed string of the key table name.
+ *
+ * The talloc'ed name string needs to be freed with talloc_free().
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
+krb5_error_code smb_krb5_kt_get_name(TALLOC_CTX *mem_ctx,
                                     krb5_context context,
                                     krb5_keytab keytab,
                                     const char **keytab_name)
@@ -1156,17 +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 ) {
@@ -1183,7 +1507,7 @@ krb5_error_code smb_krb5_kt_seek_and_delete_old_entries(krb5_context context,
        while (!krb5_kt_next_entry(context, keytab, &kt_entry, &cursor)) {
                bool name_ok = false;
                krb5_enctype kt_entry_enctype =
-                       smb_get_enctype_from_kt_entry(&kt_entry);
+                       smb_krb5_kt_get_enctype_from_entry(&kt_entry);
 
                if (!flush && (princ_s != NULL)) {
                        ret = smb_krb5_unparse_name(tmp_ctx, context,
@@ -1254,7 +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] "
@@ -1301,10 +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;
@@ -1340,7 +1664,7 @@ out:
  *
  * @return A corresponding KRB5 error code.
  *
- * @see smb_krb5_open_keytab()
+ * @see smb_krb5_kt_open()
  */
 krb5_error_code smb_krb5_kt_add_entry(krb5_context context,
                                      krb5_keytab keytab,
@@ -1587,6 +1911,27 @@ krb5_error_code smb_krb5_get_credentials(krb5_context context,
        return ret;
 }
 
+/**
+ * @brief Initialize a krb5_keyblock with the given data.
+ *
+ * Initialized a new keyblock, allocates the contents fo the key and
+ * copies the data into the keyblock.
+ *
+ * @param[in]  context  The library context
+ *
+ * @param[in]  enctype  The encryption type.
+ *
+ * @param[in]  data     The date to initialize the keyblock with.
+ *
+ * @param[in]  length   The length of the keyblock.
+ *
+ * @param[in]  key      Newly allocated keyblock structure.
+ *
+ * The key date must be freed using krb5_free_keyblock_contents() when it is
+ * no longer needed.
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
 krb5_error_code smb_krb5_keyblock_init_contents(krb5_context context,
                                                krb5_enctype enctype,
                                                const void *data,
@@ -1608,26 +1953,39 @@ krb5_error_code smb_krb5_keyblock_init_contents(krb5_context context,
 #endif
 }
 
-/*
-  simulate a kinit, putting the tgt in the given credentials cache.
-  Orignally by remus@snapserver.com
-
-  This version is built to use a keyblock, rather than needing the
-  original password.
-
-  The impersonate_principal is the principal if NULL, or the principal
-  to impersonate
-
-  The target_service defaults to the krbtgt if NULL, but could be
-   kpasswd/realm or the local service (if we are doing s4u2self)
-*/
-krb5_error_code kerberos_kinit_keyblock_cc(krb5_context ctx, krb5_ccache cc,
-                                          krb5_principal principal,
-                                          krb5_keyblock *keyblock,
-                                          const char *target_service,
-                                          krb5_get_init_creds_opt *krb_options,
-                                          time_t *expire_time,
-                                          time_t *kdc_time)
+/**
+ * @brief Simulate a kinit by putting the tgt in the given credential cache.
+ *
+ * This function uses a keyblock rather than needingthe original password.
+ *
+ * @param[in]  ctx      The library context
+ *
+ * @param[in]  cc       The credential cache to put the tgt in.
+ *
+ * @param[in]  principal The client princial
+ *
+ * @param[in]  keyblock  The keyblock to use.
+ *
+ * @param[in]  target_service The service name of the initial credentials (or NULL).
+ *
+ * @param[in]  krb_options Initial credential options.
+ *
+ * @param[in]  expire_time    A pointer to store the experation time of the
+ *                            credentials (or NULL).
+ *
+ * @param[in]  kdc_time       A pointer to store the time when the ticket becomes
+ *                            valid (or NULL).
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
+krb5_error_code smb_krb5_kinit_keyblock_ccache(krb5_context ctx,
+                                              krb5_ccache cc,
+                                              krb5_principal principal,
+                                              krb5_keyblock *keyblock,
+                                              const char *target_service,
+                                              krb5_get_init_creds_opt *krb_options,
+                                              time_t *expire_time,
+                                              time_t *kdc_time)
 {
        krb5_error_code code = 0;
        krb5_creds my_creds;
@@ -1710,13 +2068,37 @@ done:
        return code;
 }
 
-krb5_error_code kerberos_kinit_password_cc(krb5_context ctx, krb5_ccache cc,
-                                          krb5_principal principal,
-                                          const char *password,
-                                          const char *target_service,
-                                          krb5_get_init_creds_opt *krb_options,
-                                          time_t *expire_time,
-                                          time_t *kdc_time)
+/**
+ * @brief Simulate a kinit by putting the tgt in the given credential cache.
+ *
+ * @param[in]  ctx      The library context
+ *
+ * @param[in]  cc       The credential cache to put the tgt in.
+ *
+ * @param[in]  principal The client princial
+ *
+ * @param[in]  password  The password (or NULL).
+ *
+ * @param[in]  target_service The service name of the initial credentials (or NULL).
+ *
+ * @param[in]  krb_options Initial credential options.
+ *
+ * @param[in]  expire_time    A pointer to store the experation time of the
+ *                            credentials (or NULL).
+ *
+ * @param[in]  kdc_time       A pointer to store the time when the ticket becomes
+ *                            valid (or NULL).
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
+krb5_error_code smb_krb5_kinit_password_ccache(krb5_context ctx,
+                                              krb5_ccache cc,
+                                              krb5_principal principal,
+                                              const char *password,
+                                              const char *target_service,
+                                              krb5_get_init_creds_opt *krb_options,
+                                              time_t *expire_time,
+                                              time_t *kdc_time)
 {
        krb5_error_code code = 0;
        krb5_creds my_creds;
@@ -1761,29 +2143,46 @@ done:
 }
 
 #ifdef SAMBA4_USES_HEIMDAL
-/*
-  simulate a kinit, putting the tgt in the given credentials cache.
-  Orignally by remus@snapserver.com
-
-  The impersonate_principal is the principal
-
-  The self_service, should be the local service (for S4U2Self if
-  impersonate_principal is given).
-
-  The target_service defaults to the krbtgt if NULL, but could be
-  kpasswd/realm or a remote service (for S4U2Proxy)
-
-*/
-krb5_error_code kerberos_kinit_s4u2_cc(krb5_context ctx,
-                                       krb5_ccache store_cc,
-                                       krb5_principal init_principal,
-                                       const char *init_password,
-                                       krb5_principal impersonate_principal,
-                                       const char *self_service,
-                                       const char *target_service,
-                                       krb5_get_init_creds_opt *krb_options,
-                                       time_t *expire_time,
-                                       time_t *kdc_time)
+/**
+ * @brief Simulate a kinit by putting the tgt in the given credential cache.
+ *
+ * @param[in]  ctx      The library context
+ *
+ * @param[in]  cc       The credential cache to store the tgt in.
+ *
+ * @param[in]  principal The initial client princial.
+ *
+ * @param[in]  password  The password (or NULL).
+ *
+ * @param[in]  impersonate_principal The impersonatiion principal (or NULL).
+ *
+ * @param[in]  self_service The local service for S4U2Self if
+ *                          impersonate_principal is specified).
+ *
+ * @param[in]  target_service The service name of the initial credentials
+ *                            (kpasswd/REALM or a remote service). It defaults
+ *                            to the krbtgt if NULL.
+ *
+ * @param[in]  krb_options Initial credential options.
+ *
+ * @param[in]  expire_time    A pointer to store the experation time of the
+ *                            credentials (or NULL).
+ *
+ * @param[in]  kdc_time       A pointer to store the time when the ticket becomes
+ *                            valid (or NULL).
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
+krb5_error_code smb_krb5_kinit_s4u2_ccache(krb5_context ctx,
+                                          krb5_ccache store_cc,
+                                          krb5_principal init_principal,
+                                          const char *init_password,
+                                          krb5_principal impersonate_principal,
+                                          const char *self_service,
+                                          const char *target_service,
+                                          krb5_get_init_creds_opt *krb_options,
+                                          time_t *expire_time,
+                                          time_t *kdc_time)
 {
        krb5_error_code code = 0;
        krb5_get_creds_opt options;
@@ -1798,6 +2197,7 @@ krb5_error_code kerberos_kinit_s4u2_cc(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;
 
@@ -2071,7 +2471,7 @@ krb5_error_code kerberos_kinit_s4u2_cc(krb5_context ctx,
                if (code != 0) {
                        ip = NULL;
                }
-               DEBUG(1, ("kerberos_kinit_password_cc: "
+               DEBUG(1, ("smb_krb5_kinit_password_cache: "
                          "KDC returned self principal[%s] while impersonating [%s]\n",
                          sp?sp:"<no memory>",
                          ip?ip:"<no memory>"));
@@ -2101,7 +2501,7 @@ krb5_error_code kerberos_kinit_s4u2_cc(krb5_context ctx,
                if (code != 0) {
                        ep = NULL;
                }
-               DEBUG(1, ("kerberos_kinit_password_cc: "
+               DEBUG(1, ("smb_krb5_kinit_password_cache: "
                          "KDC returned wrong principal[%s] we expected [%s]\n",
                          sp?sp:"<no memory>",
                          ep?ep:"<no memory>"));
@@ -2129,6 +2529,29 @@ krb5_error_code kerberos_kinit_s4u2_cc(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;
        }
@@ -2144,6 +2567,22 @@ krb5_error_code kerberos_kinit_s4u2_cc(krb5_context ctx,
 #endif
 
 #if !defined(HAVE_KRB5_MAKE_PRINCIPAL) && defined(HAVE_KRB5_BUILD_PRINCIPAL_ALLOC_VA)
+/**
+ * @brief Create a principal name using a variable argument list.
+ *
+ * @param[in]  context  The library context.
+ *
+ * @param[inout]  principal A pointer to the principal structure.
+ *
+ * @param[in]  _realm    The realm to use. If NULL then the function will
+ *                       get the default realm name.
+ *
+ * @param[in]  ...       A list of 'char *' components, ending with NULL.
+ *
+ * Use krb5_free_principal() to free the principal when it is no longer needed.
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
 krb5_error_code smb_krb5_make_principal(krb5_context context,
                                        krb5_principal *principal,
                                        const char *_realm, ...)
@@ -2239,6 +2678,29 @@ void smb_krb5_free_checksum_contents(krb5_context ctx, krb5_checksum *cksum)
 }
 #endif
 
+/**
+ * @brief Compute a checksum operating on a keyblock.
+ *
+ * This function computes a checksum over a PAC using the keyblock for a keyed
+ * checksum.
+ *
+ * @param[in]  mem_ctx A talloc context to alocate the signature on.
+ *
+ * @param[in]  pac_data The PAC as input.
+ *
+ * @param[in]  context  The library context.
+ *
+ * @param[in]  keyblock Encryption key for a keyed checksum.
+ *
+ * @param[out] sig_type The checksum type
+ *
+ * @param[out] sig_blob The talloc'ed checksum
+ *
+ * The caller must free the sig_blob with talloc_free() when it is not needed
+ * anymore.
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
 krb5_error_code smb_krb5_make_pac_checksum(TALLOC_CTX *mem_ctx,
                                           DATA_BLOB *pac_data,
                                           krb5_context context,
@@ -2315,19 +2777,17 @@ krb5_error_code smb_krb5_make_pac_checksum(TALLOC_CTX *mem_ctx,
 }
 
 
-/*
- * smb_krb5_principal_get_realm
- *
+/**
  * @brief Get realm of a principal
  *
- * @param[in] context          The krb5_context
- * @param[in] principal                The principal
- * @return pointer to the realm
+ * @param[in] context   The library context
+ *
+ * @param[in] principal The principal to get the realm from.
  *
- * Caller must free if the return value is not NULL.
+ * @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.
  */
-
 char *smb_krb5_principal_get_realm(krb5_context context,
                                   krb5_const_principal principal)
 {
@@ -2343,18 +2803,17 @@ char *smb_krb5_principal_get_realm(krb5_context context,
 #endif
 }
 
-/*
- * smb_krb5_principal_set_realm
- *
+/**
  * @brief Get realm of a principal
  *
- * @param[in] context          The krb5_context
- * @param[in] principal                The principal
- * @param[in] realm            The realm
- * @return                     0 on success, a krb5_error_code on error.
+ * @param[in] context   The library context
+ *
+ * @param[in] principal The principal to set the realm
  *
+ * @param[in] realm     The realm as a string to set.
+ *
+ * @retur 0 on success, a Kerberos error code otherwise.
  */
-
 krb5_error_code smb_krb5_principal_set_realm(krb5_context context,
                                             krb5_principal principal,
                                             const char *realm)
@@ -2387,67 +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. */
@@ -2466,6 +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",
@@ -2474,8 +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:
@@ -2491,45 +2939,20 @@ static char *smb_krb5_get_realm_from_hostname(TALLOC_CTX *mem_ctx,
        return realm;
 }
 
-char *kerberos_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,("kerberos_get_principal_from_service_hostname: "
-                        "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.
+ *
+ * @param[in]  context  The library context.
+ *
+ * @param[in]  code     The Kerberos error code.
+ *
+ * @param[in]  mem_ctx  The talloc context to allocate the error string on.
+ *
+ * @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
+ */
 char *smb_get_krb5_error_message(krb5_context context,
                                 krb5_error_code code,
                                 TALLOC_CTX *mem_ctx)
@@ -2551,15 +2974,12 @@ char *smb_get_krb5_error_message(krb5_context context,
 
 
 /**
-* @brief Return the kerberos library setting for "libdefaults:allow_weak_crypto"
-*
-* @param context       The krb5_context
-*
-* @return krb5_boolean
-*
-* Function returns true if weak crypto is allowd, false if not
-*/
-
+ * @brief Return the kerberos library setting for: libdefaults:allow_weak_crypto
+ *
+ * @param[in]  context  The library context
+ *
+ * @return True if weak crypto is allowed, false if not.
+ */
 krb5_boolean smb_krb5_get_allowed_weak_crypto(krb5_context context)
 #if defined(HAVE_KRB5_CONFIG_GET_BOOL_DEFAULT)
 {
@@ -2603,13 +3023,14 @@ krb5_boolean smb_krb5_get_allowed_weak_crypto(krb5_context context)
 #endif
 
 /**
-* @brief Return the type of a krb5_principal
-*
-* @param context       The krb5_context
-* @param principal     The const krb5_principal
-*
-* @return integer type of the principal
-*/
+ * @brief Return the type of a krb5_principal
+ *
+ * @param[in]  context  The library context.
+ *
+ * @param[in]  principal The principal to get the type from.
+ *
+ * @return The integer type of the principal.
+ */
 int smb_krb5_principal_get_type(krb5_context context,
                                krb5_const_principal principal)
 {
@@ -2623,13 +3044,14 @@ int smb_krb5_principal_get_type(krb5_context context,
 }
 
 /**
-* @brief Set the type of a krb5_principal
-*
-* @param context       The krb5_context
-* @param principal     The const krb5_principal
-* @param type          The principal type
-*
-*/
+ * @brief Set the type of a principal
+ *
+ * @param[in]  context  The library context
+ *
+ * @param[inout] principal The principal to set the type for.
+ *
+ * @param[in]  type     The principal type to set.
+ */
 void smb_krb5_principal_set_type(krb5_context context,
                                 krb5_principal principal,
                                 int type)
@@ -2643,34 +3065,61 @@ void smb_krb5_principal_set_type(krb5_context context,
 #endif
 }
 
-/**
-* @brief Generate a krb5 warning, forwarding to com_err
-*
-* @param context       The krb5_context
-* @param fmt           The message format
-* @param ...           The message arguments
-*
-* @return
-*/
 #if !defined(HAVE_KRB5_WARNX)
+/**
+ * @brief Log a Kerberos message
+ *
+ * It sends the message to com_err.
+ *
+ * @param[in]  context  The library context
+ *
+ * @param[in]  fmt      The message format
+ *
+ * @param[in]  ...      The message arguments
+ *
+ * @return 0 on success.
+ */
 krb5_error_code krb5_warnx(krb5_context context, const char *fmt, ...)
 {
        va_list args;
 
        va_start(args, fmt);
-       com_err_va("kdb_samba", errno, fmt, args);
+       com_err_va("samba-kdc", errno, fmt, args);
        va_end(args);
 
        return 0;
 }
 #endif
 
+/**
+ * @brief Copy a credential cache.
+ *
+ * @param[in]  context  The library context.
+ *
+ * @param[in]  incc     Credential cache to be copied.
+ *
+ * @param[inout] outcc  Copy of credential cache to be filled in.
+ *
+ * @return 0 on success, a Kerberos error code otherwise.
+ */
 krb5_error_code smb_krb5_cc_copy_creds(krb5_context context,
                                       krb5_ccache incc, krb5_ccache outcc)
 {
 #ifdef HAVE_KRB5_CC_COPY_CACHE /* Heimdal */
        return krb5_cc_copy_cache(context, incc, outcc);
 #elif defined(HAVE_KRB5_CC_COPY_CREDS)
+       krb5_error_code ret;
+       krb5_principal princ = NULL;
+
+       ret = krb5_cc_get_principal(context, incc, &princ);
+       if (ret != 0) {
+               return ret;
+       }
+       ret = krb5_cc_initialize(context, outcc, princ);
+       krb5_free_principal(context, princ);
+       if (ret != 0) {
+               return ret;
+       }
        return krb5_cc_copy_creds(context, incc, outcc);
 #else
 #error UNKNOWN_KRB5_CC_COPY_CACHE_OR_CREDS_FUNCTION
@@ -2925,7 +3374,7 @@ static krb5_error_code ads_krb5_mk_req(krb5_context context,
                        if (retval != 0) {
                                DBG_WARNING("krb5_auth_con_setuseruserkey "
                                            "failed (%s)\n",
-                                           error_message(retval)));
+                                           error_message(retval));
                                goto cleanup_creds;
                        }
 
@@ -2935,7 +3384,7 @@ static krb5_error_code ads_krb5_mk_req(krb5_context context,
                                                        KRB5_AUTH_CONTEXT_USE_SUBKEY);
                        if (retval != 0) {
                                DBG_WARNING("krb5_auth_con_setflags failed (%s)\n",
-                                           error_message(retval)));
+                                           error_message(retval));
                                goto cleanup_creds;
                        }
 
@@ -2967,7 +3416,7 @@ static krb5_error_code ads_krb5_mk_req(krb5_context context,
                                retval = ads_setup_auth_context(context, auth_context);
                                if (retval != 0) {
                                        DBG_WARNING("ads_setup_auth_context failed (%s)\n",
-                                                   error_message(retval)));
+                                                   error_message(retval));
                                        goto cleanup_creds;
                                }
                        } else {