commit 41d6311cada2befe71424d79baa0bb946db4ae16 Author: tlyu tlyu@dc483132-0cff-0310-8789-dd5450dbe970 Date: Fri Feb 12 20:28:51 2010 +0000

ticket: 6660 version_fixed: 1.8 status: resolved

pull up r23716 from trunk

------------------------------------------------------------------------ r23716 | ghudson | 2010-02-11 11:07:08 -0500 (Thu, 11 Feb 2010) | 15 lines

ticket: 6660 subject: Minimal support for updating history key target_version: 1.8 tags: pullup

Add minimal support for re-randomizing the history key:

* cpw -randkey kadmin/history now works, but creates only one key. * cpw -randkey -keepold kadmin/history still fails. * libkadm5 no longer caches the history key. Performance impact is minimal since password changes are not common. * randkey no longer checks the newly randomized key against old keys, and the disabled code to do so in setkey/setv4key is gone, so now only kadm5_chpass_principal_3 accesses the password history.

------------------------------------------------------------------------

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-8@23721 dc483132-0cff-0310-8789-dd5450dbe970

doc/admin.texinfo | 28 +++++- src/lib/kadm5/server_internal.h | 12 ++ src/lib/kadm5/srv/libkadm5srv_mit.exports | 3 - src/lib/kadm5/srv/server_kdb.c | 109 +++++++++---------- src/lib/kadm5/srv/svr_principal.c | 116 ++++++++------------ .../unit-test/api.current/randkey-principal.exp | 4 +- 6 files changed, 140 insertions(+), 132 deletions(-) --- diff --git a/doc/admin.texinfo b/doc/admin.texinfo index a10a2ee..b7c87ac 100644 --- a/doc/admin.texinfo +++ b/doc/admin.texinfo @@ -2534,6 +2534,7 @@ passwords kept in the database. * Retrieving the List of Policies:: * Adding or Modifying Policies:: * Deleting Policies:: +* Updating the History Key:: @end menu

@node Retrieving Policies, Retrieving the List of Policies, Policies, Policies @@ -2653,7 +2654,7 @@ Sets the number of past keys kept for a principal to @i{number}. This option is @noindent Note: The policies are created under realm container in the LDAP database.

-@node Deleting Policies, , Adding or Modifying Policies, Policies +@node Deleting Policies, Updating the History Key, Adding or Modifying Policies, Policies @subsection Deleting Policies

To delete a policy, use the @code{kadmin} @code{delete_policy} command, @@ -2680,6 +2681,31 @@ Note that you must cancel the policy from all principals before deleting it. The @code{delete_policy} command will fail if it is in use by any principals.

+@node Updating the History Key, , Deleting Policies, Policies + +If a policy specifies a number of old keys kept of two or more, the +stored old keys are encrypted in a history key, which is found in the +key data of the kadmin/history principal. + +Currently there is no support for proper rollover of the history key, +but you can change the history key (for example, to use a better +encryption type) at the cost of invalidating currently stored old keys. +To change the history key, run: + +@smallexample +@group +@b{kadmin:} change_password -randkey kadmin/history +@end group +@end smallexample + +This command will fail if you specify the @b{-keepold} flag. Only one +new history key will be created, even if you specify multiple key/salt +combinations. + +In the future, we plan to migrate towards encrypting old keys in the +master key instead of the history key, and implementing proper rollover +support for stored old keys. + @node Global Operations on the Kerberos Database, Global Operations on the Kerberos LDAP Database, Policies, Administrating the Kerberos Database @section Global Operations on the Kerberos Database

diff --git a/src/lib/kadm5/server_internal.h b/src/lib/kadm5/server_internal.h index 7f58750..3276b27 100644 --- a/src/lib/kadm5/server_internal.h +++ b/src/lib/kadm5/server_internal.h @@ -24,6 +24,15 @@ #include <kadm5/admin.h> #include "admin_internal.h"

+/* + * This is the history key version for a newly created DB. We use this value + * for principals which have no password history yet to avoid having to look up + * the history key. Values other than 2 will cause compatibility issues with + * pre-1.8 libkadm5 code; the older code will reject key changes when it sees + * an unexpected value of admin_history_kvno. + */ +#define INITIAL_HIST_KVNO 2 + typedef struct _kadm5_server_handle_t { krb5_ui_4 magic_number; krb5_ui_4 struct_version; @@ -64,6 +73,9 @@ krb5_error_code kdb_init_master(kadm5_server_handle_t handle, char *r, int from_keyboard); krb5_error_code kdb_init_hist(kadm5_server_handle_t handle, char *r); +krb5_error_code kdb_get_hist_key(kadm5_server_handle_t handle, + krb5_keyblock *hist_keyblock, + krb5_kvno *hist_kvno); krb5_error_code kdb_get_entry(kadm5_server_handle_t handle, krb5_principal principal, krb5_db_entry *kdb, osa_princ_ent_rec *adb); diff --git a/src/lib/kadm5/srv/libkadm5srv_mit.exports b/src/lib/kadm5/srv/libkadm5srv_mit.exports index d8d3b22..7ba5c1a 100644 --- a/src/lib/kadm5/srv/libkadm5srv_mit.exports +++ b/src/lib/kadm5/srv/libkadm5srv_mit.exports @@ -9,9 +9,6 @@ adb_policy_close adb_policy_init destroy_dict find_word -hist_db -hist_key -hist_kvno hist_princ init_dict kadm5_set_use_password_server diff --git a/src/lib/kadm5/srv/server_kdb.c b/src/lib/kadm5/srv/server_kdb.c index e1ffca2..337c142 100644 --- a/src/lib/kadm5/srv/server_kdb.c +++ b/src/lib/kadm5/srv/server_kdb.c @@ -27,9 +27,6 @@ krb5_actkvno_node *active_mkey_list = NULL; krb5_db_entry master_db;

krb5_principal hist_princ; -krb5_keyblock hist_key; -krb5_db_entry hist_db; -krb5_kvno hist_kvno;

/* much of this code is stolen from the kdc. there should be some library code to deal with this. */ @@ -116,28 +113,16 @@ done: * handle (r) kadm5 api server handle * r (r) realm of history principal to use, or NULL * - * Effects: This function sets the value of the following global - * variables: - * - * hist_princ krb5_principal holding the history principal - * hist_db krb5_db_entry of the history principal - * hist_key krb5_keyblock holding the history principal's key - * hist_encblock krb5_encrypt_block holding the procssed hist_key - * hist_kvno the version number of the history key - * - * If the history principal does not already exist, this function - * attempts to create it with kadm5_create_principal. WARNING! - * If the history principal is deleted and this function is executed - * (by kadmind, or kadmin.local, or anything else with permission), - * the principal will be assigned a new random key and all existing - * password history information will become useless. + * Effects: This function sets the value of the hist_princ global variable. If + * the history principal does not already exist, this function attempts to + * create it with kadm5_create_principal. */ krb5_error_code kdb_init_hist(kadm5_server_handle_t handle, char *r) { int ret = 0; char *realm, *hist_name; krb5_key_salt_tuple ks[1]; - krb5_keyblock *tmp_mkey; + krb5_db_entry kdb;

if (r == NULL) { if ((ret = krb5_get_default_realm(handle->context, &realm))) @@ -154,78 +139,90 @@ krb5_error_code kdb_init_hist(kadm5_server_handle_t handle, char *r) if ((ret = krb5_parse_name(handle->context, hist_name, &hist_princ))) goto done;

- if ((ret = kdb_get_entry(handle, hist_princ, &hist_db, NULL))) { + if ((ret = kdb_get_entry(handle, hist_princ, &kdb, NULL))) { kadm5_principal_ent_rec ent;

if (ret != KADM5_UNK_PRINC) goto done;

- /* try to create the principal */ - + /* Create the history principal. */ memset(&ent, 0, sizeof(ent)); - ent.principal = hist_princ; ent.max_life = KRB5_KDB_DISALLOW_ALL_TIX; ent.attributes = 0; - - /* this uses hist_kvno. So we set it to 2, which will be the - correct value once the principal is created and randomized. - Of course, it doesn't make sense to keep a history for the - history principal, anyway. */ - - hist_kvno = 2; ks[0].ks_enctype = handle->params.enctype; ks[0].ks_salttype = KRB5_KDB_SALTTYPE_NORMAL; ret = kadm5_create_principal_3(handle, &ent, (KADM5_PRINCIPAL | KADM5_MAX_LIFE | KADM5_ATTRIBUTES), - 1, ks, - "to-be-random"); + 1, ks, NULL); if (ret) goto done;

- /* this won't let us randomize the hist_princ. So we cheat. */ - - hist_princ = NULL; - + /* For better compatibility with pre-1.8 libkadm5 code, we want the + * initial history kvno to be 2, so re-randomize it. */ ret = kadm5_randkey_principal_3(handle, ent.principal, 0, 1, ks, NULL, NULL); - - hist_princ = ent.principal; - if (ret) goto done; + } else { + kdb_free_entry(handle, &kdb, NULL); + }

- /* now read the newly-created kdb record out of the - database. */ +done: + free(hist_name); + if (r == NULL) + free(realm); + return ret; +}

- if ((ret = kdb_get_entry(handle, hist_princ, &hist_db, NULL))) - goto done; +/* + * Function: kdb_get_hist_key + * + * Purpose: Fetches the current history key + * + * Arguments: + * + * handle (r) kadm5 api server handle + * hist_keyblock (w) keyblock to fill in with history key + * hist_kvno (w) kvno to fill in with history kvno + * + * Effects: This function looks up the history principal and retrieves the + * current history key and version. + */ +krb5_error_code +kdb_get_hist_key(kadm5_server_handle_t handle, krb5_keyblock *hist_keyblock, + krb5_kvno *hist_kvno) +{ + krb5_error_code ret; + krb5_db_entry kdb; + krb5_keyblock *mkey;

- } + ret = kdb_get_entry(handle, hist_princ, &kdb, NULL); + if (ret) + return ret;

- if (hist_db.n_key_data <= 0) { - krb5_set_error_message(handle->context, KRB5_KDB_NO_MATCHING_KEY, + if (kdb.n_key_data <= 0) { + ret = KRB5_KDB_NO_MATCHING_KEY; + krb5_set_error_message(handle->context, ret, "History entry contains no key data"); - return KRB5_KDB_NO_MATCHING_KEY; + goto done; }

- ret = krb5_dbe_find_mkey(handle->context, master_keylist, &hist_db, - &tmp_mkey); + ret = krb5_dbe_find_mkey(handle->context, master_keylist, &kdb, + &mkey); if (ret) goto done;

- ret = krb5_dbekd_decrypt_key_data(handle->context, tmp_mkey, - &hist_db.key_data[0], &hist_key, NULL); + ret = krb5_dbekd_decrypt_key_data(handle->context, mkey, + &kdb.key_data[0], hist_keyblock, NULL); if (ret) goto done;

- hist_kvno = hist_db.key_data[0].key_data_kvno; + *hist_kvno = kdb.key_data[0].key_data_kvno;

done: - free(hist_name); - if (r == NULL) - free(realm); + kdb_free_entry(handle, &kdb, NULL); return ret; }

@@ -289,7 +286,7 @@ kdb_get_entry(kadm5_server_handle_t handle, in), and when the entry is written, the admin data will get stored correctly. */

- adb->admin_history_kvno = hist_kvno; + adb->admin_history_kvno = INITIAL_HIST_KVNO;

return(ret); } diff --git a/src/lib/kadm5/srv/svr_principal.c b/src/lib/kadm5/srv/svr_principal.c index a01f072..3cb3b6b 100644 --- a/src/lib/kadm5/srv/svr_principal.c +++ b/src/lib/kadm5/srv/svr_principal.c @@ -36,10 +36,7 @@ extern krb5_principal hist_princ; extern krb5_keyblock master_keyblock; extern krb5_keylist_node *master_keylist; extern krb5_actkvno_node *active_mkey_list; -extern krb5_keyblock hist_key; extern krb5_db_entry master_db; -extern krb5_db_entry hist_db; -extern krb5_kvno hist_kvno;

static int decrypt_key_data(krb5_context context, krb5_keyblock *mkey, int n_key_data, krb5_key_data *key_data, @@ -428,7 +425,7 @@ kadm5_create_principal_3(void *server_handle, I'm going to keep it, and make all the admin stuff occupy a single tl_data record, */

- adb.admin_history_kvno = hist_kvno; + adb.admin_history_kvno = INITIAL_HIST_KVNO; if ((mask & KADM5_POLICY)) { adb.aux_attributes = KADM5_POLICY;

@@ -1020,6 +1017,8 @@ check_pw_reuse(krb5_context context, * Arguments: * * context (r) krb5_context to use + * mkey (r) master keyblock to decrypt key data with + * hist_key (r) history keyblock to encrypt key data with * n_key_data (r) number of elements in key_data * key_data (r) keys to add to the history entry * hist (w) history entry to fill in @@ -1032,7 +1031,8 @@ check_pw_reuse(krb5_context context, * set to n_key_data. */ static -int create_history_entry(krb5_context context, krb5_keyblock *mkey, int n_key_data, +int create_history_entry(krb5_context context, krb5_keyblock *mkey, + krb5_keyblock *hist_key, int n_key_data, krb5_key_data *key_data, osa_pw_hist_ent *hist) { int i, ret; @@ -1052,7 +1052,7 @@ int create_history_entry(krb5_context context, krb5_keyblock *mkey, int n_key_da if (ret) return ret;

- ret = krb5_dbekd_encrypt_key_data(context, &hist_key, + ret = krb5_dbekd_encrypt_key_data(context, hist_key, &key, &salt, key_data[i].key_data_kvno, &hist->key_data[i]); @@ -1085,6 +1085,7 @@ void free_history_entry(krb5_context context, osa_pw_hist_ent *hist) * Arguments: * * context (r) krb5_context to use + * hist_kvno (r) kvno of current history key * adb (r/w) admin principal entry to add keys to * pol (r) adb's policy * pw (r) keys for the password to add to adb's key history @@ -1104,6 +1105,7 @@ void free_history_entry(krb5_context context, osa_pw_hist_ent *hist) * adb->old_key_len). */ static kadm5_ret_t add_to_history(krb5_context context, + krb5_kvno hist_kvno, osa_princ_ent_t adb, kadm5_policy_ent_t pol, osa_pw_hist_ent *pw) @@ -1117,6 +1119,16 @@ static kadm5_ret_t add_to_history(krb5_context context, if (nhist <= 1) return 0;

+ if (adb->admin_history_kvno != hist_kvno) { + /* The history key has changed since the last password change, so we + * have to reset the password history. */ + free(adb->old_keys); + adb->old_keys = NULL; + adb->old_key_len = 0; + adb->old_key_next = 0; + adb->admin_history_kvno = hist_kvno; + } + nkeys = adb->old_key_len; knext = adb->old_key_next; /* resize the adb->old_keys array if necessary */ @@ -1335,8 +1347,8 @@ kadm5_chpass_principal_3(void *server_handle, int have_pol = 0; kadm5_server_handle_t handle = server_handle; osa_pw_hist_ent hist; - krb5_keyblock *act_mkey; - krb5_kvno act_kvno; + krb5_keyblock *act_mkey, hist_keyblock; + krb5_kvno act_kvno, hist_kvno;

CHECK_HANDLE(server_handle);

@@ -1344,6 +1356,7 @@ kadm5_chpass_principal_3(void *server_handle,

hist_added = 0; memset(&hist, 0, sizeof(hist)); + memset(&hist_keyblock, 0, sizeof(hist_keyblock));

if (principal == NULL || password == NULL) return EINVAL; @@ -1415,32 +1428,36 @@ kadm5_chpass_principal_3(void *server_handle, } #endif

+ ret = kdb_get_hist_key(handle, &hist_keyblock, &hist_kvno); + if (ret) + goto done; + ret = create_history_entry(handle->context, - act_mkey, + act_mkey, &hist_keyblock, kdb_save.n_key_data, kdb_save.key_data, &hist); if (ret) goto done;

- ret = check_pw_reuse(handle->context, act_mkey, &hist_key, + ret = check_pw_reuse(handle->context, act_mkey, &hist_keyblock, kdb.n_key_data, kdb.key_data, 1, &hist); if (ret) goto done;

if (pol.pw_history_num > 1) { - if (adb.admin_history_kvno != hist_kvno) { - ret = KADM5_BAD_HIST_KEY; - goto done; + /* If hist_kvno has changed since the last password change, we + * can't check the history. */ + if (adb.admin_history_kvno == hist_kvno) { + ret = check_pw_reuse(handle->context, act_mkey, &hist_keyblock, + kdb.n_key_data, kdb.key_data, + adb.old_key_len, adb.old_keys); + if (ret) + goto done; }

- ret = check_pw_reuse(handle->context, act_mkey, &hist_key, - kdb.n_key_data, kdb.key_data, - adb.old_key_len, adb.old_keys); - if (ret) - goto done; - - ret = add_to_history(handle->context, &adb, &pol, &hist); + ret = add_to_history(handle->context, hist_kvno, &adb, &pol, + &hist); if (ret) goto done; hist_added = 1; @@ -1505,6 +1522,7 @@ done: kdb_free_entry(handle, &kdb, &adb); kdb_free_entry(handle, &kdb_save, NULL); krb5_db_free_principal(handle->context, &kdb, 1); + krb5_free_keyblock_contents(handle->context, &hist_keyblock);

if (have_pol && (ret2 = kadm5_free_policy_ent(handle->lhandle, &pol)) && !ret) @@ -1549,10 +1567,14 @@ kadm5_randkey_principal_3(void *server_handle,

if (principal == NULL) return EINVAL; - if (hist_princ && /* this will be NULL when initializing the databse */ - ((krb5_principal_compare(handle->context, - principal, hist_princ)) == TRUE)) - return KADM5_PROTECT_PRINCIPAL; + if (krb5_principal_compare(handle->context, principal, hist_princ)) { + /* If changing the history entry, the new entry must have exactly one + * key. */ + if (keepold) + return KADM5_PROTECT_PRINCIPAL; + ks_tuple = n_ks_tuple ? ks_tuple : handle->params.keysalts, + n_ks_tuple = 1; + }

if ((ret = kdb_get_entry(handle, principal, &kdb, &adb))) return(ret); @@ -1601,18 +1623,6 @@ kadm5_randkey_principal_3(void *server_handle, } #endif

- if(pol.pw_history_num > 1) { - if(adb.admin_history_kvno != hist_kvno) { - ret = KADM5_BAD_HIST_KEY; - goto done; - } - - ret = check_pw_reuse(handle->context, act_mkey, &hist_key, - kdb.n_key_data, kdb.key_data, - adb.old_key_len, adb.old_keys); - if (ret) - goto done; - } if (pol.pw_max_life) kdb.pw_expiration = now + pol.pw_max_life; else @@ -1776,23 +1786,6 @@ kadm5_setv4key_principal(void *server_handle, goto done; } #endif -#if 0 - /* - * Should we be checking/updating pw history here? - */ - if(pol.pw_history_num > 1) { - if(adb.admin_history_kvno != hist_kvno) { - ret = KADM5_BAD_HIST_KEY; - goto done; - } - - if (ret = check_pw_reuse(handle->context, - &hist_key, - kdb.n_key_data, kdb.key_data, - adb.old_key_len, adb.old_keys)) - goto done; - } -#endif

if (pol.pw_max_life) kdb.pw_expiration = now + pol.pw_max_life; @@ -2017,23 +2010,6 @@ kadm5_setkey_principal_3(void *server_handle, goto done; } #endif -#if 0 - /* - * Should we be checking/updating pw history here? - */ - if (pol.pw_history_num > 1) { - if(adb.admin_history_kvno != hist_kvno) { - ret = KADM5_BAD_HIST_KEY; - goto done; - } - - if (ret = check_pw_reuse(handle->context, - &hist_key, - kdb.n_key_data, kdb.key_data, - adb.old_key_len, adb.old_keys)) - goto done; - } -#endif

if (pol.pw_max_life) kdb.pw_expiration = now + pol.pw_max_life; diff --git a/src/lib/kadm5/unit-test/api.current/randkey-principal.exp b/src/lib/kadm5/unit-test/api.current/randkey-principal.exp index f003863..5fcb1c0 100644 --- a/src/lib/kadm5/unit-test/api.current/randkey-principal.exp +++ b/src/lib/kadm5/unit-test/api.current/randkey-principal.exp @@ -279,9 +279,9 @@ proc test32 {} { perror "$test: unexpected failure in init" return } - one_line_fail_test { + one_line_succeed_test { kadm5_randkey_principal $server_handle kadmin/history keys num_keys - } "PROTECT" + } if { ! [cmd {kadm5_destroy $server_handle}]} { perror "$test: unexpected failure in destroy" return