diff --git a/WHATSNEW.txt b/WHATSNEW.txt index b245e30a6f9..a204a5482e6 100644 --- a/WHATSNEW.txt +++ b/WHATSNEW.txt @@ -1,3 +1,79 @@ + ============================== + Release Notes for Samba 4.5.16 + March 13, 2018 + ============================== + + +This is a security release in order to address the following defects: + +o CVE-2018-1050 (Denial of Service Attack on external print server.) +o CVE-2018-1057 (Authenticated users can change other users' password.) + + +======= +Details +======= + +o CVE-2018-1050: + All versions of Samba from 4.0.0 onwards are vulnerable to a denial of + service attack when the RPC spoolss service is configured to be run as + an external daemon. Missing input sanitization checks on some of the + input parameters to spoolss RPC calls could cause the print spooler + service to crash. + + There is no known vulnerability associated with this error, merely a + denial of service. If the RPC spoolss service is left by default as an + internal service, all a client can do is crash its own authenticated + connection. + +o CVE-2018-1057: + On a Samba 4 AD DC the LDAP server in all versions of Samba from + 4.0.0 onwards incorrectly validates permissions to modify passwords + over LDAP allowing authenticated users to change any other users' + passwords, including administrative users. + + Possible workarounds are described at a dedicated page in the Samba wiki: + https://wiki.samba.org/index.php/CVE-2018-1057 + + +Changes since 4.5.15: +--------------------- + +o Jeremy Allison + * BUG 11343: CVE-2018-1050: Codenomicon crashes in spoolss server code. + +o Ralph Boehme + * BUG 13272: CVE-2018-1057: Unprivileged user can change any user (and admin) + password. + +o Stefan Metzmacher + * BUG 13272: CVE-2018-1057: Unprivileged user can change any user (and admin) + password. + + +####################################### +Reporting bugs & Development Discussion +####################################### + +Please discuss this release on the samba-technical mailing list or by +joining the #samba-technical IRC channel on irc.freenode.net. + +If you do report problems then please try to send high quality +feedback. If you don't provide vital information to help us track down +the problem then you will probably be ignored. All bug reports should +be filed under the "Samba 4.1 and newer" product in the project's Bugzilla +database (https://bugzilla.samba.org/). + + +====================================================================== +== Our Code, Our Bugs, Our Responsibility. +== The Samba Team +====================================================================== + + +Release notes for older releases follow: +---------------------------------------- + ============================== Release Notes for Samba 4.5.15 November 21, 2017 @@ -66,8 +142,8 @@ database (https://bugzilla.samba.org/). ====================================================================== -Release notes for older releases follow: ----------------------------------------- +---------------------------------------------------------------------- + ============================== Release Notes for Samba 4.5.14 diff --git a/source3/rpc_server/spoolss/srv_spoolss_nt.c b/source3/rpc_server/spoolss/srv_spoolss_nt.c index a3c3861202d..fb56e2bf9a6 100644 --- a/source3/rpc_server/spoolss/srv_spoolss_nt.c +++ b/source3/rpc_server/spoolss/srv_spoolss_nt.c @@ -178,6 +178,11 @@ static void prune_printername_cache(void); static const char *canon_servername(const char *servername) { const char *pservername = servername; + + if (servername == NULL) { + return ""; + } + while (*pservername == '\\') { pservername++; } @@ -2073,6 +2078,10 @@ WERROR _spoolss_DeletePrinterDriver(struct pipes_struct *p, return WERR_ACCESS_DENIED; } + if (r->in.architecture == NULL || r->in.driver == NULL) { + return WERR_INVALID_ENVIRONMENT; + } + /* check that we have a valid driver name first */ if ((version = get_version_id(r->in.architecture)) == -1) { @@ -2212,6 +2221,10 @@ WERROR _spoolss_DeletePrinterDriverEx(struct pipes_struct *p, return WERR_ACCESS_DENIED; } + if (r->in.architecture == NULL || r->in.driver == NULL) { + return WERR_INVALID_ENVIRONMENT; + } + /* check that we have a valid driver name first */ if (get_version_id(r->in.architecture) == -1) { /* this is what NT returns */ diff --git a/source4/dsdb/samdb/ldb_modules/acl.c b/source4/dsdb/samdb/ldb_modules/acl.c index 27d4e7659cc..d750362c47f 100644 --- a/source4/dsdb/samdb/ldb_modules/acl.c +++ b/source4/dsdb/samdb/ldb_modules/acl.c @@ -966,11 +966,79 @@ static int acl_check_password_rights(TALLOC_CTX *mem_ctx, { int ret = LDB_SUCCESS; unsigned int del_attr_cnt = 0, add_attr_cnt = 0, rep_attr_cnt = 0; + unsigned int del_val_cnt = 0, add_val_cnt = 0, rep_val_cnt = 0; struct ldb_message_element *el; struct ldb_message *msg; + struct ldb_control *c = NULL; const char *passwordAttrs[] = { "userPassword", "clearTextPassword", - "unicodePwd", "dBCSPwd", NULL }, **l; + "unicodePwd", NULL }, **l; TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx); + struct dsdb_control_password_acl_validation *pav = NULL; + + if (tmp_ctx == NULL) { + return LDB_ERR_OPERATIONS_ERROR; + } + + pav = talloc_zero(req, struct dsdb_control_password_acl_validation); + if (pav == NULL) { + talloc_free(tmp_ctx); + return LDB_ERR_OPERATIONS_ERROR; + } + + c = ldb_request_get_control(req, DSDB_CONTROL_PASSWORD_CHANGE_OID); + if (c != NULL) { + pav->pwd_reset = false; + + /* + * The "DSDB_CONTROL_PASSWORD_CHANGE_OID" control means that we + * have a user password change and not a set as the message + * looks like. In it's value blob it contains the NT and/or LM + * hash of the old password specified by the user. This control + * is used by the SAMR and "kpasswd" password change mechanisms. + * + * This control can't be used by real LDAP clients, + * the only caller is samdb_set_password_internal(), + * so we don't have to strict verification of the input. + */ + ret = acl_check_extended_right(tmp_ctx, + sd, + acl_user_token(module), + GUID_DRS_USER_CHANGE_PASSWORD, + SEC_ADS_CONTROL_ACCESS, + sid); + goto checked; + } + + c = ldb_request_get_control(req, DSDB_CONTROL_PASSWORD_HASH_VALUES_OID); + if (c != NULL) { + pav->pwd_reset = true; + + /* + * The "DSDB_CONTROL_PASSWORD_HASH_VALUES_OID" control, without + * "DSDB_CONTROL_PASSWORD_CHANGE_OID" control means that we + * have a force password set. + * This control is used by the SAMR/NETLOGON/LSA password + * reset mechanisms. + * + * This control can't be used by real LDAP clients, + * the only caller is samdb_set_password_internal(), + * so we don't have to strict verification of the input. + */ + ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module), + GUID_DRS_FORCE_CHANGE_PASSWORD, + SEC_ADS_CONTROL_ACCESS, + sid); + goto checked; + } + + el = ldb_msg_find_element(req->op.mod.message, "dBCSPwd"); + if (el != NULL) { + /* + * dBCSPwd is only allowed with a control. + */ + talloc_free(tmp_ctx); + return LDB_ERR_UNWILLING_TO_PERFORM; + } msg = ldb_msg_copy_shallow(tmp_ctx, req->op.mod.message); if (msg == NULL) { @@ -984,12 +1052,15 @@ static int acl_check_password_rights(TALLOC_CTX *mem_ctx, while ((el = ldb_msg_find_element(msg, *l)) != NULL) { if (LDB_FLAG_MOD_TYPE(el->flags) == LDB_FLAG_MOD_DELETE) { ++del_attr_cnt; + del_val_cnt += el->num_values; } if (LDB_FLAG_MOD_TYPE(el->flags) == LDB_FLAG_MOD_ADD) { ++add_attr_cnt; + add_val_cnt += el->num_values; } if (LDB_FLAG_MOD_TYPE(el->flags) == LDB_FLAG_MOD_REPLACE) { ++rep_attr_cnt; + rep_val_cnt += el->num_values; } ldb_msg_remove_element(msg, el); } @@ -1002,26 +1073,30 @@ static int acl_check_password_rights(TALLOC_CTX *mem_ctx, return LDB_SUCCESS; } - if (ldb_request_get_control(req, - DSDB_CONTROL_PASSWORD_CHANGE_OID) != NULL) { - /* The "DSDB_CONTROL_PASSWORD_CHANGE_OID" control means that we - * have a user password change and not a set as the message - * looks like. In it's value blob it contains the NT and/or LM - * hash of the old password specified by the user. - * This control is used by the SAMR and "kpasswd" password - * change mechanisms. */ - ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module), - GUID_DRS_USER_CHANGE_PASSWORD, - SEC_ADS_CONTROL_ACCESS, - sid); - } - else if (rep_attr_cnt > 0 || (add_attr_cnt != del_attr_cnt)) { + + if (rep_attr_cnt > 0) { + pav->pwd_reset = true; + ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module), GUID_DRS_FORCE_CHANGE_PASSWORD, SEC_ADS_CONTROL_ACCESS, sid); + goto checked; } - else if (add_attr_cnt == 1 && del_attr_cnt == 1) { + + if (add_attr_cnt != del_attr_cnt) { + pav->pwd_reset = true; + + ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module), + GUID_DRS_FORCE_CHANGE_PASSWORD, + SEC_ADS_CONTROL_ACCESS, + sid); + goto checked; + } + + if (add_val_cnt == 1 && del_val_cnt == 1) { + pav->pwd_reset = false; + ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module), GUID_DRS_USER_CHANGE_PASSWORD, SEC_ADS_CONTROL_ACCESS, @@ -1030,17 +1105,53 @@ static int acl_check_password_rights(TALLOC_CTX *mem_ctx, if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) { ret = LDB_ERR_CONSTRAINT_VIOLATION; } + goto checked; } + + if (add_val_cnt == 1 && del_val_cnt == 0) { + pav->pwd_reset = true; + + ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module), + GUID_DRS_FORCE_CHANGE_PASSWORD, + SEC_ADS_CONTROL_ACCESS, + sid); + /* Very strange, but we get constraint violation in this case */ + if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) { + ret = LDB_ERR_CONSTRAINT_VIOLATION; + } + goto checked; + } + + /* + * Everything else is handled by the password_hash module where it will + * fail, but with the correct error code when the module is again + * checking the attributes. As the change request will lack the + * DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID control, we can be sure that + * any modification attempt that went this way will be rejected. + */ + + talloc_free(tmp_ctx); + return LDB_SUCCESS; + +checked: if (ret != LDB_SUCCESS) { dsdb_acl_debug(sd, acl_user_token(module), req->op.mod.message->dn, true, 10); + talloc_free(tmp_ctx); + return ret; } - talloc_free(tmp_ctx); - return ret; -} + ret = ldb_request_add_control(req, + DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID, false, pav); + if (ret != LDB_SUCCESS) { + ldb_debug(ldb_module_get_ctx(module), LDB_DEBUG_ERROR, + "Unable to register ACL validation control!\n"); + return ret; + } + return LDB_SUCCESS; +} static int acl_modify(struct ldb_module *module, struct ldb_request *req) { @@ -1055,6 +1166,7 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req) struct ldb_control *as_system; struct ldb_control *is_undelete; bool userPassword; + bool password_rights_checked = false; TALLOC_CTX *tmp_ctx; const struct ldb_message *msg = req->op.mod.message; static const char *acl_attrs[] = { @@ -1200,6 +1312,9 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req) } else if (ldb_attr_cmp("unicodePwd", el->name) == 0 || (userPassword && ldb_attr_cmp("userPassword", el->name) == 0) || ldb_attr_cmp("clearTextPassword", el->name) == 0) { + if (password_rights_checked) { + continue; + } ret = acl_check_password_rights(tmp_ctx, module, req, @@ -1210,6 +1325,7 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req) if (ret != LDB_SUCCESS) { goto fail; } + password_rights_checked = true; } else if (ldb_attr_cmp("servicePrincipalName", el->name) == 0) { ret = acl_check_spn(tmp_ctx, module, diff --git a/source4/dsdb/samdb/ldb_modules/password_hash.c b/source4/dsdb/samdb/ldb_modules/password_hash.c index e5bee6fae53..06abf66f1a7 100644 --- a/source4/dsdb/samdb/ldb_modules/password_hash.c +++ b/source4/dsdb/samdb/ldb_modules/password_hash.c @@ -3188,7 +3188,35 @@ static int setup_io(struct ph_context *ac, /* On "add" we have only "password reset" */ ac->pwd_reset = true; } else if (ac->req->operation == LDB_MODIFY) { - if (io->og.cleartext_utf8 || io->og.cleartext_utf16 + struct ldb_control *pav_ctrl = NULL; + struct dsdb_control_password_acl_validation *pav = NULL; + + pav_ctrl = ldb_request_get_control(ac->req, + DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID); + if (pav_ctrl != NULL) { + pav = talloc_get_type_abort(pav_ctrl->data, + struct dsdb_control_password_acl_validation); + } + + if (pav == NULL && ac->update_password) { + bool ok; + + /* + * If the DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID + * control is missing, we require system access! + */ + ok = dsdb_module_am_system(ac->module); + if (!ok) { + return ldb_module_operr(ac->module); + } + } + + if (pav != NULL) { + /* + * We assume what the acl module has validated. + */ + ac->pwd_reset = pav->pwd_reset; + } else if (io->og.cleartext_utf8 || io->og.cleartext_utf16 || io->og.nt_hash || io->og.lm_hash) { /* If we have an old password specified then for sure it * is a user "password change" */ @@ -3921,25 +3949,26 @@ static int password_hash_modify(struct ldb_module *module, struct ldb_request *r } while ((passwordAttr = ldb_msg_find_element(msg, *l)) != NULL) { - if (LDB_FLAG_MOD_TYPE(passwordAttr->flags) == LDB_FLAG_MOD_DELETE) { + unsigned int mtype = LDB_FLAG_MOD_TYPE(passwordAttr->flags); + unsigned int nvalues = passwordAttr->num_values; + + if (mtype == LDB_FLAG_MOD_DELETE) { ++del_attr_cnt; } - if (LDB_FLAG_MOD_TYPE(passwordAttr->flags) == LDB_FLAG_MOD_ADD) { + if (mtype == LDB_FLAG_MOD_ADD) { ++add_attr_cnt; } - if (LDB_FLAG_MOD_TYPE(passwordAttr->flags) == LDB_FLAG_MOD_REPLACE) { + if (mtype == LDB_FLAG_MOD_REPLACE) { ++rep_attr_cnt; } - if ((passwordAttr->num_values != 1) && - (LDB_FLAG_MOD_TYPE(passwordAttr->flags) == LDB_FLAG_MOD_ADD)) { + if ((nvalues != 1) && (mtype == LDB_FLAG_MOD_ADD)) { talloc_free(ac); ldb_asprintf_errstring(ldb, "'%s' attribute must have exactly one value on add operations!", *l); return LDB_ERR_CONSTRAINT_VIOLATION; } - if ((passwordAttr->num_values > 1) && - (LDB_FLAG_MOD_TYPE(passwordAttr->flags) == LDB_FLAG_MOD_DELETE)) { + if ((nvalues > 1) && (mtype == LDB_FLAG_MOD_DELETE)) { talloc_free(ac); ldb_asprintf_errstring(ldb, "'%s' attribute must have zero or one value(s) on delete operations!", diff --git a/source4/dsdb/samdb/samdb.h b/source4/dsdb/samdb/samdb.h index 586a3bfaf0e..6390258141e 100644 --- a/source4/dsdb/samdb/samdb.h +++ b/source4/dsdb/samdb/samdb.h @@ -182,6 +182,15 @@ struct dsdb_control_password_user_account_control { /* passed when we want to thoroughly delete linked attributes */ #define DSDB_CONTROL_REPLMD_VANISH_LINKS "1.3.6.1.4.1.7165.4.3.29" +/* + * Used to pass "user password change" vs "password reset" from the ACL to the + * password_hash module, ensuring both modules treat the request identical. + */ +#define DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID "1.3.6.1.4.1.7165.4.3.33" +struct dsdb_control_password_acl_validation { + bool pwd_reset; +}; + #define DSDB_EXTENDED_REPLICATED_OBJECTS_OID "1.3.6.1.4.1.7165.4.4.1" struct dsdb_extended_replicated_object { struct ldb_message *msg; diff --git a/source4/dsdb/tests/python/passwords.py b/source4/dsdb/tests/python/passwords.py index db013ea46ad..be1f34d2312 100755 --- a/source4/dsdb/tests/python/passwords.py +++ b/source4/dsdb/tests/python/passwords.py @@ -1020,6 +1020,55 @@ userPassword: thatsAcomplPASS4 # Reset the "minPwdLength" as it was before self.ldb.set_minPwdLength(minPwdLength) + def test_pw_change_delete_no_value_userPassword(self): + """Test password change with userPassword where the delete attribute doesn't have a value""" + + try: + self.ldb2.modify_ldif(""" +dn: cn=testuser,cn=users,""" + self.base_dn + """ +changetype: modify +delete: userPassword +add: userPassword +userPassword: thatsAcomplPASS1 +""") + except LdbError, (num, msg): + self.assertEquals(num, ERR_CONSTRAINT_VIOLATION) + else: + self.fail() + + def test_pw_change_delete_no_value_clearTextPassword(self): + """Test password change with clearTextPassword where the delete attribute doesn't have a value""" + + try: + self.ldb2.modify_ldif(""" +dn: cn=testuser,cn=users,""" + self.base_dn + """ +changetype: modify +delete: clearTextPassword +add: clearTextPassword +clearTextPassword: thatsAcomplPASS2 +""") + except LdbError, (num, msg): + self.assertTrue(num == ERR_CONSTRAINT_VIOLATION or + num == ERR_NO_SUCH_ATTRIBUTE) # for Windows + else: + self.fail() + + def test_pw_change_delete_no_value_unicodePwd(self): + """Test password change with unicodePwd where the delete attribute doesn't have a value""" + + try: + self.ldb2.modify_ldif(""" +dn: cn=testuser,cn=users,""" + self.base_dn + """ +changetype: modify +delete: unicodePwd +add: unicodePwd +unicodePwd:: """ + base64.b64encode("\"thatsAcomplPASS3\"".encode('utf-16-le')) + """ +""") + except LdbError, (num, msg): + self.assertEquals(num, ERR_CONSTRAINT_VIOLATION) + else: + self.fail() + def tearDown(self): super(PasswordTests, self).tearDown() delete_force(self.ldb, "cn=testuser,cn=users," + self.base_dn) diff --git a/source4/libcli/ldap/ldap_controls.c b/source4/libcli/ldap/ldap_controls.c index 9df95c32a9d..7ecc9080cd1 100644 --- a/source4/libcli/ldap/ldap_controls.c +++ b/source4/libcli/ldap/ldap_controls.c @@ -1262,6 +1262,7 @@ static const struct ldap_control_handler ldap_known_controls[] = { { DSDB_CONTROL_PASSWORD_CHANGE_STATUS_OID, NULL, NULL }, { DSDB_CONTROL_PASSWORD_HASH_VALUES_OID, NULL, NULL }, { DSDB_CONTROL_PASSWORD_CHANGE_OID, NULL, NULL }, + { DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID, NULL, NULL }, { DSDB_CONTROL_APPLY_LINKS, NULL, NULL }, { LDB_CONTROL_BYPASS_OPERATIONAL_OID, NULL, NULL }, { DSDB_CONTROL_CHANGEREPLMETADATA_OID, NULL, NULL }, diff --git a/source4/setup/schema_samba4.ldif b/source4/setup/schema_samba4.ldif index 04505de2daf..0a27f8a991e 100644 --- a/source4/setup/schema_samba4.ldif +++ b/source4/setup/schema_samba4.ldif @@ -217,6 +217,8 @@ #Allocated: DSDB_CONTROL_PASSWORD_USER_ACCOUNT_CONTROL_OID 1.3.6.1.4.1.7165.4.3.27 #Allocated: DSDB_CONTROL_SKIP_DUPLICATES_CHECK_OID 1.3.6.1.4.1.7165.4.3.28 #Allocated: DSDB_CONTROL_REPLMD_VANISH_LINKS 1.3.6.1.4.1.7165.4.3.29 +#Allocated: DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID 1.3.6.1.4.1.7165.4.3.33 + # Extended 1.3.6.1.4.1.7165.4.4.x #Allocated: DSDB_EXTENDED_REPLICATED_OBJECTS_OID 1.3.6.1.4.1.7165.4.4.1