From 0b9da247534f735fa96141e9285fd22e0f2bb442 Mon Sep 17 00:00:00 2001 From: Douglas Bagnall Date: Wed, 22 May 2019 12:58:01 +1200 Subject: [PATCH 1/3] CVE-2019-12435 rpc/dns: avoid NULL deference if zone not found in DnssrvOperation We still want to return DOES_NOT_EXIST when request_filter is not 0. BUG: https://bugzilla.samba.org/show_bug.cgi?id=13922 Signed-off-by: Douglas Bagnall Reviewed-by: Andrew Bartlett --- python/samba/tests/dcerpc/dnsserver.py | 25 +++++++++++++++++++ .../rpc_server/dnsserver/dcerpc_dnsserver.c | 7 +++++- 2 files changed, 31 insertions(+), 1 deletion(-) diff --git a/python/samba/tests/dcerpc/dnsserver.py b/python/samba/tests/dcerpc/dnsserver.py index 8e485c540dd..bfe86323e0c 100644 --- a/python/samba/tests/dcerpc/dnsserver.py +++ b/python/samba/tests/dcerpc/dnsserver.py @@ -28,6 +28,7 @@ from samba.dcerpc import dnsp, dnsserver, security from samba.tests import RpcInterfaceTestCase, env_get_var_value from samba.netcmd.dns import ARecord, AAAARecord, PTRRecord, CNameRecord, NSRecord, MXRecord, SRVRecord, TXTRecord from samba import sd_utils, descriptor +from samba import WERRORError, werror class DnsserverTests(RpcInterfaceTestCase): @@ -707,6 +708,30 @@ class DnsserverTests(RpcInterfaceTestCase): 'ServerInfo') self.assertEquals(dnsserver.DNSSRV_TYPEID_SERVER_INFO, typeid) + + # This test is to confirm that we do not support multizone operations, + # which are designated by a non-zero dwContext value (the 3rd argument + # to DnssrvOperation). + def test_operation_invalid(self): + non_zone = 'a-zone-that-does-not-exist' + typeid = dnsserver.DNSSRV_TYPEID_NAME_AND_PARAM + name_and_param = dnsserver.DNS_RPC_NAME_AND_PARAM() + name_and_param.pszNodeName = 'AllowUpdate' + name_and_param.dwParam = dnsp.DNS_ZONE_UPDATE_SECURE + try: + res = self.conn.DnssrvOperation(self.server, + non_zone, + 1, + 'ResetDwordProperty', + typeid, + name_and_param) + except WERRORError as e: + if e.args[0] == werror.WERR_DNS_ERROR_ZONE_DOES_NOT_EXIST: + return + + # We should always encounter a DOES_NOT_EXIST error. + self.fail() + def test_operation2(self): client_version = dnsserver.DNS_CLIENT_VERSION_LONGHORN rev_zone = '1.168.192.in-addr.arpa' diff --git a/source4/rpc_server/dnsserver/dcerpc_dnsserver.c b/source4/rpc_server/dnsserver/dcerpc_dnsserver.c index 841557814a0..bdf894634ce 100644 --- a/source4/rpc_server/dnsserver/dcerpc_dnsserver.c +++ b/source4/rpc_server/dnsserver/dcerpc_dnsserver.c @@ -2018,7 +2018,12 @@ static WERROR dcesrv_DnssrvOperation(struct dcesrv_call_state *dce_call, TALLOC_ &r->in.pData); } else { z = dnsserver_find_zone(dsstate->zones, r->in.pszZone); - if (z == NULL && request_filter == 0) { + /* + * In the case that request_filter is not 0 and z is NULL, + * the request is for a multizone operation, which we do not + * yet support, so just error on NULL zone name. + */ + if (z == NULL) { return WERR_DNS_ERROR_ZONE_DOES_NOT_EXIST; } -- 2.17.1 From d32b96aeff0022c7a9052f15adbc7cd36643ca22 Mon Sep 17 00:00:00 2001 From: Douglas Bagnall Date: Wed, 22 May 2019 13:23:25 +1200 Subject: [PATCH 2/3] CVE-2019-12435 rpc/dns: avoid NULL deference if zone not found in DnssrvOperation2 We still want to return DOES_NOT_EXIST when request_filter is not 0. BUG: https://bugzilla.samba.org/show_bug.cgi?id=13922 Signed-off-by: Douglas Bagnall Reviewed-by: Andrew Bartlett --- python/samba/tests/dcerpc/dnsserver.py | 26 +++++++++++++++++++ .../rpc_server/dnsserver/dcerpc_dnsserver.c | 7 ++++- 2 files changed, 32 insertions(+), 1 deletion(-) diff --git a/python/samba/tests/dcerpc/dnsserver.py b/python/samba/tests/dcerpc/dnsserver.py index bfe86323e0c..0da9614d066 100644 --- a/python/samba/tests/dcerpc/dnsserver.py +++ b/python/samba/tests/dcerpc/dnsserver.py @@ -732,6 +732,32 @@ class DnsserverTests(RpcInterfaceTestCase): # We should always encounter a DOES_NOT_EXIST error. self.fail() + # This test is to confirm that we do not support multizone operations, + # which are designated by a non-zero dwContext value (the 5th argument + # to DnssrvOperation2). + def test_operation2_invalid(self): + client_version = dnsserver.DNS_CLIENT_VERSION_LONGHORN + non_zone = 'a-zone-that-does-not-exist' + typeid = dnsserver.DNSSRV_TYPEID_NAME_AND_PARAM + name_and_param = dnsserver.DNS_RPC_NAME_AND_PARAM() + name_and_param.pszNodeName = 'AllowUpdate' + name_and_param.dwParam = dnsp.DNS_ZONE_UPDATE_SECURE + try: + res = self.conn.DnssrvOperation2(client_version, + 0, + self.server, + non_zone, + 1, + 'ResetDwordProperty', + typeid, + name_and_param) + except WERRORError as e: + if e.args[0] == werror.WERR_DNS_ERROR_ZONE_DOES_NOT_EXIST: + return + + # We should always encounter a DOES_NOT_EXIST error. + self.fail() + def test_operation2(self): client_version = dnsserver.DNS_CLIENT_VERSION_LONGHORN rev_zone = '1.168.192.in-addr.arpa' diff --git a/source4/rpc_server/dnsserver/dcerpc_dnsserver.c b/source4/rpc_server/dnsserver/dcerpc_dnsserver.c index bdf894634ce..f8a8f0bae61 100644 --- a/source4/rpc_server/dnsserver/dcerpc_dnsserver.c +++ b/source4/rpc_server/dnsserver/dcerpc_dnsserver.c @@ -2230,7 +2230,12 @@ static WERROR dcesrv_DnssrvOperation2(struct dcesrv_call_state *dce_call, TALLOC &r->in.pData); } else { z = dnsserver_find_zone(dsstate->zones, r->in.pszZone); - if (z == NULL && request_filter == 0) { + /* + * In the case that request_filter is not 0 and z is NULL, + * the request is for a multizone operation, which we do not + * yet support, so just error on NULL zone name. + */ + if (z == NULL) { return WERR_DNS_ERROR_ZONE_DOES_NOT_EXIST; } -- 2.17.1 From c48920093da7f5f6cbbca42d516b86b9cf51eea6 Mon Sep 17 00:00:00 2001 From: Douglas Bagnall Date: Fri, 17 May 2019 14:42:24 +1200 Subject: [PATCH 3/3] CVE-2019-12436 dsdb/paged_results: ignore successful results without messages So that we don't dereference result->msgs[0] when it doesn't exist. This can happen when the object has changed in such a way that it no longer matches the original search query. BUG: https://bugzilla.samba.org/show_bug.cgi?id=13951 Signed-off-by: Douglas Bagnall Reviewed-by: Andrew Bartlett --- .../dsdb/samdb/ldb_modules/paged_results.c | 3 +- source4/dsdb/tests/python/vlv.py | 50 ++++++++++++++++++- 2 files changed, 51 insertions(+), 2 deletions(-) diff --git a/source4/dsdb/samdb/ldb_modules/paged_results.c b/source4/dsdb/samdb/ldb_modules/paged_results.c index 78ad44f6601..5cad398ab61 100644 --- a/source4/dsdb/samdb/ldb_modules/paged_results.c +++ b/source4/dsdb/samdb/ldb_modules/paged_results.c @@ -266,7 +266,8 @@ static int paged_results(struct paged_context *ac) ret = paged_search_by_dn_guid(ac->module, ac, &result, guid, ac->req->op.search.attrs, ac->store->expr); - if (ret == LDAP_NO_SUCH_OBJECT /* TODO or no result */) { + if (ret == LDAP_NO_SUCH_OBJECT || + (ret == LDB_SUCCESS && result->count == 0)) { /* The thing isn't there TODO, which we quietly ignore and go on to send an extra one instead. */ diff --git a/source4/dsdb/tests/python/vlv.py b/source4/dsdb/tests/python/vlv.py index 8550a38e287..bc07a53d575 100644 --- a/source4/dsdb/tests/python/vlv.py +++ b/source4/dsdb/tests/python/vlv.py @@ -105,6 +105,7 @@ class TestsWithUserOU(samba.tests.TestCase): 'givenName': "abcdefghijklmnopqrstuvwxyz"[i % 26], "roomNumber": "%sbc" % (n - i), "carLicense": "后来经", + "facsimileTelephoneNumber": name, "employeeNumber": "%s%sx" % (abs(i * (99 - i)), '\n' * (i & 255)), "accountExpires": "%s" % (10 ** 9 + 1000000 * i), "msTSExpireDate4": "19%02d0101010000.0Z" % (i % 100), @@ -1334,7 +1335,7 @@ class PagedResultsTests(TestsWithUserOU): self.assertEqual(results, expected_results) - def test_paged_modify_during_search(self): + def test_paged_rename_during_search(self): expr = "(objectClass=*)" # Start new search @@ -1421,6 +1422,53 @@ class PagedResultsTests(TestsWithUserOU): self.assertEqual(results, expected_results) + def test_paged_modify_one_during_search(self): + prefix = "change_during_search_" + num_users = 5 + users = [self.create_user(i, num_users, prefix=prefix) + for i in range(num_users)] + expr = "(&(objectClass=user)(facsimileTelephoneNumber=%s*))" % (prefix) + + # Get the first page, then change the searched attribute and + # try for the second page. + results, cookie = self.paged_search(expr, page_size=1) + self.assertEqual(len(results), 1) + unwalked_users = [u for u in users if u['cn'] != results[0]] + self.assertEqual(len(unwalked_users), num_users-1) + + mod_dn = unwalked_users[0]['dn'] + self.ldb.modify_ldif("dn: %s\n" + "changetype: modify\n" + "replace: facsimileTelephoneNumber\n" + "facsimileTelephoneNumber: 123" % mod_dn) + + results, _ = self.paged_search(expr, cookie=cookie, + page_size=len(self.users)) + expected_cns = {u['cn'] for u in unwalked_users if u['dn'] != mod_dn} + self.assertEqual(set(results), expected_cns) + + def test_paged_modify_all_during_search(self): + prefix = "change_during_search_" + num_users = 5 + users = [self.create_user(i, num_users, prefix=prefix) + for i in range(num_users)] + expr = "(&(objectClass=user)(facsimileTelephoneNumber=%s*))" % (prefix) + + # Get the first page, then change the searched attribute and + # try for the second page. + results, cookie = self.paged_search(expr, page_size=1) + unwalked_users = [u for u in users if u['cn'] != results[0]] + + for u in users: + self.ldb.modify_ldif("dn: %s\n" + "changetype: modify\n" + "replace: facsimileTelephoneNumber\n" + "facsimileTelephoneNumber: 123" % u['dn']) + + results, _ = self.paged_search(expr, cookie=cookie, + page_size=len(self.users)) + self.assertEqual(results, []) + def assertPagedSearchRaises(self, err_num, expr, cookie, attrs=None, extra_ctrls=None): try: -- 2.17.1