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dbchecker: Fixing up incorrect DNs wasn't working

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dbcheck would fail to fix up attributes where the extended DN's GUID is
correct, but the DN itself is incorrect. The code failed attempting to
remove the old/incorrect DN, e.g.

 NOTE: old (due to rename or delete) DN string component for
 objectCategory in object CN=alice,CN=Users,DC=samba,DC=example,DC=com -
 <GUID=7bfdf9d8-62f9-420c-8a71-e3d3e931c91e>;
   CN=Person,CN=Schema,CN=Configuration,DC=samba,DC=bad,DC=com
 Change DN to <GUID=7bfdf9d8-62f9-420c-8a71-e3d3e931c91e>;
   CN=Person,CN=Schema,CN=Configuration,DC=samba,DC=example,DC=com?
 [y/N/all/none] y
 Failed to fix old DN string on attribute objectCategory : (16,
 "attribute 'objectCategory': no matching attribute value while deleting
 attribute on 'CN=alice,CN=Users,DC=samba,DC=example,DC=com'")

The problem was the LDB message specified the value to delete with its
full DN, including the GUID. The LDB code then helpfully corrected this
value on the way through, so that the DN got updated to reflect the
correct DN (i.e. 'DC=example,DC=com') of the object matching that GUID,
rather than the incorrect DN (i.e. 'DC=bad,DC=com') that we were trying
to remove. Because the requested value and the existing DB value didn't
match, the operation failed.

We can avoid this problem by passing down just the DN (not the extended
DN) of the value we want to delete. Without the GUID portion of the DN,
the LDB code will no longer try to correct it on the way through, and
the dbcheck operation will succeed.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13495

Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Gary Lockyer <gary@catalyst.net.nz>
Pair-programmed-with: Andrew Bartlett <abartlet@samba.org>
This commit is contained in:
Tim Beale 2018-05-25 14:05:27 +12:00 committed by Gary Lockyer
parent c7fd68088d
commit 22208f52e6
7 changed files with 171 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
python/samba/dbchecker.py
View File

@ -656,7 +656,8 @@ newSuperior: %s""" % (str(from_dn), str(to_rdn), str(to_base)))
m.dn = dn
m['old_value'] = ldb.MessageElement(val, ldb.FLAG_MOD_DELETE, attrname)
m['new_value'] = ldb.MessageElement(str(dsdb_dn), ldb.FLAG_MOD_ADD, attrname)
if self.do_modify(m, ["show_recycled:1"],
if self.do_modify(m, ["show_recycled:1",
"local_oid:%s:1" % dsdb.DSDB_CONTROL_DBCHECK_FIX_LINK_DN_NAME],
"Failed to fix old DN string on attribute %s" % (attrname)):
self.report("Fixed old DN string on attribute %s" % (attrname))
@ -1298,14 +1299,22 @@ newSuperior: %s""" % (str(from_dn), str(to_rdn), str(to_base)))
res[0].dn, "SID")
continue
# Only for non-links, not even forward-only links
# (otherwise this breaks repl_meta_data):
#
# Now we have checked the GUID and SID, offer to fix old
# DN strings as a non-error (for forward links with no
# DN strings as a non-error (DNs, not links so no
# backlink). Samba does not maintain this string
# otherwise, so we don't increment error_count.
if reverse_link_name is None:
if str(res[0].dn) != str(dsdb_dn.dn):
self.err_dn_string_component_old(obj.dn, attrname, val, dsdb_dn,
res[0].dn)
if linkID == 0 and str(res[0].dn) != str(dsdb_dn.dn):
# Pass in the old/bad DN without the <GUID=...> part,
# otherwise the LDB code will correct it on the way through
# (Note: we still want to preserve the DSDB DN prefix in the
# case of binary DNs)
bad_dn = dsdb_dn.prefix + dsdb_dn.dn.get_linearized()
self.err_dn_string_component_old(obj.dn, attrname, bad_dn,
dsdb_dn, res[0].dn)
continue
# check the reverse_link is correct if there should be one

1
source4/dsdb/pydsdb.c
View File

@ -1582,6 +1582,7 @@ MODULE_INIT_FUNC(dsdb)
ADD_DSDB_STRING(DSDB_CONTROL_DBCHECK);
ADD_DSDB_STRING(DSDB_CONTROL_DBCHECK_MODIFY_RO_REPLICA);
ADD_DSDB_STRING(DSDB_CONTROL_DBCHECK_FIX_DUPLICATE_LINKS);
ADD_DSDB_STRING(DSDB_CONTROL_DBCHECK_FIX_LINK_DN_NAME);
ADD_DSDB_STRING(DSDB_CONTROL_REPLMD_VANISH_LINKS);
ADD_DSDB_STRING(DSDB_CONTROL_PERMIT_INTERDOMAIN_TRUST_UAC_OID);
ADD_DSDB_STRING(DSDB_CONTROL_SKIP_DUPLICATES_CHECK_OID);

64
source4/dsdb/samdb/ldb_modules/repl_meta_data.c
View File

@ -3333,6 +3333,7 @@ static int replmd_modify(struct ldb_module *module, struct ldb_request *req)
const struct ldb_message_element *guid_el = NULL;
struct ldb_control *sd_propagation_control;
struct ldb_control *fix_links_control = NULL;
struct ldb_control *fix_dn_name_control = NULL;
struct replmd_private *replmd_private =
talloc_get_type(ldb_module_get_private(module), struct replmd_private);
@ -3391,6 +3392,69 @@ static int replmd_modify(struct ldb_module *module, struct ldb_request *req)
return ldb_next_request(module, req);
}
fix_dn_name_control = ldb_request_get_control(req,
DSDB_CONTROL_DBCHECK_FIX_LINK_DN_NAME);
if (fix_dn_name_control != NULL) {
struct dsdb_schema *schema = NULL;
const struct dsdb_attribute *sa = NULL;
if (req->op.mod.message->num_elements != 2) {
return ldb_module_operr(module);
}
if (req->op.mod.message->elements[0].flags != LDB_FLAG_MOD_DELETE) {
return ldb_module_operr(module);
}
if (req->op.mod.message->elements[1].flags != LDB_FLAG_MOD_ADD) {
return ldb_module_operr(module);
}
if (req->op.mod.message->elements[0].num_values != 1) {
return ldb_module_operr(module);
}
if (req->op.mod.message->elements[1].num_values != 1) {
return ldb_module_operr(module);
}
schema = dsdb_get_schema(ldb, req);
if (schema == NULL) {
return ldb_module_operr(module);
}
if (ldb_attr_cmp(req->op.mod.message->elements[0].name,
req->op.mod.message->elements[1].name) != 0) {
return ldb_module_operr(module);
}
sa = dsdb_attribute_by_lDAPDisplayName(schema,
req->op.mod.message->elements[0].name);
if (sa == NULL) {
return ldb_module_operr(module);
}
if (sa->dn_format == DSDB_INVALID_DN) {
return ldb_module_operr(module);
}
if (sa->linkID != 0) {
return ldb_module_operr(module);
}
/*
* If we are run from dbcheck and we are not updating
* a link (as these would need to be sorted and so
* can't go via such a simple update, then do not
* trigger replicated updates and a new USN from this
* change, it wasn't a real change, just a new
* (correct) string DN
*/
fix_dn_name_control->critical = false;
return ldb_next_request(module, req);
}
ldb_debug(ldb, LDB_DEBUG_TRACE, "replmd_modify\n");
guid_el = ldb_msg_find_element(req->op.mod.message, "objectGUID");

3
source4/dsdb/samdb/samdb.h
View File

@ -132,6 +132,9 @@ struct dsdb_control_password_change {
/* passed by dbcheck to fix duplicate linked attributes (bug #13095) */
#define DSDB_CONTROL_DBCHECK_FIX_DUPLICATE_LINKS "1.3.6.1.4.1.7165.4.3.19.2"
/* passed by dbcheck to fix the DN strong of a one-way-link (bug #13495) */
#define DSDB_CONTROL_DBCHECK_FIX_LINK_DN_NAME "1.3.6.1.4.1.7165.4.3.19.3"
/* passed when importing plain text password on upgrades */
#define DSDB_CONTROL_PASSWORD_BYPASS_LAST_SET_OID "1.3.6.1.4.1.7165.4.3.20"

19
source4/selftest/provisions/release-4-5-0-pre1/expected-after-dbcheck-oneway-link-corruption.ldif Normal file
View File

@ -0,0 +1,19 @@
# record 1
dn: OU=dangling-ou2,DC=release-4-5-0-pre1,DC=samba,DC=corp
# record 2
dn: OU=dangling-from,DC=release-4-5-0-pre1,DC=samba,DC=corp
seeAlso: OU=dangling-ou2,DC=release-4-5-0-pre1,DC=samba,DC=corp
# Referral
ref: ldap:///CN=Configuration,DC=release-4-5-0-pre1,DC=samba,DC=corp
# Referral
ref: ldap:///DC=DomainDnsZones,DC=release-4-5-0-pre1,DC=samba,DC=corp
# Referral
ref: ldap:///DC=ForestDnsZones,DC=release-4-5-0-pre1,DC=samba,DC=corp
# returned 5 records
# 2 entries
# 3 referrals

5
source4/selftest/provisions/release-4-5-0-pre1/expected-dbcheck-link-output-oneway-link-corruption.txt Normal file
View File

@ -0,0 +1,5 @@
Checking 228 objects
NOTE: old (due to rename or delete) DN string component for seeAlso in object OU=dangling-from,DC=release-4-5-0-pre1,DC=samba,DC=corp - OU=dangling-ou,DC=release-4-5-0-pre1,DC=samba,DC=corp
Change DN to <GUID=20600e7c-92bb-492e-9552-f3ed7f8a2cad>;OU=dangling-ou2,DC=release-4-5-0-pre1,DC=samba,DC=corp? [YES]
Fixed old DN string on attribute seeAlso
Checked 228 objects (0 errors)

65
testprogs/blackbox/dbcheck-links.sh
View File

@ -205,6 +205,67 @@ check_expected_after_dbcheck_forward_link_corruption() {
fi
}
oneway_link_corruption() {
#
# Step1: add OU "dangling-ou"
#
ldif=$PREFIX_ABS/${RELEASE}/oneway_link_corruption.ldif
cat > $ldif <<EOF
dn: OU=dangling-ou,DC=release-4-5-0-pre1,DC=samba,DC=corp
changetype: add
objectclass: organizationalUnit
objectGUID: 20600e7c-92bb-492e-9552-f3ed7f8a2cad
EOF
out=$(TZ=UTC $ldbmodify -H tdb://$PREFIX_ABS/${RELEASE}/private/sam.ldb --relax $ldif)
if [ "$?" != "0" ]; then
echo "ldbmodify returned:\n$out"
return 1
fi
#
# Step2: add msExchConfigurationContainer "dangling-msexch"
#
ldif=$PREFIX_ABS/${RELEASE}/oneway_link_corruption2.ldif
cat > $ldif <<EOF
dn: OU=dangling-from,DC=release-4-5-0-pre1,DC=samba,DC=corp
changetype: add
objectclass: organizationalUnit
seeAlso: OU=dangling-ou,DC=release-4-5-0-pre1,DC=samba,DC=corp
EOF
out=$(TZ=UTC $ldbmodify -H tdb://$PREFIX_ABS/${RELEASE}/private/sam.ldb $ldif)
if [ "$?" != "0" ]; then
echo "ldbmodify returned:\n$out"
return 1
fi
#
# Step3: rename dangling-ou to dangling-ou2
#
# Because this is a one-way link we don't fix it at runtime
#
out=$(TZ=UTC $ldbrename -H tdb://$PREFIX_ABS/${RELEASE}/private/sam.ldb OU=dangling-ou,DC=release-4-5-0-pre1,DC=samba,DC=corp OU=dangling-ou2,DC=release-4-5-0-pre1,DC=samba,DC=corp)
if [ "$?" != "0" ]; then
echo "ldbmodify returned:\n$out"
return 1
fi
}
dbcheck_oneway_link_corruption() {
dbcheck "-oneway-link-corruption" "0" ""
return $?
}
check_expected_after_dbcheck_oneway_link_corruption() {
tmpldif=$PREFIX_ABS/$RELEASE/expected-after-dbcheck-oneway-link-corruption.ldif.tmp
TZ=UTC $ldbsearch -H tdb://$PREFIX_ABS/${RELEASE}/private/sam.ldb '(|(ou=dangling-ou)(ou=dangling-ou2)(ou=dangling-from))' -s sub -b DC=release-4-5-0-pre1,DC=samba,DC=corp --show-deleted --sorted seeAlso > $tmpldif
diff $tmpldif $release_dir/expected-after-dbcheck-oneway-link-corruption.ldif
if [ "$?" != "0" ]; then
return 1
fi
}
dbcheck_dangling_multi_valued() {
$PYTHON $BINDIR/samba-tool dbcheck -H tdb://$PREFIX_ABS/${RELEASE}/private/sam.ldb --fix --yes
@ -276,6 +337,10 @@ if [ -d $release_dir ]; then
testit "dbcheck_forward_link_corruption" dbcheck_forward_link_corruption
testit "check_expected_after_dbcheck_forward_link_corruption" check_expected_after_dbcheck_forward_link_corruption
testit "forward_link_corruption_clean" dbcheck_clean
testit "oneway_link_corruption" oneway_link_corruption
testit "dbcheck_oneway_link_corruption" dbcheck_oneway_link_corruption
testit "check_expected_after_dbcheck_oneway_link_corruption" check_expected_after_dbcheck_oneway_link_corruption
testit "oneway_link_corruption_clean" dbcheck_clean
testit "dangling_one_way_link" dangling_one_way_link
testit "dbcheck_one_way" dbcheck_one_way
testit "dbcheck_clean2" dbcheck_clean