From a7ee52bd4b0bce82402a581ee16659ebb2f8d96e Mon Sep 17 00:00:00 2001
From: Thierry Bordaz <tbordaz@redhat.com>
Date: Wed, 24 Oct 2018 15:31:25 +0200
Subject: [PATCH 1/2] Ticket 49967 - entry cache corruption after failed MODRDN

Bug Description:
	During a MODRDN the DN cache is updated to replace
	source DN with the target DN (modrdn_rename_entry_update_indexes)
	If later a failure occurs (for example if BETXN_POSTOP fails) and
	the txn is aborted, the target DN (for the specific entryID) remains
	in the DN cache.

	If the entry is returned in a search, to build the DN there is
	a lookup of the DN cache with the entryID. It retrieves the target DN
	rather than the source DN

Fix Description:
	In case of failure of the operation, the entry (from the entryID)
	need to be cleared from the DN cache

https://pagure.io/389-ds-base/issue/49967

Reviewed by: Mark Reynolds

Platforms tested: F27

Flag Day: no

Doc impact: no

(cherry picked from commit ab4af68ef49fcdc5f2f6d0c1f5c7b9a5333b1bee)
---
 ldap/servers/slapd/back-ldbm/ldbm_modrdn.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/ldap/servers/slapd/back-ldbm/ldbm_modrdn.c b/ldap/servers/slapd/back-ldbm/ldbm_modrdn.c
index 71e2a8fe0..e2e9d1b46 100644
--- a/ldap/servers/slapd/back-ldbm/ldbm_modrdn.c
+++ b/ldap/servers/slapd/back-ldbm/ldbm_modrdn.c
@@ -1400,6 +1400,19 @@ common_return:
                 }
             }
         }
+
+        if (ec && retval) {
+            /* if the operation failed, the destination entry does not exist
+             * but it has been added in dncache during cache_add_tentative
+             * we need to remove it. Else a retrieval from ep_id can give the wrong DN
+             */
+            struct backdn *bdn = dncache_find_id(&inst->inst_dncache, ec->ep_id);
+            slapi_log_err(SLAPI_LOG_CACHE, "ldbm_back_modrdn",
+                                      "operation failed, the target entry is cleared from dncache (%s)\n", slapi_entry_get_dn(ec->ep_entry));
+            CACHE_REMOVE(&inst->inst_dncache, bdn);
+            CACHE_RETURN(&inst->inst_dncache, &bdn);
+        }
+
         /* remove the new entry from the cache if the op failed -
            otherwise, leave it in */
         if (ec && inst) {
-- 
2.17.2