Fix for Bug #41597 - After rename of user, there are additional grants when

                     grants are reapplied.


After renaming a user and trying to re-apply grants results in additional
grants.

This is because we use username as part of the key for GRANT_TABLE structure.
When the user is renamed, we only change the username stored and the hash key
still contains the old user name and this results in the extra privileges

Fixed by rebuilding the hash key and updating the column_priv_hash structure
when the user is renamed

mysql-test/r/grant3.result:
  Bug #41597 - After rename of user, there are additional grants when 
               grants are reapplied.
  
  Testcase for BUG#41597
mysql-test/t/grant3.test:
  Bug #41597 - After rename of user, there are additional grants when 
               grants are reapplied.
  
  Testcase for BUG#41597
sql/sql_acl.cc:
  Bug #41597 - After rename of user, there are additional grants when 
               grants are reapplied.
  
  Fixed handle_grant_struct() to update the hash key when the user is renamed.
  Added to set_user_details() method to GRANT_NAME class

1 files changed, 34 insertions, 12 deletions

diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index ea17a4227ef..8f1e2c70fe6 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -2096,6 +2096,8 @@ public:
   GRANT_NAME (TABLE *form);
   virtual ~GRANT_NAME() {};
   virtual bool ok() { return privs != 0; }
+  void set_user_details(const char *h, const char *d,
+                        const char *u, const char *t);
 };
 
 
@@ -2113,27 +2115,36 @@ public:
 };
 
 
-
-GRANT_NAME::GRANT_NAME(const char *h, const char *d,const char *u,
-                       const char *t, ulong p)
-  :privs(p)
+void GRANT_NAME::set_user_details(const char *h, const char *d,
+                                  const char *u, const char *t)
 {
   /* Host given by user */
   update_hostname(&host, strdup_root(&memex, h));
-  db =   strdup_root(&memex,d);
+  if (db != d)
+  {
+    db= strdup_root(&memex, d);
+    if (lower_case_table_names)
+      my_casedn_str(files_charset_info, db);
+  }
   user = strdup_root(&memex,u);
   sort=  get_sort(3,host.hostname,db,user);
-  tname= strdup_root(&memex,t);
-  if (lower_case_table_names)
+  if (tname != t)
   {
-    my_casedn_str(files_charset_info, db);
-    my_casedn_str(files_charset_info, tname);
+    tname= strdup_root(&memex, t);
+    if (lower_case_table_names)
+      my_casedn_str(files_charset_info, tname);
   }
   key_length =(uint) strlen(d)+(uint) strlen(u)+(uint) strlen(t)+3;
   hash_key = (char*) alloc_root(&memex,key_length);
   strmov(strmov(strmov(hash_key,user)+1,db)+1,tname);
 }
 
+GRANT_NAME::GRANT_NAME(const char *h, const char *d,const char *u,
+                       const char *t, ulong p)
+  :db(0), tname(0), privs(p)
+{
+  set_user_details(h, d, u, t);
+}
 
 GRANT_TABLE::GRANT_TABLE(const char *h, const char *d,const char *u,
                 	 const char *t, ulong p, ulong c)
@@ -5183,9 +5194,20 @@ static int handle_grant_struct(uint struct_no, bool drop,
 
       case 2:
       case 3:
-        grant_name->user= strdup_root(&mem, user_to->user.str);
-        update_hostname(&grant_name->host,
-                        strdup_root(&mem, user_to->host.str));
+        /* 
+          Update the grant structure with the new user name and
+          host name
+        */
+        grant_name->set_user_details(user_to->host.str, grant_name->db,
+                                   user_to->user.str, grant_name->tname);
+
+        /*
+          Since username is part of the hash key, when the user name
+          is renamed, the hash key is changed. Update the hash to
+          ensure that the position matches the new hash key value
+        */
+        hash_update(&column_priv_hash, (byte *)grant_name,
+                    grant_name->hash_key, grant_name->key_length);
 	break;
       }
     }