Re: [BUGS] BUG #1134: ALTER USER ... RENAME breaks md5 passwords

Tom Lane wrote:
> Bruce Momjian  writes:
> > The attached patch clears the password field on rename:
> 
> I think you should clear the password field *only* if it's
> MD5-encrypted.

Patch attached and applied.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
Index: doc/src/sgml/ref/alter_user.sgml
===================================================================
RCS file: /cvsroot/pgsql-server/doc/src/sgml/ref/alter_user.sgml,v
retrieving revision 1.32
diff -c -c -r1.32 alter_user.sgml
*** doc/src/sgml/ref/alter_user.sgml	29 Nov 2003 19:51:38 -0000	1.32
--- doc/src/sgml/ref/alter_user.sgml	5 May 2004 03:06:44 -0000
***************
*** 57,62 ****
--- 57,65 ----
     The second variant changes the name of the user.  Only a database
     superuser can rename user accounts.  The session user cannot be
     renamed.  (Connect as a different user if you need to do that.)
+    Because MD5</>-encrypted passwords use the username as
+    cryptographic salt, renaming a user clears their MD5</>
+    password.
    
  
    
Index: src/backend/commands/user.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/commands/user.c,v
retrieving revision 1.139
diff -c -c -r1.139 user.c
*** src/backend/commands/user.c	16 Mar 2004 05:05:57 -0000	1.139
--- src/backend/commands/user.c	5 May 2004 03:06:46 -0000
***************
*** 959,966 ****
  				(errcode(ERRCODE_UNDEFINED_OBJECT),
  				 errmsg("user \"%s\" does not exist", stmt->user)));
  
! 	if (!(superuser()
! 	 || ((Form_pg_shadow) GETSTRUCT(oldtuple))->usesysid == GetUserId()))
  		ereport(ERROR,
  				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
  				 errmsg("permission denied")));
--- 959,966 ----
  				(errcode(ERRCODE_UNDEFINED_OBJECT),
  				 errmsg("user \"%s\" does not exist", stmt->user)));
  
! 	if (!(superuser() ||
! 	    ((Form_pg_shadow) GETSTRUCT(oldtuple))->usesysid == GetUserId()))
  		ereport(ERROR,
  				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
  				 errmsg("permission denied")));
***************
*** 1157,1172 ****
  void
  RenameUser(const char *oldname, const char *newname)
  {
! 	HeapTuple	tup;
  	Relation	rel;
! 
  	/* ExclusiveLock because we need to update the password file */
  	rel = heap_openr(ShadowRelationName, ExclusiveLock);
  
! 	tup = SearchSysCacheCopy(SHADOWNAME,
  							 CStringGetDatum(oldname),
  							 0, 0, 0);
! 	if (!HeapTupleIsValid(tup))
  		ereport(ERROR,
  				(errcode(ERRCODE_UNDEFINED_OBJECT),
  				 errmsg("user \"%s\" does not exist", oldname)));
--- 1157,1181 ----
  void
  RenameUser(const char *oldname, const char *newname)
  {
! 	HeapTuple	oldtuple,
! 				newtuple;
! 	TupleDesc	dsc;
  	Relation	rel;
! 	Datum		datum;
! 	bool		isnull;
! 	Datum		repl_val[Natts_pg_shadow];
! 	char		repl_null[Natts_pg_shadow];
! 	char		repl_repl[Natts_pg_shadow];
! 	int			i;
! 	
  	/* ExclusiveLock because we need to update the password file */
  	rel = heap_openr(ShadowRelationName, ExclusiveLock);
+ 	dsc = RelationGetDescr(rel);
  
! 	oldtuple = SearchSysCache(SHADOWNAME,
  							 CStringGetDatum(oldname),
  							 0, 0, 0);
! 	if (!HeapTupleIsValid(oldtuple))
  		ereport(ERROR,
  				(errcode(ERRCODE_UNDEFINED_OBJECT),
  				 errmsg("user \"%s\" does not exist", oldname)));
***************
*** 1177,1183 ****
  	 * not be an actual problem besides a little confusion, so think about
  	 * this and decide.
  	 */
! 	if (((Form_pg_shadow) GETSTRUCT(tup))->usesysid == GetSessionUserId())
  		ereport(ERROR,
  				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  				 errmsg("session user may not be renamed")));
--- 1186,1192 ----
  	 * not be an actual problem besides a little confusion, so think about
  	 * this and decide.
  	 */
! 	if (((Form_pg_shadow) GETSTRUCT(oldtuple))->usesysid == GetSessionUserId())
  		ereport(ERROR,
  				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  				 errmsg("session user may not be renamed")));
***************
*** 1196,1208 ****
  				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
  				 errmsg("must be superuser to rename users")));
  
! 	/* rename */
! 	namestrcpy(&(((Form_pg_shadow) GETSTRUCT(tup))->usename), newname);
! 	simple_heap_update(rel, &tup->t_self, tup);
! 	CatalogUpdateIndexes(rel, tup);
  
  	heap_close(rel, NoLock);
- 	heap_freetuple(tup);
  
  	user_file_update_needed = true;
  }
--- 1205,1237 ----
  				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
  				 errmsg("must be superuser to rename users")));
  
! 	for (i = 0; i < Natts_pg_shadow; i++)
! 		repl_repl[i] = ' ';
! 
! 	repl_repl[Anum_pg_shadow_usename - 1] = 'r';
! 	repl_val[Anum_pg_shadow_usename - 1] = DirectFunctionCall1(namein,
! 											CStringGetDatum(newname));
! 	repl_null[Anum_pg_shadow_usename - 1] = ' ';
! 
! 	datum = heap_getattr(oldtuple, Anum_pg_shadow_passwd, dsc, &isnull);
! 
! 	if (!isnull && isMD5(DatumGetCString(DirectFunctionCall1(textout, datum))))
! 	{
! 		/* MD5 uses the username as salt, so just clear it on a rename */
! 		repl_repl[Anum_pg_shadow_passwd - 1] = 'r';
! 		repl_null[Anum_pg_shadow_passwd - 1] = 'n';
! 	
! 		ereport(NOTICE,
! 			(errmsg("MD5 password cleared because of user rename")));
! 	}
! 			 
! 	newtuple = heap_modifytuple(oldtuple, rel, repl_val, repl_null, repl_repl);
! 	simple_heap_update(rel, &oldtuple->t_self, newtuple);
! 	
! 	CatalogUpdateIndexes(rel, newtuple);
  
+ 	ReleaseSysCache(oldtuple);
  	heap_close(rel, NoLock);
  
  	user_file_update_needed = true;
  }