Erase MD5 user passwords when a user is renamed because the username is

used as salt for the MD5 password.

diff --git a/doc/src/sgml/ref/alter_user.sgml b/doc/src/sgml/ref/alter_user.sgml
index 4af08885094cc791306e30117d7ec661db32c501..e74da13c877f03c81cbec096fe03c406091b581c 100644 (file)
--- a/doc/src/sgml/ref/alter_user.sgml
+++ b/doc/src/sgml/ref/alter_user.sgml
@@ -1,5 +1,5 @@
 
 
@@ -57,6 +57,9 @@ ALTER USER name RESET 
    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.
   
 
   

diff --git a/src/backend/commands/user.c b/src/backend/commands/user.c
index d646c8e14b33e7fac4f4b49409ed5ee765d6fb70..476e7e1865e4597899db327b80dae2f870dae9a7 100644 (file)
--- a/src/backend/commands/user.c
+++ b/src/backend/commands/user.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/commands/user.c,v 1.139 2004/03/16 05:05:57 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/user.c,v 1.140 2004/05/06 16:59:16 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -959,8 +959,8 @@ AlterUserSet(AlterUserSetStmt *stmt)
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("user \"%s\" does not exist", stmt->user)));
 
-   if (!(superuser()
-    || ((Form_pg_shadow) GETSTRUCT(oldtuple))->usesysid == GetUserId()))
+   if (!(superuser() ||
+       ((Form_pg_shadow) GETSTRUCT(oldtuple))->usesysid == GetUserId()))
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("permission denied")));
@@ -1157,16 +1157,25 @@ DropUser(DropUserStmt *stmt)
 void
 RenameUser(const char *oldname, const char *newname)
 {
-   HeapTuple   tup;
+   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);
 
-   tup = SearchSysCacheCopy(SHADOWNAME,
+   oldtuple = SearchSysCache(SHADOWNAME,
                             CStringGetDatum(oldname),
                             0, 0, 0);
-   if (!HeapTupleIsValid(tup))
+   if (!HeapTupleIsValid(oldtuple))
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("user \"%s\" does not exist", oldname)));
@@ -1177,7 +1186,7 @@ RenameUser(const char *oldname, const char *newname)
     * not be an actual problem besides a little confusion, so think about
     * this and decide.
     */
-   if (((Form_pg_shadow) GETSTRUCT(tup))->usesysid == GetSessionUserId())
+   if (((Form_pg_shadow) GETSTRUCT(oldtuple))->usesysid == GetSessionUserId())
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("session user may not be renamed")));
@@ -1196,13 +1205,33 @@ RenameUser(const char *oldname, const char *newname)
                (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);
+   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);
-   heap_freetuple(tup);
 
    user_file_update_needed = true;
 }