From 22a2c4b576fe1423382e68b418d954208555ba34 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Thu, 6 May 2004 16:59:16 +0000
Subject: [PATCH] Erase MD5 user passwords when a user is renamed because the
username is used as salt for the MD5 password.
---
doc/src/sgml/ref/alter_user.sgml | 5 ++-
src/backend/commands/user.c | 55 ++++++++++++++++++++++++--------
2 files changed, 46 insertions(+), 14 deletions(-)
diff --git a/doc/src/sgml/ref/alter_user.sgml b/doc/src/sgml/ref/alter_user.sgml
index 4af08885094..e74da13c877 100644
--- a/doc/src/sgml/ref/alter_user.sgml
+++ b/doc/src/sgml/ref/alter_user.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/alter_user.sgml,v 1.32 2003/11/29 19:51:38 pgsql Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/alter_user.sgml,v 1.33 2004/05/06 16:59:16 momjian Exp $
PostgreSQL documentation
-->
@@ -57,6 +57,9 @@ ALTER USER <replaceable class="PARAMETER">name</replaceable> RESET <replaceable>
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 <literal>MD5</>-encrypted passwords use the username as
+ cryptographic salt, renaming a user clears their <literal>MD5</>
+ password.
</para>
<para>
diff --git a/src/backend/commands/user.c b/src/backend/commands/user.c
index d646c8e14b3..476e7e1865e 100644
--- 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;
}
--
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