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

used as salt for the MD5 password.
This commit is contained in:
Bruce Momjian 2004-05-06 16:59:16 +00:00
parent d8f6973df3
commit 22a2c4b576
2 changed files with 46 additions and 14 deletions
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5
doc/src/sgml/ref/alter_user.sgml
View File

@ -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>

55
src/backend/commands/user.c
View File

@ -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;
}