[PATCH] setuid(2) buggy or bad docs

John Fremlin (vii@users.sourceforge.net)
20 Jun 2001 01:37:51 +0100


--=-=-=

setuid(2) differs from the OpenBSD setuid(2) in that -EPERM is
returned by the syscall even if the euid of the process matches the
uid passed to it.

Either I am non compos or the thing is very wrong. The docs
(man-pages-1.35) say

ERRORS
EPERM The user is not the super-user, and uid does not
match the effective or saved user ID of the calling
process.

The following untested patch changes the kernel to match the
documentated behaviour.

--=-=-=
Content-Type: text/x-patch
Content-Disposition: attachment; filename=linux-2.4.4-setuid.patch

--- linux-2.4.4-orig/kernel/sys.c Tue May 1 14:34:43 2001
+++ linux-2.4.4/kernel/sys.c Wed Jun 20 01:32:46 2001
@@ -603,7 +603,9 @@ asmlinkage long sys_setuid(uid_t uid)
if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
return -EAGAIN;
new_suid = uid;
- } else if ((uid != current->uid) && (uid != new_suid))
+ } else if ((uid != current->uid)
+ && (uid != new_suid)
+ && (uid != old_euid))
return -EPERM;

if (old_euid != uid)

--=-=-=

-- 
Summer job urgently sought due to last minute visa trouble!
Please see http://ape.n3.net/cv.html

--=-=-=-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/