Date: Sun, 13 Aug 1995 15:09:18 +0200 (MET DST) From: roberto@blaise.ibp.fr (Ollivier Robert) To: wosch@cs.tu-berlin.de Cc: current@FreeBSD.org (Current's list FreeBSD), davidg@FreeBSD.org Subject: Re: kern/679: chown(2) ignores set-user-id and set-group-id bits for root Message-ID: <199508131309.PAA28497@blaise.ibp.fr> In-Reply-To: <199508130851.KAA00428@localhost> from "Wolfram Schneider" at Aug 13, 95 10:51:52 am
next in thread | previous in thread | raw e-mail | index | archive | help
> That's all right and should not been changed. Unfortunately chown
> does not clear set-user-id and set-group-id bits if you are root.
>
> $ touch Grunewald
> $ chmod 4777 Grunewald
> $ ls -lg Grunewald
> -rwsrwxrwx 1 wosch wheel 0 Aug 13 10:38 Grunewald
>
> $ su root
> # chown bin Grunewald
> # ls -lg Grunewald
> -rwsrwxrwx 1 bin wheel 0 Aug 13 10:38 Grunewald
> ^ ^^^
> >Fix:
I suggest the following patch (please review it David):
PS: be gentle, it is my first attempt at kernel hacking :-)
I can probably do the same thing without ovattr but it
seems cleaner to do it that way as only modified fields
are initialized in vattr. I didn't bothered to clear the
sticky bit because I don't see it as a problem but it
is easy to add it.
It works here:
207 [15:03] roberto@keltia:/var/tmp> ll foo
-r-sr-sr-x 1 roberto wheel 0 Aug 13 14:51 foo*
208 [15:03] roberto@keltia:~> ...
Password:
209 [15:04] root@keltia:/var/tmp# chown bin foo
210 [15:04] root@keltia:/var/tmp# ll foo
-r-xr-xr-x 1 bin wheel 0 Aug 13 14:51 foo*
Index: vfs_syscalls.c
===================================================================
RCS file: /spare/FreeBSD-current/src/sys/kern/vfs_syscalls.c,v
retrieving revision 1.30
diff -u -r1.30 vfs_syscalls.c
--- 1.30 1995/08/01 18:50:39
+++ vfs_syscalls.c 1995/08/13 12:09:43
@@ -1526,6 +1526,7 @@
int *retval;
{
register struct vnode *vp;
+ struct vattr ovattr;
struct vattr vattr;
int error;
struct nameidata nd;
@@ -1540,9 +1541,15 @@
if (vp->v_mount->mnt_flag & MNT_RDONLY)
error = EROFS;
else {
+ error = VOP_GETATTR(vp, &ovattr, p->p_ucred, p);
+ if (error) {
+ vput(vp);
+ return (error);
+ }
VATTR_NULL(&vattr);
vattr.va_uid = uap->uid;
vattr.va_gid = uap->gid;
+ vattr.va_mode = ovattr.va_mode & ~(VSUID | VSGID);
error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
}
vput(vp);
@@ -1564,6 +1571,7 @@
register struct fchown_args *uap;
int *retval;
{
+ struct vattr ovattr;
struct vattr vattr;
struct vnode *vp;
struct file *fp;
@@ -1578,9 +1586,15 @@
if (vp->v_mount->mnt_flag & MNT_RDONLY)
error = EROFS;
else {
+ error = VOP_GETATTR(vp, &ovattr, p->p_ucred, p);
+ if (error) {
+ VOP_UNLOCK(vp);
+ return (error);
+ }
VATTR_NULL(&vattr);
vattr.va_uid = uap->uid;
vattr.va_gid = uap->gid;
+ vattr.va_mode = ovattr.va_mode & ~(VSUID | VSGID);
error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
}
VOP_UNLOCK(vp);
--
Ollivier ROBERT -=- The daemon is FREE! -=- roberto@FreeBSD.ORG
FreeBSD 2.2-CURRENT #5: Fri Jul 14 12:28:04 MET DST 1995
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199508131309.PAA28497>