Re: permissions: udev vs. pam_devperm.so

[Kay Sievers <kay.sievers@vrfy.org>]

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On Tue, Oct 26, 2004 at 03:20:40PM +0200, Frank Steiner wrote:
> Kay Sievers wrote
> 
> >Empty fields mean default permissions, so this will not work. udev will
> >overwrite everything on "add". Only the inode may be preserved, if the
> >node already exists with the correct major/minor.
> 
> Just one comment:
> Having "hdc*:root:disk:660" in udev.permissions and calling "udevstart"
> will always set /dev/hdc to root:disk and 600. With owner and group
> fields empty, udevstart will not change the owner and the group. I'm
> not sure if udevstart triggers "add" events, likely not?

Sure, udevstart simulates a "add" event for every device it can find. I
can't reproduce the failure. I expect you have a earlier line matching in
one of your .permissions files.
udev searches the list from the top and the first match will make it. Do
you have "hd*:..." or similar before the "hdc*"?

> With the permission field empty, udevstart will set the permissions
> to 000, although udev.conf specifies 0600 as default, so I guess this
> is wrong...

Yes, it is wrong. We only apply the defaults if we don't match any rule.
The attached patch should fix this.

Thanks,
Kay

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===== namedev.c 1.154 vs edited =====
--- 1.154/namedev.c	2004-10-20 03:59:11 +02:00
+++ edited/namedev.c	2004-10-27 01:46:02 +02:00
@@ -798,11 +798,10 @@
 		set_empty_perms(udev, perm->mode,
 				      perm->owner,
 				      perm->group);
-	} else {
-		set_empty_perms(udev, get_default_mode(),
-				      get_default_owner(),
-				      get_default_group());
 	}
+	set_empty_perms(udev, get_default_mode(),
+			      get_default_owner(),
+			      get_default_group());
 
 	dbg("name, '%s' is going to have owner='%s', group='%s', mode = %#o",
 	    udev->name, udev->owner, udev->group, udev->mode);
===== test/udev-test.pl 1.60 vs edited =====
--- 1.60/test/udev-test.pl	2004-10-18 15:17:42 +02:00
+++ edited/test/udev-test.pl	2004-10-27 01:50:06 +02:00
@@ -550,11 +550,11 @@
 EOF
 	},
 	{
-		desc		=> "permissions tty3:::",
+		desc		=> "permissions tty3::: (default mode applied)",
 		subsys		=> "tty",
 		devpath		=> "/class/tty/tty3",
 		exp_name	=> "tty3",
-		exp_perms	=> "0:0:0",
+		exp_perms	=> "0:0:600",
 		conf		=> <<EOF
 KERNEL="tty3", NAME="tty3"
 EOF