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Date: Tue, 27 Jan 1998 21:30:02 -0800 (PST)
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From: Bruce Evans <bde@zeta.org.au>
Subject: Re: bin/5575: mount_msdos won't run setuid-root
Reply-To: Bruce Evans <bde@zeta.org.au>
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The following reply was made to PR bin/5575; it has been noted by GNATS.

From: Bruce Evans <bde@zeta.org.au>
To: FreeBSD-gnats-submit@FreeBSD.ORG, rhh@ct.picker.com
Cc:  Subject: Re: bin/5575: mount_msdos won't run setuid-root
Date: Wed, 28 Jan 1998 16:10:26 +1100

 >	The best solution might be for FreeBSD to implement a mechanism
 >	for granting mount access to groups on a per-device basis.
 
 It already does.  Access is controlled by:
 
 1) ownership of the mount point.  If the euid of the caller is not root,
   then the uid of the mount point must match this euid.  This is enforced
   by kern/vfs_syscalls.c:mount().
 
 2) appropriate permissions on the device or file system being mounted.
    For devices, the appropriate permissions are read-write access to
    the device.  Support for this is missing in ffs and ext2fs, and
    broken in msdsofs.  These file systems still do things in the
    pre-Lite2 way, which is to depend on kern/vfs_syscalls.c:mount()
    doing everything and hack around it doing too much for msdosfs.
    The msdosfs hack now conflicts with (1).
 
 3) The vfs.usermount sysctl.  Since access control is mostly broken,
    vfs.usermount defaults to 1 so that access control almost reverts
    to the pre-Lite2 model.
 
 Bruce