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Subject: kern/23990: access(2) system call reports an immutable file as writable
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>Number:         23990
>Category:       kern
>Synopsis:       access(2) system call reports an immutable file as writable
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Jan 01 04:10:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Jukka A. Ukkonen
>Release:        3.5.1
>Organization:
Finnish UNIX Users' Group
>Environment:
FreeBSD mjolnir.thunderbolt.fi 3.5.1-RELEASE FreeBSD 3.5.1-RELEASE #2: Mon Oct 16 13:00:59 EET DST 2000     jau@mjolnir.thunderbolt.fi:/usr/src/sys/compile/Mjolnir  i386

>Description:
The access(2) system call reports an immutable file as writable
though the reasonable approach would be to report "not writable".

This is a problem for programs that rely on accept(2) providing
them correct information about the accessibilty of files.
Especially when someone wants to quickly review one's files'
accessibility with a program like access(1) the current behaviour
produces misleading results and is logically in contradiction with
reporting files on read-only mounted file systems as "not writable".

Currently the only way to really know whether writing is OK or not
is by trying to open the file for writing.

>How-To-Repeat:
# touch testfile
# chflags uchg testfile
# access -w testfile


>Fix:
Should be relatively straight forward by adding
a VOP_GETATTR(vp, &va, p->p_ucred, p) call and
(va.va_flags & IMMUTABLE) test to access(2).


>Release-Note:
>Audit-Trail:
>Unformatted:


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