linux-kernel - Re: RFC: reject unknown open flags

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 30 Mar 2017 12:02:04 -0700
From:   Paul Eggert <eggert@...ucla.edu>
To:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Christoph Hellwig <hch@....de>
Cc:     Alexander Viro <viro@...iv.linux.org.uk>,
        Linux API <linux-api@...r.kernel.org>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        libc-alpha <libc-alpha@...rceware.org>
Subject: Re: RFC: reject unknown open flags

On 03/30/2017 11:19 AM, Linus Torvalds wrote:
> like "dd" growing an atomic flag and setting it on stdout),

'dd' typically assumes that if a flag O_FOO is not #defined by 
<fcntl.h>, then 'dd' can "#define O_FOO 0" and the rest of dd's code can 
assume O_FOO works "well enough" on older systems. I hope this 
backward-compatibility hack will suffice for O_ATOMIC too.

> I'm assuming you'd also possible want to be able to use F_SETFL to set
> O_ATOMIC after the fact

Just for fun, one thread can set O_ATOMIC at the same time another 
thread is doing a 'write'....