linux-kernel - Re: [RFC PATCH 01/14] fs/proc/vmcore: Update read_from

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] [day] [month] [year] [list]

Message-ID: <20211207111526.GA18554@lst.de>
Date:   Tue, 7 Dec 2021 12:15:26 +0100
From:   Christoph Hellwig <hch@....de>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     Christoph Hellwig <hch@....de>,
        Amit Daniel Kachhap <amit.kachhap@....com>,
        linux-kernel@...r.kernel.org,
        Vincenzo Frascino <Vincenzo.Frascino@....com>,
        Kevin Brodsky <kevin.brodsky@....com>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        kexec <kexec@...ts.infradead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Young <dyoung@...hat.com>, Baoquan He <bhe@...hat.com>,
        Vivek Goyal <vgoyal@...hat.com>, x86 <x86@...nel.org>
Subject: Re: [RFC PATCH 01/14] fs/proc/vmcore: Update read_from_oldmem()
 for user pointer

On Mon, Dec 06, 2021 at 03:07:15PM +0000, Matthew Wilcox wrote:
> > > What do you think to adding a generic copy_pfn_to_iter()?  Not sure
> > > which APIs to use to implement it ... some architectures have weird
> > > requirements about which APIs can be used for what kinds of PFNs.
> > 
> > Hmm.  I though kmap_local_pfn(_prot) is all we need?
> 
> In the !HIGHMEM case, that calls pfn_to_page(), and I think the
> point of this path is that we don't have a struct page for this pfn.

Indeed.  But to me this suggest that the !highmem stub is broken and
we should probably fix it rather than adding yet another interface.