linux-kernel - Re: [PATCH v2] riscv: Make mmap() with PROT_WRITE imply PROT

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]

Message-ID: <CALE4mHpO5eFk9-G=RCk97JiwnBMMFLiB4qvV-XXO+N8oxz0QTA@mail.gmail.com>
Date:   Thu, 8 Sep 2022 15:18:02 -0400
From:   Andrew Bresticker <abrestic@...osinc.com>
To:     SS JieJi <c141028@...il.com>
Cc:     Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Atish Patra <atishp@...shpatra.org>,
        Celeste Liu <coelacanthus@...look.com>,
        dram <dramforever@...e.com>, linux-riscv@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] riscv: Make mmap() with PROT_WRITE imply PROT_READ

On Thu, Sep 8, 2022 at 2:57 PM SS JieJi <c141028@...il.com> wrote:
>
> The v2 patch looks great,
> > -       if (unlikely((prot & PROT_WRITE) && !(prot & PROT_READ)))
> > -               return -EINVAL;
> > -
> This also removes the check for --x pages, which used to be present in
> previous versions (before the submission of the to-be-reverted patch).
> Is this intended? Thanks!

There's no change in behavior for --X mappings; those have always been
allowed as it's a valid set of PTE permissions.

This patch does allow -WX mappings, which were originally disallowed
in commit e0d17c842c0f ("RISC-V: Don't allow write+exec only page
mapping request in mmap"), by implying read permissions for such
mappings as well. I have a note in the commit message about this.

-Andrew