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  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:   Wed, 13 May 2020 16:03:20 -0700
From:   Linus Torvalds <>
To:     Daniel Borkmann <>
Cc:     Christoph Hellwig <>,
        "the arch/x86 maintainers" <>,
        Alexei Starovoitov <>,
        Masami Hiramatsu <>,
        Andrew Morton <>,,
        linux-um <>,
        Netdev <>,,
        Linux-MM <>,
        Linux Kernel Mailing List <>
Subject: Re: [PATCH 11/18] maccess: remove strncpy_from_unsafe

On Wed, May 13, 2020 at 3:36 PM Daniel Borkmann <> wrote:
> It's used for both.

Daniel, BPF real;ly needs to make up its mind about that.

You *cannot* use ti for both.

Yes, it happens to work on x86 and some other architectures.

But on other architectures, the exact same pointer value can be a
kernel pointer or a user pointer.

> Given this is enabled on pretty much all program types, my
> assumption would be that usage is still more often on kernel memory than user one.

You need to pick one.

If you know it is a user pointer, use strncpy_from_user() (possibly
with disable_pagefault() aka strncpy_from_user_nofault()).

And if you know it is a kernel pointer, use strncpy_from_unsafe() (aka

You really can't pick the "randomly one or the other guess what I mean " option.


Powered by blists - more mailing lists