Received-SPF: pass (google.com: domain of linux-kernel+bounces-60291-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Date: Fri, 09 Feb 2024 22:20:22 -0800
From: Kees Cook <kees@kernel.org>
To: Alice Ryhl <aliceryhl@google.com>,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Trevor Gross <tmgross@umich.edu>, Miguel Ojeda <ojeda@kernel.org>,
 Alex Gaynor <alex.gaynor@gmail.com>,
 Wedson Almeida Filho <wedsonaf@gmail.com>, Boqun Feng <boqun.feng@gmail.com>,
 Gary Guo <gary@garyguo.net>,
 =?ISO-8859-1?Q?Bj=F6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
 Benno Lossin <benno.lossin@proton.me>,
 Andreas Hindborg <a.hindborg@samsung.com>, Kees Cook <keescook@chromium.org>,
 Al Viro <viro@zeniv.linux.org.uk>, Andrew Morton <akpm@linux-foundation.org>,
 =?ISO-8859-1?Q?Arve_Hj=F8nnev=E5g?= <arve@android.com>,
 Todd Kjos <tkjos@android.com>, Martijn Coenen <maco@android.com>,
 Joel Fernandes <joel@joelfernandes.org>, Carlos Llamas <cmllamas@google.com>,
 Suren Baghdasaryan <surenb@google.com>, Arnd Bergmann <arnd@arndb.de>,
 linux-mm@kvack.org, linux-kernel@vger.kernel.org,
 rust-for-linux@vger.kernel.org, Christian Brauner <brauner@kernel.org>
Subject: Re: [PATCH 1/3] rust: add userspace pointers
User-Agent: K-9 Mail for Android
In-Reply-To: <CAH5fLgikdGGdjEUxyMWjkfHbRmvtMavwHFDwRC+4GVt46qmHWw@mail.gmail.com>
References: <20240124-alice-mm-v1-0-d1abcec83c44@google.com> <20240124-alice-mm-v1-1-d1abcec83c44@google.com> <CALNs47uDaD05oD8TtZoSqUBc4SaRig80u2_1P0qMCXtE3H9_Vw@mail.gmail.com> <CAH5fLggdwWoq4wKv7VxZ-_VbWMV_Ui03rGOCMPbWn8=ewznmvA@mail.gmail.com> <2024020859-lusty-ladylike-29d4@gregkh> <CAH5fLgikdGGdjEUxyMWjkfHbRmvtMavwHFDwRC+4GVt46qmHWw@mail.gmail.com>
Message-ID: <9FD5FF49-6C8D-4073-9CE5-EA19C607FAD2@kernel.org>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain;
 charset=utf-8
Content-Transfer-Encoding: quoted-printable


On February 8, 2024 7:41:52 AM PST, Alice Ryhl <aliceryhl@google=2Ecom> wr=
ote:
>On Thu, Feb 8, 2024 at 4:35=E2=80=AFPM Greg Kroah-Hartman
><gregkh@linuxfoundation=2Eorg> wrote:
>>
>> On Thu, Feb 08, 2024 at 01:53:20PM +0100, Alice Ryhl wrote:
>> > > Is some sort of `Debug` implementation useful?
>> >
>> > Leaking pointer addresses in logs is frowned upon in the kernel, so I
>> > don't think we should include that=2E
>>
>> s/frowned upon/forbidden/ :)
>
>:)
>
>> Along those lines, you all are tieing in the "I want to print a pointer=
,
>> so hash it properly before I do so" logic from rust like we have in c,
>> right?  Ideally you'd use the same logic if at all possible=2E
>>
>> If not, that probably needs to be done so that you don't accidentally
>> start leaking things=2E
>
>I don't know what the status of this is=2E For anything I've added, I've
>just made it entirely impossible to print addresses, hashed or not=2E

Thank you! That is certainly the preferred[1] approach=2E :)

-Kees

[1] https://www=2Ekernel=2Eorg/doc/html/next/process/deprecated=2Ehtml#p-f=
ormat-specifier

--=20
Kees Cook