linux-kernel - Re: [PATCH v10 5/8] rust: security: add abstraction for secctx

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: <202409151325.09E4F3C2F@keescook>
Date: Sun, 15 Sep 2024 13:58:25 -0700
From: Kees Cook <kees@...nel.org>
To: Alice Ryhl <aliceryhl@...gle.com>
Cc: Paul Moore <paul@...l-moore.com>, James Morris <jmorris@...ei.org>,
	"Serge E. Hallyn" <serge@...lyn.com>,
	Miguel Ojeda <ojeda@...nel.org>,
	Christian Brauner <brauner@...nel.org>,
	Alex Gaynor <alex.gaynor@...il.com>,
	Wedson Almeida Filho <wedsonaf@...il.com>,
	Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>,
	Björn Roy Baron <bjorn3_gh@...tonmail.com>,
	Benno Lossin <benno.lossin@...ton.me>,
	Andreas Hindborg <a.hindborg@...sung.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Arve Hjønnevåg <arve@...roid.com>,
	Todd Kjos <tkjos@...roid.com>, Martijn Coenen <maco@...roid.com>,
	Joel Fernandes <joel@...lfernandes.org>,
	Carlos Llamas <cmllamas@...gle.com>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Dan Williams <dan.j.williams@...el.com>,
	Matthew Wilcox <willy@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>, Daniel Xu <dxu@...uu.xyz>,
	Martin Rodriguez Reboredo <yakoyoku@...il.com>,
	Trevor Gross <tmgross@...ch.edu>, linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org,
	rust-for-linux@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v10 5/8] rust: security: add abstraction for secctx

On Sun, Sep 15, 2024 at 02:31:31PM +0000, Alice Ryhl wrote:
> Add an abstraction for viewing the string representation of a security
> context.

Hm, this may collide with "LSM: Move away from secids" is going to happen.
https://lore.kernel.org/all/20240830003411.16818-1-casey@schaufler-ca.com/

This series is not yet landed, but in the future, the API changes should
be something like this, though the "lsmblob" name is likely to change to
"lsmprop"?
security_cred_getsecid()   -> security_cred_getlsmblob()
security_secid_to_secctx() -> security_lsmblob_to_secctx()

> This is needed by Rust Binder because it has a feature where a process
> can view the string representation of the security context for incoming
> transactions. The process can use that to authenticate incoming
> transactions, and since the feature is provided by the kernel, the
> process can trust that the security context is legitimate.
> 
> This abstraction makes the following assumptions about the C side:
> * When a call to `security_secid_to_secctx` is successful, it returns a
>   pointer and length. The pointer references a byte string and is valid
>   for reading for that many bytes.

Yes. (len includes trailing C-String NUL character.)

> * The string may be referenced until `security_release_secctx` is
>   called.

Yes.

> * If CONFIG_SECURITY is set, then the three methods mentioned in
>   rust/helpers are available without a helper. (That is, they are not a
>   #define or `static inline`.)

Yes.

> 
> Reviewed-by: Benno Lossin <benno.lossin@...ton.me>
> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@...il.com>
> Reviewed-by: Trevor Gross <tmgross@...ch.edu>
> Reviewed-by: Gary Guo <gary@...yguo.net>
> Signed-off-by: Alice Ryhl <aliceryhl@...gle.com>

Reviewed-by: Kees Cook <kees@...nel.org>

-- 
Kees Cook