linux-kernel - Re: [PATCH v2] fs: ocfs2: Replace strlcpy with sysfs

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Message-ID: <202308311404.875ABB0A@keescook>
Date:   Thu, 31 Aug 2023 14:04:48 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Azeem Shaikh <azeemshaikh38@...il.com>
Cc:     Mark Fasheh <mark@...heh.com>, Joel Becker <jlbec@...lplan.org>,
        Joseph Qi <joseph.qi@...ux.alibaba.com>,
        linux-hardening@...r.kernel.org, ocfs2-devel@...ts.linux.dev,
        linux-kernel@...r.kernel.org,
        Christian Brauner <brauner@...nel.org>,
        Dave Chinner <dchinner@...hat.com>, Jan Kara <jack@...e.cz>,
        Jeff Layton <jlayton@...nel.org>
Subject: Re: [PATCH v2] fs: ocfs2: Replace strlcpy with sysfs_emit

On Thu, Aug 31, 2023 at 07:38:27PM +0000, Azeem Shaikh wrote:
> strlcpy() reads the entire source buffer first.
> This read may exceed the destination size limit.
> This is both inefficient and can lead to linear read
> overflows if a source string is not NUL-terminated [1].
> In an effort to remove strlcpy() completely [2], replace
> strlcpy() here with sysfs_emit().
> 
> Direct replacement is safe here since its ok for `kernel_param_ops.get()`
> to return -errno [3].
> 
> [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
> [2] https://github.com/KSPP/linux/issues/89
> [3] https://elixir.bootlin.com/linux/v6.5/source/include/linux/moduleparam.h#L52
> 
> Signed-off-by: Azeem Shaikh <azeemshaikh38@...il.com>

Reviewed-by: Kees Cook <keescook@...omium.org>

-- 
Kees Cook