linux-kernel - Re: + procfs-replace-all-non-returning-strlcpy-with-strscpy.patch added to mm-nonmm-unstable branch

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Date:   Sat, 13 May 2023 13:55:22 +0300
From:   Alexey Dobriyan <adobriyan@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, wangkefeng.wang@...wei.com,
        lstoakes@...il.com, liushixin2@...wei.com, david@...hat.com,
        bhe@...hat.com, azeemshaikh38@...il.com, akpm@...ux-foundation.org
Subject: Re: + procfs-replace-all-non-returning-strlcpy-with-strscpy.patch
 added to mm-nonmm-unstable branch

On Wed, May 10, 2023 at 09:34:49PM -0700, Andrew Morton wrote:
> Subject: procfs: replace all non-returning strlcpy with strscpy
> 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].

This is funny. C strings are always NUL-terminated by definition.

Reviewed-by: Alexey Dobriyan <adobriyan@...il.com>

> --- a/fs/proc/kcore.c~procfs-replace-all-non-returning-strlcpy-with-strscpy
> +++ a/fs/proc/kcore.c
> @@ -419,7 +419,7 @@ static ssize_t read_kcore_iter(struct ki
>  		char *notes;
>  		size_t i = 0;
>  
> -		strlcpy(prpsinfo.pr_psargs, saved_command_line,
> +		strscpy(prpsinfo.pr_psargs, saved_command_line,
>  			sizeof(prpsinfo.pr_psargs));
>  
>  		notes = kzalloc(notes_len, GFP_KERNEL);