Re: [PATCH 6.6] arm64: kaslr: fix nokaslr cmdline parsing

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Jul 28, 2025 at 12:46:44PM +0000, Chen Ridong wrote:
> From: Chen Ridong <chenridong@huawei.com>
> 
> Currently, when the command line contains "nokaslrxxx", it was incorrectly
> treated as a request to disable KASLR virtual memory. However, the behavior
> is different from physical address handling.
> 
> This issue exists before the commit af73b9a2dd39 ("arm64: kaslr: Use
> feature override instead of parsing the cmdline again"). This patch fixes
> the parsing logic for the 'nokaslr' command line argument. Only the exact
> strings, 'nokaslr', will disable KASLR. Other inputs such as 'xxnokaslr',
> 'xxnokaslrxx', or 'xxnokaslr=xx' will not disable KASLR.
> 
> Fixes: f80fb3a3d508 ("arm64: add support for kernel ASLR")
> Signed-off-by: Chen Ridong <chenridong@huawei.com>
> ---
>  arch/arm64/kernel/pi/kaslr_early.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/pi/kaslr_early.c b/arch/arm64/kernel/pi/kaslr_early.c
> index 17bff6e399e4..731d0a3f1a89 100644
> --- a/arch/arm64/kernel/pi/kaslr_early.c
> +++ b/arch/arm64/kernel/pi/kaslr_early.c
> @@ -35,9 +35,14 @@ static char *__strstr(const char *s1, const char *s2)
>  static bool cmdline_contains_nokaslr(const u8 *cmdline)
>  {
>  	const u8 *str;
> +	size_t len = strlen("nokaslr");
> +	const char *after = cmdline + len;
>  
>  	str = __strstr(cmdline, "nokaslr");
> -	return str == cmdline || (str > cmdline && *(str - 1) == ' ');
> +	if ((str == cmdline || (str > cmdline && *(str - 1) == ' ')) &&
> +	    (*after == ' ' || *after == '\0'))
> +		return true;
> +	return false;
>  }
>  
>  static bool is_kaslr_disabled_cmdline(void *fdt)
> -- 
> 2.34.1
> 
> 

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>