Re: [PATCH] prctl.2: Document PR_SET_MDWE and PR_GET_MDWE

[Catalin Marinas <catalin.marinas@arm.com>]

On Tue, Oct 03, 2023 at 05:50:10PM +0200, Florent Revest wrote:
> Memory-Deny-Write-Execute is a W^X process control originally introduced
> by Joey Gouly. I'm the author of the PR_MDWE_NO_INHERIT flag.
> 
> Signed-off-by: Florent Revest <revest@chromium.org>
> ---
>  man2/prctl.2 | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/man2/prctl.2 b/man2/prctl.2
> index d845b0905..67e6e2ff0 100644
> --- a/man2/prctl.2
> +++ b/man2/prctl.2
> @@ -2041,6 +2041,33 @@ the copy will be truncated.
>  Return (as the function result)
>  the full length of the auxiliary vector.
>  \fIarg4\fP and \fIarg5\fP must be 0.
> +.TP
> +.BR PR_SET_MDWE " (since Linux 6.3)"
> +.\" commit b507808ebce23561d4ff8c2aa1fb949fe402bc61
> +Set the process' Memory-Deny-Write-Execute protection mask.
> +.IR arg2
> +must be a bitmask of:
> +.RS
> +.\"
> +.TP
> +.B PR_MDWE_REFUSE_EXEC_GAIN
> +New memory mapping protections can't be writable and executable. Non-executable
> +mappings can't become executable.
> +.TP
> +.B PR_MDWE_NO_INHERIT " (since Linux 6.6)"
> +.\" commit 2a87e5520554034e8c423479740f95bea4a086a0
> +Do not propagate MDWE protection to child processes on

Should this mention that PR_MDWE_NO_INHERIT requires
PR_MDWE_REFUSE_EXEC_GAIN (unless I forgot how this was supposed to
work).

-- 
Catalin