Re: [patch] mount.2: document SELinux use of MS_NOSUID mount flag

Michael Kerrisk (man-pages)
2021-06-20T03:54:49Z

Helo Topi,

On 6/12/21 8:51 PM, Topi Miettinen wrote:
> Using mount flag `MS_NOSUID` also affects SELinux domain transitions but
> this has not been documented well.
>
> Signed-off-by: Topi Miettinen <toiwoton@gmail.com>

Thanks. Patch applied.

Cheers,

Michael

> ---
> man2/mount.2 | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/man2/mount.2 b/man2/mount.2
> index d8521880b..d7d5b2ad4 100644
> --- a/man2/mount.2
> +++ b/man2/mount.2
> @@ -220,7 +220,9 @@ Do not allow programs to be executed from this filesystem.
> .TP
> .B MS_NOSUID
> Do not honor set-user-ID and set-group-ID bits or file capabilities
> -when executing programs from this filesystem.
> +when executing programs from this filesystem. In addition, SELinux domain
> +transitions require permission nosuid_transition, which in turn needs
> +also policy capability nnp_nosuid_transition.
> .\" (This is a security feature to prevent users executing set-user-ID and
> .\" set-group-ID programs from removable disk devices.)
> .TP
>

--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/