Re: [9front] [PATCH] kernel: disallow executing from #| or #d

[Jacob Moody <moody@mail.posixcafe.org>]

On 5/11/22 10:32, Amavect wrote:
> If we don't decide on that route,
> then devpipe should disallow wstat.

The roundabout way of checking for permission bits was
my first pass at removing this capability. I am much
more in favor of just disabling wstat for devpipe
personally. If you did want to make one end
of a pipe read only or write only, doing it through
wstat feels obtuse due to the attach semantics.

> 
>> RFNOMNT does not remove access to #|, #d, #e, #c, or #p
> That's what I get for only reading the man page without testing.

Yeah the man page should not lie, how's this instead?

thanks,
moody

diff 51669adf2446385b38bab4efcb4133c19e9be806 uncommitted
--- a//sys/man/2/fork
+++ b//sys/man/2/fork
@@ -70,9 +70,16 @@
 .TP
 .B RFNOMNT
 If set, subsequent mounts into the new name space and dereferencing
-of pathnames starting with
+of most pathnames starting with
 .B #
-are disallowed.
+are disallowed. Specifically
+.IR pipe(3) ,
+.IR dup(3) ,
+.IR env(3) ,
+.IR cons(3) ,
+and
+.IR proc(3)
+are still permitted.
 .TP
 .B RFENVG
 If set, the environment variables are copied;