[patch] enable calling chroot(2) after calling pledge(2)

[Matt Miller]

I would like to be able to call chroot(2) in a program that uses pledge(2).
The following (untested) patch makes this possible as part of the  
"rpath" promise.

Does this seem like a reasonable idea?


--- sys/kern/kern_pledge.c    Thu Jun 29 00:10:07 2017
+++ sys/kern/kern_pledge.c.with_chroot  Mon Jul 17 22:32:43 2017
@@ -292,6 +292,7 @@
        [SYS_execve] = PLEDGE_EXEC,

        [SYS_chdir] = PLEDGE_RPATH,
+       [SYS_chroot] = PLEDGE_RPATH,
        [SYS_openat] = PLEDGE_RPATH | PLEDGE_WPATH,
        [SYS_fstatat] = PLEDGE_RPATH | PLEDGE_WPATH,
        [SYS_faccessat] = PLEDGE_RPATH | PLEDGE_WPATH,