fcaps: clear the same personality flags as suid when fcaps are used

commit d52fc5dde171f030170a6cb78034d166b13c9445 upstream

If a process increases permissions using fcaps all of the dangerous
personality flags which are cleared for suid apps should also be cleared.
Thus programs given priviledge with fcaps will continue to have address space
randomization enabled even if the parent tried to disable it to make it
easier to attack.

Signed-off-by: Eric Paris <eparis@redhat.com>
Reviewed-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/security/commoncap.c b/security/commoncap.c
index fe30751a6cd9cb8862fa7fcbd19a3b818264c934..30972d69f57a50182b868913c94abbc759d06f4f 100644 (file)
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -511,6 +511,11 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
        }
 skip:
 
+       /* if we have fs caps, clear dangerous personality flags */
+       if (!cap_issubset(new->cap_permitted, old->cap_permitted))
+               bprm->per_clear |= PER_CLEAR_ON_SETID;
+
+
        /* Don't let someone trace a set[ug]id/setpcap binary with the revised
         * credentials unless they have the appropriate permit
         */