coredump: kill MMF_DUMPABLE and MMF_DUMP_SECURELY

Nobody actually needs MMF_DUMPABLE/MMF_DUMP_SECURELY, they are only used
to enforce the encoding of SUID_DUMP_* enum in mm->flags &
MMF_DUMPABLE_MASK.

Now that set_dumpable() updates both bits atomically we can kill them and
simply store the value "as is" in 2 lower bits.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Alex Kelly <alex.page.kelly@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 3 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 485234d2fd42..124430ba569b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -400,10 +400,8 @@ extern int get_dumpable(struct mm_struct *mm);
 #define SUID_DUMP_ROOT          2       /* Dump as root */
 
 /* mm flags */
-/* dumpable bits */
-#define MMF_DUMPABLE      0  /* core dump is permitted */
-#define MMF_DUMP_SECURELY 1  /* core file is readable only by root */
 
+/* for SUID_DUMP_* above */
 #define MMF_DUMPABLE_BITS 2
 #define MMF_DUMPABLE_MASK ((1 << MMF_DUMPABLE_BITS) - 1)