From 3863935f06bd8d43a7fb4fbf65a33a5596060974 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= <mic@linux.microsoft.com>
Date: Fri, 30 Oct 2020 13:38:49 +0100
Subject: [PATCH] seccomp: Set PF_SUPERPRIV when checking capability
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit fb14528e443646dd3fd02df4437fcf5265b66baa upstream.

Replace the use of security_capable(current_cred(), ...) with
ns_capable_noaudit() which set PF_SUPERPRIV.

Since commit 98f368e9e263 ("kernel: Add noaudit variant of
ns_capable()"), a new ns_capable_noaudit() helper is available.  Let's
use it!

Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: Will Drewry <wad@chromium.org>
Cc: stable@vger.kernel.org
Fixes: e2cfabdfd075 ("seccomp: add system call filtering using BPF")
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Reviewed-by: Jann Horn <jannh@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201030123849.770769-3-mic@digikod.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 kernel/seccomp.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 56e69203b658..b9bd5a6b5138 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -36,7 +36,7 @@
 #include <linux/filter.h>
 #include <linux/pid.h>
 #include <linux/ptrace.h>
-#include <linux/security.h>
+#include <linux/capability.h>
 #include <linux/tracehook.h>
 #include <linux/uaccess.h>
 
@@ -383,8 +383,7 @@ static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog)
 	 * behavior of privileged children.
 	 */
 	if (!task_no_new_privs(current) &&
-	    security_capable(current_cred(), current_user_ns(),
-				     CAP_SYS_ADMIN, CAP_OPT_NOAUDIT) != 0)
+			!ns_capable_noaudit(current_user_ns(), CAP_SYS_ADMIN))
 		return ERR_PTR(-EACCES);
 
 	/* Allocate a new seccomp_filter */