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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jann Horn <jannh@google.com>,
        Kees Cook <keescook@chromium.org>,
        Tyler Hicks <tyhicks@linux.microsoft.com>,
        Will Drewry <wad@chromium.org>,
        =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= <mic@linux.microsoft.com>
Subject: [PATCH 5.4 153/158] seccomp: Set PF_SUPERPRIV when checking capability
Date:   Mon, 23 Nov 2020 13:23:01 +0100
Message-Id: <20201123121827.314118849@linuxfoundation.org>
In-Reply-To: <20201123121819.943135899@linuxfoundation.org>
References: <20201123121819.943135899@linuxfoundation.org>
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From: Mickaël Salaün <mic@linux.microsoft.com>

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(-)

--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -37,7 +37,7 @@
 #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>
 #include <linux/anon_inodes.h>
@@ -453,8 +453,7 @@ static struct seccomp_filter *seccomp_pr
 	 * 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 */