[PATCH 4.19 89/91] seccomp: Set PF_SUPERPRIV when checking capability

Greg Kroah-Hartman
2020-11-23T12:33:53Z

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
@@ -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_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 */