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From: bmgordon@google.com
To: linux-kernel@vger.kernel.org
Cc: Benjamin Gordon <bmgordon@google.com>,
	John Stultz <john.stultz@linaro.org>,
	Kees Cook <keescook@chromium.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Arjan van de Ven <arjan@linux.intel.com>,
	Oren Laadan <orenl@cellrox.com>,
	Ruchi Kandoi <kandoiruchi@google.com>,
	Rom Lemarchand <romlem@android.com>, Todd Kjos <tkjos@google.com>,
	Colin Cross <ccross@android.com>, Nick Kralevich <nnk@google.com>,
	Dmitry Shmidt <dimitrysh@google.com>,
	Elliott Hughes <enh@google.com>,
	Android Kernel Team <kernel-team@android.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH] proc: use ns_capable instead of capable for timerslack_ns
Date: Wed, 17 Oct 2018 16:47:38 -0600	[thread overview]
Message-ID: <20181017224738.193598-1-bmgordon@google.com> (raw)

From: Benjamin Gordon <bmgordon@google.com>

Access to timerslack_ns is controlled by a process having CAP_SYS_NICE
in its effective capability set, but the current check looks in the root
namespace instead of the process' user namespace.  Since a process is
allowed to do other activities controlled by CAP_SYS_NICE inside a
namespace, it should also be able to adjust timerslack_ns.

Signed-off-by: Benjamin Gordon <bmgordon@google.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Oren Laadan <orenl@cellrox.com>
Cc: Ruchi Kandoi <kandoiruchi@google.com>
Cc: Rom Lemarchand <romlem@android.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Colin Cross <ccross@android.com>
Cc: Nick Kralevich <nnk@google.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Elliott Hughes <enh@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 fs/proc/base.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 7e9f07bf260d..4b50937dff80 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2356,7 +2356,7 @@ static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
 		return -ESRCH;
 
 	if (p != current) {
-		if (!capable(CAP_SYS_NICE)) {
+		if (!ns_capable(file->f_cred->user_ns, CAP_SYS_NICE)) {
 			count = -EPERM;
 			goto out;
 		}
@@ -2393,7 +2393,7 @@ static int timerslack_ns_show(struct seq_file *m, void *v)
 
 	if (p != current) {
 
-		if (!capable(CAP_SYS_NICE)) {
+		if (!ns_capable(seq_user_ns(m), CAP_SYS_NICE)) {
 			err = -EPERM;
 			goto out;
 		}
-- 
2.19.1.331.ge82ca0e54c-goog


             reply	other threads:[~2018-10-17 22:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-17 22:47 bmgordon [this message]
2018-10-25 17:09 ` Benjamin Gordon
2018-10-25 17:20 ` John Stultz
2018-10-25 18:56 ` Eric W. Biederman
2018-10-30 16:40   ` Benjamin Gordon

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