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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,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Allen <steven@stebalien.com>,
	Minchan Kim <minchan@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 4.8 08/33] zram: restrict add/remove attributes to root only
Date: Tue, 13 Dec 2016 09:16:09 -0800	[thread overview]
Message-ID: <20161213171534.519005404@linuxfoundation.org> (raw)
In-Reply-To: <20161213171534.171564506@linuxfoundation.org>

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

commit 5c7e9ccd91b90d87029261f8856294ee51934cab upstream.

zram hot_add sysfs attribute is a very 'special' attribute - reading
from it creates a new uninitialized zram device.  This file, by a
mistake, can be read by a 'normal' user at the moment, while only root
must be able to create a new zram device, therefore hot_add attribute
must have S_IRUSR mode, not S_IRUGO.

[akpm@linux-foundation.org: s/sence/sense/, reflow comment to use 80 cols]
Fixes: 6566d1a32bf72 ("zram: add dynamic device add/remove functionality")
Link: http://lkml.kernel.org/r/20161205155845.20129-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Steven Allen <steven@stebalien.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/block/zram/zram_drv.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1413,8 +1413,14 @@ static ssize_t hot_remove_store(struct c
 	return ret ? ret : count;
 }
 
+/*
+ * NOTE: hot_add attribute is not the usual read-only sysfs attribute. In a
+ * sense that reading from this file does alter the state of your system -- it
+ * creates a new un-initialized zram device and returns back this device's
+ * device_id (or an error code if it fails to create a new device).
+ */
 static struct class_attribute zram_control_class_attrs[] = {
-	__ATTR_RO(hot_add),
+	__ATTR(hot_add, 0400, hot_add_show, NULL),
 	__ATTR_WO(hot_remove),
 	__ATTR_NULL,
 };

  parent reply	other threads:[~2016-12-13 17:21 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20161213171629epcas1p4dc2737fb27df6f1d6148edf348dde1c7@epcas1p4.samsung.com>
2016-12-13 17:16 ` [PATCH 4.8 00/33] 4.8.15-stable review Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 01/33] powerpc/eeh: Fix deadlock when PE frozen state cant be cleared Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 02/33] powerpc/mm: Fix lazy icache flush on pre-POWER5 Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 03/33] powerpc/boot: Fix build failure in 32-bit boot wrapper Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 04/33] fuse: fix clearing suid, sgid for chown() Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 05/33] parisc: Purge TLB before setting PTE Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 06/33] parisc: Remove unnecessary TLB purges from flush_dcache_page_asm and flush_icache_page_asm Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 07/33] parisc: Fix TLB related boot crash on SMP machines Greg Kroah-Hartman
2016-12-13 17:16   ` Greg Kroah-Hartman [this message]
2016-12-13 17:16   ` [PATCH 4.8 09/33] locking/rtmutex: Prevent dequeue vs. unlock race Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 10/33] locking/rtmutex: Use READ_ONCE() in rt_mutex_owner() Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 11/33] device-dax: fix private mapping restriction, permit read-only Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 12/33] scsi: lpfc: fix oops/BUG in lpfc_sli_ringtxcmpl_put() Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 13/33] sched/autogroup: Fix 64-bit kernel nice level adjustment Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 14/33] vhost-vsock: fix orphan connection reset Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 15/33] perf/x86: Fix full width counter, counter overflow Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 16/33] acpi, nfit: fix extended status translations for ACPI DSMs Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 17/33] acpi, nfit, libnvdimm: fix / harden ars_status output length handling Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 18/33] acpi, nfit: validate ars_status output buffer size Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 19/33] acpi, nfit: fix bus vs dimm confusion in xlat_status Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 20/33] crypto: marvell - Dont copy hash operation twice into the SRAM Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 22/33] crypto: mcryptd - Check mcryptd algorithm compatibility Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 23/33] crypto: marvell - Dont corrupt state of an STD req for re-stepped ahash Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 24/33] can: raw: raw_setsockopt: limit number of can_filter that can be set Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 26/33] Revert "ACPI: Execute _PTS before system reboot" Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 27/33] ARM: dts: orion5x: fix number of sata port for linkstation ls-gl Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 28/33] ARM: dts: imx7d: fix LCDIF clock assignment Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 29/33] ceph: dont set req->r_locked_dir in ceph_d_revalidate Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 30/33] m68k: Fix ndelay() macro Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 31/33] batman-adv: Check for alloc errors when preparing TT local data Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 32/33] hotplug: Make register and unregister notifier API symmetric Greg Kroah-Hartman
2016-12-13 17:16   ` [PATCH 4.8 33/33] crypto: rsa - Add Makefile dependencies to fix parallel builds Greg Kroah-Hartman
2016-12-13 19:32   ` [PATCH 4.8 00/33] 4.8.15-stable review Shuah Khan
2016-12-13 20:07     ` Greg Kroah-Hartman
2016-12-14  4:13   ` Guenter Roeck
2016-12-14 12:49     ` Greg Kroah-Hartman

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