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46 lines
1.6 KiB
Diff
46 lines
1.6 KiB
Diff
From ab676b7d6fbf4b294bf198fb27ade5b0e865c7ce Mon Sep 17 00:00:00 2001
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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
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Date: Mon, 9 Mar 2015 23:11:12 +0200
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Subject: pagemap: do not leak physical addresses to non-privileged userspace
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As pointed by recent post[1] on exploiting DRAM physical imperfection,
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/proc/PID/pagemap exposes sensitive information which can be used to do
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attacks.
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This disallows anybody without CAP_SYS_ADMIN to read the pagemap.
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[1] http://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html
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[ Eventually we might want to do anything more finegrained, but for now
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this is the simple model. - Linus ]
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Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
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Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
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Acked-by: Andy Lutomirski <luto@amacapital.net>
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Cc: Pavel Emelyanov <xemul@parallels.com>
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Cc: Andrew Morton <akpm@linux-foundation.org>
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Cc: Mark Seaborn <mseaborn@chromium.org>
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Cc: stable@vger.kernel.org
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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fs/proc/task_mmu.c | 3 +++
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1 file changed, 3 insertions(+)
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diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
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index 956b75d..6dee68d 100644
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--- a/fs/proc/task_mmu.c
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+++ b/fs/proc/task_mmu.c
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@@ -1325,6 +1325,9 @@ out:
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static int pagemap_open(struct inode *inode, struct file *file)
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{
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+ /* do not disclose physical addresses: attack vector */
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+ if (!capable(CAP_SYS_ADMIN))
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+ return -EPERM;
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pr_warn_once("Bits 55-60 of /proc/PID/pagemap entries are about "
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"to stop being page-shift some time soon. See the "
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"linux/Documentation/vm/pagemap.txt for details.\n");
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--
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cgit v1.1
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