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Date: Tue, 05 May 2015 02:16:39 +0100
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC: akpm@...ux-foundation.org,
"Konstantin Khlebnikov" <khlebnikov@...nvz.org>,
"Mark Seaborn" <mseaborn@...omium.org>,
"Andy Lutomirski" <luto@...capital.net>,
"mancha security" <mancha1@...o.com>,
"Linus Torvalds" <torvalds@...ux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
"Pavel Emelyanov" <xemul@...allels.com>
Subject: [PATCH 3.2 135/221] pagemap: do not leak physical addresses to
non-privileged userspace
3.2.69-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
commit ab676b7d6fbf4b294bf198fb27ade5b0e865c7ce upstream.
As pointed by recent post[1] on exploiting DRAM physical imperfection,
/proc/PID/pagemap exposes sensitive information which can be used to do
attacks.
This disallows anybody without CAP_SYS_ADMIN to read the pagemap.
[1] http://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html
[ Eventually we might want to do anything more finegrained, but for now
this is the simple model. - Linus ]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@...nvz.org>
Acked-by: Andy Lutomirski <luto@...capital.net>
Cc: Pavel Emelyanov <xemul@...allels.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Mark Seaborn <mseaborn@...omium.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
[mancha security: Backported to 3.10]
Signed-off-by: mancha security <mancha1@...o.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
fs/proc/task_mmu.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -864,9 +864,19 @@ out:
return ret;
}
+static int pagemap_open(struct inode *inode, struct file *file)
+{
+ /* do not disclose physical addresses to unprivileged
+ userspace (closes a rowhammer attack vector) */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ return 0;
+}
+
const struct file_operations proc_pagemap_operations = {
.llseek = mem_lseek, /* borrow this */
.read = pagemap_read,
+ .open = pagemap_open,
};
#endif /* CONFIG_PROC_PAGE_MONITOR */
--
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