[RFC, PATCH] pagemap: do not leak physical addresses to non-privileged userspace
[Posted April 28, 2015 by corbet]
| From: |
| "Kirill A. Shutemov" <kirill-AT-shutemov.name> |
| To: |
| linux-mm-AT-kvack.org, linux-kernel-AT-vger.kernel.org, Andrew Morton <akpm-AT-linux-foundation.org>, Linus Torvalds <torvalds-AT-linux-foundation.org> |
| Subject: |
| [RFC, PATCH] pagemap: do not leak physical addresses to non-privileged userspace |
| Date: |
| Mon, 9 Mar 2015 23:11:12 +0200 |
| Message-ID: |
| <1425935472-17949-1-git-send-email-kirill@shutemov.name> |
| Cc: |
| "Kirill A. Shutemov" <kirill.shutemov-AT-linux.intel.com>, Pavel Emelyanov <xemul-AT-parallels.com>, Konstantin Khlebnikov <khlebnikov-AT-openvz.org>, Mark Seaborn <mseaborn-AT-chromium.org>, Andy Lutomirski <luto-AT-amacapital.net> |
| Archive‑link: | |
Article |
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
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 is RFC patch which disallow anybody without CAP_SYS_ADMIN to read
the pagemap.
Any comments?
[1] http://googleprojectzero.blogspot.com/2015/03/exploiting-...
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Seaborn <mseaborn@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
---
fs/proc/task_mmu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 246eae84b13b..b72b36e64286 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1322,6 +1322,9 @@ out:
static int pagemap_open(struct inode *inode, struct file *file)
{
+ /* do not disclose physical addresses: attack vector */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
pr_warn_once("Bits 55-60 of /proc/PID/pagemap entries are about "
"to stop being page-shift some time soon. See the "
"linux/Documentation/vm/pagemap.txt for details.\n");
--
2.3.1
--
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