This is a note to let you know that I've just added the patch titled
pagemap: do not leak physical addresses to non-privileged userspace
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pagemap-do-not-leak-physical-addresses-to-non-privileged-userspace.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ab676b7d6fbf4b294bf198fb27ade5b0e865c7ce Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Date: Mon, 9 Mar 2015 23:11:12 +0200
Subject: pagemap: do not leak physical addresses to non-privileged userspace
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Acked-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Mark Seaborn <mseaborn@xxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: mancha security <mancha1@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1110,9 +1110,19 @@ 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 */
Patches currently in stable-queue which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
queue-3.10/pagemap-do-not-leak-physical-addresses-to-non-privileged-userspace.patch
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