Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934032AbbDUQOF (ORCPT ); Tue, 21 Apr 2015 12:14:05 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:57364 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755968AbbDUPdo (ORCPT ); Tue, 21 Apr 2015 11:33:44 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Kirill A. Shutemov" , Pavel Emelyanov , Andrew Morton , Mark Seaborn , Linus Torvalds , Luis Henriques Subject: [PATCH 3.16.y-ckt 057/144] pagemap: do not leak physical addresses to non-privileged userspace Date: Tue, 21 Apr 2015 16:30:42 +0100 Message-Id: <1429630329-21748-58-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1429630329-21748-1-git-send-email-luis.henriques@canonical.com> References: <1429630329-21748-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1919 Lines: 50 3.16.7-ckt10 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "Kirill A. Shutemov" 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 Acked-by: Konstantin Khlebnikov Acked-by: Andy Lutomirski Cc: Pavel Emelyanov Cc: Andrew Morton Cc: Mark Seaborn Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques --- 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 a6b314919d9d..5825f6d944ce 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1260,6 +1260,9 @@ 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"); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/