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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2015-03-09 23:11:12 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2015-03-17 09:31:30 -0700
commitab676b7d6fbf4b294bf198fb27ade5b0e865c7ce (patch)
tree93fdcd656a687ca3fa5f717f9ce078cd8aea6c70
parent06e5801b8cb3fc057d88cb4dc03c0b64b2744cda (diff)
pagemap: do not leak physical addresses to non-privileged userspace
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@linux.intel.com> Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: Andy Lutomirski <luto@amacapital.net> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Mark Seaborn <mseaborn@chromium.org> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/task_mmu.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 956b75d..6dee68d 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1325,6 +1325,9 @@ 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");