diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2015-03-09 23:11:12 +0200 |
|---|---|---|
| committer | Mark Salyzyn <salyzyn@google.com> | 2015-11-17 10:32:46 -0800 |
| commit | 0549ddb90f1553553dcb1b348e2884076e7cba3e (patch) | |
| tree | bde23dd6cf830775a6007e42560be5addeb00dd0 | |
| parent | 24dc742abc1fa4f953b42750ec08e3ec4586de42 (diff) | |
UPSTREAM: pagemap: do not leak physical addresses to non-privileged userspace
(cherry pick from commit ab676b7d6fbf4b294bf198fb27ade5b0e865c7ce)
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>
Bug: 25739721
Change-Id: I0b0cf101125b10a3316ef54959e24d7ca1d3a3c6
| -rw-r--r-- | fs/proc/task_mmu.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index dcbe86f031eb..cd55bf71906d 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1363,6 +1363,9 @@ 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"); |