From: "Kirill A. Shutemov" <kirill.shute...@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-dram-rowhammer-bug-to-gain.html Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com> Cc: Pavel Emelyanov <xe...@parallels.com> Cc: Konstantin Khlebnikov <khlebni...@openvz.org> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Mark Seaborn <mseab...@chromium.org> Cc: Andy Lutomirski <l...@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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
