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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2015-03-09 23:11:12 +0200
committerMark Salyzyn <salyzyn@google.com>2015-11-17 10:27:20 -0800
commit64d52c07bef88839ccc0d93e0f2ff56fdbc3e6fc (patch)
treec5ac00756a15b5739eb18ce0c315ed56eda627db
parent7acde36bcee74c4adf1fa338d02a879939d0033a (diff)
downloadlinux-linaro-stable-64d52c07bef88839ccc0d93e0f2ff56fdbc3e6fc.tar.gz
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: Iedd746b8d74163622d257984942d85fb76f797fa
-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 d54d00fb6b4c..cb0e2477548a 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1288,6 +1288,9 @@ 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");