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ANDROID: pagemap: do not leak physical addresses to non-privileged userspace

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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 ]

We add this patch again for pass CTS
FileSystemPermissionTest: Assert /proc/self/pagemap not readable

Change-Id: Id4bf9ea27af000734356b921cd723868802b4335
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>
Signed-off-by: Huang, Tao <huangtao@rock-chips.com>
This commit is contained in:
Kirill A. Shutemov
2015-03-09 23:11:12 +02:00
committed by Huang, Tao
parent 292ff06061
commit f662f0e624
1 changed files with 10 additions and 0 deletions
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10
fs/proc/task_mmu.c
View File

@@ -1396,6 +1396,16 @@ static int pagemap_open(struct inode *inode, struct file *file)
{
struct mm_struct *mm;
#if defined(CONFIG_ARCH_ROCKCHIP) && defined(CONFIG_ANDROID)
/*
* For pass CTS
* FileSystemPermissionTest: Assert /proc/self/pagemap not readable
*/
/* do not disclose physical addresses: attack vector */
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
#endif
mm = proc_mem_open(inode, PTRACE_MODE_READ);
if (IS_ERR(mm))
return PTR_ERR(mm);