This is a note to let you know that I've just added the patch titled
mm/mempolicy.c: fix error handling in set_mempolicy and mbind.
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-mempolicy.c-fix-error-handling-in-set_mempolicy-and-mbind.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From cf01fb9985e8deb25ccf0ea54d916b8871ae0e62 Mon Sep 17 00:00:00 2001
From: Chris Salls <salls@xxxxxxxxxxx>
Date: Fri, 7 Apr 2017 23:48:11 -0700
Subject: mm/mempolicy.c: fix error handling in set_mempolicy and mbind.
From: Chris Salls <salls@xxxxxxxxxxx>
commit cf01fb9985e8deb25ccf0ea54d916b8871ae0e62 upstream.
In the case that compat_get_bitmap fails we do not want to copy the
bitmap to the user as it will contain uninitialized stack data and leak
sensitive data.
Signed-off-by: Chris Salls <salls@xxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1492,7 +1492,6 @@ COMPAT_SYSCALL_DEFINE5(get_mempolicy, in
COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
compat_ulong_t, maxnode)
{
- long err = 0;
unsigned long __user *nm = NULL;
unsigned long nr_bits, alloc_size;
DECLARE_BITMAP(bm, MAX_NUMNODES);
@@ -1501,14 +1500,13 @@ COMPAT_SYSCALL_DEFINE3(set_mempolicy, in
alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
if (nmask) {
- err = compat_get_bitmap(bm, nmask, nr_bits);
+ if (compat_get_bitmap(bm, nmask, nr_bits))
+ return -EFAULT;
nm = compat_alloc_user_space(alloc_size);
- err |= copy_to_user(nm, bm, alloc_size);
+ if (copy_to_user(nm, bm, alloc_size))
+ return -EFAULT;
}
- if (err)
- return -EFAULT;
-
return sys_set_mempolicy(mode, nm, nr_bits+1);
}
@@ -1516,7 +1514,6 @@ COMPAT_SYSCALL_DEFINE6(mbind, compat_ulo
compat_ulong_t, mode, compat_ulong_t __user *, nmask,
compat_ulong_t, maxnode, compat_ulong_t, flags)
{
- long err = 0;
unsigned long __user *nm = NULL;
unsigned long nr_bits, alloc_size;
nodemask_t bm;
@@ -1525,14 +1522,13 @@ COMPAT_SYSCALL_DEFINE6(mbind, compat_ulo
alloc_size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
if (nmask) {
- err = compat_get_bitmap(nodes_addr(bm), nmask, nr_bits);
+ if (compat_get_bitmap(nodes_addr(bm), nmask, nr_bits))
+ return -EFAULT;
nm = compat_alloc_user_space(alloc_size);
- err |= copy_to_user(nm, nodes_addr(bm), alloc_size);
+ if (copy_to_user(nm, nodes_addr(bm), alloc_size))
+ return -EFAULT;
}
- if (err)
- return -EFAULT;
-
return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
}
Patches currently in stable-queue which might be from salls@xxxxxxxxxxx are
queue-4.4/mm-mempolicy.c-fix-error-handling-in-set_mempolicy-and-mbind.patch