3.2.89-rc1 review patch. If anyone has any objections, please let me know.
------------------
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: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1446,7 +1446,6 @@ asmlinkage long compat_sys_get_mempolicy
asmlinkage long compat_sys_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);
@@ -1455,14 +1454,13 @@ asmlinkage long compat_sys_set_mempolicy
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);
}
@@ -1470,7 +1468,6 @@ asmlinkage long compat_sys_mbind(compat_
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;
@@ -1479,14 +1476,13 @@ asmlinkage long compat_sys_mbind(compat_
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);
}