Commit aa612d59 authored by Chris Salls's avatar Chris Salls Committed by Sasha Levin

mm/mempolicy.c: fix error handling in set_mempolicy and mbind.

[ Upstream commit cf01fb99 ]

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: default avatarChris Salls <salls@cs.ucsb.edu>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
parent 00fc586e
......@@ -1495,7 +1495,6 @@ COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy,
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);
......@@ -1504,14 +1503,13 @@ COMPAT_SYSCALL_DEFINE3(set_mempolicy, int, mode, compat_ulong_t __user *, nmask,
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);
}
......@@ -1519,7 +1517,6 @@ COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
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;
......@@ -1528,14 +1525,13 @@ COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len,
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);
}
......
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