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authorChris Salls <salls@cs.ucsb.edu>2017-04-08 06:48:11 (GMT)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-04-12 10:41:15 (GMT)
commitcddab768d13469d1e254fb8c0e1629f93c8dfaca (patch)
tree5ebc41c261be8f1b3c457a942f56484c5cbe241d /mm
parent24317cb6b400d7fc567e4c8d1fdca587113c6423 (diff)
downloadlinux-cddab768d13469d1e254fb8c0e1629f93c8dfaca.tar.xz
mm/mempolicy.c: fix error handling in set_mempolicy and mbind.
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@cs.ucsb.edu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mempolicy.c20
1 files changed, 8 insertions, 12 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index f757047..23471526 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1524,7 +1524,6 @@ 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);
@@ -1533,14 +1532,13 @@ 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);
}
@@ -1548,7 +1546,6 @@ 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;
@@ -1557,14 +1554,13 @@ 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);
}