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 4.10-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-4.10 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 @@ -1526,7 +1526,6 @@ 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); @@ -1535,14 +1534,13 @@ 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); } @@ -1550,7 +1548,6 @@ 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; @@ -1559,14 +1556,13 @@ 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-4.10/mm-mempolicy.c-fix-error-handling-in-set_mempolicy-and-mbind.patch