queue-4.4/genwqe-prevent-an-integer-overflow-in-the-ioctl.patch

   1 From 110080cea0d0e4dfdb0b536e7f8a5633ead6a781 Mon Sep 17 00:00:00 2001
   2 From: Dan Carpenter <dan.carpenter@oracle.com>
   3 Date: Tue, 7 May 2019 11:36:34 +0300
   4 Subject: genwqe: Prevent an integer overflow in the ioctl
   5
   6 From: Dan Carpenter <dan.carpenter@oracle.com>
   7
   8 commit 110080cea0d0e4dfdb0b536e7f8a5633ead6a781 upstream.
   9
  10 There are a couple potential integer overflows here.
  11
  12         round_up(m->size + (m->addr & ~PAGE_MASK), PAGE_SIZE);
  13
  14 The first thing is that the "m->size + (...)" addition could overflow,
  15 and the second is that round_up() overflows to zero if the result is
  16 within PAGE_SIZE of the type max.
  17
  18 In this code, the "m->size" variable is an u64 but we're saving the
  19 result in "map_size" which is an unsigned long and genwqe_user_vmap()
  20 takes an unsigned long as well.  So I have used ULONG_MAX as the upper
  21 bound.  From a practical perspective unsigned long is fine/better than
  22 trying to change all the types to u64.
  23
  24 Fixes: eaf4722d4645 ("GenWQE Character device and DDCB queue")
  25 Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
  26 Cc: stable <stable@vger.kernel.org>
  27 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  28
  29 ---
  30  drivers/misc/genwqe/card_dev.c   |    2 ++
  31  drivers/misc/genwqe/card_utils.c |    4 ++++
  32  2 files changed, 6 insertions(+)
  33
  34 --- a/drivers/misc/genwqe/card_dev.c
  35 +++ b/drivers/misc/genwqe/card_dev.c
  36 @@ -782,6 +782,8 @@ static int genwqe_pin_mem(struct genwqe_
  37
  38         if ((m->addr == 0x0) || (m->size == 0))
  39                 return -EINVAL;
  40 +       if (m->size > ULONG_MAX - PAGE_SIZE - (m->addr & ~PAGE_MASK))
  41 +               return -EINVAL;
  42
  43         map_addr = (m->addr & PAGE_MASK);
  44         map_size = round_up(m->size + (m->addr & ~PAGE_MASK), PAGE_SIZE);
  45 --- a/drivers/misc/genwqe/card_utils.c
  46 +++ b/drivers/misc/genwqe/card_utils.c
  47 @@ -582,6 +582,10 @@ int genwqe_user_vmap(struct genwqe_dev *
  48         /* determine space needed for page_list. */
  49         data = (unsigned long)uaddr;
  50         offs = offset_in_page(data);
  51 +       if (size > ULONG_MAX - PAGE_SIZE - offs) {
  52 +               m->size = 0;    /* mark unused and not added */
  53 +               return -EINVAL;
  54 +       }
  55         m->nr_pages = DIV_ROUND_UP(offs + size, PAGE_SIZE);
  56
  57         m->page_list = kcalloc(m->nr_pages,