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    Subject[PATCH 4.14 24/35] genwqe: Prevent an integer overflow in the ioctl
    Date
    From: Dan Carpenter <dan.carpenter@oracle.com>

    commit 110080cea0d0e4dfdb0b536e7f8a5633ead6a781 upstream.

    There are a couple potential integer overflows here.

    round_up(m->size + (m->addr & ~PAGE_MASK), PAGE_SIZE);

    The first thing is that the "m->size + (...)" addition could overflow,
    and the second is that round_up() overflows to zero if the result is
    within PAGE_SIZE of the type max.

    In this code, the "m->size" variable is an u64 but we're saving the
    result in "map_size" which is an unsigned long and genwqe_user_vmap()
    takes an unsigned long as well. So I have used ULONG_MAX as the upper
    bound. From a practical perspective unsigned long is fine/better than
    trying to change all the types to u64.

    Fixes: eaf4722d4645 ("GenWQE Character device and DDCB queue")
    Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/misc/genwqe/card_dev.c | 2 ++
    drivers/misc/genwqe/card_utils.c | 4 ++++
    2 files changed, 6 insertions(+)

    --- a/drivers/misc/genwqe/card_dev.c
    +++ b/drivers/misc/genwqe/card_dev.c
    @@ -782,6 +782,8 @@ static int genwqe_pin_mem(struct genwqe_

    if ((m->addr == 0x0) || (m->size == 0))
    return -EINVAL;
    + if (m->size > ULONG_MAX - PAGE_SIZE - (m->addr & ~PAGE_MASK))
    + return -EINVAL;

    map_addr = (m->addr & PAGE_MASK);
    map_size = round_up(m->size + (m->addr & ~PAGE_MASK), PAGE_SIZE);
    --- a/drivers/misc/genwqe/card_utils.c
    +++ b/drivers/misc/genwqe/card_utils.c
    @@ -582,6 +582,10 @@ int genwqe_user_vmap(struct genwqe_dev *
    /* determine space needed for page_list. */
    data = (unsigned long)uaddr;
    offs = offset_in_page(data);
    + if (size > ULONG_MAX - PAGE_SIZE - offs) {
    + m->size = 0; /* mark unused and not added */
    + return -EINVAL;
    + }
    m->nr_pages = DIV_ROUND_UP(offs + size, PAGE_SIZE);

    m->page_list = kcalloc(m->nr_pages,

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