| From: Dan Carpenter <dan.carpenter@oracle.com> |
| Date: Tue, 7 May 2019 11:36:34 +0300 |
| Subject: genwqe: Prevent an integer overflow in the ioctl |
| |
| 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| 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 |
| @@ -779,6 +779,8 @@ 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 |
| @@ -571,6 +571,10 @@ 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, |