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genwqe: Prevent an integer overflow in the ioctl

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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>
This commit is contained in:
Dan Carpenter 2019-05-07 11:36:34 +03:00 committed by prashantpaddune
parent 337b596e91
commit b6812d3c04
2 changed files with 6 additions and 0 deletions
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2
drivers/misc/genwqe/card_dev.c
View File

@ -782,6 +782,8 @@ static int genwqe_pin_mem(struct genwqe_file *cfile, struct genwqe_mem *m)
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);

4
drivers/misc/genwqe/card_utils.c
View File

@ -582,6 +582,10 @@ int genwqe_user_vmap(struct genwqe_dev *cd, struct dma_mapping *m, void *uaddr,
/* 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,