From 110080cea0d0e4dfdb0b536e7f8a5633ead6a781 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Tue, 7 May 2019 11:36:34 +0300 Subject: genwqe: Prevent an integer overflow in the ioctl 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 Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/misc/genwqe/card_utils.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/misc/genwqe/card_utils.c') diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c index 89cff9d1012b..7571700abc6e 100644 --- a/drivers/misc/genwqe/card_utils.c +++ b/drivers/misc/genwqe/card_utils.c @@ -586,6 +586,10 @@ 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, -- cgit