Commit 5460fc03 authored May 13, 2013 by Dan Carpenter Committed by Matthew Wilcox May 17, 2013

NVMe: check for integer overflow in nvme_map_user_pages()



You need to have CAP_SYS_ADMIN to trigger this overflow but it makes the
static checkers complain so we should fix it.  The worry is that
"length" comes from copy_from_user() so we need to check that "length +
offset" can't overflow.

I also changed the min_t() cast to be unsigned instead of signed.  Now
that we cap "length" to INT_MAX it doesn't make a difference, but it's a
little easier for reviewers to know that large values aren't cast to
negative.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

parent 5be37bf9

drivers/block/nvme-core.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -1206,7 +1206,7 @@ struct nvme_iod nvme_map_user_pages(struct nvme_dev dev, int write,

		if (addr & 3)
		return ERR_PTR(-EINVAL);
		if (!length)
		if (!length \|\| length > INT_MAX - PAGE_SIZE)
		return ERR_PTR(-EINVAL);

		offset = offset_in_page(addr);
		@@ -1227,7 +1227,8 @@ struct nvme_iod nvme_map_user_pages(struct nvme_dev dev, int write,
		sg_init_table(sg, count);
		for (i = 0; i < count; i++) {
		sg_set_page(&sg[i], pages[i],
		min_t(int, length, PAGE_SIZE - offset), offset);
		min_t(unsigned, length, PAGE_SIZE - offset),
		offset);
		length -= (PAGE_SIZE - offset);
		offset = 0;
		}