Messages in this thread Patch in this message | | | From | "Wilcox, Matthew R" <> | Subject | RE: [patch] NVMe: check for integer overflow in nvme_map_user_pages() | Date | Mon, 13 May 2013 13:53:11 +0000 |
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Why didn't you send this patch to the linux-nvme mailing list or the address listed in MAINTAINERS? Now Exchange & Outlook have hold of it, and it's mangled.
NVM EXPRESS DRIVER M: Matthew Wilcox <willy@linux.intel.com> L: linux-nvme@lists.infradead.org
________________________________________ From: Dan Carpenter [dan.carpenter@oracle.com] Sent: May 11, 2013 9:31 AM To: Wilcox, Matthew R Cc: Busch, Keith; Verma, Vishal L; linux-kernel@vger.kernel.org; kernel-janitors@vger.kernel.org Subject: [patch] 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>
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c index 8efdfaa..4376375 100644 --- a/drivers/block/nvme-core.c +++ b/drivers/block/nvme-core.c @@ -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; }
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