[3.13.y-ckt stable] Patch "IB/uverbs: Prevent integer overflow in ib_umem_get address arithmetic" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    IB/uverbs: Prevent integer overflow in ib_umem_get address arithmetic

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt20.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 5eafec14c02a1ebe32088c0a0a82fc0247bd04c0 Mon Sep 17 00:00:00 2001
From: Shachar Raindel <raindel at mellanox.com>
Date: Wed, 18 Mar 2015 17:39:08 +0000
Subject: IB/uverbs: Prevent integer overflow in ib_umem_get address arithmetic

commit 8494057ab5e40df590ef6ef7d66324d3ae33356b upstream.

Properly verify that the resulting page aligned end address is larger
than both the start address and the length of the memory area requested.

Both the start and length arguments for ib_umem_get are controlled by
the user. A misbehaving user can provide values which will cause an
integer overflow when calculating the page aligned end address.

This overflow can cause also miscalculation of the number of pages
mapped, and additional logic issues.

Addresses: CVE-2014-8159
Signed-off-by: Shachar Raindel <raindel at mellanox.com>
Signed-off-by: Jack Morgenstein <jackm at mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz at mellanox.com>
Signed-off-by: Roland Dreier <roland at purestorage.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/infiniband/core/umem.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index a841123..055ebeb 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -94,6 +94,14 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 	if (dmasync)
 		dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);

+	/*
+	 * If the combination of the addr and size requested for this memory
+	 * region causes an integer overflow, return error.
+	 */
+	if ((PAGE_ALIGN(addr + size) <= size) ||
+	    (PAGE_ALIGN(addr + size) <= addr))
+		return ERR_PTR(-EINVAL);
+
 	if (!can_do_mlock())
 		return ERR_PTR(-EPERM);

--
1.9.1