From: Shachar Raindel <raindel@mellanox.com>
Date: Sun, 4 Jan 2015 18:30:32 +0200
Subject: [PATCH] IB/core: Prevent integer overflow in ib_umem_get address
 arithmetic

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.

Issue: 470602
Change-Id: Iee88441db454af291fc5a376009d840603398d23
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Jack Morgenstein <jackm@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.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 aec7a6aa2951..8c014b5dab4c 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -99,6 +99,14 @@ 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);
 
-- 
2.1.0