[3.19.y-ckt stable] Patch "ARM: 8426/1: dma-mapping: add missing range check in dma_mmap()" has been added to staging queue

[Kamal Mostafa]

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

    ARM: 8426/1: dma-mapping: add missing range check in dma_mmap()

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt11.

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

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 1209f181b11cc7813fbfe9bfd49ba08afc599bd5 Mon Sep 17 00:00:00 2001
From: Marek Szyprowski <m.szyprowski at samsung.com>
Date: Fri, 28 Aug 2015 09:41:39 +0100
Subject: ARM: 8426/1: dma-mapping: add missing range check in dma_mmap()

commit 371f0f085f629fc0f66695f572373ca4445a67ad upstream.

dma_mmap() function in IOMMU-based dma-mapping implementation lacked
a check for valid range of mmap parameters (offset and buffer size), what
might have caused access beyond the allocated buffer. This patch fixes
this issue.

Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/arm/mm/dma-mapping.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index bc074ef..30558bb 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1365,12 +1365,17 @@ static int arm_iommu_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
 	unsigned long uaddr = vma->vm_start;
 	unsigned long usize = vma->vm_end - vma->vm_start;
 	struct page **pages = __iommu_get_pages(cpu_addr, attrs);
+	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	unsigned long off = vma->vm_pgoff;

 	vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);

 	if (!pages)
 		return -ENXIO;

+	if (off >= nr_pages || (usize >> PAGE_SHIFT) > nr_pages - off)
+		return -ENXIO;
+
 	do {
 		int ret = vm_insert_page(vma, uaddr, *pages++);
 		if (ret) {
--
1.9.1