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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: David Airlie <airlied@linux.ie>
Cc: Tom Lendacky <thomas.lendacky@amd.com>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	Eyal Itkin <eyalit@checkpoint.com>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	Cihangir Akturk <cakturk@gmail.com>,
	dri-devel@lists.freedesktop.org, Ingo Molnar <mingo@kernel.org>
Subject: [PATCH] drm: udl: Properly check framebuffer mmap offsets
Date: Wed, 21 Mar 2018 16:45:53 +0100	[thread overview]
Message-ID: <20180321154553.GA18454@kroah.com> (raw)

The memmap options sent to the udl framebuffer driver were not being
checked for all sets of possible crazy values.  Fix this up by properly
bounding the allowed values.

Reported-by: Eyal Itkin <eyalit@checkpoint.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/udl/udl_fb.c b/drivers/gpu/drm/udl/udl_fb.c
index b5b335c9b2bb..2ebdc6d5a76e 100644
--- a/drivers/gpu/drm/udl/udl_fb.c
+++ b/drivers/gpu/drm/udl/udl_fb.c
@@ -159,10 +159,15 @@ static int udl_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 {
 	unsigned long start = vma->vm_start;
 	unsigned long size = vma->vm_end - vma->vm_start;
-	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+	unsigned long offset;
 	unsigned long page, pos;
 
-	if (offset + size > info->fix.smem_len)
+	if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
+		return -EINVAL;
+
+	offset = vma->vm_pgoff << PAGE_SHIFT;
+
+	if (offset > info->fix.smem_len || size > info->fix.smem_len - offset)
 		return -EINVAL;
 
 	pos = (unsigned long)info->fix.smem_start + offset;
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             reply	other threads:[~2018-03-21 15:45 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-21 15:45 Greg Kroah-Hartman [this message]
2018-03-22  6:59 ` [PATCH] drm: udl: Properly check framebuffer mmap offsets Daniel Vetter
2018-03-22  8:03   ` Greg Kroah-Hartman
2018-03-22  9:54     ` Daniel Vetter
2018-03-23  0:14       ` Kees Cook
2018-03-26  8:26         ` Daniel Vetter

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