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Message-Id: <20200227132236.904370274@linuxfoundation.org>
Date: Thu, 27 Feb 2020 14:35:13 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Christopher Head <chead@...ad.ca>,
Arvind Sankar <nivedita@...m.mit.edu>,
Borislav Petkov <bp@...e.de>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 039/165] x86/sysfb: Fix check for bad VRAM size
From: Arvind Sankar <nivedita@...m.mit.edu>
[ Upstream commit dacc9092336be20b01642afe1a51720b31f60369 ]
When checking whether the reported lfb_size makes sense, the height
* stride result is page-aligned before seeing whether it exceeds the
reported size.
This doesn't work if height * stride is not an exact number of pages.
For example, as reported in the kernel bugzilla below, an 800x600x32 EFI
framebuffer gets skipped because of this.
Move the PAGE_ALIGN to after the check vs size.
Reported-by: Christopher Head <chead@...ad.ca>
Tested-by: Christopher Head <chead@...ad.ca>
Signed-off-by: Arvind Sankar <nivedita@...m.mit.edu>
Signed-off-by: Borislav Petkov <bp@...e.de>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206051
Link: https://lkml.kernel.org/r/20200107230410.2291947-1-nivedita@alum.mit.edu
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
arch/x86/kernel/sysfb_simplefb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/sysfb_simplefb.c b/arch/x86/kernel/sysfb_simplefb.c
index 85195d447a922..f3215346e47fd 100644
--- a/arch/x86/kernel/sysfb_simplefb.c
+++ b/arch/x86/kernel/sysfb_simplefb.c
@@ -94,11 +94,11 @@ __init int create_simplefb(const struct screen_info *si,
if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
size <<= 16;
length = mode->height * mode->stride;
- length = PAGE_ALIGN(length);
if (length > size) {
printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
return -EINVAL;
}
+ length = PAGE_ALIGN(length);
/* setup IORESOURCE_MEM as framebuffer memory */
memset(&res, 0, sizeof(res));
--
2.20.1
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