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Date: Fri, 14 Feb 2020 11:08:10 -0500 From: Sasha Levin <sashal@...nel.org> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org Cc: Arvind Sankar <nivedita@...m.mit.edu>, Christopher Head <chead@...ad.ca>, Borislav Petkov <bp@...e.de>, Sasha Levin <sashal@...nel.org> Subject: [PATCH AUTOSEL 4.19 035/252] 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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