linux-kernel - [PATCH 5.0 21/89] arm64: mm: Ensure tail of unaligned initrd is reserved

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Date:   Tue, 30 Apr 2019 13:38:12 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Will Deacon <will.deacon@....com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Catalin Marinas <catalin.marinas@....com>
Subject: [PATCH 5.0 21/89] arm64: mm: Ensure tail of unaligned initrd is reserved

From: Bjorn Andersson <bjorn.andersson@...aro.org>

commit d4d18e3ec6091843f607e8929a56723e28f393a6 upstream.

In the event that the start address of the initrd is not aligned, but
has an aligned size, the base + size will not cover the entire initrd
image and there is a chance that the kernel will corrupt the tail of the
image.

By aligning the end of the initrd to a page boundary and then
subtracting the adjusted start address the memblock reservation will
cover all pages that contains the initrd.

Fixes: c756c592e442 ("arm64: Utilize phys_initrd_start/phys_initrd_size")
Cc: stable@...r.kernel.org
Acked-by: Will Deacon <will.deacon@....com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arm64/mm/init.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -406,7 +406,7 @@ void __init arm64_memblock_init(void)
 		 * Otherwise, this is a no-op
 		 */
 		u64 base = phys_initrd_start & PAGE_MASK;
-		u64 size = PAGE_ALIGN(phys_initrd_size);
+		u64 size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base;
 
 		/*
 		 * We can only add back the initrd memory if we don't end up