Commit 9bcd5cee authored Feb 27, 2017 by Oleksandr Tyshchenko Committed by Greg Kroah-Hartman Oct 08, 2017

iommu/io-pgtable-arm: Check for leaf entry before dereferencing it




[ Upstream commit ed46e66cc1b3d684042f92dfa2ab15ee917b4cac ]

Do a check for already installed leaf entry at the current level before
dereferencing it in order to avoid walking the page table down with
wrong pointer to the next level.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent cadfa3a6

drivers/iommu/io-pgtable-arm.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -335,8 +335,12 @@ static int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
		if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_NS)
		pte \|= ARM_LPAE_PTE_NSTABLE;
		__arm_lpae_set_pte(ptep, pte, cfg);
		} else {
		} else if (!iopte_leaf(pte, lvl)) {
		cptep = iopte_deref(pte, data);
		} else {
		/* We require an unmap first */
		WARN_ON(!selftest_running);
		return -EEXIST;
		}

		/* Rinse, repeat */