This is a note to let you know that I've just added the patch titled
iommu/io-pgtable-arm: Check for leaf entry before dereferencing it
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iommu-io-pgtable-arm-check-for-leaf-entry-before-dereferencing-it.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Oct 5 10:49:14 CEST 2017
From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
Date: Mon, 27 Feb 2017 14:30:25 +0200
Subject: iommu/io-pgtable-arm: Check for leaf entry before dereferencing it
From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
[ 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@xxxxxxxx>
CC: Will Deacon <will.deacon@xxxxxxx>
CC: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/iommu/io-pgtable-arm.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -335,8 +335,12 @@ static int __arm_lpae_map(struct arm_lpa
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 */
Patches currently in stable-queue which might be from oleksandr_tyshchenko@xxxxxxxx are
queue-4.4/iommu-io-pgtable-arm-check-for-leaf-entry-before-dereferencing-it.patch