[PATCH v3 03/10] swiotlb: Limit tlb address range inside slot pool

Lu Baolu
2019-04-21T01:25:01Z

In swiotlb_tbl_free_tlb(), when the tlb range is out of
the scope of the tlb slot pool, return directly with a
warning message. Otherwise, kernel data might be blindly
changed.

Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
kernel/dma/swiotlb.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 173122d16b7f..dbb937ce79c8 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -560,6 +560,12 @@ swiotlb_tbl_free_tlb(struct device *hwdev, phys_addr_t tlb_addr, size_t size)
int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;

+ /* Return directly if the tlb address is out of slot pool. */
+ if (tlb_addr < io_tlb_start || tlb_addr + size > io_tlb_end) {
+ dev_warn(hwdev, "invalid tlb address\n");
+ return;
+ }
+
/*
* Return the buffer to the free list by setting the corresponding
* entries to indicate the number of contiguous entries available.
--
2.17.1