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From:   Lu Baolu <baolu.lu@linux.intel.com>
To:     David Woodhouse <dwmw2@infradead.org>,
        Joerg Roedel <joro@8bytes.org>
Cc:     ashok.raj@intel.com, jacob.jun.pan@intel.com, alan.cox@intel.com,
        kevin.tian@intel.com, mika.westerberg@linux.intel.com,
        pengfei.xu@intel.com,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Christoph Hellwig <hch@lst.de>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Robin Murphy <robin.murphy@arm.com>,
        iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
        Lu Baolu <baolu.lu@linux.intel.com>
Subject: [PATCH v3 03/10] swiotlb: Limit tlb address range inside slot pool
Date:   Sun, 21 Apr 2019 09:17:12 +0800
Message-Id: <20190421011719.14909-4-baolu.lu@linux.intel.com>
In-Reply-To: <20190421011719.14909-1-baolu.lu@linux.intel.com>
References: <20190421011719.14909-1-baolu.lu@linux.intel.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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