linux-kernel - [PATCH] PCI: fix a potential uninitentional integer overflow issue

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Date:   Wed,  7 Oct 2020 12:46:15 +0100
From:   Colin King <colin.king@...onical.com>
To:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Christian König <christian.koenig@....com>,
        Stephen Bates <sbates@...thlin.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org
Subject: [PATCH] PCI: fix a potential uninitentional integer overflow issue

From: Colin Ian King <colin.king@...onical.com>

The shift of 1 by align_order is evaluated using 32 bit arithmetic
and the result is assigned to a resource_size_t type variable that
is a 64 bit unsigned integer on 64 bit platforms. Fix an overflow
before widening issue by using the BIT_ULL macro to perform the
shift.

Addresses-Coverity: ("Uninitentional integer overflow")
Fixes: 07d8d7e57c28 ("PCI: Make specifying PCI devices in kernel parameters reusable")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/pci/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6d4d5a2f923d..1a5844d7af35 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -6209,7 +6209,7 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
 			if (align_order == -1)
 				align = PAGE_SIZE;
 			else
-				align = 1 << align_order;
+				align = BIT_ULL(align_order);
 			break;
 		} else if (ret < 0) {
 			pr_err("PCI: Can't parse resource_alignment parameter: %s\n",
-- 
2.27.0