linux-kernel - [PATCH 1/3] PCI: pci-host-generic: Fix lookup of linux,pci-probe-only property

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 14 Aug 2015 15:41:06 +0100
From:	Marc Zyngier <marc.zyngier@....com>
To:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Michael Ellerman <mpe@...erman.id.au>,
	Will Deacon <will.deacon@....com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Cc:	Alexander Graf <agraf@...e.de>, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linuxppc-dev@...ts.ozlabs.org, linux-pci@...r.kernel.org
Subject: [PATCH 1/3] PCI: pci-host-generic: Fix lookup of linux,pci-probe-only property

When pci-host-generic looks for the probe-only property, it seems
to trust the DT to be correctly written, and assumes that there
is a parameter to the property.

Unfortunately, this is not always the case, and some firmware expose
this property naked. The driver ends up making a decision based on
whatever the property pointer points to, which is likely to be junk.

Instead, let's check for the validity of the property, and ignore
it if the firmware couldn't make up its mind.

Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
 drivers/pci/host/pci-host-generic.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c
index 265dd25..2b2e2ff 100644
--- a/drivers/pci/host/pci-host-generic.c
+++ b/drivers/pci/host/pci-host-generic.c
@@ -211,6 +211,7 @@ static int gen_pci_probe(struct platform_device *pdev)
 	const char *type;
 	const struct of_device_id *of_id;
 	const int *prop;
+	int len;
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	struct gen_pci *pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
@@ -225,12 +226,16 @@ static int gen_pci_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	prop = of_get_property(of_chosen, "linux,pci-probe-only", NULL);
+	prop = of_get_property(of_chosen, "linux,pci-probe-only", &len);
 	if (prop) {
-		if (*prop)
-			pci_add_flags(PCI_PROBE_ONLY);
-		else
-			pci_clear_flags(PCI_PROBE_ONLY);
+		if (len) {
+			if (be32_to_cpup(prop))
+				pci_add_flags(PCI_PROBE_ONLY);
+			else
+				pci_clear_flags(PCI_PROBE_ONLY);
+		} else {
+			dev_warn(&pdev->dev, "linux,pci-probe-only set without value, ignoring\n");
+		}
 	}
 
 	of_id = of_match_node(gen_pci_of_match, np);
-- 
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/