[PATCH 3.19 093/123] PCI: Dont read past the end of sysfs "driver_override" buffer

[Greg Kroah-Hartman]

3.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sasha Levin <sasha.levin@xxxxxxxxxx>

commit 4efe874aace57dba967624ce1c48322da2447b75 upstream.

When printing the driver_override parameter when it is 4095 and 4094 bytes
long, the printing code would access invalid memory because we need count+1
bytes for printing.

Fixes: 782a985d7af2 ("PCI: Introduce new device binding path using pci_dev.driver_override")
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Acked-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
CC: Alexander Graf <agraf@xxxxxxx>
CC: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/pci/pci-sysfs.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -521,7 +521,8 @@ static ssize_t driver_override_store(str
 	struct pci_dev *pdev = to_pci_dev(dev);
 	char *driver_override, *old = pdev->driver_override, *cp;
 
-	if (count > PATH_MAX)
+	/* We need to keep extra room for a newline */
+	if (count >= (PAGE_SIZE - 1))
 		return -EINVAL;
 
 	driver_override = kstrndup(buf, count, GFP_KERNEL);
@@ -549,7 +550,7 @@ static ssize_t driver_override_show(stru
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 
-	return sprintf(buf, "%s\n", pdev->driver_override);
+	return snprintf(buf, PAGE_SIZE, "%s\n", pdev->driver_override);
 }
 static DEVICE_ATTR_RW(driver_override);
 


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