2015-02-04 22:38:46

by Sasha Levin

Subject: [PATCH v3] PCI/sysfs: off by two when checking the limit on driver_override length

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.

Cc: <[email protected]> # v3.16+
Fixes: 782a985d ("PCI: Introduce new device binding path using pci_dev.driver_override")
Cc: Alex Williamson <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Alexander Graf <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
drivers/pci/pci-sysfs.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index aa012fb..312f23a 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -521,7 +521,8 @@ static ssize_t driver_override_store(struct device *dev,
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(struct device *dev,
{
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);

--
1.7.10.4

2015-02-04 23:09:21

by Alex Williamson

Subject: Re: [PATCH v3] PCI/sysfs: off by two when checking the limit on driver_override length

On Wed, 2015-02-04 at 17:38 -0500, Sasha Levin wrote:
> 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.
>
> Cc: <[email protected]> # v3.16+
> Fixes: 782a985d ("PCI: Introduce new device binding path using pci_dev.driver_override")
> Cc: Alex Williamson <[email protected]>
> Cc: Bjorn Helgaas <[email protected]>
> Cc: Konrad Rzeszutek Wilk <[email protected]>
> Cc: Alexander Graf <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Signed-off-by: Sasha Levin <[email protected]>
> ---
> drivers/pci/pci-sysfs.c | 5 +++--
> 1 files changed, 3 insertions(+), 2 deletions(-)


Acked-by: Alex Williamson <[email protected]>


> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index aa012fb..312f23a 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -521,7 +521,8 @@ static ssize_t driver_override_store(struct device *dev,
> 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(struct device *dev,
> {
> 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);
>

2015-02-24 23:36:10

by Bjorn Helgaas

Subject: Re: [PATCH v3] PCI/sysfs: off by two when checking the limit on driver_override length

On Wed, Feb 04, 2015 at 05:38:15PM -0500, Sasha Levin wrote:
> 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.
>
> Cc: <[email protected]> # v3.16+
> Fixes: 782a985d ("PCI: Introduce new device binding path using pci_dev.driver_override")
> Cc: Alex Williamson <[email protected]>
> Cc: Bjorn Helgaas <[email protected]>
> Cc: Konrad Rzeszutek Wilk <[email protected]>
> Cc: Alexander Graf <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Signed-off-by: Sasha Levin <[email protected]>

Applied with Alex's ack to for-linus for v4.0, thanks!

> ---
> drivers/pci/pci-sysfs.c | 5 +++--
> 1 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index aa012fb..312f23a 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -521,7 +521,8 @@ static ssize_t driver_override_store(struct device *dev,
> 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(struct device *dev,
> {
> 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);
>
> --
> 1.7.10.4
>