* [PATCH] PCI/sysfs: off by two and memory corruption in driver_override parameter
@ 2015-01-02 0:27 Sasha Levin
2015-01-03 15:09 ` Bjorn Helgaas
0 siblings, 1 reply; 2+ messages in thread
From: Sasha Levin @ 2015-01-02 0:27 UTC (permalink / raw)
To: linux-kernel; +Cc: gregkh, Sasha Levin, Bjorn Helgaas, open list:PCI SUBSYSTEM
There are two different issues fixed here:
- On nun-NULL terminated input a random byte of memory would get flipped
from '\n' to '\0'.
- When printing the driver_override parameter when it is 4095 and 4094 bytes
long the printing code would access invalid memory.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
---
drivers/pci/pci-sysfs.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index aa012fb..be6b2b1 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -521,17 +521,17 @@ 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 >= (PATH_MAX - 1))
return -EINVAL;
driver_override = kstrndup(buf, count, GFP_KERNEL);
if (!driver_override)
return -ENOMEM;
- cp = strchr(driver_override, '\n');
- if (cp)
- *cp = '\0';
-
+ driver_override[count] = '\0';
+ if (driver_override[count - 1] == '\n')
+ driver_override[count - 1] = 0;
if (strlen(driver_override)) {
pdev->driver_override = driver_override;
} else {
--
1.7.10.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] PCI/sysfs: off by two and memory corruption in driver_override parameter
2015-01-02 0:27 [PATCH] PCI/sysfs: off by two and memory corruption in driver_override parameter Sasha Levin
@ 2015-01-03 15:09 ` Bjorn Helgaas
0 siblings, 0 replies; 2+ messages in thread
From: Bjorn Helgaas @ 2015-01-03 15:09 UTC (permalink / raw)
To: Sasha Levin; +Cc: linux-kernel, Greg Kroah-Hartman, open list:PCI SUBSYSTEM
On Thu, Jan 1, 2015 at 5:27 PM, Sasha Levin <sasha.levin@oracle.com> wrote:
> There are two different issues fixed here:
>
> - On nun-NULL terminated input a random byte of memory would get flipped
> from '\n' to '\0'.
> - When printing the driver_override parameter when it is 4095 and 4094 bytes
> long the printing code would access invalid memory.
Thanks, Sasha.
Can you please:
- Split these two fixes into two separate patches
- Look up the commit that introduced this code
- CC the author
- Add "Fixes: " lines
- Add stable tags for the relevant kernels
Bjorn
> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
> ---
> drivers/pci/pci-sysfs.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index aa012fb..be6b2b1 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -521,17 +521,17 @@ 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 >= (PATH_MAX - 1))
> return -EINVAL;
>
> driver_override = kstrndup(buf, count, GFP_KERNEL);
> if (!driver_override)
> return -ENOMEM;
>
> - cp = strchr(driver_override, '\n');
> - if (cp)
> - *cp = '\0';
> -
> + driver_override[count] = '\0';
> + if (driver_override[count - 1] == '\n')
> + driver_override[count - 1] = 0;
> if (strlen(driver_override)) {
> pdev->driver_override = driver_override;
> } else {
> --
> 1.7.10.4
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2015-01-03 15:09 ` Bjorn Helgaas
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