2012-11-23 05:46:11

by Lothar Waßmann

Subject: [BUGFIX PATCH] USB: chipidea: fix use after free bug

The pointer to a platform_device struct must not be dereferenced after
the device has been unregistered.

This bug produces a crash when unloading the ci13xxx kernel module
compiled with CONFIG_PAGE_POISONING enabled.

Signed-off-by: Lothar Waßmann <[email protected]>
---
drivers/usb/chipidea/core.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index f69d029..b726c49 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -385,8 +385,9 @@ EXPORT_SYMBOL_GPL(ci13xxx_add_device);

void ci13xxx_remove_device(struct platform_device *pdev)
{
+ int id = pdev->id;
platform_device_unregister(pdev);
- ida_simple_remove(&ci_ida, pdev->id);
+ ida_simple_remove(&ci_ida, id);
}
EXPORT_SYMBOL_GPL(ci13xxx_remove_device);

--
1.7.2.5

2012-11-22 18:56:27

by Alexander Shishkin

Subject: Re: [BUGFIX PATCH] USB: chipidea: fix use after free bug

Lothar Waßmann <[email protected]> writes:

> The pointer to a platform_device struct must not be dereferenced after
> the device has been unregistered.
>
> This bug produces a crash when unloading the ci13xxx kernel module
> compiled with CONFIG_PAGE_POISONING enabled.
>
> Signed-off-by: Lothar Waßmann <[email protected]>

Good one, thanks.

Acked-by: Alexander Shishkin <[email protected]>

Greg, this is -stable material, applicable starting from v3.6.

> ---
> drivers/usb/chipidea/core.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
> index f69d029..b726c49 100644
> --- a/drivers/usb/chipidea/core.c
> +++ b/drivers/usb/chipidea/core.c
> @@ -385,8 +385,9 @@ EXPORT_SYMBOL_GPL(ci13xxx_add_device);
>
> void ci13xxx_remove_device(struct platform_device *pdev)
> {
> + int id = pdev->id;
> platform_device_unregister(pdev);
> - ida_simple_remove(&ci_ida, pdev->id);
> + ida_simple_remove(&ci_ida, id);
> }
> EXPORT_SYMBOL_GPL(ci13xxx_remove_device);
>
> --
> 1.7.2.5