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* mmc: core: fix possible use after free of host
@ 2019-04-17  8:28 Pan Bian
  2019-04-26  8:41 ` Mathieu Malaterre
  2019-04-29 10:44 ` Ulf Hansson
  0 siblings, 2 replies; 3+ messages in thread
From: Pan Bian @ 2019-04-17  8:28 UTC (permalink / raw)
  To: Ulf Hansson, Linus Walleij, Shawn Lin, Martin Blumenstingl,
	Gustavo A. R. Silva
  Cc: Tony Lindgren, Mathieu Malaterre, linux-mmc, linux-kernel, Pan Bian

In the function mmc_alloc_host, the function put_device is called to
release allocated resources when mmc_gpio_alloc fails. Finally, the
function pointed by host->class_dev.class->dev_release (i.e.,
mmc_host_classdev_release) is used to release resources including the
host structure. However, after put_device, host is used and released
again. Resulting in a use-after-free bug.

Fixes: 1ed21719448("mmc: core: fix error path in mmc_host_alloc")
Signed-off-by: Pan Bian <bianpan2016@163.com>
---
 drivers/mmc/core/host.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 3a4402a..f8ac567 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -429,8 +429,6 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 
 	if (mmc_gpio_alloc(host)) {
 		put_device(&host->class_dev);
-		ida_simple_remove(&mmc_host_ida, host->index);
-		kfree(host);
 		return NULL;
 	}
 
-- 
2.7.4



^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: mmc: core: fix possible use after free of host
  2019-04-17  8:28 mmc: core: fix possible use after free of host Pan Bian
@ 2019-04-26  8:41 ` Mathieu Malaterre
  2019-04-29 10:44 ` Ulf Hansson
  1 sibling, 0 replies; 3+ messages in thread
From: Mathieu Malaterre @ 2019-04-26  8:41 UTC (permalink / raw)
  To: Pan Bian
  Cc: Ulf Hansson, Linus Walleij, Shawn Lin, Martin Blumenstingl,
	Gustavo A. R. Silva, Tony Lindgren, linux-mmc, LKML,
	Heiner Kallweit

On Wed, Apr 17, 2019 at 10:28 AM Pan Bian <bianpan2016@163.com> wrote:
>
> In the function mmc_alloc_host, the function put_device is called to
> release allocated resources when mmc_gpio_alloc fails. Finally, the
> function pointed by host->class_dev.class->dev_release (i.e.,
> mmc_host_classdev_release) is used to release resources including the
> host structure. However, after put_device, host is used and released
> again. Resulting in a use-after-free bug.
>
> Fixes: 1ed21719448("mmc: core: fix error path in mmc_host_alloc")

The original commit 1ed21719448 looks correct to me (see
mmc_host_classdev_release).

> Signed-off-by: Pan Bian <bianpan2016@163.com>
> ---
>  drivers/mmc/core/host.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 3a4402a..f8ac567 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -429,8 +429,6 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
>
>         if (mmc_gpio_alloc(host)) {
>                 put_device(&host->class_dev);
> -               ida_simple_remove(&mmc_host_ida, host->index);
> -               kfree(host);
>                 return NULL;
>         }
>
> --
> 2.7.4
>
>

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: mmc: core: fix possible use after free of host
  2019-04-17  8:28 mmc: core: fix possible use after free of host Pan Bian
  2019-04-26  8:41 ` Mathieu Malaterre
@ 2019-04-29 10:44 ` Ulf Hansson
  1 sibling, 0 replies; 3+ messages in thread
From: Ulf Hansson @ 2019-04-29 10:44 UTC (permalink / raw)
  To: Pan Bian
  Cc: Linus Walleij, Shawn Lin, Martin Blumenstingl,
	Gustavo A. R. Silva, Tony Lindgren, Mathieu Malaterre, linux-mmc,
	Linux Kernel Mailing List

On Wed, 17 Apr 2019 at 10:29, Pan Bian <bianpan2016@163.com> wrote:
>
> In the function mmc_alloc_host, the function put_device is called to
> release allocated resources when mmc_gpio_alloc fails. Finally, the
> function pointed by host->class_dev.class->dev_release (i.e.,
> mmc_host_classdev_release) is used to release resources including the
> host structure. However, after put_device, host is used and released
> again. Resulting in a use-after-free bug.
>
> Fixes: 1ed21719448("mmc: core: fix error path in mmc_host_alloc")
> Signed-off-by: Pan Bian <bianpan2016@163.com>

Applied for next, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/core/host.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 3a4402a..f8ac567 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -429,8 +429,6 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
>
>         if (mmc_gpio_alloc(host)) {
>                 put_device(&host->class_dev);
> -               ida_simple_remove(&mmc_host_ida, host->index);
> -               kfree(host);
>                 return NULL;
>         }
>
> --
> 2.7.4
>
>

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2019-04-29 10:45 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2019-04-17  8:28 mmc: core: fix possible use after free of host Pan Bian
2019-04-26  8:41 ` Mathieu Malaterre
2019-04-29 10:44 ` Ulf Hansson

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