[PATCH] usb: gadget: Fix double free of device descriptor pointers

[PATCH] usb: gadget: Fix double free of device descriptor pointers

[Wesley Cheng]

From: Hemant Kumar <hemantk@codeaurora.org>

Upon driver unbind usb_free_all_descriptors() function frees all
speed descriptor pointers without setting them to NULL. In case
gadget speed changes (i.e from super speed plus to super speed)
after driver unbind only upto super speed descriptor pointers get
populated. Super speed plus desc still holds the stale (already
freed) pointer. Fix this issue by setting all descriptor pointers
to NULL after freeing them in usb_free_all_descriptors().

Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
---
 drivers/usb/gadget/config.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/gadget/config.c b/drivers/usb/gadget/config.c
index 2d11535..8bb2577 100644
--- a/drivers/usb/gadget/config.c
+++ b/drivers/usb/gadget/config.c
@@ -194,9 +194,13 @@ EXPORT_SYMBOL_GPL(usb_assign_descriptors);
 void usb_free_all_descriptors(struct usb_function *f)
 {
 	usb_free_descriptors(f->fs_descriptors);
+	f->fs_descriptors = NULL;
 	usb_free_descriptors(f->hs_descriptors);
+	f->hs_descriptors = NULL;
 	usb_free_descriptors(f->ss_descriptors);
+	f->ss_descriptors = NULL;
 	usb_free_descriptors(f->ssp_descriptors);
+	f->ssp_descriptors = NULL;
 }
 EXPORT_SYMBOL_GPL(usb_free_all_descriptors);
 
-- 
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a Linux Foundation Collaborative Project

Re: [PATCH] usb: gadget: Fix double free of device descriptor pointers

[Peter Chen]

On 21-04-19 12:57:20, Wesley Cheng wrote:
> From: Hemant Kumar <hemantk@codeaurora.org>
> 
> Upon driver unbind usb_free_all_descriptors() function frees all
> speed descriptor pointers without setting them to NULL. In case
> gadget speed changes (i.e from super speed plus to super speed)
> after driver unbind only upto super speed descriptor pointers get
> populated. Super speed plus desc still holds the stale (already
> freed) pointer. Fix this issue by setting all descriptor pointers
> to NULL after freeing them in usb_free_all_descriptors().
> 
> Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
> Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
> ---
>  drivers/usb/gadget/config.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/usb/gadget/config.c b/drivers/usb/gadget/config.c
> index 2d11535..8bb2577 100644
> --- a/drivers/usb/gadget/config.c
> +++ b/drivers/usb/gadget/config.c
> @@ -194,9 +194,13 @@ EXPORT_SYMBOL_GPL(usb_assign_descriptors);
>  void usb_free_all_descriptors(struct usb_function *f)
>  {
>  	usb_free_descriptors(f->fs_descriptors);
> +	f->fs_descriptors = NULL;
>  	usb_free_descriptors(f->hs_descriptors);
> +	f->hs_descriptors = NULL;
>  	usb_free_descriptors(f->ss_descriptors);
> +	f->ss_descriptors = NULL;
>  	usb_free_descriptors(f->ssp_descriptors);
> +	f->ssp_descriptors = NULL;
>  }
>  EXPORT_SYMBOL_GPL(usb_free_all_descriptors);
>  

Reviewed-by: Peter Chen <peter.chen@kernel.org>

You may add Fixed-by tag, and cc to stable tree.

-- 

Thanks,
Peter Chen