* [PATCH v2] usb: dwc3: gadget: Free gadget structure only after freeing endpoints
2021-05-01 9:30 [PATCH] usb: dwc3: gadget: Free gadget structure only after freeing endpoints Jack Pham
@ 2021-05-01 9:35 ` Jack Pham
2021-05-06 16:02 ` Jack Pham
` (2 more replies)
2021-05-01 11:48 ` [PATCH] " kernel test robot
2021-05-01 13:11 ` kernel test robot
2 siblings, 3 replies; 7+ messages in thread
From: Jack Pham @ 2021-05-01 9:35 UTC (permalink / raw)
To: Felipe Balbi, Greg Kroah-Hartman
Cc: linux-usb, linux-arm-msm, Peter Chen, Sandeep Maheswaram,
Wesley Cheng, Elliot Berman, Prasad Sodagudi, Jack Pham
As part of commit e81a7018d93a ("usb: dwc3: allocate gadget structure
dynamically") the dwc3_gadget_release() was added which will free
the dwc->gadget structure upon the device's removal when
usb_del_gadget_udc() is called in dwc3_gadget_exit().
However, simply freeing the gadget results a dangling pointer
situation: the endpoints created in dwc3_gadget_init_endpoints()
have their dep->endpoint.ep_list members chained off the list_head
anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed,
the first dwc3_ep in the list now has a dangling prev pointer and
likewise for the next pointer of the dwc3_ep at the tail of the list.
The dwc3_gadget_free_endpoints() that follows will result in a
use-after-free when it calls list_del().
This was caught by enabling KASAN and performing a driver unbind.
The recent commit 568262bf5492 ("usb: dwc3: core: Add shutdown
callback for dwc3") also exposes this as a panic during shutdown.
There are a few possibilities to fix this. One could be to perform
a list_del() of the gadget->ep_list itself which removes it from
the rest of the dwc3_ep chain.
Another approach is what this patch does, by splitting up the
usb_del_gadget_udc() call into its separate "del" and "put"
components. This allows dwc3_gadget_free_endpoints() to be
called before the gadget is finally freed with usb_put_gadget().
Fixes: e81a7018d93a ("usb: dwc3: allocate gadget structure dynamically")
Signed-off-by: Jack Pham <jackp@codeaurora.org>
---
v2: Fix silly typo: usb_del_gadget_put -> usb_put_gadget (brain fart
when manually recomposing the patch)
drivers/usb/dwc3/gadget.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 6eab78f8a1a7..c7e5f5a07f3b 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -4062,8 +4062,9 @@ int dwc3_gadget_init(struct dwc3 *dwc)
void dwc3_gadget_exit(struct dwc3 *dwc)
{
- usb_del_gadget_udc(dwc->gadget);
+ usb_del_gadget(dwc->gadget);
dwc3_gadget_free_endpoints(dwc);
+ usb_put_gadget(dwc->gadget);
dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
dwc->bounce_addr);
kfree(dwc->setup_buf);
--
2.24.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v2] usb: dwc3: gadget: Free gadget structure only after freeing endpoints
2021-05-01 9:35 ` [PATCH v2] " Jack Pham
@ 2021-05-06 16:02 ` Jack Pham
2021-05-08 6:21 ` Peter Chen
2021-05-10 12:12 ` Felipe Balbi
2 siblings, 0 replies; 7+ messages in thread
From: Jack Pham @ 2021-05-06 16:02 UTC (permalink / raw)
To: Felipe Balbi, Greg Kroah-Hartman
Cc: linux-usb, linux-arm-msm, Peter Chen, Sandeep Maheswaram,
Wesley Cheng, Elliot Berman, Prasad Sodagudi
Hi Felipe,
I know it may still be early in the merge window but do you have any
feedback for this? We have some internal testers getting hit by this
use-after-free when enabling SLUB_DEBUG or KASAN enabled builds. This
fix resolves the issue in those cases so was hoping for a review soon
so we can eventually queue it up for stable too.
(I sent V2 quickly after V1 but before the kernel bot caught my obvious
blunder on V1. But I sent V2 as a threaded-reply, so not sure if that
made this get buried in people's inboxes...)
Thanks
Jack
On Sat, May 01, 2021 at 02:35:58AM -0700, Jack Pham wrote:
> As part of commit e81a7018d93a ("usb: dwc3: allocate gadget structure
> dynamically") the dwc3_gadget_release() was added which will free
> the dwc->gadget structure upon the device's removal when
> usb_del_gadget_udc() is called in dwc3_gadget_exit().
>
> However, simply freeing the gadget results a dangling pointer
> situation: the endpoints created in dwc3_gadget_init_endpoints()
> have their dep->endpoint.ep_list members chained off the list_head
> anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed,
> the first dwc3_ep in the list now has a dangling prev pointer and
> likewise for the next pointer of the dwc3_ep at the tail of the list.
> The dwc3_gadget_free_endpoints() that follows will result in a
> use-after-free when it calls list_del().
>
> This was caught by enabling KASAN and performing a driver unbind.
> The recent commit 568262bf5492 ("usb: dwc3: core: Add shutdown
> callback for dwc3") also exposes this as a panic during shutdown.
>
> There are a few possibilities to fix this. One could be to perform
> a list_del() of the gadget->ep_list itself which removes it from
> the rest of the dwc3_ep chain.
>
> Another approach is what this patch does, by splitting up the
> usb_del_gadget_udc() call into its separate "del" and "put"
> components. This allows dwc3_gadget_free_endpoints() to be
> called before the gadget is finally freed with usb_put_gadget().
>
> Fixes: e81a7018d93a ("usb: dwc3: allocate gadget structure dynamically")
> Signed-off-by: Jack Pham <jackp@codeaurora.org>
> ---
> v2: Fix silly typo: usb_del_gadget_put -> usb_put_gadget (brain fart
> when manually recomposing the patch)
>
> drivers/usb/dwc3/gadget.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 6eab78f8a1a7..c7e5f5a07f3b 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -4062,8 +4062,9 @@ int dwc3_gadget_init(struct dwc3 *dwc)
>
> void dwc3_gadget_exit(struct dwc3 *dwc)
> {
> - usb_del_gadget_udc(dwc->gadget);
> + usb_del_gadget(dwc->gadget);
> dwc3_gadget_free_endpoints(dwc);
> + usb_put_gadget(dwc->gadget);
> dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
> dwc->bounce_addr);
> kfree(dwc->setup_buf);
> --
> 2.24.0
>
--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] usb: dwc3: gadget: Free gadget structure only after freeing endpoints
2021-05-01 9:35 ` [PATCH v2] " Jack Pham
2021-05-06 16:02 ` Jack Pham
@ 2021-05-08 6:21 ` Peter Chen
2021-05-10 12:12 ` Felipe Balbi
2 siblings, 0 replies; 7+ messages in thread
From: Peter Chen @ 2021-05-08 6:21 UTC (permalink / raw)
To: Jack Pham
Cc: Felipe Balbi, Greg Kroah-Hartman, linux-usb, linux-arm-msm,
Peter Chen, Sandeep Maheswaram, Wesley Cheng, Elliot Berman,
Prasad Sodagudi
On 21-05-01 02:35:58, Jack Pham wrote:
> As part of commit e81a7018d93a ("usb: dwc3: allocate gadget structure
> dynamically") the dwc3_gadget_release() was added which will free
> the dwc->gadget structure upon the device's removal when
> usb_del_gadget_udc() is called in dwc3_gadget_exit().
>
> However, simply freeing the gadget results a dangling pointer
> situation: the endpoints created in dwc3_gadget_init_endpoints()
> have their dep->endpoint.ep_list members chained off the list_head
> anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed,
> the first dwc3_ep in the list now has a dangling prev pointer and
> likewise for the next pointer of the dwc3_ep at the tail of the list.
> The dwc3_gadget_free_endpoints() that follows will result in a
> use-after-free when it calls list_del().
>
> This was caught by enabling KASAN and performing a driver unbind.
> The recent commit 568262bf5492 ("usb: dwc3: core: Add shutdown
> callback for dwc3") also exposes this as a panic during shutdown.
>
> There are a few possibilities to fix this. One could be to perform
> a list_del() of the gadget->ep_list itself which removes it from
> the rest of the dwc3_ep chain.
>
> Another approach is what this patch does, by splitting up the
> usb_del_gadget_udc() call into its separate "del" and "put"
> components. This allows dwc3_gadget_free_endpoints() to be
> called before the gadget is finally freed with usb_put_gadget().
>
> Fixes: e81a7018d93a ("usb: dwc3: allocate gadget structure dynamically")
> Signed-off-by: Jack Pham <jackp@codeaurora.org>
> ---
> v2: Fix silly typo: usb_del_gadget_put -> usb_put_gadget (brain fart
> when manually recomposing the patch)
>
> drivers/usb/dwc3/gadget.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 6eab78f8a1a7..c7e5f5a07f3b 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -4062,8 +4062,9 @@ int dwc3_gadget_init(struct dwc3 *dwc)
>
> void dwc3_gadget_exit(struct dwc3 *dwc)
> {
> - usb_del_gadget_udc(dwc->gadget);
> + usb_del_gadget(dwc->gadget);
> dwc3_gadget_free_endpoints(dwc);
> + usb_put_gadget(dwc->gadget);
> dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
> dwc->bounce_addr);
> kfree(dwc->setup_buf);
> --
Reviewed-by: Peter Chen <peter.chen@kernel.org>
--
Thanks,
Peter Chen
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] usb: dwc3: gadget: Free gadget structure only after freeing endpoints
2021-05-01 9:35 ` [PATCH v2] " Jack Pham
2021-05-06 16:02 ` Jack Pham
2021-05-08 6:21 ` Peter Chen
@ 2021-05-10 12:12 ` Felipe Balbi
2 siblings, 0 replies; 7+ messages in thread
From: Felipe Balbi @ 2021-05-10 12:12 UTC (permalink / raw)
To: Jack Pham, Greg Kroah-Hartman
Cc: linux-usb, linux-arm-msm, Peter Chen, Sandeep Maheswaram,
Wesley Cheng, Elliot Berman, Prasad Sodagudi, Jack Pham
[-- Attachment #1: Type: text/plain, Size: 1860 bytes --]
Hi,
Jack Pham <jackp@codeaurora.org> writes:
> As part of commit e81a7018d93a ("usb: dwc3: allocate gadget structure
> dynamically") the dwc3_gadget_release() was added which will free
> the dwc->gadget structure upon the device's removal when
> usb_del_gadget_udc() is called in dwc3_gadget_exit().
>
> However, simply freeing the gadget results a dangling pointer
> situation: the endpoints created in dwc3_gadget_init_endpoints()
> have their dep->endpoint.ep_list members chained off the list_head
> anchored at dwc->gadget->ep_list. Thus when dwc->gadget is freed,
> the first dwc3_ep in the list now has a dangling prev pointer and
> likewise for the next pointer of the dwc3_ep at the tail of the list.
> The dwc3_gadget_free_endpoints() that follows will result in a
> use-after-free when it calls list_del().
>
> This was caught by enabling KASAN and performing a driver unbind.
> The recent commit 568262bf5492 ("usb: dwc3: core: Add shutdown
> callback for dwc3") also exposes this as a panic during shutdown.
>
> There are a few possibilities to fix this. One could be to perform
> a list_del() of the gadget->ep_list itself which removes it from
> the rest of the dwc3_ep chain.
>
> Another approach is what this patch does, by splitting up the
> usb_del_gadget_udc() call into its separate "del" and "put"
> components. This allows dwc3_gadget_free_endpoints() to be
> called before the gadget is finally freed with usb_put_gadget().
>
> Fixes: e81a7018d93a ("usb: dwc3: allocate gadget structure dynamically")
> Signed-off-by: Jack Pham <jackp@codeaurora.org>
> ---
> v2: Fix silly typo: usb_del_gadget_put -> usb_put_gadget (brain fart
> when manually recomposing the patch)
I thought I had acked this one already, looks like I missed it:
Acked-by: Felipe Balbi <balbi@kernel.org>
--
balbi
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 511 bytes --]
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] usb: dwc3: gadget: Free gadget structure only after freeing endpoints
2021-05-01 9:30 [PATCH] usb: dwc3: gadget: Free gadget structure only after freeing endpoints Jack Pham
2021-05-01 9:35 ` [PATCH v2] " Jack Pham
@ 2021-05-01 11:48 ` kernel test robot
2021-05-01 13:11 ` kernel test robot
2 siblings, 0 replies; 7+ messages in thread
From: kernel test robot @ 2021-05-01 11:48 UTC (permalink / raw)
To: Jack Pham, Felipe Balbi, Greg Kroah-Hartman
Cc: kbuild-all, linux-usb, linux-arm-msm, Peter Chen,
Sandeep Maheswaram, Wesley Cheng, Elliot Berman, Prasad Sodagudi,
Jack Pham
[-- Attachment #1: Type: text/plain, Size: 2523 bytes --]
Hi Jack,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on usb/usb-testing]
[also build test ERROR on peter.chen-usb/for-usb-next linus/master balbi-usb/testing/next v5.12 next-20210430]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Jack-Pham/usb-dwc3-gadget-Free-gadget-structure-only-after-freeing-endpoints/20210501-173239
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
config: alpha-allmodconfig (attached as .config)
compiler: alpha-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/5b2764c7c290946657e27890a4265bd11bccc0dc
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Jack-Pham/usb-dwc3-gadget-Free-gadget-structure-only-after-freeing-endpoints/20210501-173239
git checkout 5b2764c7c290946657e27890a4265bd11bccc0dc
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=alpha
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
drivers/usb/dwc3/gadget.c: In function 'dwc3_gadget_exit':
>> drivers/usb/dwc3/gadget.c:4063:2: error: implicit declaration of function 'usb_del_gadget_put'; did you mean 'usb_del_gadget_udc'? [-Werror=implicit-function-declaration]
4063 | usb_del_gadget_put(dwc->gadget);
| ^~~~~~~~~~~~~~~~~~
| usb_del_gadget_udc
cc1: some warnings being treated as errors
vim +4063 drivers/usb/dwc3/gadget.c
4058
4059 void dwc3_gadget_exit(struct dwc3 *dwc)
4060 {
4061 usb_del_gadget(dwc->gadget);
4062 dwc3_gadget_free_endpoints(dwc);
> 4063 usb_del_gadget_put(dwc->gadget);
4064 dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
4065 dwc->bounce_addr);
4066 kfree(dwc->setup_buf);
4067 dma_free_coherent(dwc->sysdev, sizeof(*dwc->ep0_trb) * 2,
4068 dwc->ep0_trb, dwc->ep0_trb_addr);
4069 }
4070
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 67594 bytes --]
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] usb: dwc3: gadget: Free gadget structure only after freeing endpoints
2021-05-01 9:30 [PATCH] usb: dwc3: gadget: Free gadget structure only after freeing endpoints Jack Pham
2021-05-01 9:35 ` [PATCH v2] " Jack Pham
2021-05-01 11:48 ` [PATCH] " kernel test robot
@ 2021-05-01 13:11 ` kernel test robot
2 siblings, 0 replies; 7+ messages in thread
From: kernel test robot @ 2021-05-01 13:11 UTC (permalink / raw)
To: Jack Pham, Felipe Balbi, Greg Kroah-Hartman
Cc: kbuild-all, clang-built-linux, linux-usb, linux-arm-msm,
Peter Chen, Sandeep Maheswaram, Wesley Cheng, Elliot Berman,
Prasad Sodagudi, Jack Pham
[-- Attachment #1: Type: text/plain, Size: 2807 bytes --]
Hi Jack,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on usb/usb-testing]
[also build test ERROR on peter.chen-usb/for-usb-next linus/master balbi-usb/testing/next v5.12 next-20210430]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Jack-Pham/usb-dwc3-gadget-Free-gadget-structure-only-after-freeing-endpoints/20210501-173239
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
config: x86_64-randconfig-a012-20210501 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 8f5a2a5836cc8e4c1def2bdeb022e7b496623439)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install x86_64 cross compiling tool for clang build
# apt-get install binutils-x86-64-linux-gnu
# https://github.com/0day-ci/linux/commit/5b2764c7c290946657e27890a4265bd11bccc0dc
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Jack-Pham/usb-dwc3-gadget-Free-gadget-structure-only-after-freeing-endpoints/20210501-173239
git checkout 5b2764c7c290946657e27890a4265bd11bccc0dc
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
>> drivers/usb/dwc3/gadget.c:4063:2: error: implicit declaration of function 'usb_del_gadget_put' [-Werror,-Wimplicit-function-declaration]
usb_del_gadget_put(dwc->gadget);
^
drivers/usb/dwc3/gadget.c:4063:2: note: did you mean 'usb_del_gadget_udc'?
include/linux/usb/gadget.h:477:13: note: 'usb_del_gadget_udc' declared here
extern void usb_del_gadget_udc(struct usb_gadget *gadget);
^
1 error generated.
vim +/usb_del_gadget_put +4063 drivers/usb/dwc3/gadget.c
4058
4059 void dwc3_gadget_exit(struct dwc3 *dwc)
4060 {
4061 usb_del_gadget(dwc->gadget);
4062 dwc3_gadget_free_endpoints(dwc);
> 4063 usb_del_gadget_put(dwc->gadget);
4064 dma_free_coherent(dwc->sysdev, DWC3_BOUNCE_SIZE, dwc->bounce,
4065 dwc->bounce_addr);
4066 kfree(dwc->setup_buf);
4067 dma_free_coherent(dwc->sysdev, sizeof(*dwc->ep0_trb) * 2,
4068 dwc->ep0_trb, dwc->ep0_trb_addr);
4069 }
4070
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 35907 bytes --]
^ permalink raw reply [flat|nested] 7+ messages in thread