[PATCH] Staging:gasket:core: Fix a double free in gasket_enable_device

[PATCH] Staging:gasket:core: Fix a double free in gasket_enable_device

[Lv Yunlong]

In gasket_enable_device, it calls gasket_interrupt_init().
Inside gasket_interrupt_init, interrupt_data is allocated via
kzalloc() and then is assigned to gasket_dev->interrupt_data.
If the later two kzalloc() failed, interrupt_data will be freed
and gasket_dev->interrupt_data will point to a freed memory.

After gasket_enable_device received the error, the freed
gasket_dev->interrupt_data is freed again in
gasket_interrupt_cleanup(gasket_dev).

My patch moves the "gasket_dev->interrupt_data = interrupt_data"
assignment behind the later kzalloc() all successd, to avoid
gasket_dev->interrupt_data pointing to a freed memory

Fixes: 80666096eb78f ("staging: gasket: core: remove static function forward declarations")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
 drivers/staging/gasket/gasket_interrupt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/gasket/gasket_interrupt.c b/drivers/staging/gasket/gasket_interrupt.c
index 864342acfd86..d4993d7abb87 100644
--- a/drivers/staging/gasket/gasket_interrupt.c
+++ b/drivers/staging/gasket/gasket_interrupt.c
@@ -322,7 +322,6 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
 	interrupt_data = kzalloc(sizeof(*interrupt_data), GFP_KERNEL);
 	if (!interrupt_data)
 		return -ENOMEM;
-	gasket_dev->interrupt_data = interrupt_data;
 	interrupt_data->name = driver_desc->name;
 	interrupt_data->type = driver_desc->interrupt_type;
 	interrupt_data->pci_dev = gasket_dev->pci_dev;
@@ -349,6 +348,8 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
 		return -ENOMEM;
 	}
 
+	gasket_dev->interrupt_data = interrupt_data;
+
 	switch (interrupt_data->type) {
 	case PCI_MSIX:
 		ret = gasket_interrupt_msix_init(interrupt_data);
-- 
2.25.1

Re: [PATCH] Staging:gasket:core: Fix a double free in gasket_enable_device

[Fabio Aiuto]

Hi Lv,

I fear gasket is no more on staging tree, I think it's no more on
kernel. Try fetch again from remote.

On Tue, Apr 27, 2021 at 07:11:29AM -0700, Lv Yunlong wrote:
> In gasket_enable_device, it calls gasket_interrupt_init().
> Inside gasket_interrupt_init, interrupt_data is allocated via
> kzalloc() and then is assigned to gasket_dev->interrupt_data.
> If the later two kzalloc() failed, interrupt_data will be freed
> and gasket_dev->interrupt_data will point to a freed memory.
> 
> After gasket_enable_device received the error, the freed
> gasket_dev->interrupt_data is freed again in
> gasket_interrupt_cleanup(gasket_dev).
> 
> My patch moves the "gasket_dev->interrupt_data = interrupt_data"
> assignment behind the later kzalloc() all successd, to avoid
> gasket_dev->interrupt_data pointing to a freed memory
> 
> Fixes: 80666096eb78f ("staging: gasket: core: remove static function forward declarations")
> Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
> ---
>  drivers/staging/gasket/gasket_interrupt.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/gasket/gasket_interrupt.c b/drivers/staging/gasket/gasket_interrupt.c
> index 864342acfd86..d4993d7abb87 100644
> --- a/drivers/staging/gasket/gasket_interrupt.c
> +++ b/drivers/staging/gasket/gasket_interrupt.c
> @@ -322,7 +322,6 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
>  	interrupt_data = kzalloc(sizeof(*interrupt_data), GFP_KERNEL);
>  	if (!interrupt_data)
>  		return -ENOMEM;
> -	gasket_dev->interrupt_data = interrupt_data;
>  	interrupt_data->name = driver_desc->name;
>  	interrupt_data->type = driver_desc->interrupt_type;
>  	interrupt_data->pci_dev = gasket_dev->pci_dev;
> @@ -349,6 +348,8 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
>  		return -ENOMEM;
>  	}
>  
> +	gasket_dev->interrupt_data = interrupt_data;
> +
>  	switch (interrupt_data->type) {
>  	case PCI_MSIX:
>  		ret = gasket_interrupt_msix_init(interrupt_data);
> -- 
> 2.25.1
> 
> 
> 

thank you,

fabio

Re: Re: [PATCH] Staging:gasket:core: Fix a double free in gasket_enable_device

[lyl2019]

> -----原始邮件-----
> 发件人: "Fabio Aiuto" <fabioaiuto83@gmail.com>
> 发送时间: 2021-04-27 22:26:00 (星期二)
> 收件人: "Lv Yunlong" <lyl2019@mail.ustc.edu.cn>
> 抄送: rspringer@google.com, toddpoynor@google.com, benchan@chromium.org, rcy@google.com, gregkh@linuxfoundation.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
> 主题: Re: [PATCH] Staging:gasket:core: Fix a double free in gasket_enable_device
> 
> Hi Lv,
> 
> I fear gasket is no more on staging tree, I think it's no more on
> kernel. Try fetch again from remote.
> 
> On Tue, Apr 27, 2021 at 07:11:29AM -0700, Lv Yunlong wrote:
> > In gasket_enable_device, it calls gasket_interrupt_init().
> > Inside gasket_interrupt_init, interrupt_data is allocated via
> > kzalloc() and then is assigned to gasket_dev->interrupt_data.
> > If the later two kzalloc() failed, interrupt_data will be freed
> > and gasket_dev->interrupt_data will point to a freed memory.
> > 
> > After gasket_enable_device received the error, the freed
> > gasket_dev->interrupt_data is freed again in
> > gasket_interrupt_cleanup(gasket_dev).
> > 
> > My patch moves the "gasket_dev->interrupt_data = interrupt_data"
> > assignment behind the later kzalloc() all successd, to avoid
> > gasket_dev->interrupt_data pointing to a freed memory
> > 
> > Fixes: 80666096eb78f ("staging: gasket: core: remove static function forward declarations")
> > Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
> > ---
> >  drivers/staging/gasket/gasket_interrupt.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/staging/gasket/gasket_interrupt.c b/drivers/staging/gasket/gasket_interrupt.c
> > index 864342acfd86..d4993d7abb87 100644
> > --- a/drivers/staging/gasket/gasket_interrupt.c
> > +++ b/drivers/staging/gasket/gasket_interrupt.c
> > @@ -322,7 +322,6 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
> >  	interrupt_data = kzalloc(sizeof(*interrupt_data), GFP_KERNEL);
> >  	if (!interrupt_data)
> >  		return -ENOMEM;
> > -	gasket_dev->interrupt_data = interrupt_data;
> >  	interrupt_data->name = driver_desc->name;
> >  	interrupt_data->type = driver_desc->interrupt_type;
> >  	interrupt_data->pci_dev = gasket_dev->pci_dev;
> > @@ -349,6 +348,8 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
> >  		return -ENOMEM;
> >  	}
> >  
> > +	gasket_dev->interrupt_data = interrupt_data;
> > +
> >  	switch (interrupt_data->type) {
> >  	case PCI_MSIX:
> >  		ret = gasket_interrupt_msix_init(interrupt_data);
> > -- 
> > 2.25.1
> > 
> > 
> > 
> 
> thank you,
> 
> fabio


Thanks for your reminder.