* [PATCH 2/2] cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter()
2022-11-11 14:54 [PATCH 1/2] cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter() Yang Yingliang
@ 2022-11-11 14:54 ` Yang Yingliang
2022-11-16 18:07 ` Frederic Barrat
2022-11-21 5:35 ` Andrew Donnellan
2022-11-16 18:04 ` [PATCH 1/2] cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter() Frederic Barrat
` (2 subsequent siblings)
3 siblings, 2 replies; 7+ messages in thread
From: Yang Yingliang @ 2022-11-11 14:54 UTC (permalink / raw)
To: linuxppc-dev; +Cc: fbarrat, gregkh, ajd, arnd, yangyingliang
If device_register() fails in cxl_pci_afu|adapter(), the device
is not added, device_unregister() can not be called in the error
path, otherwise it will cause a null-ptr-deref because of removing
not added device.
As comment of device_register() says, it should use put_device() to give
up the reference in the error path. So split device_unregister() into
device_del() and put_device(), then goes to put dev when register fails.
Fixes: f204e0b8cedd ("cxl: Driver code for powernv PCIe based cards for userspace access")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
drivers/misc/cxl/pci.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index 3de0aea62ade..6d495d641c95 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -1164,10 +1164,10 @@ static int pci_init_afu(struct cxl *adapter, int slice, struct pci_dev *dev)
* if it returns an error!
*/
if ((rc = cxl_register_afu(afu)))
- goto err_put1;
+ goto err_put_dev;
if ((rc = cxl_sysfs_afu_add(afu)))
- goto err_put1;
+ goto err_del_dev;
adapter->afu[afu->slice] = afu;
@@ -1176,10 +1176,12 @@ static int pci_init_afu(struct cxl *adapter, int slice, struct pci_dev *dev)
return 0;
-err_put1:
+err_del_dev:
+ device_del(&afu->dev);
+err_put_dev:
pci_deconfigure_afu(afu);
cxl_debugfs_afu_remove(afu);
- device_unregister(&afu->dev);
+ put_device(&afu->dev);
return rc;
err_free_native:
@@ -1667,23 +1669,25 @@ static struct cxl *cxl_pci_init_adapter(struct pci_dev *dev)
* even if it returns an error!
*/
if ((rc = cxl_register_adapter(adapter)))
- goto err_put1;
+ goto err_put_dev;
if ((rc = cxl_sysfs_adapter_add(adapter)))
- goto err_put1;
+ goto err_del_dev;
/* Release the context lock as adapter is configured */
cxl_adapter_context_unlock(adapter);
return adapter;
-err_put1:
+err_del_dev:
+ device_del(&adapter->dev);
+err_put_dev:
/* This should mirror cxl_remove_adapter, except without the
* sysfs parts
*/
cxl_debugfs_adapter_remove(adapter);
cxl_deconfigure_adapter(adapter);
- device_unregister(&adapter->dev);
+ put_device(&adapter->dev);
return ERR_PTR(rc);
err_release:
--
2.25.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH 2/2] cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter()
2022-11-11 14:54 ` [PATCH 2/2] cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter() Yang Yingliang
@ 2022-11-16 18:07 ` Frederic Barrat
2022-11-21 5:35 ` Andrew Donnellan
1 sibling, 0 replies; 7+ messages in thread
From: Frederic Barrat @ 2022-11-16 18:07 UTC (permalink / raw)
To: Yang Yingliang, linuxppc-dev; +Cc: gregkh, ajd, arnd
On 11/11/2022 15:54, Yang Yingliang wrote:
> If device_register() fails in cxl_pci_afu|adapter(), the device
> is not added, device_unregister() can not be called in the error
> path, otherwise it will cause a null-ptr-deref because of removing
> not added device.
>
> As comment of device_register() says, it should use put_device() to give
> up the reference in the error path. So split device_unregister() into
> device_del() and put_device(), then goes to put dev when register fails.
>
> Fixes: f204e0b8cedd ("cxl: Driver code for powernv PCIe based cards for userspace access")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Fred
> drivers/misc/cxl/pci.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
> index 3de0aea62ade..6d495d641c95 100644
> --- a/drivers/misc/cxl/pci.c
> +++ b/drivers/misc/cxl/pci.c
> @@ -1164,10 +1164,10 @@ static int pci_init_afu(struct cxl *adapter, int slice, struct pci_dev *dev)
> * if it returns an error!
> */
> if ((rc = cxl_register_afu(afu)))
> - goto err_put1;
> + goto err_put_dev;
>
> if ((rc = cxl_sysfs_afu_add(afu)))
> - goto err_put1;
> + goto err_del_dev;
>
> adapter->afu[afu->slice] = afu;
>
> @@ -1176,10 +1176,12 @@ static int pci_init_afu(struct cxl *adapter, int slice, struct pci_dev *dev)
>
> return 0;
>
> -err_put1:
> +err_del_dev:
> + device_del(&afu->dev);
> +err_put_dev:
> pci_deconfigure_afu(afu);
> cxl_debugfs_afu_remove(afu);
> - device_unregister(&afu->dev);
> + put_device(&afu->dev);
> return rc;
>
> err_free_native:
> @@ -1667,23 +1669,25 @@ static struct cxl *cxl_pci_init_adapter(struct pci_dev *dev)
> * even if it returns an error!
> */
> if ((rc = cxl_register_adapter(adapter)))
> - goto err_put1;
> + goto err_put_dev;
>
> if ((rc = cxl_sysfs_adapter_add(adapter)))
> - goto err_put1;
> + goto err_del_dev;
>
> /* Release the context lock as adapter is configured */
> cxl_adapter_context_unlock(adapter);
>
> return adapter;
>
> -err_put1:
> +err_del_dev:
> + device_del(&adapter->dev);
> +err_put_dev:
> /* This should mirror cxl_remove_adapter, except without the
> * sysfs parts
> */
> cxl_debugfs_adapter_remove(adapter);
> cxl_deconfigure_adapter(adapter);
> - device_unregister(&adapter->dev);
> + put_device(&adapter->dev);
> return ERR_PTR(rc);
>
> err_release:
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH 2/2] cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter()
2022-11-11 14:54 ` [PATCH 2/2] cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter() Yang Yingliang
2022-11-16 18:07 ` Frederic Barrat
@ 2022-11-21 5:35 ` Andrew Donnellan
1 sibling, 0 replies; 7+ messages in thread
From: Andrew Donnellan @ 2022-11-21 5:35 UTC (permalink / raw)
To: Yang Yingliang, linuxppc-dev; +Cc: fbarrat, gregkh, arnd
On Fri, 2022-11-11 at 22:54 +0800, Yang Yingliang wrote:
> If device_register() fails in cxl_pci_afu|adapter(), the device
> is not added, device_unregister() can not be called in the error
> path, otherwise it will cause a null-ptr-deref because of removing
> not added device.
>
> As comment of device_register() says, it should use put_device() to
> give
> up the reference in the error path. So split device_unregister() into
> device_del() and put_device(), then goes to put dev when register
> fails.
>
> Fixes: f204e0b8cedd ("cxl: Driver code for powernv PCIe based cards
> for userspace access")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
See reply to patch #1.
This patch puts a few things between the device_del() call and the
put_device() call, but that looks fine - we don't touch afu->dev in the
middle.
Thanks for the fix!
Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
> drivers/misc/cxl/pci.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
> index 3de0aea62ade..6d495d641c95 100644
> --- a/drivers/misc/cxl/pci.c
> +++ b/drivers/misc/cxl/pci.c
> @@ -1164,10 +1164,10 @@ static int pci_init_afu(struct cxl *adapter,
> int slice, struct pci_dev *dev)
> * if it returns an error!
> */
> if ((rc = cxl_register_afu(afu)))
> - goto err_put1;
> + goto err_put_dev;
>
> if ((rc = cxl_sysfs_afu_add(afu)))
> - goto err_put1;
> + goto err_del_dev;
>
> adapter->afu[afu->slice] = afu;
>
> @@ -1176,10 +1176,12 @@ static int pci_init_afu(struct cxl *adapter,
> int slice, struct pci_dev *dev)
>
> return 0;
>
> -err_put1:
> +err_del_dev:
> + device_del(&afu->dev);
> +err_put_dev:
> pci_deconfigure_afu(afu);
> cxl_debugfs_afu_remove(afu);
> - device_unregister(&afu->dev);
> + put_device(&afu->dev);
> return rc;
>
> err_free_native:
> @@ -1667,23 +1669,25 @@ static struct cxl
> *cxl_pci_init_adapter(struct pci_dev *dev)
> * even if it returns an error!
> */
> if ((rc = cxl_register_adapter(adapter)))
> - goto err_put1;
> + goto err_put_dev;
>
> if ((rc = cxl_sysfs_adapter_add(adapter)))
> - goto err_put1;
> + goto err_del_dev;
>
> /* Release the context lock as adapter is configured */
> cxl_adapter_context_unlock(adapter);
>
> return adapter;
>
> -err_put1:
> +err_del_dev:
> + device_del(&adapter->dev);
> +err_put_dev:
> /* This should mirror cxl_remove_adapter, except without the
> * sysfs parts
> */
> cxl_debugfs_adapter_remove(adapter);
> cxl_deconfigure_adapter(adapter);
> - device_unregister(&adapter->dev);
> + put_device(&adapter->dev);
> return ERR_PTR(rc);
>
> err_release:
--
Andrew Donnellan OzLabs, ADL Canberra
ajd@linux.ibm.com IBM Australia Limited
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter()
2022-11-11 14:54 [PATCH 1/2] cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter() Yang Yingliang
2022-11-11 14:54 ` [PATCH 2/2] cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter() Yang Yingliang
@ 2022-11-16 18:04 ` Frederic Barrat
2022-11-21 5:18 ` Andrew Donnellan
2022-11-30 9:24 ` Michael Ellerman
3 siblings, 0 replies; 7+ messages in thread
From: Frederic Barrat @ 2022-11-16 18:04 UTC (permalink / raw)
To: Yang Yingliang, linuxppc-dev; +Cc: gregkh, ajd, arnd
On 11/11/2022 15:54, Yang Yingliang wrote:
> If device_register() fails in cxl_register_afu|adapter(), the device
> is not added, device_unregister() can not be called in the error path,
> otherwise it will cause a null-ptr-deref because of removing not added
> device.
>
> As comment of device_register() says, it should use put_device() to give
> up the reference in the error path. So split device_unregister() into
> device_del() and put_device(), then goes to put dev when register fails.
>
> Fixes: 14baf4d9c739 ("cxl: Add guest-specific code")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
Thanks for fixing it!
At first, I was slightly uneasy about calling device_del() and
put_device() directly, i.e. it would be better not to worry about what's
under the hood of device_unregister(). But 1) I don't see how else to
fix it and 2) more importantly, I looked at the history of
device_unregister() to see how frequently it changed. I can now rest
easy :-)
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Fred
> drivers/misc/cxl/guest.c | 24 ++++++++++++++----------
> 1 file changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c
> index 375f692ae9d6..fb95a2d5cef4 100644
> --- a/drivers/misc/cxl/guest.c
> +++ b/drivers/misc/cxl/guest.c
> @@ -965,10 +965,10 @@ int cxl_guest_init_afu(struct cxl *adapter, int slice, struct device_node *afu_n
> * if it returns an error!
> */
> if ((rc = cxl_register_afu(afu)))
> - goto err_put1;
> + goto err_put_dev;
>
> if ((rc = cxl_sysfs_afu_add(afu)))
> - goto err_put1;
> + goto err_del_dev;
>
> /*
> * pHyp doesn't expose the programming models supported by the
> @@ -984,7 +984,7 @@ int cxl_guest_init_afu(struct cxl *adapter, int slice, struct device_node *afu_n
> afu->modes_supported = CXL_MODE_DIRECTED;
>
> if ((rc = cxl_afu_select_best_mode(afu)))
> - goto err_put2;
> + goto err_remove_sysfs;
>
> adapter->afu[afu->slice] = afu;
>
> @@ -1004,10 +1004,12 @@ int cxl_guest_init_afu(struct cxl *adapter, int slice, struct device_node *afu_n
>
> return 0;
>
> -err_put2:
> +err_remove_sysfs:
> cxl_sysfs_afu_remove(afu);
> -err_put1:
> - device_unregister(&afu->dev);
> +err_del_dev:
> + device_del(&afu->dev);
> +err_put_dev:
> + put_device(&afu->dev);
> free = false;
> guest_release_serr_irq(afu);
> err2:
> @@ -1141,18 +1143,20 @@ struct cxl *cxl_guest_init_adapter(struct device_node *np, struct platform_devic
> * even if it returns an error!
> */
> if ((rc = cxl_register_adapter(adapter)))
> - goto err_put1;
> + goto err_put_dev;
>
> if ((rc = cxl_sysfs_adapter_add(adapter)))
> - goto err_put1;
> + goto err_del_dev;
>
> /* release the context lock as the adapter is configured */
> cxl_adapter_context_unlock(adapter);
>
> return adapter;
>
> -err_put1:
> - device_unregister(&adapter->dev);
> +err_del_dev:
> + device_del(&adapter->dev);
> +err_put_dev:
> + put_device(&adapter->dev);
> free = false;
> cxl_guest_remove_chardev(adapter);
> err1:
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH 1/2] cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter()
2022-11-11 14:54 [PATCH 1/2] cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter() Yang Yingliang
2022-11-11 14:54 ` [PATCH 2/2] cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter() Yang Yingliang
2022-11-16 18:04 ` [PATCH 1/2] cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter() Frederic Barrat
@ 2022-11-21 5:18 ` Andrew Donnellan
2022-11-30 9:24 ` Michael Ellerman
3 siblings, 0 replies; 7+ messages in thread
From: Andrew Donnellan @ 2022-11-21 5:18 UTC (permalink / raw)
To: Yang Yingliang, linuxppc-dev; +Cc: fbarrat, gregkh, arnd
On Fri, 2022-11-11 at 22:54 +0800, Yang Yingliang wrote:
> If device_register() fails in cxl_register_afu|adapter(), the device
> is not added, device_unregister() can not be called in the error
> path,
> otherwise it will cause a null-ptr-deref because of removing not
> added
> device.
>
> As comment of device_register() says, it should use put_device() to
> give
> up the reference in the error path. So split device_unregister() into
> device_del() and put_device(), then goes to put dev when register
> fails.
The comment around device_add() is relevant too:
Rule of thumb is: if device_add() succeeds, you should call
device_del() when you want to get rid of it. If device_add() has
*not* succeeded, use *only* put_device() to drop the reference count.
>
> Fixes: 14baf4d9c739 ("cxl: Add guest-specific code")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Thanks for the fix!
Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
> drivers/misc/cxl/guest.c | 24 ++++++++++++++----------
> 1 file changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c
> index 375f692ae9d6..fb95a2d5cef4 100644
> --- a/drivers/misc/cxl/guest.c
> +++ b/drivers/misc/cxl/guest.c
> @@ -965,10 +965,10 @@ int cxl_guest_init_afu(struct cxl *adapter, int
> slice, struct device_node *afu_n
> * if it returns an error!
> */
> if ((rc = cxl_register_afu(afu)))
> - goto err_put1;
> + goto err_put_dev;
>
> if ((rc = cxl_sysfs_afu_add(afu)))
> - goto err_put1;
> + goto err_del_dev;
>
> /*
> * pHyp doesn't expose the programming models supported by
> the
> @@ -984,7 +984,7 @@ int cxl_guest_init_afu(struct cxl *adapter, int
> slice, struct device_node *afu_n
> afu->modes_supported = CXL_MODE_DIRECTED;
>
> if ((rc = cxl_afu_select_best_mode(afu)))
> - goto err_put2;
> + goto err_remove_sysfs;
>
> adapter->afu[afu->slice] = afu;
>
> @@ -1004,10 +1004,12 @@ int cxl_guest_init_afu(struct cxl *adapter,
> int slice, struct device_node *afu_n
>
> return 0;
>
> -err_put2:
> +err_remove_sysfs:
> cxl_sysfs_afu_remove(afu);
> -err_put1:
> - device_unregister(&afu->dev);
> +err_del_dev:
> + device_del(&afu->dev);
> +err_put_dev:
> + put_device(&afu->dev);
> free = false;
> guest_release_serr_irq(afu);
> err2:
> @@ -1141,18 +1143,20 @@ struct cxl *cxl_guest_init_adapter(struct
> device_node *np, struct platform_devic
> * even if it returns an error!
> */
> if ((rc = cxl_register_adapter(adapter)))
> - goto err_put1;
> + goto err_put_dev;
>
> if ((rc = cxl_sysfs_adapter_add(adapter)))
> - goto err_put1;
> + goto err_del_dev;
>
> /* release the context lock as the adapter is configured */
> cxl_adapter_context_unlock(adapter);
>
> return adapter;
>
> -err_put1:
> - device_unregister(&adapter->dev);
> +err_del_dev:
> + device_del(&adapter->dev);
> +err_put_dev:
> + put_device(&adapter->dev);
> free = false;
> cxl_guest_remove_chardev(adapter);
> err1:
--
Andrew Donnellan OzLabs, ADL Canberra
ajd@linux.ibm.com IBM Australia Limited
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH 1/2] cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter()
2022-11-11 14:54 [PATCH 1/2] cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter() Yang Yingliang
` (2 preceding siblings ...)
2022-11-21 5:18 ` Andrew Donnellan
@ 2022-11-30 9:24 ` Michael Ellerman
3 siblings, 0 replies; 7+ messages in thread
From: Michael Ellerman @ 2022-11-30 9:24 UTC (permalink / raw)
To: Yang Yingliang, linuxppc-dev; +Cc: fbarrat, gregkh, ajd, arnd
On Fri, 11 Nov 2022 22:54:39 +0800, Yang Yingliang wrote:
> If device_register() fails in cxl_register_afu|adapter(), the device
> is not added, device_unregister() can not be called in the error path,
> otherwise it will cause a null-ptr-deref because of removing not added
> device.
>
> As comment of device_register() says, it should use put_device() to give
> up the reference in the error path. So split device_unregister() into
> device_del() and put_device(), then goes to put dev when register fails.
>
> [...]
Applied to powerpc/next.
[1/2] cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter()
https://git.kernel.org/powerpc/c/f949ccee1dde970bc77dc871b4f0b5e651577344
[2/2] cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter()
https://git.kernel.org/powerpc/c/8bf03f557d6c6e108cf47bea32f4a68e276e1157
cheers
^ permalink raw reply [flat|nested] 7+ messages in thread