diff mbox series

[v3,11/11] rpmsg: Fix kfree() of static memory on setting driver_override

Message ID 20220227135329.145862-5-krzysztof.kozlowski@canonical.com (mailing list archive)
State New, archived
Headers show
Series Fix broken usage of driver_override (and kfree of static memory) | expand

Commit Message

Krzysztof Kozlowski Feb. 27, 2022, 1:53 p.m. UTC 
The driver_override field from platform driver should not be initialized
from static memory (string literal) because the core later kfree() it,
for example when driver_override is set via sysfs.

Use dedicated helper to set driver_override properly.

Fixes: 950a7388f02b ("rpmsg: Turn name service into a stand alone driver")
Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
---
 drivers/rpmsg/rpmsg_core.c     |  3 ++-
 drivers/rpmsg/rpmsg_internal.h | 13 +++++++++++--
 drivers/rpmsg/rpmsg_ns.c       | 14 ++++++++++++--
 include/linux/rpmsg.h          |  6 ++++--
 4 files changed, 29 insertions(+), 7 deletions(-)

Comments

Bjorn Andersson March 11, 2022, 8:19 p.m. UTC | #1 
On Sun 27 Feb 07:53 CST 2022, Krzysztof Kozlowski wrote:

> The driver_override field from platform driver should not be initialized
> from static memory (string literal) because the core later kfree() it,
> for example when driver_override is set via sysfs.
> 
> Use dedicated helper to set driver_override properly.
> 
> Fixes: 950a7388f02b ("rpmsg: Turn name service into a stand alone driver")
> Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> ---
>  drivers/rpmsg/rpmsg_core.c     |  3 ++-
>  drivers/rpmsg/rpmsg_internal.h | 13 +++++++++++--
>  drivers/rpmsg/rpmsg_ns.c       | 14 ++++++++++++--
>  include/linux/rpmsg.h          |  6 ++++--
>  4 files changed, 29 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
> index d9e612f4f0f2..6e2bf2742973 100644
> --- a/drivers/rpmsg/rpmsg_core.c
> +++ b/drivers/rpmsg/rpmsg_core.c
> @@ -397,7 +397,8 @@ field##_store(struct device *dev, struct device_attribute *attr,	\
>  	      const char *buf, size_t sz)				\
>  {									\
>  	struct rpmsg_device *rpdev = to_rpmsg_device(dev);		\
> -	char *new, *old;						\
> +	const char *old;						\
> +	char *new;							\
>  									\
>  	new = kstrndup(buf, sz, GFP_KERNEL);				\
>  	if (!new)							\
> diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
> index b1245d3ed7c6..31345d6e9a7e 100644
> --- a/drivers/rpmsg/rpmsg_internal.h
> +++ b/drivers/rpmsg/rpmsg_internal.h
> @@ -92,10 +92,19 @@ int rpmsg_release_channel(struct rpmsg_device *rpdev,
>   */
>  static inline int rpmsg_chrdev_register_device(struct rpmsg_device *rpdev)
>  {
> +	int ret;
> +
>  	strcpy(rpdev->id.name, "rpmsg_chrdev");
> -	rpdev->driver_override = "rpmsg_chrdev";
> +	ret = driver_set_override(&rpdev->dev, &rpdev->driver_override,
> +				  "rpmsg_chrdev", strlen("rpmsg_chrdev"));
> +	if (ret)
> +		return ret;
> +
> +	ret = rpmsg_register_device(rpdev);
> +	if (ret)
> +		kfree(rpdev->driver_override);
>  
> -	return rpmsg_register_device(rpdev);
> +	return ret;
>  }
>  
>  #endif
> diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c
> index 762ff1ae279f..95a51543f5ad 100644
> --- a/drivers/rpmsg/rpmsg_ns.c
> +++ b/drivers/rpmsg/rpmsg_ns.c
> @@ -20,12 +20,22 @@
>   */
>  int rpmsg_ns_register_device(struct rpmsg_device *rpdev)
>  {
> +	int ret;
> +
>  	strcpy(rpdev->id.name, "rpmsg_ns");
> -	rpdev->driver_override = "rpmsg_ns";
> +	ret = driver_set_override(&rpdev->dev, &rpdev->driver_override,
> +				  "rpmsg_ns", strlen("rpmsg_ns"));
> +	if (ret)
> +		return ret;
> +
>  	rpdev->src = RPMSG_NS_ADDR;
>  	rpdev->dst = RPMSG_NS_ADDR;
>  
> -	return rpmsg_register_device(rpdev);
> +	ret = rpmsg_register_device(rpdev);
> +	if (ret)
> +		kfree(rpdev->driver_override);
> +
> +	return ret;
>  }
>  EXPORT_SYMBOL(rpmsg_ns_register_device);
>  
> diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
> index 02fa9116cd60..20c8cd1cde21 100644
> --- a/include/linux/rpmsg.h
> +++ b/include/linux/rpmsg.h
> @@ -41,7 +41,9 @@ struct rpmsg_channel_info {
>   * rpmsg_device - device that belong to the rpmsg bus
>   * @dev: the device struct
>   * @id: device id (used to match between rpmsg drivers and devices)
> - * @driver_override: driver name to force a match
> + * @driver_override: driver name to force a match; do not set directly,
> + *                   because core frees it; use driver_set_override() to
> + *                   set or clear it.
>   * @src: local address
>   * @dst: destination address
>   * @ept: the rpmsg endpoint of this channel
> @@ -51,7 +53,7 @@ struct rpmsg_channel_info {
>  struct rpmsg_device {
>  	struct device dev;
>  	struct rpmsg_device_id id;
> -	char *driver_override;
> +	const char *driver_override;
>  	u32 src;
>  	u32 dst;
>  	struct rpmsg_endpoint *ept;
> -- 
> 2.32.0
>
diff mbox series

Patch

diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index d9e612f4f0f2..6e2bf2742973 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -397,7 +397,8 @@  field##_store(struct device *dev, struct device_attribute *attr,	\
 	      const char *buf, size_t sz)				\
 {									\
 	struct rpmsg_device *rpdev = to_rpmsg_device(dev);		\
-	char *new, *old;						\
+	const char *old;						\
+	char *new;							\
 									\
 	new = kstrndup(buf, sz, GFP_KERNEL);				\
 	if (!new)							\
diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index b1245d3ed7c6..31345d6e9a7e 100644
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -92,10 +92,19 @@  int rpmsg_release_channel(struct rpmsg_device *rpdev,
  */
 static inline int rpmsg_chrdev_register_device(struct rpmsg_device *rpdev)
 {
+	int ret;
+
 	strcpy(rpdev->id.name, "rpmsg_chrdev");
-	rpdev->driver_override = "rpmsg_chrdev";
+	ret = driver_set_override(&rpdev->dev, &rpdev->driver_override,
+				  "rpmsg_chrdev", strlen("rpmsg_chrdev"));
+	if (ret)
+		return ret;
+
+	ret = rpmsg_register_device(rpdev);
+	if (ret)
+		kfree(rpdev->driver_override);
 
-	return rpmsg_register_device(rpdev);
+	return ret;
 }
 
 #endif
diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c
index 762ff1ae279f..95a51543f5ad 100644
--- a/drivers/rpmsg/rpmsg_ns.c
+++ b/drivers/rpmsg/rpmsg_ns.c
@@ -20,12 +20,22 @@ 
  */
 int rpmsg_ns_register_device(struct rpmsg_device *rpdev)
 {
+	int ret;
+
 	strcpy(rpdev->id.name, "rpmsg_ns");
-	rpdev->driver_override = "rpmsg_ns";
+	ret = driver_set_override(&rpdev->dev, &rpdev->driver_override,
+				  "rpmsg_ns", strlen("rpmsg_ns"));
+	if (ret)
+		return ret;
+
 	rpdev->src = RPMSG_NS_ADDR;
 	rpdev->dst = RPMSG_NS_ADDR;
 
-	return rpmsg_register_device(rpdev);
+	ret = rpmsg_register_device(rpdev);
+	if (ret)
+		kfree(rpdev->driver_override);
+
+	return ret;
 }
 EXPORT_SYMBOL(rpmsg_ns_register_device);
 
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index 02fa9116cd60..20c8cd1cde21 100644
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -41,7 +41,9 @@  struct rpmsg_channel_info {
  * rpmsg_device - device that belong to the rpmsg bus
  * @dev: the device struct
  * @id: device id (used to match between rpmsg drivers and devices)
- * @driver_override: driver name to force a match
+ * @driver_override: driver name to force a match; do not set directly,
+ *                   because core frees it; use driver_set_override() to
+ *                   set or clear it.
  * @src: local address
  * @dst: destination address
  * @ept: the rpmsg endpoint of this channel
@@ -51,7 +53,7 @@  struct rpmsg_channel_info {
 struct rpmsg_device {
 	struct device dev;
 	struct rpmsg_device_id id;
-	char *driver_override;
+	const char *driver_override;
 	u32 src;
 	u32 dst;
 	struct rpmsg_endpoint *ept;