[PATCH 1/3] fanotify: Ensure consistent variable type for response

[PATCH 1/3] fanotify: Ensure consistent variable type for response

[Steve Grubb]

The user space API for the response variable is __u32. This patch makes
sure that the whole path through the kernel uses __u32 so that there is
no sign extension or truncation of the user space response.

Signed-off-by: Steve Grubb <sgrubb@redhat.com>
---
 fs/notify/fanotify/fanotify.h      | 2 +-
 fs/notify/fanotify/fanotify_user.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 8ce7ccfc4b0d..c397993830ac 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -165,7 +165,7 @@ FANOTIFY_PE(struct fanotify_event *event)
 struct fanotify_perm_event {
 	struct fanotify_event fae;
 	struct path path;
-	unsigned short response;	/* userspace answer to the event */
+	__u32 response;			/* userspace answer to the event */
 	unsigned short state;		/* state of the event */
 	int fd;		/* fd we passed to userspace for this event */
 };
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 63b5dffdca9e..c8da9ea1e76e 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -157,7 +157,7 @@ static int create_fd(struct fsnotify_group *group, struct path *path,
  */
 static void finish_permission_event(struct fsnotify_group *group,
 				    struct fanotify_perm_event *event,
-				    unsigned int response)
+				    __u32 response)
 				    __releases(&group->notification_lock)
 {
 	bool destroy = false;
@@ -178,7 +178,7 @@ static int process_access_response(struct fsnotify_group *group,
 {
 	struct fanotify_perm_event *event;
 	int fd = response_struct->fd;
-	int response = response_struct->response;
+	__u32 response = response_struct->response;
 
 	pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group,
 		 fd, response);
-- 
2.26.2




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Re: [PATCH 1/3] fanotify: Ensure consistent variable type for response

[Jan Kara]

On Wed 30-09-20 12:12:24, Steve Grubb wrote:
> The user space API for the response variable is __u32. This patch makes
> sure that the whole path through the kernel uses __u32 so that there is
> no sign extension or truncation of the user space response.
> 
> Signed-off-by: Steve Grubb <sgrubb@redhat.com>
> ---
>  fs/notify/fanotify/fanotify.h      | 2 +-
>  fs/notify/fanotify/fanotify_user.c | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)

Looks good, just one nit below:

> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 63b5dffdca9e..c8da9ea1e76e 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -157,7 +157,7 @@ static int create_fd(struct fsnotify_group *group, struct path *path,
>   */
>  static void finish_permission_event(struct fsnotify_group *group,
>  				    struct fanotify_perm_event *event,
> -				    unsigned int response)
> +				    __u32 response)
>  				    __releases(&group->notification_lock)
>  {
>  	bool destroy = false;
> @@ -178,7 +178,7 @@ static int process_access_response(struct fsnotify_group *group,
>  {
>  	struct fanotify_perm_event *event;
>  	int fd = response_struct->fd;
> -	int response = response_struct->response;
> +	__u32 response = response_struct->response;
>  
>  	pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group,
>  		 fd, response);

You want to print the response with "%u" here I guess...

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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