Skip to contentSkip to conversation

fanotify: Ensure consistent variable type for response

PATCH In review Steve Grubb 2 participants 2 messages Sep 30, 2020 – Oct 1, 2020

Subsystems (3)
VFS Fsnotify: filesystem notification infrastructure Fanotify
lore
Share & tools
lore

Steve Grubb

author
#0 lore raw

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

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 <[email protected]>
---
 fs/notify/fanotify/fanotify.h      | 2 +-
 fs/notify/fanotify/fanotify_user.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)
fs/notify/fanotify/fanotify.h +1 -1
index 8ce7ccfc4b0d..c397993830ac 100644
@@ -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 */
 };
fs/notify/fanotify/fanotify_user.c +2 -2
index 63b5dffdca9e..c8da9ea1e76e 100644
@@ -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);
Signature · 1 line
2.26.2
maintainer
#1 lore raw
Quoted 9 lines · 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 <[email protected]>
---
 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:

Quoted 14 lines
fs/notify/fanotify/fanotify_user.c +1 -1
index 63b5dffdca9e..c8da9ea1e76e 100644
@@ -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;

fs/notify/fanotify/fanotify_user.c static int process_access_response(struct fsnotify_group *group, · line 184

Quoted 8 lines
fs/notify/fanotify/fanotify_user.c +1 -1
@@ -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

Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR