diff options
| author | Jiri Kosina <jkosina@suse.cz> | 2013-04-16 15:40:09 -0700 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2013-04-30 10:09:31 +0200 |
| commit | 2353f2bea307390e015493118e425152b8a5a431 (patch) | |
| tree | beb7fd2471690bbd8b0d0982c3b1f40f6784adba | |
| parent | a5f04b9df1113e0c16271afe5e43028f0d763f13 (diff) | |
HID: protect hid_debug_list
Accesses to hid_device->hid_debug_list are not serialized properly, which
could result in SMP concurrency issues when HID debugfs events are accessesed
by multiple userspace processess.
Serialize all the list operations by a mutex.
Spotted by Al Viro.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| -rw-r--r-- | drivers/hid/hid-core.c | 1 | ||||
| -rw-r--r-- | drivers/hid/hid-debug.c | 6 | ||||
| -rw-r--r-- | include/linux/hid.h | 1 |
3 files changed, 8 insertions, 0 deletions
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index f86dd9708ca..e7765ede339 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -2319,6 +2319,7 @@ struct hid_device *hid_allocate_device(void) init_waitqueue_head(&hdev->debug_wait); INIT_LIST_HEAD(&hdev->debug_list); + mutex_init(&hdev->debug_list_lock); sema_init(&hdev->driver_lock, 1); return hdev; diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c index 094cbcfe1e1..7e56cb3855e 100644 --- a/drivers/hid/hid-debug.c +++ b/drivers/hid/hid-debug.c @@ -580,12 +580,14 @@ void hid_debug_event(struct hid_device *hdev, char *buf) int i; struct hid_debug_list *list; + mutex_lock(&hdev->debug_list_lock); list_for_each_entry(list, &hdev->debug_list, node) { for (i = 0; i < strlen(buf); i++) list->hid_debug_buf[(list->tail + i) % HID_DEBUG_BUFSIZE] = buf[i]; list->tail = (list->tail + i) % HID_DEBUG_BUFSIZE; } + mutex_unlock(&hdev->debug_list_lock); wake_up_interruptible(&hdev->debug_wait); } @@ -990,7 +992,9 @@ static int hid_debug_events_open(struct inode *inode, struct file *file) file->private_data = list; mutex_init(&list->read_mutex); + mutex_lock(&list->hdev->debug_list_lock); list_add_tail(&list->node, &list->hdev->debug_list); + mutex_unlock(&list->hdev->debug_list_lock); out: return err; @@ -1085,7 +1089,9 @@ static int hid_debug_events_release(struct inode *inode, struct file *file) { struct hid_debug_list *list = file->private_data; + mutex_lock(&list->hdev->debug_list_lock); list_del(&list->node); + mutex_unlock(&list->hdev->debug_list_lock); kfree(list->hid_debug_buf); kfree(list); diff --git a/include/linux/hid.h b/include/linux/hid.h index e14b465b114..06579c72d19 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -512,6 +512,7 @@ struct hid_device { /* device report descriptor */ struct dentry *debug_rdesc; struct dentry *debug_events; struct list_head debug_list; + struct mutex debug_list_lock; wait_queue_head_t debug_wait; }; |