HID: hidraw: fix list->buffer memleak

commit 4c7b417ecb756e85dfc955b0e7a04fd45585533e upstream.

If we don't read fast enough hidraw device, hidraw_report_event
will cycle and we will leak list->buffer.
Also list->buffer are not free on release.
After this patch, kmemleak report nothing.

Signed-off-by: Matthieu CASTET <matthieu.castet@parrot.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 36fa77b..3b6f7bf 100644 (file)
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -96,6 +96,7 @@ static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count,
                }
 
                kfree(list->buffer[list->tail].value);
+               list->buffer[list->tail].value = NULL;
                list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
        }
 out:
@@ -300,6 +301,7 @@ static int hidraw_release(struct inode * inode, struct file * file)
        struct hidraw *dev;
        struct hidraw_list *list = file->private_data;
        int ret;
+       int i;
 
        mutex_lock(&minors_lock);
        if (!hidraw_table[minor]) {
@@ -317,6 +319,9 @@ static int hidraw_release(struct inode * inode, struct file * file)
                        kfree(list->hidraw);
                }
        }
+
+       for (i = 0; i < HIDRAW_BUFFER_SIZE; ++i)
+               kfree(list->buffer[i].value);
        kfree(list);
        ret = 0;
 unlock:
@@ -446,12 +451,17 @@ int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
        int ret = 0;
 
        list_for_each_entry(list, &dev->list, node) {
+               int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
+
+               if (new_head == list->tail)
+                       continue;
+
                if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
                        ret = -ENOMEM;
                        break;
                }
                list->buffer[list->head].len = len;
-               list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
+               list->head = new_head;
                kill_fasync(&list->fasync, SIGIO, POLL_IN);
        }