Commit 717adfda authored by Daniel Rosenberg's avatar Daniel Rosenberg Committed by Jiri Kosina

HID: debug: check length before copy_to_user()

If our length is greater than the size of the buffer, we
overflow the buffer

Cc: stable@vger.kernel.org
Signed-off-by: default avatarDaniel Rosenberg <drosen@google.com>
Reviewed-by: Benjamin Tissoires's avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 8f732850
......@@ -1154,6 +1154,8 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer,
goto out;
if (list->tail > list->head) {
len = list->tail - list->head;
if (len > count)
len = count;
if (copy_to_user(buffer + ret, &list->hid_debug_buf[list->head], len)) {
ret = -EFAULT;
......@@ -1163,6 +1165,8 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer,
list->head += len;
} else {
len = HID_DEBUG_BUFSIZE - list->head;
if (len > count)
len = count;
if (copy_to_user(buffer, &list->hid_debug_buf[list->head], len)) {
ret = -EFAULT;
......@@ -1170,7 +1174,9 @@ static ssize_t hid_debug_events_read(struct file *file, char __user *buffer,
}
list->head = 0;
ret += len;
goto copy_rest;
count -= len;
if (count > 0)
goto copy_rest;
}
}
......
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