4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Daniel Rosenberg drosen@google.com
commit 717adfdaf14704fd3ec7fa2c04520c0723247eac upstream.
If our length is greater than the size of the buffer, we overflow the buffer
Cc: stable@vger.kernel.org Signed-off-by: Daniel Rosenberg drosen@google.com Reviewed-by: Benjamin Tissoires benjamin.tissoires@redhat.com Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/hid/hid-debug.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/hid/hid-debug.c +++ b/drivers/hid/hid-debug.c @@ -1152,6 +1152,8 @@ copy_rest: 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; @@ -1161,6 +1163,8 @@ copy_rest: 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; @@ -1168,7 +1172,9 @@ copy_rest: } list->head = 0; ret += len; - goto copy_rest; + count -= len; + if (count > 0) + goto copy_rest; }
}