firewire: cdev: disallow receive packets without header

In receive contexts, reject packets with header_length==0.  This would
be an instruction to queue zero packets which would not make sense.

This prevents a division by zero in the OHCI driver.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 8be720b278b7..bbb8160e2c99 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -968,7 +968,8 @@ static int ioctl_queue_iso(struct client *client, union ioctl_arg *arg)
                         if (ctx->header_size == 0) {
                                 if (u.packet.header_length > 0)
                                         return -EINVAL;
-                        } else if (u.packet.header_length % ctx->header_size != 0) {
+                        } else if (u.packet.header_length == 0 ||
+                                   u.packet.header_length % ctx->header_size != 0) {
                                 return -EINVAL;
                         }
                         header_length = 0;