firewire: fix NULL pointer deref. and resource leak
By supplying ioctl()s in the wrong order, a userspace client was able to
trigger NULL pointer dereferences. Furthermore, by calling
ioctl_create_iso_context more than once, new contexts could be created
without ever freeing the previously created contexts.
Thanks to Anders Blomdell for the report.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/fw-cdev.c b/drivers/firewire/fw-cdev.c
index 44ccee2..46bc197 100644
--- a/drivers/firewire/fw-cdev.c
+++ b/drivers/firewire/fw-cdev.c
@@ -646,6 +646,10 @@
struct fw_cdev_create_iso_context *request = buffer;
struct fw_iso_context *context;
+ /* We only support one context at this time. */
+ if (client->iso_context != NULL)
+ return -EBUSY;
+
if (request->channel > 63)
return -EINVAL;
@@ -792,8 +796,9 @@
{
struct fw_cdev_start_iso *request = buffer;
- if (request->handle != 0)
+ if (client->iso_context == NULL || request->handle != 0)
return -EINVAL;
+
if (client->iso_context->type == FW_ISO_CONTEXT_RECEIVE) {
if (request->tags == 0 || request->tags > 15)
return -EINVAL;
@@ -810,7 +815,7 @@
{
struct fw_cdev_stop_iso *request = buffer;
- if (request->handle != 0)
+ if (client->iso_context == NULL || request->handle != 0)
return -EINVAL;
return fw_iso_context_stop(client->iso_context);