Date: Wed, 20 Feb 2008 21:10:06 +0100 (CET) From: Stefan Richter Subject: 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 --- drivers/firewire/fw-cdev.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) Index: linux/drivers/firewire/fw-cdev.c =================================================================== --- linux.orig/drivers/firewire/fw-cdev.c +++ linux/drivers/firewire/fw-cdev.c @@ -646,6 +646,10 @@ static int ioctl_create_iso_context(stru 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 @@ static int ioctl_start_iso(struct client { 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 @@ static int ioctl_stop_iso(struct client { 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);