From stern@rowland.harvard.edu Mon Feb 5 06:56:22 2007 From: Alan Stern Date: Mon, 5 Feb 2007 09:56:15 -0500 (EST) Subject: USB: fix concurrent buffer access in the hub driver To: Greg KH Message-ID: This patch (as849) fixes a bug in the USB hub driver. A single pre-allocated buffer is used for all port status reads, but nothing guarantees exclusive use of the buffer. A mutex is added to provide this guarantee. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 6 ++++++ 1 file changed, 6 insertions(+) --- gregkh-2.6.orig/drivers/usb/core/hub.c +++ gregkh-2.6/drivers/usb/core/hub.c @@ -44,6 +44,7 @@ struct usb_hub { struct usb_hub_status hub; struct usb_port_status port; } *status; /* buffer for status reports */ + struct mutex status_mutex; /* for the status buffer */ int error; /* last reported error */ int nerrors; /* track consecutive errors */ @@ -535,6 +536,7 @@ static int hub_hub_status(struct usb_hub { int ret; + mutex_lock(&hub->status_mutex); ret = get_hub_status(hub->hdev, &hub->status->hub); if (ret < 0) dev_err (hub->intfdev, @@ -544,6 +546,7 @@ static int hub_hub_status(struct usb_hub *change = le16_to_cpu(hub->status->hub.wHubChange); ret = 0; } + mutex_unlock(&hub->status_mutex); return ret; } @@ -617,6 +620,7 @@ static int hub_configure(struct usb_hub ret = -ENOMEM; goto fail; } + mutex_init(&hub->status_mutex); hub->descriptor = kmalloc(sizeof(*hub->descriptor), GFP_KERNEL); if (!hub->descriptor) { @@ -1396,6 +1400,7 @@ static int hub_port_status(struct usb_hu { int ret; + mutex_lock(&hub->status_mutex); ret = get_port_status(hub->hdev, port1, &hub->status->port); if (ret < 4) { dev_err (hub->intfdev, @@ -1407,6 +1412,7 @@ static int hub_port_status(struct usb_hu *change = le16_to_cpu(hub->status->port.wPortChange); ret = 0; } + mutex_unlock(&hub->status_mutex); return ret; }