From 9180135bc80ab11199d482b6111e23f74d65af4a Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Mon, 29 Jun 2009 11:04:54 -0400 Subject: [PATCH] USB: handle zero-length usbfs submissions correctly This patch (as1262) fixes a bug in usbfs: It refuses to accept zero-length transfers, and it insists that the buffer pointer be valid even if there is no data being transferred. The patch also consolidates a bunch of repetitive access_ok() checks into a single check, which incidentally fixes the lack of such a check for Isochronous URBs. Signed-off-by: Alan Stern Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/devio.c | 41 ++++++++++++++++++++-------------------- 1 file changed, 20 insertions(+), 21 deletions(-) diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 46ca2af5ef1c..38b8bce782d6 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -995,7 +995,7 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb, USBDEVFS_URB_ZERO_PACKET | USBDEVFS_URB_NO_INTERRUPT)) return -EINVAL; - if (!uurb->buffer) + if (uurb->buffer_length > 0 && !uurb->buffer) return -EINVAL; if (!(uurb->type == USBDEVFS_URB_TYPE_CONTROL && (uurb->endpoint & ~USB_ENDPOINT_DIR_MASK) == 0)) { @@ -1051,11 +1051,6 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb, is_in = 0; uurb->endpoint &= ~USB_DIR_IN; } - if (!access_ok(is_in ? VERIFY_WRITE : VERIFY_READ, - uurb->buffer, uurb->buffer_length)) { - kfree(dr); - return -EFAULT; - } snoop(&ps->dev->dev, "control urb: bRequest=%02x " "bRrequestType=%02x wValue=%04x " "wIndex=%04x wLength=%04x\n", @@ -1075,9 +1070,6 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb, uurb->number_of_packets = 0; if (uurb->buffer_length > MAX_USBFS_BUFFER_SIZE) return -EINVAL; - if (!access_ok(is_in ? VERIFY_WRITE : VERIFY_READ, - uurb->buffer, uurb->buffer_length)) - return -EFAULT; snoop(&ps->dev->dev, "bulk urb\n"); break; @@ -1119,28 +1111,35 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb, return -EINVAL; if (uurb->buffer_length > MAX_USBFS_BUFFER_SIZE) return -EINVAL; - if (!access_ok(is_in ? VERIFY_WRITE : VERIFY_READ, - uurb->buffer, uurb->buffer_length)) - return -EFAULT; snoop(&ps->dev->dev, "interrupt urb\n"); break; default: return -EINVAL; } - as = alloc_async(uurb->number_of_packets); - if (!as) { + if (uurb->buffer_length > 0 && + !access_ok(is_in ? VERIFY_WRITE : VERIFY_READ, + uurb->buffer, uurb->buffer_length)) { kfree(isopkt); kfree(dr); - return -ENOMEM; + return -EFAULT; } - as->urb->transfer_buffer = kmalloc(uurb->buffer_length, GFP_KERNEL); - if (!as->urb->transfer_buffer) { + as = alloc_async(uurb->number_of_packets); + if (!as) { kfree(isopkt); kfree(dr); - free_async(as); return -ENOMEM; } + if (uurb->buffer_length > 0) { + as->urb->transfer_buffer = kmalloc(uurb->buffer_length, + GFP_KERNEL); + if (!as->urb->transfer_buffer) { + kfree(isopkt); + kfree(dr); + free_async(as); + return -ENOMEM; + } + } as->urb->dev = ps->dev; as->urb->pipe = (uurb->type << 30) | __create_pipe(ps->dev, uurb->endpoint & 0xf) | @@ -1182,7 +1181,7 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb, kfree(isopkt); as->ps = ps; as->userurb = arg; - if (uurb->endpoint & USB_DIR_IN) + if (is_in && uurb->buffer_length > 0) as->userbuffer = uurb->buffer; else as->userbuffer = NULL; @@ -1192,9 +1191,9 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb, as->uid = cred->uid; as->euid = cred->euid; security_task_getsecid(current, &as->secid); - if (!is_in) { + if (!is_in && uurb->buffer_length > 0) { if (copy_from_user(as->urb->transfer_buffer, uurb->buffer, - as->urb->transfer_buffer_length)) { + uurb->buffer_length)) { free_async(as); return -EFAULT; } -- 2.20.1