Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Mon, 06 Nov 2017 23:03:07 +0000 | Subject | [PATCH 3.2 088/147] USB: fix out-of-bounds in usb_set_configuration |
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3.2.95-rc1 review patch. If anyone has any objections, please let me know.
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bd7a3fe770ebd8391d1c7d072ff88e9e76d063eb upstream.
Andrey Konovalov reported a possible out-of-bounds problem for a USB interface association descriptor. He writes: It seems there's no proper size check of a USB_DT_INTERFACE_ASSOCIATION descriptor. It's only checked that the size is >= 2 in usb_parse_configuration(), so find_iad() might do out-of-bounds access to intf_assoc->bInterfaceCount.
And he's right, we don't check for crazy descriptors of this type very well, so resolve this problem. Yet another issue found by syzkaller...
Reported-by: Andrey Konovalov <andreyknvl@google.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/usb/core/config.c | 14 +++++++++++--- include/linux/usb/ch9.h | 1 + 2 files changed, 12 insertions(+), 3 deletions(-)
--- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -609,15 +609,23 @@ static int usb_parse_configuration(struc } else if (header->bDescriptorType == USB_DT_INTERFACE_ASSOCIATION) { + struct usb_interface_assoc_descriptor *d; + + d = (struct usb_interface_assoc_descriptor *)header; + if (d->bLength < USB_DT_INTERFACE_ASSOCIATION_SIZE) { + dev_warn(ddev, + "config %d has an invalid interface association descriptor of length %d, skipping\n", + cfgno, d->bLength); + continue; + } + if (iad_num == USB_MAXIADS) { dev_warn(ddev, "found more Interface " "Association Descriptors " "than allocated for in " "configuration %d\n", cfgno); } else { - config->intf_assoc[iad_num] = - (struct usb_interface_assoc_descriptor - *)header; + config->intf_assoc[iad_num] = d; iad_num++; } --- a/include/linux/usb/ch9.h +++ b/include/linux/usb/ch9.h @@ -686,6 +686,7 @@ struct usb_interface_assoc_descriptor { __u8 iFunction; } __attribute__ ((packed)); +#define USB_DT_INTERFACE_ASSOCIATION_SIZE 8 /*-------------------------------------------------------------------------*/
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