| From | Ben Hutchings <> | Date | Mon, 21 Oct 2013 09:46:28 +0100 | Subject | [PATCH 3.2 022/149] usb: config->desc.bLength may not exceed amount of data returned by the device |
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3.2.52-rc1 review patch. If anyone has any objections, please let me know.
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From: Hans de Goede <hdegoede@redhat.com>
commit b4f17a488ae2e09bfcf95c0e0b4219c246f1116a upstream.
While reading the config parsing code I noticed this check is missing, without this check config->desc.wTotalLength can end up with a value larger then the dev->rawdescriptors length for the config, and when userspace then tries to get the rawdescriptors bad things may happen.
Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/usb/core/config.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -424,7 +424,8 @@ static int usb_parse_configuration(struc memcpy(&config->desc, buffer, USB_DT_CONFIG_SIZE); if (config->desc.bDescriptorType != USB_DT_CONFIG || - config->desc.bLength < USB_DT_CONFIG_SIZE) { + config->desc.bLength < USB_DT_CONFIG_SIZE || + config->desc.bLength > size) { dev_err(ddev, "invalid descriptor for config index %d: " "type = 0x%X, length = %d\n", cfgidx, config->desc.bDescriptorType, config->desc.bLength);
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