usb: gadget: rndis: check size of RNDIS_MSG_SET command

Check the size of the RNDIS_MSG_SET command given to us before
attempting to respond to an invalid message size.

Reported-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Cc: stable@kernel.org
Tested-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/function/rndis.c b/drivers/usb/gadget/function/rndis.c
index 431d5a7..b7ccf18 100644 (file)
--- a/drivers/usb/gadget/function/rndis.c
+++ b/drivers/usb/gadget/function/rndis.c
@@ -637,14 +637,17 @@ static int rndis_set_response(struct rndis_params *params,
        rndis_set_cmplt_type *resp;
        rndis_resp_t *r;
 
+       BufLength = le32_to_cpu(buf->InformationBufferLength);
+       BufOffset = le32_to_cpu(buf->InformationBufferOffset);
+       if ((BufLength > RNDIS_MAX_TOTAL_SIZE) ||
+           (BufOffset + 8 >= RNDIS_MAX_TOTAL_SIZE))
+                   return -EINVAL;
+
        r = rndis_add_response(params, sizeof(rndis_set_cmplt_type));
        if (!r)
                return -ENOMEM;
        resp = (rndis_set_cmplt_type *)r->buf;
 
-       BufLength = le32_to_cpu(buf->InformationBufferLength);
-       BufOffset = le32_to_cpu(buf->InformationBufferOffset);
-
 #ifdef VERBOSE_DEBUG
        pr_debug("%s: Length: %d\n", __func__, BufLength);
        pr_debug("%s: Offset: %d\n", __func__, BufOffset);