Check message size too when figuring whenever we should expect more data. Fix debug message to show useful data, p->iov.size is fixed anyway if we land there, print how much we got meanwhile instead.
Also check announced message size against actual message size. That is a more general fix for CVE-2017-5898 than commit "c7dfbf3 usb: ccid: check ccid apdu length". Signed-off-by: Gerd Hoffmann <kra...@redhat.com> --- hw/usb/dev-smartcard-reader.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/hw/usb/dev-smartcard-reader.c b/hw/usb/dev-smartcard-reader.c index 1acc1fb..7cd4ed0 100644 --- a/hw/usb/dev-smartcard-reader.c +++ b/hw/usb/dev-smartcard-reader.c @@ -1011,12 +1011,19 @@ static void ccid_handle_bulk_out(USBCCIDState *s, USBPacket *p) } ccid_header = (CCID_Header *)s->bulk_out_data; - if (p->iov.size == CCID_MAX_PACKET_SIZE) { + if ((s->bulk_out_pos - 10 < ccid_header->dwLength) && + (p->iov.size == CCID_MAX_PACKET_SIZE)) { DPRINTF(s, D_VERBOSE, - "usb-ccid: bulk_in: expecting more packets (%zd/%d)\n", - p->iov.size, ccid_header->dwLength); + "usb-ccid: bulk_in: expecting more packets (%d/%d)\n", + s->bulk_out_pos - 10, ccid_header->dwLength); return; } + if (s->bulk_out_pos - 10 != ccid_header->dwLength) { + DPRINTF(s, 1, + "usb-ccid: bulk_in: message size mismatch (got %d, expected %d)\n", + s->bulk_out_pos - 10, ccid_header->dwLength); + goto err; + } DPRINTF(s, D_MORE_INFO, "%s %x %s\n", __func__, ccid_header->bMessageType, -- 1.8.3.1