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[Qemu-devel] [PATCH 3/3] usb-ccid: add check message size checks
From: |
Gerd Hoffmann |
Subject: |
[Qemu-devel] [PATCH 3/3] usb-ccid: add check message size checks |
Date: |
Thu, 16 Feb 2017 14:13:39 +0100 |
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 <address@hidden>
---
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