CVE-2017-5203/BOOTP: Add a bounds check

This fix GitHub issue #557

diff --git a/print-bootp.c b/print-bootp.c
index 26ac0de92c67c23296f4747cb0501875689db3c3..fe798a0483da50311042ed48a93856a7a7f2272d 100644 (file)
--- a/print-bootp.c
+++ b/print-bootp.c
@@ -293,6 +293,7 @@ bootp_print(netdissect_options *ndo,
        ND_PRINT((ndo, "BOOTP/DHCP, %s",
                  tok2str(bootp_op_values, "unknown (0x%02x)", bp->bp_op)));
 
+       ND_TCHECK(bp->bp_hlen);
        if (bp->bp_htype == 1 && bp->bp_hlen == 6 && bp->bp_op == BOOTPREQUEST) {
                ND_TCHECK2(bp->bp_chaddr[0], 6);
                ND_PRINT((ndo, " from %s", etheraddr_string(ndo, bp->bp_chaddr)));