From: Guy Harris <guy@alum.mit.edu>
Date: Wed, 5 Oct 2016 19:21:28 +0000 (-0700)
Subject: Before fetching the flags2 field, make sure we have it.
X-Git-Tag: tcpdump-4.9.0-bp~45
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/97d372ef7040c30c90faca545e697af1af9b1b39

Before fetching the flags2 field, make sure we have it.

Also, don't fetch it until we need it, so we can do a little more
dissection before reporting a truncated packet.
---

diff --git a/print-smb.c b/print-smb.c
index dd0f1045..af86cddb 100644
--- a/print-smb.c
+++ b/print-smb.c
@@ -806,9 +806,6 @@ print_smb(netdissect_options *ndo,
 
     ND_TCHECK(buf[9]);
     request = (buf[9] & 0x80) ? 0 : 1;
-    flags2 = EXTRACT_LE_16BITS(&buf[10]);
-    unicodestr = flags2 & 0x8000;
-    nterrcodes = flags2 & 0x4000;
     startbuf = buf;
 
     command = buf[4];
@@ -823,6 +820,11 @@ print_smb(netdissect_options *ndo,
     if (ndo->ndo_vflag < 2)
 	return;
 
+    ND_TCHECK_16BITS(&buf[10]);
+    flags2 = EXTRACT_LE_16BITS(&buf[10]);
+    unicodestr = flags2 & 0x8000;
+    nterrcodes = flags2 & 0x4000;
+
     /* print out the header */
     smb_fdata(ndo, buf, fmt_smbheader, buf + 33, unicodestr);