X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/ba8a8cd5a385e86a857b90d2d087dd6f2cd5b083..396e94ff55a80d554b1fe46bf107db1e91008d6c:/print-nsh.c

diff --git a/print-nsh.c b/print-nsh.c
index a5b464e9..abd722d4 100644
--- a/print-nsh.c
+++ b/print-nsh.c
@@ -21,6 +21,10 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+/* \summary: Network Service Header (NSH) printer */
+
+/* specification: draft-ietf-sfc-nsh-01 */
+
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -39,11 +43,7 @@ static const struct tok nsh_flags [] = {
 
 #define NSH_BASE_HDR_LEN 4
 #define NSH_SERVICE_PATH_HDR_LEN 4
-#define NSH_HDR_WORD_SIZE 4
-
-/*
- * NSH, draft-ietf-sfc-nsh-01 Network Service Header
- */
+#define NSH_HDR_WORD_SIZE 4U
 
 void
 nsh_print(netdissect_options *ndo, const u_char *bp, u_int len)
@@ -97,12 +97,23 @@ nsh_print(netdissect_options *ndo, const u_char *bp, u_int len)
     ND_PRINT((ndo, "service-path-id 0x%06x, ", service_path_id));
     ND_PRINT((ndo, "service-index 0x%x", service_index));
 
-    /* print Context Headers */
+    /* Make sure we have all the headers */
     if (len < length * NSH_HDR_WORD_SIZE)
         goto trunc;
 
     ND_TCHECK2(*bp, length * NSH_HDR_WORD_SIZE);
 
+    /*
+     * length includes the lengths of the Base and Service Path headers.
+     * That means it must be at least 2.
+     */
+    if (length < 2)
+        goto trunc;
+
+    /*
+     * Print, or skip, the Context Headers.
+     * (length - 2) is the length of those headers.
+     */
     if (ndo->ndo_vflag > 2) {
         if (md_type == 0x01) {
             for (n = 0; n < length - 2; n++) {
@@ -159,7 +170,7 @@ nsh_print(netdissect_options *ndo, const u_char *bp, u_int len)
         ip6_print(ndo, bp, next_len);
         break;
     case 0x3:
-        ether_print(ndo, bp, next_len, next_len, NULL, NULL);
+        ether_print(ndo, bp, next_len, ndo->ndo_snapend - bp, NULL, NULL);
         break;
     default:
         ND_PRINT((ndo, "ERROR: unknown-next-protocol"));