X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/aad6ac30ce7904f688226dbc61021ca4f907274f..a63600a1fc28dbc7ae7ce9f996829c49a25fb33c:/print-ppp.c

diff --git a/print-ppp.c b/print-ppp.c
index fe036247..38505355 100644
--- a/print-ppp.c
+++ b/print-ppp.c
@@ -42,8 +42,6 @@
 #include <net/if_ppp.h>
 #endif
 
-#include <stdlib.h>
-
 #include "netdissect.h"
 #include "extract.h"
 #include "addrtoname.h"
@@ -1133,7 +1131,7 @@ print_ipcp_config_options(netdissect_options *ndo,
 			print_unknown_data(ndo, p + 2, "\n\t    ", len - 2);
 		break;
 	}
-	if (ndo->ndo_vflag > 1)
+	if (ndo->ndo_vflag > 1 && ND_TTEST_LEN(p + 2, len - 2))
 		print_unknown_data(ndo, p + 2, "\n\t    ", len - 2); /* exclude TLV header */
 	return len;
 
@@ -1365,7 +1363,7 @@ ppp_hdlc(netdissect_options *ndo,
 	u_char *b, *t, c;
 	const u_char *s;
 	u_int i, proto;
-	const void *se;
+	const void *sb, *se;
 
 	if (caplen == 0)
 		return;
@@ -1379,7 +1377,7 @@ ppp_hdlc(netdissect_options *ndo,
 
 	/*
 	 * Unescape all the data into a temporary, private, buffer.
-	 * Do this so that we dont overwrite the original packet
+	 * Do this so that we don't overwrite the original packet
 	 * contents.
 	 */
 	for (s = p, t = b, i = caplen; i != 0; i--) {
@@ -1397,8 +1395,11 @@ ppp_hdlc(netdissect_options *ndo,
 
 	/*
 	 * Change the end pointer, so bounds checks work.
+	 * Change the pointer to packet data to help debugging.
 	 */
+	sb = ndo->ndo_packetp;
 	se = ndo->ndo_snapend;
+	ndo->ndo_packetp = b;
 	ndo->ndo_snapend = t;
 	length = ND_BYTES_AVAILABLE_AFTER(b);
 
@@ -1427,18 +1428,26 @@ ppp_hdlc(netdissect_options *ndo,
             if (length < 4)
                 goto trunc;
             proto = GET_BE_U_2(b + 2); /* load the PPP proto-id */
-            handle_ppp(ndo, proto, b + 4, length - 4);
+            if ((proto & 0xff00) == 0x7e00)
+                ND_PRINT("(protocol 0x%04x invalid)", proto);
+            else
+                handle_ppp(ndo, proto, b + 4, length - 4);
             break;
         default: /* last guess - proto must be a PPP proto-id */
-            handle_ppp(ndo, proto, b + 2, length - 2);
+            if ((proto & 0xff00) == 0x7e00)
+                ND_PRINT("(protocol 0x%04x invalid)", proto);
+            else
+                handle_ppp(ndo, proto, b + 2, length - 2);
             break;
         }
 
 cleanup:
+	ndo->ndo_packetp = sb;
 	ndo->ndo_snapend = se;
         return;
 
 trunc:
+	ndo->ndo_packetp = sb;
 	ndo->ndo_snapend = se;
 	nd_print_trunc(ndo);
 }
@@ -1561,11 +1570,18 @@ ppp_print(netdissect_options *ndo,
 		hdr_len += 2;
 	}
 
-	if (ndo->ndo_eflag)
-		ND_PRINT("%s (0x%04x), length %u: ",
-		          tok2str(ppptype2str, "unknown", proto),
+	if (ndo->ndo_eflag) {
+		const char *typestr;
+		typestr = tok2str(ppptype2str, "unknown", proto);
+		ND_PRINT("%s (0x%04x), length %u",
+		          typestr,
 		          proto,
 		          olen);
+		if (*typestr == 'u')	/* "unknown" */
+			return hdr_len;
+
+		ND_PRINT(": ");
+	}
 
 	handle_ppp(ndo, proto, p, length);
 	return (hdr_len);