X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/c1c3c77463d592cc576eaa491e604752044ca55a..1fb50928ce27360c1c987312774f686b23c69b51:/print-gre.c

diff --git a/print-gre.c b/print-gre.c
index ee26d0d3..505752a1 100644
--- a/print-gre.c
+++ b/print-gre.c
@@ -31,8 +31,10 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+/* \summary: Generic Routing Encapsulation (GRE) printer */
+
 /*
- * tcpdump filter for GRE - Generic Routing Encapsulation
+ * netdissect printer for GRE - Generic Routing Encapsulation
  * RFC1701 (GRE), RFC1702 (GRE IPv4), and RFC2637 (Enhanced GRE)
  */
 
@@ -40,11 +42,12 @@
 #include "config.h"
 #endif
 
-#include <tcpdump-stdinc.h>
+#include <netdissect-stdinc.h>
 
 #include <string.h>
 
 #include "netdissect.h"
+#include "addrtostr.h"
 #include "extract.h"
 #include "ethertype.h"
 
@@ -77,19 +80,18 @@ static const struct tok gre_flag_values[] = {
 
 static void gre_print_0(netdissect_options *, const u_char *, u_int);
 static void gre_print_1(netdissect_options *, const u_char *, u_int);
-static void gre_sre_print(netdissect_options *, uint16_t, uint8_t, uint8_t, const u_char *, u_int);
-static void gre_sre_ip_print(netdissect_options *, uint8_t, uint8_t, const u_char *, u_int);
-static void gre_sre_asn_print(netdissect_options *, uint8_t, uint8_t, const u_char *, u_int);
+static int gre_sre_print(netdissect_options *, uint16_t, uint8_t, uint8_t, const u_char *, u_int);
+static int gre_sre_ip_print(netdissect_options *, uint8_t, uint8_t, const u_char *, u_int);
+static int gre_sre_asn_print(netdissect_options *, uint8_t, uint8_t, const u_char *, u_int);
 
 void
 gre_print(netdissect_options *ndo, const u_char *bp, u_int length)
 {
 	u_int len = length, vers;
 
-	if (len < 2) {
-		ND_PRINT((ndo, "%s", tstr));
-		return;
-	}
+	ND_TCHECK2(*bp, 2);
+	if (len < 2)
+		goto trunc;
 	vers = EXTRACT_16BITS(bp) & GRE_VERS_MASK;
         ND_PRINT((ndo, "GREv%u",vers));
 
@@ -104,6 +106,11 @@ gre_print(netdissect_options *ndo, const u_char *bp, u_int length)
             ND_PRINT((ndo, " ERROR: unknown-version"));
             break;
         }
+        return;
+
+trunc:
+	ND_PRINT((ndo, "%s", tstr));
+	return;
 }
 
 static void
@@ -120,6 +127,7 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
 	len -= 2;
 	bp += 2;
 
+	ND_TCHECK2(*bp, 2);
 	if (len < 2)
 		goto trunc;
 	prot = EXTRACT_16BITS(bp);
@@ -127,6 +135,7 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
 	bp += 2;
 
 	if ((flags & GRE_CP) | (flags & GRE_RP)) {
+		ND_TCHECK2(*bp, 2);
 		if (len < 2)
 			goto trunc;
 		if (ndo->ndo_vflag)
@@ -134,6 +143,7 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
 		bp += 2;
 		len -= 2;
 
+		ND_TCHECK2(*bp, 2);
 		if (len < 2)
 			goto trunc;
 		ND_PRINT((ndo, ", off 0x%x", EXTRACT_16BITS(bp)));
@@ -142,6 +152,7 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
 	}
 
 	if (flags & GRE_KP) {
+		ND_TCHECK2(*bp, 4);
 		if (len < 4)
 			goto trunc;
 		ND_PRINT((ndo, ", key=0x%x", EXTRACT_32BITS(bp)));
@@ -150,6 +161,7 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
 	}
 
 	if (flags & GRE_SP) {
+		ND_TCHECK2(*bp, 4);
 		if (len < 4)
 			goto trunc;
 		ND_PRINT((ndo, ", seq %u", EXTRACT_32BITS(bp)));
@@ -163,6 +175,7 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
 			uint8_t sreoff;
 			uint8_t srelen;
 
+			ND_TCHECK2(*bp, 4);
 			if (len < 4)
 				goto trunc;
 			af = EXTRACT_16BITS(bp);
@@ -174,7 +187,8 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
 			if (af == 0 && srelen == 0)
 				break;
 
-			gre_sre_print(ndo, af, sreoff, srelen, bp, len);
+			if (!gre_sre_print(ndo, af, sreoff, srelen, bp, len))
+				goto trunc;
 
 			if (len < srelen)
 				goto trunc;
@@ -212,10 +226,10 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
 		atalk_print(ndo, bp, len);
 		break;
 	case ETHERTYPE_GRE_ISO:
-		isoclns_print(ndo, bp, len, len);
+		isoclns_print(ndo, bp, len, ndo->ndo_snapend - bp);
 		break;
 	case ETHERTYPE_TEB:
-		ether_print(ndo, bp, len, len, NULL, NULL);
+		ether_print(ndo, bp, len, ndo->ndo_snapend - bp, NULL, NULL);
 		break;
 	default:
 		ND_PRINT((ndo, "gre-proto-0x%x", prot));
@@ -240,6 +254,7 @@ gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
             ND_PRINT((ndo, ", Flags [%s]",
                    bittok2str(gre_flag_values,"none",flags)));
 
+	ND_TCHECK2(*bp, 2);
 	if (len < 2)
 		goto trunc;
 	prot = EXTRACT_16BITS(bp);
@@ -250,6 +265,7 @@ gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
 	if (flags & GRE_KP) {
 		uint32_t k;
 
+		ND_TCHECK2(*bp, 4);
 		if (len < 4)
 			goto trunc;
 		k = EXTRACT_32BITS(bp);
@@ -259,6 +275,7 @@ gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
 	}
 
 	if (flags & GRE_SP) {
+		ND_TCHECK2(*bp, 4);
 		if (len < 4)
 			goto trunc;
 		ND_PRINT((ndo, ", seq %u", EXTRACT_32BITS(bp)));
@@ -267,6 +284,7 @@ gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
 	}
 
 	if (flags & GRE_AP) {
+		ND_TCHECK2(*bp, 4);
 		if (len < 4)
 			goto trunc;
 		ND_PRINT((ndo, ", ack %u", EXTRACT_32BITS(bp)));
@@ -306,62 +324,68 @@ trunc:
 	ND_PRINT((ndo, "%s", tstr));
 }
 
-static void
+static int
 gre_sre_print(netdissect_options *ndo, uint16_t af, uint8_t sreoff,
     uint8_t srelen, const u_char *bp, u_int len)
 {
+	int ret;
+
 	switch (af) {
 	case GRESRE_IP:
 		ND_PRINT((ndo, ", (rtaf=ip"));
-		gre_sre_ip_print(ndo, sreoff, srelen, bp, len);
+		ret = gre_sre_ip_print(ndo, sreoff, srelen, bp, len);
 		ND_PRINT((ndo, ")"));
 		break;
 	case GRESRE_ASN:
 		ND_PRINT((ndo, ", (rtaf=asn"));
-		gre_sre_asn_print(ndo, sreoff, srelen, bp, len);
+		ret = gre_sre_asn_print(ndo, sreoff, srelen, bp, len);
 		ND_PRINT((ndo, ")"));
 		break;
 	default:
 		ND_PRINT((ndo, ", (rtaf=0x%x)", af));
+		ret = 1;
 	}
+	return (ret);
 }
 
-static void
+static int
 gre_sre_ip_print(netdissect_options *ndo, uint8_t sreoff, uint8_t srelen,
                  const u_char *bp, u_int len)
 {
-	struct in_addr a;
 	const u_char *up = bp;
+	char buf[INET_ADDRSTRLEN];
 
 	if (sreoff & 3) {
 		ND_PRINT((ndo, ", badoffset=%u", sreoff));
-		return;
+		return (1);
 	}
 	if (srelen & 3) {
 		ND_PRINT((ndo, ", badlength=%u", srelen));
-		return;
+		return (1);
 	}
 	if (sreoff >= srelen) {
 		ND_PRINT((ndo, ", badoff/len=%u/%u", sreoff, srelen));
-		return;
+		return (1);
 	}
 
-	for (;;) {
-		if (len < 4 || srelen == 0)
-			return;
+	while (srelen != 0) {
+		if (!ND_TTEST2(*bp, 4))
+			return (0);
+		if (len < 4)
+			return (0);
 
-		memcpy(&a, bp, sizeof(a));
+		addrtostr(bp, buf, sizeof(buf));
 		ND_PRINT((ndo, " %s%s",
-		    ((bp - up) == sreoff) ? "*" : "",
-		    inet_ntoa(a)));
+		    ((bp - up) == sreoff) ? "*" : "", buf));
 
 		bp += 4;
 		len -= 4;
 		srelen -= 4;
 	}
+	return (1);
 }
 
-static void
+static int
 gre_sre_asn_print(netdissect_options *ndo, uint8_t sreoff, uint8_t srelen,
                   const u_char *bp, u_int len)
 {
@@ -369,20 +393,22 @@ gre_sre_asn_print(netdissect_options *ndo, uint8_t sreoff, uint8_t srelen,
 
 	if (sreoff & 1) {
 		ND_PRINT((ndo, ", badoffset=%u", sreoff));
-		return;
+		return (1);
 	}
 	if (srelen & 1) {
 		ND_PRINT((ndo, ", badlength=%u", srelen));
-		return;
+		return (1);
 	}
 	if (sreoff >= srelen) {
 		ND_PRINT((ndo, ", badoff/len=%u/%u", sreoff, srelen));
-		return;
+		return (1);
 	}
 
-	for (;;) {
-		if (len < 2 || srelen == 0)
-			return;
+	while (srelen != 0) {
+		if (!ND_TTEST2(*bp, 2))
+			return (0);
+		if (len < 2)
+			return (0);
 
 		ND_PRINT((ndo, " %s%x",
 		    ((bp - up) == sreoff) ? "*" : "",
@@ -392,4 +418,5 @@ gre_sre_asn_print(netdissect_options *ndo, uint8_t sreoff, uint8_t srelen,
 		len -= 2;
 		srelen -= 2;
 	}
+	return (1);
 }