X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/11f73ad248fa22461ca040baa8dc94b864509efa..5287bffd3f4fa1fda9d7734b45f8cf02391d3855:/print-domain.c

diff --git a/print-domain.c b/print-domain.c
index c3066f7d..3eea6ac7 100644
--- a/print-domain.c
+++ b/print-domain.c
@@ -19,6 +19,8 @@
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
+/* \summary: Domain Name System (DNS) printer */
+
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -149,15 +151,14 @@ ns_nprint(netdissect_options *ndo,
 	register u_int i, l;
 	register const u_char *rp = NULL;
 	register int compress = 0;
-	int chars_processed;
 	int elt;
-	int data_size = ndo->ndo_snapend - bp;
+	u_int offset, max_offset;
 
 	if ((l = labellen(ndo, cp)) == (u_int)-1)
 		return(NULL);
 	if (!ND_TTEST2(*cp, 1))
 		return(NULL);
-	chars_processed = 1;
+	max_offset = (u_int)(cp - bp);
 	if (((i = *cp++) & INDIR_MASK) != INDIR_MASK) {
 		compress = 0;
 		rp = cp + l;
@@ -172,24 +173,28 @@ ns_nprint(netdissect_options *ndo,
 				}
 				if (!ND_TTEST2(*cp, 1))
 					return(NULL);
-				cp = bp + (((i << 8) | *cp) & 0x3fff);
+				offset = (((i << 8) | *cp) & 0x3fff);
+				/*
+				 * This must move backwards in the packet.
+				 * No RFC explicitly says that, but BIND's
+				 * name decompression code requires it,
+				 * as a way of preventing infinite loops
+				 * and other bad behavior, and it's probably
+				 * what was intended (compress by pointing
+				 * to domain name suffixes already seen in
+				 * the packet).
+				 */
+				if (offset >= max_offset) {
+					ND_PRINT((ndo, "<BAD PTR>"));
+					return(NULL);
+				}
+				max_offset = offset;
+				cp = bp + offset;
 				if ((l = labellen(ndo, cp)) == (u_int)-1)
 					return(NULL);
 				if (!ND_TTEST2(*cp, 1))
 					return(NULL);
 				i = *cp++;
-				chars_processed++;
-
-				/*
-				 * If we've looked at every character in
-				 * the message, this pointer will make
-				 * us look at some character again,
-				 * which means we're looping.
-				 */
-				if (chars_processed >= data_size) {
-					ND_PRINT((ndo, "<LOOP>"));
-					return (NULL);
-				}
 				continue;
 			}
 			if ((i & INDIR_MASK) == EDNS0_MASK) {
@@ -210,14 +215,12 @@ ns_nprint(netdissect_options *ndo,
 			}
 
 			cp += l;
-			chars_processed += l;
 			ND_PRINT((ndo, "."));
 			if ((l = labellen(ndo, cp)) == (u_int)-1)
 				return(NULL);
 			if (!ND_TTEST2(*cp, 1))
 				return(NULL);
 			i = *cp++;
-			chars_processed++;
 			if (!compress)
 				rp += l + 1;
 		}
@@ -329,11 +332,11 @@ ns_qprint(netdissect_options *ndo,
 		return(NULL);
 
 	/* print the qtype */
-	i = EXTRACT_16BITS(cp);
+	i = EXTRACT_BE_16BITS(cp);
 	cp += 2;
 	ND_PRINT((ndo, " %s", tok2str(ns_type2str, "Type%d", i)));
 	/* print the qclass (if it's not IN) */
-	i = EXTRACT_16BITS(cp);
+	i = EXTRACT_BE_16BITS(cp);
 	cp += 2;
 	if (is_mdns)
 		class = (i & ~C_QU);
@@ -370,10 +373,10 @@ ns_rprint(netdissect_options *ndo,
 		return (ndo->ndo_snapend);
 
 	/* print the type/qtype */
-	typ = EXTRACT_16BITS(cp);
+	typ = EXTRACT_BE_16BITS(cp);
 	cp += 2;
 	/* print the class (if it's not IN and the type isn't OPT) */
-	i = EXTRACT_16BITS(cp);
+	i = EXTRACT_BE_16BITS(cp);
 	cp += 2;
 	if (is_mdns)
 		class = (i & ~C_CACHE_FLUSH);
@@ -389,13 +392,13 @@ ns_rprint(netdissect_options *ndo,
 	if (typ == T_OPT) {
 		/* get opt flags */
 		cp += 2;
-		opt_flags = EXTRACT_16BITS(cp);
+		opt_flags = EXTRACT_BE_16BITS(cp);
 		/* ignore rest of ttl field */
 		cp += 2;
 	} else if (ndo->ndo_vflag > 2) {
 		/* print ttl */
 		ND_PRINT((ndo, " ["));
-		relts_print(ndo, EXTRACT_32BITS(cp));
+		unsigned_relts_print(ndo, EXTRACT_BE_32BITS(cp));
 		ND_PRINT((ndo, "]"));
 		cp += 4;
 	} else {
@@ -403,7 +406,7 @@ ns_rprint(netdissect_options *ndo,
 		cp += 4;
 	}
 
-	len = EXTRACT_16BITS(cp);
+	len = EXTRACT_BE_16BITS(cp);
 	cp += 2;
 
 	rp = cp + len;
@@ -416,7 +419,7 @@ ns_rprint(netdissect_options *ndo,
 	case T_A:
 		if (!ND_TTEST2(*cp, sizeof(struct in_addr)))
 			return(NULL);
-		ND_PRINT((ndo, " %s", intoa(htonl(EXTRACT_32BITS(cp)))));
+		ND_PRINT((ndo, " %s", intoa(htonl(EXTRACT_BE_32BITS(cp)))));
 		break;
 
 	case T_NS:
@@ -441,15 +444,15 @@ ns_rprint(netdissect_options *ndo,
 			return(NULL);
 		if (!ND_TTEST2(*cp, 5 * 4))
 			return(NULL);
-		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
+		ND_PRINT((ndo, " %u", EXTRACT_BE_32BITS(cp)));
 		cp += 4;
-		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
+		ND_PRINT((ndo, " %u", EXTRACT_BE_32BITS(cp)));
 		cp += 4;
-		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
+		ND_PRINT((ndo, " %u", EXTRACT_BE_32BITS(cp)));
 		cp += 4;
-		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
+		ND_PRINT((ndo, " %u", EXTRACT_BE_32BITS(cp)));
 		cp += 4;
-		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
+		ND_PRINT((ndo, " %u", EXTRACT_BE_32BITS(cp)));
 		cp += 4;
 		break;
 	case T_MX:
@@ -458,7 +461,7 @@ ns_rprint(netdissect_options *ndo,
 			return(NULL);
 		if (ns_nprint(ndo, cp + 2, bp) == NULL)
 			return(NULL);
-		ND_PRINT((ndo, " %d", EXTRACT_16BITS(cp)));
+		ND_PRINT((ndo, " %d", EXTRACT_BE_16BITS(cp)));
 		break;
 
 	case T_TXT:
@@ -477,8 +480,8 @@ ns_rprint(netdissect_options *ndo,
 			return(NULL);
 		if (ns_nprint(ndo, cp + 6, bp) == NULL)
 			return(NULL);
-		ND_PRINT((ndo, ":%d %d %d", EXTRACT_16BITS(cp + 4),
-			EXTRACT_16BITS(cp), EXTRACT_16BITS(cp + 2)));
+		ND_PRINT((ndo, ":%d %d %d", EXTRACT_BE_16BITS(cp + 4),
+			  EXTRACT_BE_16BITS(cp), EXTRACT_BE_16BITS(cp + 2)));
 		break;
 
 	case T_AAAA:
@@ -547,23 +550,23 @@ ns_rprint(netdissect_options *ndo,
 		cp += 6;
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
-		ND_PRINT((ndo, " fudge=%u", EXTRACT_16BITS(cp)));
+		ND_PRINT((ndo, " fudge=%u", EXTRACT_BE_16BITS(cp)));
 		cp += 2;
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
-		ND_PRINT((ndo, " maclen=%u", EXTRACT_16BITS(cp)));
-		cp += 2 + EXTRACT_16BITS(cp);
+		ND_PRINT((ndo, " maclen=%u", EXTRACT_BE_16BITS(cp)));
+		cp += 2 + EXTRACT_BE_16BITS(cp);
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
-		ND_PRINT((ndo, " origid=%u", EXTRACT_16BITS(cp)));
+		ND_PRINT((ndo, " origid=%u", EXTRACT_BE_16BITS(cp)));
 		cp += 2;
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
-		ND_PRINT((ndo, " error=%u", EXTRACT_16BITS(cp)));
+		ND_PRINT((ndo, " error=%u", EXTRACT_BE_16BITS(cp)));
 		cp += 2;
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
-		ND_PRINT((ndo, " otherlen=%u", EXTRACT_16BITS(cp)));
+		ND_PRINT((ndo, " otherlen=%u", EXTRACT_BE_16BITS(cp)));
 		cp += 2;
 	    }
 	}
@@ -571,7 +574,7 @@ ns_rprint(netdissect_options *ndo,
 }
 
 void
-ns_print(netdissect_options *ndo,
+domain_print(netdissect_options *ndo,
          register const u_char *bp, u_int length, int is_mdns)
 {
 	register const HEADER *np;
@@ -582,15 +585,15 @@ ns_print(netdissect_options *ndo,
 	np = (const HEADER *)bp;
 	ND_TCHECK(*np);
 	/* get the byte-order right */
-	qdcount = EXTRACT_16BITS(&np->qdcount);
-	ancount = EXTRACT_16BITS(&np->ancount);
-	nscount = EXTRACT_16BITS(&np->nscount);
-	arcount = EXTRACT_16BITS(&np->arcount);
+	qdcount = EXTRACT_BE_16BITS(&np->qdcount);
+	ancount = EXTRACT_BE_16BITS(&np->ancount);
+	nscount = EXTRACT_BE_16BITS(&np->nscount);
+	arcount = EXTRACT_BE_16BITS(&np->arcount);
 
 	if (DNS_QR(np)) {
 		/* this is a response */
 		ND_PRINT((ndo, "%d%s%s%s%s%s%s",
-			EXTRACT_16BITS(&np->id),
+			EXTRACT_BE_16BITS(&np->id),
 			ns_ops[DNS_OPCODE(np)],
 			ns_resp[DNS_RCODE(np)],
 			DNS_AA(np)? "*" : "",
@@ -603,7 +606,7 @@ ns_print(netdissect_options *ndo,
 		/* Print QUESTION section on -vv */
 		cp = (const u_char *)(np + 1);
 		while (qdcount--) {
-			if (qdcount < EXTRACT_16BITS(&np->qdcount) - 1)
+			if (qdcount < EXTRACT_BE_16BITS(&np->qdcount) - 1)
 				ND_PRINT((ndo, ","));
 			if (ndo->ndo_vflag > 1) {
 				ND_PRINT((ndo, " q:"));
@@ -657,12 +660,12 @@ ns_print(netdissect_options *ndo,
 	}
 	else {
 		/* this is a request */
-		ND_PRINT((ndo, "%d%s%s%s", EXTRACT_16BITS(&np->id), ns_ops[DNS_OPCODE(np)],
-		    DNS_RD(np) ? "+" : "",
-		    DNS_CD(np) ? "%" : ""));
+		ND_PRINT((ndo, "%d%s%s%s", EXTRACT_BE_16BITS(&np->id), ns_ops[DNS_OPCODE(np)],
+			  DNS_RD(np) ? "+" : "",
+			  DNS_CD(np) ? "%" : ""));
 
 		/* any weirdness? */
-		b2 = EXTRACT_16BITS(((const u_short *)np)+1);
+		b2 = EXTRACT_BE_16BITS(((const u_short *)np) + 1);
 		if (b2 & 0x6cf)
 			ND_PRINT((ndo, " [b2&3=0x%x]", b2));