IPX: Add a length check

[tcpdump] / print-ether.c

diff --git a/print-ether.c b/print-ether.c
index 373103dcc0e3dc2ecd53500ebee658b828188952..ba48834341c0db164e560a5832aabe03078a2dea 100644 (file)
--- a/print-ether.c
+++ b/print-ether.c
@@ -106,7 +106,8 @@ const struct tok ethertype_values[] = {
 
 static void
 ether_hdr_print(netdissect_options *ndo,
-                const u_char *bp, u_int length)
+                const u_char *bp, u_int length,
+               u_int hdrlen)
 {
        const struct ether_header *ehp;
        uint16_t length_type;
@@ -117,7 +118,8 @@ ether_hdr_print(netdissect_options *ndo,
                     etheraddr_string(ndo, ehp->ether_shost),
                     etheraddr_string(ndo, ehp->ether_dhost));
 
-       length_type = EXTRACT_BE_U_2(ehp->ether_length_type);
+       length_type = EXTRACT_BE_U_2(bp +
+                                    (hdrlen - sizeof(ehp->ether_length_type)));
        if (!ndo->ndo_qflag) {
                if (length_type <= MAX_ETHERNET_LENGTH_VAL) {
                        ND_PRINT(", 802.3");
@@ -138,7 +140,8 @@ ether_hdr_print(netdissect_options *ndo,
 }
 
 /*
- * Print an Ethernet frame.
+ * Print an Ethernet frame while specyfing a non-standard Ethernet header
+ * length.
  * This might be encapsulated within another frame; we might be passed
  * a pointer to a function that can print header information for that
  * frame's protocol, and an argument to pass to that function.
@@ -146,45 +149,52 @@ ether_hdr_print(netdissect_options *ndo,
  * FIXME: caplen can and should be derived from ndo->ndo_snapend and p.
  */
 u_int
-ether_print(netdissect_options *ndo,
+ether_print_hdr_len(netdissect_options *ndo,
             const u_char *p, u_int length, u_int caplen,
-            void (*print_encap_header)(netdissect_options *ndo, const u_char *), const u_char *encap_header_arg)
+            void (*print_encap_header)(netdissect_options *ndo, const u_char *),
+            const u_char *encap_header_arg, u_int hdrlen)
 {
        const struct ether_header *ehp;
        u_int orig_length;
        u_short length_type;
-       u_int hdrlen;
        int llc_hdrlen;
        struct lladdr_info src, dst;
 
-       ndo->ndo_protocol = "ether";
-       if (caplen < ETHER_HDRLEN) {
+       /* Unless specified otherwise, assume a standard Ethernet header */
+       if (hdrlen == ETHER_HDRLEN)
+               ndo->ndo_protocol = "ether";
+
+       if (caplen < hdrlen) {
                nd_print_trunc(ndo);
                return (caplen);
        }
-       if (length < ETHER_HDRLEN) {
+       if (length < hdrlen) {
                nd_print_trunc(ndo);
                return (length);
        }
 
+       /* If the offset is set, then the upper printer is responsible for
+        * printing the relevant part of the Ethernet header.
+        */
        if (ndo->ndo_eflag) {
                if (print_encap_header != NULL)
                        (*print_encap_header)(ndo, encap_header_arg);
-               ether_hdr_print(ndo, p, length);
+               ether_hdr_print(ndo, p, length, hdrlen);
        }
+
        orig_length = length;
 
-       length -= ETHER_HDRLEN;
-       caplen -= ETHER_HDRLEN;
+       length -= hdrlen;
+       caplen -= hdrlen;
        ehp = (const struct ether_header *)p;
-       p += ETHER_HDRLEN;
-       hdrlen = ETHER_HDRLEN;
+       p += hdrlen;
 
        src.addr = ehp->ether_shost;
        src.addr_string = etheraddr_string;
        dst.addr = ehp->ether_dhost;
        dst.addr_string = etheraddr_string;
-       length_type = EXTRACT_BE_U_2(ehp->ether_length_type);
+       length_type = EXTRACT_BE_U_2((const u_char *)ehp +
+                                    (hdrlen - sizeof(ehp->ether_length_type)));
 
 recurse:
        /*
@@ -209,11 +219,13 @@ recurse:
                 * the enclosed type field.
                 */
                if (caplen < 4) {
-                       ND_PRINT("[|vlan]");
+                       ndo->ndo_protocol = "vlan";
+                       nd_print_trunc(ndo);
                        return (hdrlen + caplen);
                }
                if (length < 4) {
-                       ND_PRINT("[|vlan]");
+                       ndo->ndo_protocol = "vlan";
+                       nd_print_trunc(ndo);
                        return (hdrlen + length);
                }
                if (ndo->ndo_eflag) {
@@ -255,7 +267,8 @@ recurse:
                        if (!ndo->ndo_eflag) {
                                if (print_encap_header != NULL)
                                        (*print_encap_header)(ndo, encap_header_arg);
-                               ether_hdr_print(ndo, (const u_char *)ehp, orig_length);
+                               ether_hdr_print(ndo, (const u_char *)ehp, orig_length,
+                                               hdrlen);
                        }
 
                        if (!ndo->ndo_suppress_default_print)
@@ -265,6 +278,25 @@ recurse:
        return (hdrlen);
 }
 
+/*
+ * Print an Ethernet frame.
+ * This might be encapsulated within another frame; we might be passed
+ * a pointer to a function that can print header information for that
+ * frame's protocol, and an argument to pass to that function.
+ *
+ * FIXME: caplen can and should be derived from ndo->ndo_snapend and p.
+ */
+u_int
+ether_print(netdissect_options *ndo,
+            const u_char *p, u_int length, u_int caplen,
+            void (*print_encap_header)(netdissect_options *ndo, const u_char *),
+            const u_char *encap_header_arg)
+{
+       return (ether_print_hdr_len(ndo, p, length, caplen,
+                                         print_encap_header, encap_header_arg,
+                                         ETHER_HDRLEN));
+}
+
 /*
  * This is the top level routine of the printer.  'p' points
  * to the ether header of the packet, 'h->len' is the length
@@ -296,7 +328,7 @@ netanalyzer_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h,
         * Fail if we don't have enough data for the Hilscher pseudo-header.
         */
        ndo->ndo_protocol = "netanalyzer_if";
-       if (h->len < 4 || h->caplen < 4) {
+       if (h->caplen < 4) {
                nd_print_trunc(ndo);
                return (h->caplen);
        }
@@ -325,7 +357,7 @@ netanalyzer_transparent_if_print(netdissect_options *ndo,
         * preamble, and SOF.
         */
        ndo->ndo_protocol = "netanalyzer_transparent_if";
-       if (h->len < 12 || h->caplen < 12) {
+       if (h->caplen < 12) {
                nd_print_trunc(ndo);
                return (h->caplen);
        }
@@ -383,7 +415,8 @@ ethertype_print(netdissect_options *ndo,
 
        case ETHERTYPE_ISO:
                if (length == 0 || caplen == 0) {
-                       ND_PRINT(" [|osi]");
+                       ndo->ndo_protocol = "isoclns";
+                       nd_print_trunc(ndo);
                        return (1);
                }
                isoclns_print(ndo, p + 1, length - 1);