NFLOG: Add some bounds checks

[tcpdump] / print-nflog.c

diff --git a/print-nflog.c b/print-nflog.c
index d8328ec861af1fb1ab3f96b9a566df2941c3cf39..522d212ce06f33832da31c747c00d0d8ff99889a 100644 (file)
--- a/print-nflog.c
+++ b/print-nflog.c
@@ -34,6 +34,7 @@
 #include "netdissect-stdinc.h"
 
 #include "netdissect.h"
+static const char tstr[] = " [|nflog]";
 
 #if defined(DLT_NFLOG) && defined(HAVE_PCAP_NFLOG_H)
 #include <pcap/nflog.h>
@@ -71,17 +72,15 @@ nflog_if_print(netdissect_options *ndo,
                           const struct pcap_pkthdr *h, const u_char *p)
 {
        const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
-       const nflog_tlv_t *tlv;
        uint16_t size;
        uint16_t h_size = sizeof(nflog_hdr_t);
        u_int caplen = h->caplen;
        u_int length = h->len;
 
-       if (caplen < sizeof(nflog_hdr_t) || length < sizeof(nflog_hdr_t)) {
-               ND_PRINT("[|nflog]");
-               return h_size;
-       }
+       if (caplen < sizeof(nflog_hdr_t) || length < sizeof(nflog_hdr_t))
+               goto trunc;
 
+       ND_TCHECK_SIZE(hdr);
        if (hdr->nflog_version != 0) {
                ND_PRINT("version %u (unknown)", hdr->nflog_version);
                return h_size;
@@ -95,31 +94,25 @@ nflog_if_print(netdissect_options *ndo,
        caplen -= sizeof(nflog_hdr_t);
 
        while (length > 0) {
+               const nflog_tlv_t *tlv;
+
                /* We have some data.  Do we have enough for the TLV header? */
-               if (caplen < sizeof(nflog_tlv_t) || length < sizeof(nflog_tlv_t)) {
-                       /* No. */
-                       ND_PRINT("[|nflog]");
-                       return h_size;
-               }
+               if (caplen < sizeof(nflog_tlv_t) || length < sizeof(nflog_tlv_t))
+                       goto trunc;     /* No. */
 
                tlv = (const nflog_tlv_t *) p;
+               ND_TCHECK_SIZE(tlv);
                size = tlv->tlv_length;
                if (size % 4 != 0)
                        size += 4 - size % 4;
 
                /* Is the TLV's length less than the minimum? */
-               if (size < sizeof(nflog_tlv_t)) {
-                       /* Yes. Give up now. */
-                       ND_PRINT("[|nflog]");
-                       return h_size;
-               }
+               if (size < sizeof(nflog_tlv_t))
+                       goto trunc;     /* Yes. Give up now. */
 
                /* Do we have enough data for the full TLV? */
-               if (caplen < size || length < size) {
-                       /* No. */
-                       ND_PRINT("[|nflog]");
-                       return h_size;
-               }
+               if (caplen < size || length < size)
+                       goto trunc;     /* No. */
 
                if (tlv->tlv_type == NFULA_PAYLOAD) {
                        /*
@@ -162,6 +155,9 @@ nflog_if_print(netdissect_options *ndo,
                break;
        }
 
+       return h_size;
+trunc:
+       ND_PRINT("%s", tstr);
        return h_size;
 }