SLL/SLL2: Use ND_TCHECK_LEN() for bounds checks

Moreover:
Define ND_LONGJMP_FROM_TCHECK.
Remove 2 ndo_ll_hdr_len increments in truncation cases.
Remove 2 comments: "can't happen" is wrong (fuzzing, etc.)

diff --git a/print-sll.c b/print-sll.c
index ad0ae7f1e6bf52332e1ca09b2cde3156f32512b8..19d2973edadec81cc1ad0fa18c25eb0ba96e2e03 100644 (file)
--- a/print-sll.c
+++ b/print-sll.c
@@ -31,6 +31,7 @@
 
 #include "netdissect-stdinc.h"
 
+#define ND_LONGJMP_FROM_TCHECK
 #include "netdissect.h"
 #include "addrtoname.h"
 #include "ethertype.h"
@@ -223,16 +224,7 @@ sll_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char
        u_int hdrlen;
 
        ndo->ndo_protocol = "sll";
-       if (caplen < SLL_HDR_LEN) {
-               /*
-                * XXX - this "can't happen" because "pcap-linux.c" always
-                * adds this many bytes of header to every packet in a
-                * cooked socket capture.
-                */
-               nd_print_trunc(ndo);
-               ndo->ndo_ll_hdr_len += caplen;
-               return;
-       }
+       ND_TCHECK_LEN(p, SLL_HDR_LEN);
 
        sllp = (const struct sll_header *)p;
 
@@ -419,16 +411,7 @@ sll2_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char
 #endif
 
        ndo->ndo_protocol = "sll2";
-       if (caplen < SLL2_HDR_LEN) {
-               /*
-                * XXX - this "can't happen" because "pcap-linux.c" always
-                * adds this many bytes of header to every packet in a
-                * cooked socket capture.
-                */
-               nd_print_trunc(ndo);
-               ndo->ndo_ll_hdr_len += caplen;
-               return;
-       }
+       ND_TCHECK_LEN(p, SLL2_HDR_LEN);
 
        sllp = (const struct sll2_header *)p;
 #ifdef HAVE_NET_IF_H