boundary checking for print_nsap()

[tcpdump] / print-isoclns.c

diff --git a/print-isoclns.c b/print-isoclns.c
index 6f99c534827cee6a7f72d2540fee79a7cbc4fb3f..9ac90f206a2843524ea8ff663596357e88a0c447 100644 (file)
--- a/print-isoclns.c
+++ b/print-isoclns.c
@@ -26,7 +26,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-isoclns.c,v 1.58 2002-08-20 00:17:23 hannes Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-isoclns.c,v 1.59 2002-09-01 21:08:02 hannes Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -433,28 +433,29 @@ struct isis_tlv_lsp {
  * xx.xxxx.xxxx.xxxx.xxxx.xxxx.xxxx
  * 32 bytes plus one termination byte */
 static char *
-print_nsap(register const u_char *cp, register int length)
+print_nsap(register const u_char *pptr, register int nsap_length)
 {
-       int i;
-       static char nsap[33];
-        char *pos = nsap;
-
-        if (length==0) {
-               *(pos) = '0';
-                *(pos+1) = '\0';
-                return (nsap);
+       int nsap_idx;
+       static char nsap_ascii_output[33];
+        char *junk_buf = nsap_ascii_output;
+
+        if (nsap_length < 1 || nsap_length > 13) {
+                junk_buf+=sprintf(junk_buf, "illegal length");
+               *(junk_buf) = '\0';
+                return (nsap_ascii_output);
         }
 
-       for (i = 0; i < length; i++) {
-               if (!TTEST2(*cp, 1))
+       for (nsap_idx = 0; nsap_idx < nsap_length; nsap_idx++) {
+               if (!TTEST2(*pptr, 1))
                        return (0);
-               pos+=sprintf(pos, "%02x", *cp++);
-               if (((i & 1) == 0) && (i + 1 < length)) {
-                       pos+=sprintf(pos, ".");
+               junk_buf+=sprintf(junk_buf, "%02x", *pptr++);
+               if (((nsap_idx & 1) == 0) &&
+                     (nsap_idx + 1 < nsap_length)) {
+                       junk_buf+=sprintf(junk_buf, ".");
                }
        }
-        *(pos) = '\0';
-       return (nsap);
+        *(junk_buf) = '\0';
+       return (nsap_ascii_output);
 }
 
 #define ISIS_COMMON_HEADER_SIZE (sizeof(struct isis_common_header))