CVE-2017-13029/PPP: Fix a bounds check, and clean up other bounds checks.

[tcpdump] / print-icmp.c

diff --git a/print-icmp.c b/print-icmp.c
index 17e7a752cf6ec272e42c768b84104de8c0778f80..366094eff829c08e519017334fdaa656ce40e333 100644 (file)
--- a/print-icmp.c
+++ b/print-icmp.c
@@ -580,8 +580,8 @@ icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *
                bp += 8;
                ND_PRINT((ndo, "\n\t"));
                ip = (const struct ip *)bp;
-               ndo->ndo_snaplen = ndo->ndo_snapend - bp;
                 snapend_save = ndo->ndo_snapend;
+               ND_TCHECK_16BITS(&ip->ip_len);
                ip_print(ndo, bp, EXTRACT_16BITS(&ip->ip_len));
                 ndo->ndo_snapend = snapend_save;
        }
@@ -599,7 +599,8 @@ icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *
              * to check if an extension header is present. This is expedient,
              * however not all implementations set the length field proper.
              */
-            if (!ext_dp->icmp_length) {
+            if (!ext_dp->icmp_length &&
+                ND_TTEST2(ext_dp->icmp_ext_version_res, plen - ICMP_EXTD_MINLEN)) {
                 vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
                 vec[0].len = plen - ICMP_EXTD_MINLEN;
                 if (in_cksum(vec, 1)) {
@@ -620,12 +621,14 @@ icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *
             }
 
             hlen = plen - ICMP_EXTD_MINLEN;
-            vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
-            vec[0].len = hlen;
-            ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
-                   EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
-                   in_cksum(vec, 1) ? "in" : "",
-                   hlen));
+            if (ND_TTEST2(ext_dp->icmp_ext_version_res, hlen)) {
+                vec[0].ptr = (const uint8_t *)(const void *)&ext_dp->icmp_ext_version_res;
+                vec[0].len = hlen;
+                ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
+                       EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
+                       in_cksum(vec, 1) ? "in" : "",
+                       hlen));
+            }
 
             hlen -= 4; /* subtract common header size */
             obj_tptr = (const uint8_t *)ext_dp->icmp_ext_data;