babeld: Hop Count must not be 0.

According to RFC 8966:
Hop Count The maximum number of times that this TLV may be forwarded, plus 1. This MUST NOT be 0.
Signed-off-by: zmw12306 <zmw12306@gmail.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/babeld/message.c b/babeld/message.c
index 5a33d5c288..15022093c5 100644
--- a/babeld/message.c
+++ b/babeld/message.c
@@ -693,6 +693,10 @@ parse_packet(const unsigned char *from, struct interface *ifp,
                 memcpy(src_prefix, zeroes, 16);
                 src_plen = 0;
             }
+            if(message[6] == 0) {
+                debugf(BABEL_DEBUG_COMMON, "Received seqno request with invalid hop count 0");
+                goto done;
+            }
             rc = parse_request_subtlv(message[2], message + 4 + rc,
                                       len - 2 - rc, src_prefix, &src_plen);
             if(rc < 0)