From 7cb64f2a4314a5e6ac8406def11ac98f522bbc48 Mon Sep 17 00:00:00 2001
From: likewise <likewise>
Date: Thu, 1 May 2003 08:03:51 +0000
Subject: [PATCH] Patch #1183 applied. This drops short UDP/TCP packets.

---
 src/core/tcp_in.c | 11 ++++++++++-
 src/core/udp.c    | 12 +++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/core/tcp_in.c b/src/core/tcp_in.c
index a4c3cd4e..6af24014 100644
--- a/src/core/tcp_in.c
+++ b/src/core/tcp_in.c
@@ -113,7 +113,16 @@ tcp_input(struct pbuf *p, struct netif *inp)
   iphdr = p->payload;
   tcphdr = (struct tcp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4);
  
-  pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4)));
+  if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4)))) {
+    /* drop short packets */
+    DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%u bytes) discarded\n", p->tot_len));
+#ifdef TCP_STATS
+    ++lwip_stats.tcp.lenerr;
+    ++lwip_stats.tcp.drop;
+#endif /* TCP_STATS */
+    pbuf_free(p);
+    return;
+  }
   
   /* Don't even process incoming broadcasts/multicasts. */
   if(ip_addr_isbroadcast(&(iphdr->dest), &(inp->netmask)) ||
diff --git a/src/core/udp.c b/src/core/udp.c
index 759b4090..b000ed18 100644
--- a/src/core/udp.c
+++ b/src/core/udp.c
@@ -175,7 +175,17 @@ udp_input(struct pbuf *p, struct netif *inp)
 
   iphdr = p->payload;
 
-  pbuf_header(p, -((s16_t)(UDP_HLEN + IPH_HL(iphdr) * 4)));
+  if (pbuf_header(p, -((s16_t)(UDP_HLEN + IPH_HL(iphdr) * 4)))) {
+    /* drop short packets */
+	  DEBUGF(UDP_DEBUG, ("udp_input: short UDP datagram (%u bytes) discarded\n", p->tot_len));
+#ifdef UDP_STATS
+  	++lwip_stats.udp.lenerr;
+  	++lwip_stats.udp.drop;
+#endif /* UDP_STATS */
+    snmp_inc_udpinerrors();
+  	pbuf_free(p);
+  	goto end;
+  }
 
   udphdr = (struct udp_hdr *)((u8_t *)p->payload - UDP_HLEN);