net: wget: Avoid packet queue overflow

Make sure to stay within bounds, as a misbehaving HTTP server
can trigger a buffer overflow if not properly handled.

Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/net/wget.c b/net/wget.c
index 2dbfeb1..8bb4d72 100644 (file)
--- a/net/wget.c
+++ b/net/wget.c
@@ -35,7 +35,8 @@ struct pkt_qd {
  * The actual packet bufers are in the kernel space, and are
  * expected to be overwritten by the downloaded image.
  */
-static struct pkt_qd pkt_q[PKTBUFSRX / 4];
+#define PKTQ_SZ (PKTBUFSRX / 4)
+static struct pkt_qd pkt_q[PKTQ_SZ];
 static int pkt_q_idx;
 static unsigned long content_length;
 static unsigned int packets;
@@ -202,6 +203,13 @@ static void wget_connected(uchar *pkt, unsigned int tcp_seq_num,
                pkt_q[pkt_q_idx].tcp_seq_num = tcp_seq_num;
                pkt_q[pkt_q_idx].len = len;
                pkt_q_idx++;
+
+               if (pkt_q_idx >= PKTQ_SZ) {
+                       printf("wget: Fatal error, queue overrun!\n");
+                       net_set_state(NETLOOP_FAIL);
+
+                       return;
+               }
        } else {
                debug_cond(DEBUG_WGET, "wget: Connected HTTP Header %p\n", pkt);
                /* sizeof(http_eom) - 1 is the string length of (http_eom) */