gentoo-overlay/games-action/0verkill/files/0verkill-0.16-underflow-check.patch

The vulnerability is cause due to an integer underflow error in "recv_packet()"
within the handling of a received UDP packet. This can be exploited to cause
out-of-bounds memory access which crashes the server process via a UDP packet
that is smaller than 12 bytes in size.

http://bugs.gentoo.org/136222

--- 0verkill-0.16/net.c
+++ 0verkill-0.16/net.c
@@ -84,6 +84,7 @@
 	p=mem_alloc(max_len+12);
 	if (!p)return -1;  /* not enough memory */
 	retval=recvfrom(fd,p,max_len+12,0,addr,addr_len);
+	if (retval<12)return -1; /* not enough data from network */
 	memcpy(packet,p+12,max_len);
 	crc=p[0]+(p[1]<<8)+(p[2]<<16)+(p[3]<<24);
 	s=p[4]+(p[5]<<8)+(p[6]<<16)+(p[7]<<24);