This fixes an insecure use of tainted data as argument to functions that
allocate memory and read from files, which could be tricked into getting
networkctl to allocate a large amount of memory and fill it with file
data.
This was uncovered by Coverity. Fixes CID 1393254.
if (l != sizeof(u))
return -EBADMSG;
+ /* each LLDP packet is at most MTU size, but let's allow up to 4KiB just in case */
+ if (le64toh(u) >= 4096)
+ return -EBADMSG;
+
raw = new(uint8_t, le64toh(u));
if (!raw)
return -ENOMEM;