fix(objects): fix a buffer overflow issue in find_sigid_algs. (#175)

Author: zhuizhuhaomeng

lib/resty/openssl/objects.lua

@@ -57,7 +57,7 @@ local function txtnid2nid(txt_nid)
 end
 
 local function find_sigid_algs(nid)
-  local out = ffi.new("int[0]")
+  local out = ffi.new("int[1]")
   if C.OBJ_find_sigid_algs(nid, out, nil) == 0 then
     return 0, "objects.find_sigid_algs: invalid sigid " .. nid
   end
@@ -71,4 +71,4 @@ return {
   txtnid2nid = txtnid2nid,
   find_sigid_algs = find_sigid_algs,
   create = C.OBJ_create,
-}
+}