Fix invalid memory write on lua stack overflow {CVE-2021-32626}
When LUA call our C code, by default, the LUA stack has room for 20 elements. In most cases, this is more than enough but sometimes it's not and the caller must verify the LUA stack size before he pushes elements. On 3 places in the code, there was no verification of the LUA stack size. On specific inputs this missing verification could have lead to invalid memory write: 1. On 'luaReplyToRedisReply', one might return a nested reply that will explode the LUA stack. 2. On 'redisProtocolToLuaType', the Redis reply might be deep enough to explode the LUA stack (notice that currently there is no such command in Redis that returns such a nested reply, but modules might do it) 3. On 'ldbRedis', one might give a command with enough arguments to explode the LUA stack (all the arguments will be pushed to the LUA stack) This commit is solving all those 3 issues by calling 'lua_checkstack' and verify that there is enough roo...
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