GetBlockTag() dereferenced GetBlockFromAddress()'s result without a
null check, unlike every other accessor in this file. Callers
(NetAdhocCommon.cpp, sceNet.cpp, sceNetAdhocMatching.cpp) pass the
result straight into strcmp() while recovering from a stale address
left over from an old/corrupted savestate - precisely the situation
where the address may no longer resolve to a block. Return "" instead
of dereferencing a null block, so strcmp() simply reports a mismatch
(correctly triggering those callers' recovery path) instead of
crashing.
DoState() read the saved block count directly from the savestate with
no validation before looping that many times allocating Blocks - a
corrupt/malicious savestate claiming an enormous count would drive an
effectively unbounded allocation loop. Clamp it to how many block
records could plausibly still fit in the remaining stream data.
Henrik Rydgård
eb68bdba0b