[io] Bound key and free-list reads - #23134
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ReadKeys and ReadFree still used the unbounded ReadKeyBuffer overload. A keys record can lie about TString lengths and walk off the heap buffer. ReadFree also had no remaining-size check, so a truncated free list never hit GetLast() > fEND.
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Summary
TKey::ReadKeyBufferoverload inTDirectoryFile::ReadKeysandTFile::ReadFree. Recover already calls it; the normal open path did not.TFree::ReadBuffer(char *&, std::size_t)and stop the free-list loop when the record is truncated, instead of looping untilGetLast() > fEND.TDatime(UInt_t) in the key header size check.This is leftover from #22190 / #22169: a keys record can still report a
TStringlength far larger than the buffer.AI-assisted disclosure: Cursor/LLM assistance was used during analysis and implementation. I have personally reviewed, tested, and understand the changes and take full responsibility for them.
Test plan
io/io/test/TFile—ReadKeysValid,ReadKeysOversizedString,ReadFreeValid,TFree.ReadBufferBoundsio/io/testTFile gtest