The format-data rendezvous had the same single-slot race the file-contents
path just fixed: the channel thread rewrote clipboard->hmem with no lock while
explorer-thread consumers read/freed it, nothing serialized concurrent
requests, and no flag told an expected response from a stray one.
- Add format_request_mutex (serializes the whole request/response cycle) and
hmem_mutex (guards the hmem hand-off and formatDataRespExpected).
- cliprdr_send_data_request now takes ownership of the response buffer under
hmem_mutex and returns it to the caller, so a later response cannot touch a
buffer a consumer is using. All three consumers (GetData, WM_RENDERFORMAT,
DELAYED_RENDERING) and the WM_CLIPBOARDUPDATE cleanup use the returned/taken
handle instead of the shared slot.
- The response handler drops any response arriving while formatDataRespExpected
is clear (late/duplicate/unsolicited), consumes the flag on the first
response, and no longer dereferences a NULL clipboard in the SetEvent path.
Pre-existing issue, not introduced by this branch; generalizes the
file-contents hardening to the format-data path.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
- Reject a negative FILECONTENTS_SIZE result: m_lSize is unsigned, so a
negative value became a huge bogus stream size that keeps reads going.
- Use a unique per-stream counter as the CLIPRDR streamId instead of a
truncated IStream pointer, which could collide or be reused after free
(and leaked heap addresses to the peer).
- Add req_f_request_mutex to serialize whole file-contents request/response
cycles, enforcing the previously assumed one-outstanding-request
invariant when multiple streams are read concurrently. Bounded acquire
so a wedged request fails the read instead of hanging a consumer.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Cover the zeroed optional request fields, stream ID filtering,
oversized/NULL response rejection and the zero-byte EOF path.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
