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Pull request overview
Fixes a use-after-free crash in the PHP SSH2 extension when ssh2_disconnect() is called while SFTP streams are still open, by ensuring stream close handlers don’t call into libssh2 after the underlying session has been closed.
Changes:
- Add a session-liveness guard in
php_ssh2_sftp_stream_close()before callinglibssh2_sftp_close(). - Add the same guard in
php_ssh2_sftp_dirstream_close()to avoid dereferencing freed session state.
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A use-after-free crash when
ssh2_disconnect()is called while SFTP streams are still open. The session dtor already had a guard (session_rsrc->ptr != NULLcheck), but bothphp_ssh2_sftp_stream_closeandphp_ssh2_sftp_dirstream_closecalledlibssh2_sftp_close()unconditionally. If the session was already destroyed, this dereferences freed memory.Fixed by adding the same guard to both stream close functions. Skip
libssh2_sftp_close()if the session has already been freed.