Fix use-after-free on re-entrant ftp_close() during a transfer#22400
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iliaal wants to merge 1 commit into
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Fix use-after-free on re-entrant ftp_close() during a transfer#22400iliaal wants to merge 1 commit into
iliaal wants to merge 1 commit into
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A user stream wrapper passed to ftp_get(), ftp_put(), ftp_append() or the ftp_nb_* variants can call ftp_close() from its stream_read or stream_write handler while the engine still holds the freed ftpbuf_t and databuf_t on the C stack, so the transfer resumes on freed memory. Guard each engine transfer with an in_use flag and make ftp_close() throw while it is set. Closes phpGH-22400
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A user stream wrapper's stream_read/stream_write handler can call ftp_close() mid-transfer (during ftp_get/ftp_put/ftp_append or the ftp_nb_* variants), freeing the
ftpbuf_tthe engine still holds on the C stack, so the transfer resumes on freed memory (valgrind: invalid reads in the ftp_get receive loop). The fix guards each engine transfer with anin_useflag and makes ftp_close() throw while a transfer is in progress. Reported privately as GHSA-vr2x-x6ff-4586, rejected per the security policy because the trigger is PHP code, not the FTP server.