On 07 Oct 2015, at 5:53 PM, Jim Jagielski <j...@jagunet.com> wrote: >> As I understand we’re using openssl in non blocking mode, which means that >> openssl will ask us permission before attempting any read or write. >> >> The core will then in turn either read or write as requested by openssl >> based on the “sense” flags CONN_SENSE_WANT_READ or CONN_SENSE_WANT_WRITE. >> >> If openssl has a bug and reads/writes without first asking permission we’ll >> block, but by the same token if openssl as asking us permission using >> SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE and we’re ignoring openssl, >> we’ll block for the same reason. > > But certainly these are situations which it's "safer" to block > in any case, right? Of course, they could also be vectors for some > sort of DDoS, but even then, that would be relying on pretty > nasty bugs.
The blocking isn’t really the problem, it’s accidentally waiting for a socket to be readable when openssl asked you to tell it when the socket is writable. I suspect turning on the “flush” is masking a bug. Regards, Graham —
