Hi May be this problem could nothing to do with OpenSSL?
I experienced this problem under a , non SSL, private protocol for sending files to a server. The symptons were VERY similar: a hang after sending a file to a server, then exchanging little packets betwen client and server. I made experiments with the "low watermark" socket option, used by select( ) to detect when a packet has come to a socket. I remember that lowering that parameter could improve the situation but then I discovered the same effects in a LAN with fragmented packets incorrectly handled by broken routers and forget that tests. I suppose this is not your problem , unless something very ugly is happening on your OS. Not sure if this can help, or distract you. Anyway, hope it can help. ----- Original Message ----- From: "Dr. Stephen Henson" <[EMAIL PROTECTED]> To: "Paul L. Allen" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Tuesday, February 24, 2004 2:50 PM Subject: Re: OpenSSL session hangs > <moved to private mail> > > On Mon, Feb 23, 2004, Paul L. Allen wrote: > > > > > OK, here's where it took me: > > > > The setup is a stack consisting of a buffered BIO, an SSL BIO, and > > a socket BIO. In a typical test run, client and server have had a > > conversation of a hundred or so messages. The most recent exchange > > involved a message from the client of about 4500 bytes. Messages are > > newline-delimited ASCII lines exchanged via BIO_puts()/BIO_gets(), > > with a BIO_flush() after each BIO_puts(). > > > > The client sends a 4-byte message using BIO_puts(). > > buffer_write() stashes the bytes in the buffer and returns. > > The client calls BIO_flush() on the buffered BIO. > > In buffer_ctl(), BIO_write() gets called to get the SSL BIO to write the > > bytes. > > BIO_write() calls the bwrite method on the SSL BIO, which resolves to > > ssl_write(). > > ssl_write() calls SSL_write(). > > SSL_write() calls ssl->method->ssl_write, which resolves to ssl3_write(). > > ssl3_write() calls ssl3_write_bytes(). > > ssl3_write_bytes() calls do_ssl3_write(). > > do_ssl3_write() calls s->method->ssl3_enc->mac(), which hangs until a > > SIGALRM gets delivered in about 60 seconds. > > > > On all prior runs down this pathway, s->method->ssl3_enc->mac() > > returns OK, s->method->ssl3_enc->enc() is called, followed by s2n(), > > ssl3_write_pending() gets called to ask the socket BIO to write the > > data, and we return back up the stack to where BIO_flush() returns to > > my code. The above experiment is with the 2/19 snapshot of the OpenSSL > > code, liberally sprinkled with fprintf's. It's possible that I've > > missed some links in the chain, although I've tried pretty hard not to. > > > > The hang always involves a short message from the client following > > an interchange involving a long message from the client. If I move > > the transaction containing the long line around in the sequence of > > test transactions, the client sometimes does not hang. But when it > > does hang, it is always right after a long transaction. Interestingly, > > the "long" transactions consist of a 4500 byte message from the client, > > a short (100 bytes) message from the server, another short message from > > the client (which always succeeds), and another short message from the > > server. When the hang happens, it is on the next message from the > > client (the second short client message after a long one). > > > > I'm stumped! > > > > I'm not immediately sure what the problem is either. It might be stack > corruption somewhere or something confusing the malloc library. Have you tried > it under a debugging malloc library that can detect and out of bounds > accesses? > > Have you tried this under a different OS to see if you get the same behaviour? > > I could look into this as part of my commercial consultancy services if you > can't get anywhere. Maybe with a discount if it turned out to be an OpenSSL > bug :-) > > Steve. > -- > Dr Stephen N. Henson. Email, S/MIME and PGP keys: see homepage > OpenSSL project core developer and freelance consultant. > Funding needed! Details on homepage. > Homepage: http://www.drh-consultancy.demon.co.uk > ______________________________________________________________________ > OpenSSL Project http://www.openssl.org > User Support Mailing List [EMAIL PROTECTED] > Automated List Manager [EMAIL PROTECTED] > ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List [EMAIL PROTECTED] Automated List Manager [EMAIL PROTECTED]
