On 07/11/2014 08:39 PM, Alvaro Herrera wrote:
Heikki Linnakangas wrote:

I did again the refactoring you did back in 2006, patch attached.
One thing I did differently: I moved the raw, non-encrypted,
read/write functions to separate functions: pqsecure_raw_read and
pqsecure_raw_write. Those functions encapsulate the SIGPIPE
handling. The OpenSSL code implements a custom BIO, which calls to
pqsecure_raw_read/write to do the low-level I/O.  Similarly in the
server-side, there are be_tls_raw_read and pg_tls_raw_write
functions, which do the
prepare_for_client_read()/client_read_ended() dance, so that the SSL
implementation doesn't need to know about that.

I'm skimming over this patch (0001).  There are some issues:

* You duplicated the long comment under the IDENTIFICATION tag that was
   in be-secure.c; it's now both in that file and also in
   be-secure-openssl.c.  I think it should be removed from be-secure.c.
   Also, the hardcoded DH params are duplicated in be-secure.c, but they
   belong in -openssl.c only now.

Hmm. Once we add other SSL implementations, shouldn't they share the hardcoded DH parameters? That would warrant keeping them in be-secure.c.

* There is some mixup regarding USE_SSL and USE_OPENSSL in be-secure.c.
   I think anything that's OpenSSL-specific should be in
   be-secure-openssl.c only; any new SSL implementation will need to
   implement all those functions.  For instance, be_tls_init().


   I imagine that if we select any SSL implementation, USE_SSL would get
   defined, and each SSL implementation would additionally define its own

Yeah, that was the idea.

* ssl_renegotiation_limit is also duplicated.  But removing this one is
   probably not going to be as easy as deleting a line from be-secure.c,
   because guc.c depends on that one.  I think that variable should be
   defined in be-secure.c (i.e. delete it from -openssl) and make sure
   that all SSL implementations enforce it on their own somehow.


The DISABLE_SIGPIPE thingy looks wrong in pqsecure_write.  I think it
should be like this:

pqsecure_write(PGconn *conn, const void *ptr, size_t len)
        ssize_t         n;

#ifdef USE_SSL
        if (conn->ssl_in_use)

                DISABLE_SIGPIPE(conn, spinfo, return -1);

                n = pgtls_write(conn, ptr, len);

#endif   /* USE_OPENSSL */
                n = pqsecure_raw_write(conn, ptr, len);

        return n;

You are missing the restore call, and I moved the declaration inside the
ssl_in_use block since otherwise it's not useful.  The other path is
fine since pqsecure_raw_write disables and restores the flag by itself.
Also, you're missing DECLARE/DISABLE/RESTORE in the ssl_in_use block in
pqsecure_read.  (The original code does not have that code in the
non-SSL path.  I assume, without checking, that that's okay.)  I also
assume without checking that all SSL implementations would be fine with
this SIGPIPE handling.

Another thing that seems wrong is the REMEMBER_EPIPE stuff.  The
fe-secure-openssl.c code should be setting the flag, but AFAICS only the
non-SSL code is doing it.

I think you're missing a change to the way fe-secure-openssl.c now uses the OpenSSL library: it defines custom read/write functions, my_sock_read and my_sock_write, which in turn call pqsecure_raw_read/write. So all the actual I/O now goes through pqsecure_raw_read/write. I believe it's therefore enough to put do the REMEMBER_EPIPE in pqsecure_raw_write. Come to think of it, pqsecure_write() shouldn't be doing any SIGPIGE stuff at all anymore.

- Heikki

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