From 42d7f920c2732b5ea47bffd7bc1dc03b36fb6d05 Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Sun, 11 Mar 2018 08:53:33 -0400 Subject: [PATCH] Set libpq sslcompression to off by default Since SSL compression is no longer recommended, turn the default in libpq from on to off. OpenSSL 1.1.0 and many distribution packages already turn compression off by default, so such a server won't accept compression anyway. So this will mainly affect users of older OpenSSL installations. Also update the documentation to make clear that this setting is no longer recommended. --- doc/src/sgml/libpq.sgml | 24 +++++++++++++----------- src/interfaces/libpq/fe-connect.c | 2 +- src/interfaces/libpq/fe-secure-openssl.c | 8 ++++---- 3 files changed, 18 insertions(+), 16 deletions(-) diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml index da9421486b..18686bcad3 100644 --- a/doc/src/sgml/libpq.sgml +++ b/doc/src/sgml/libpq.sgml @@ -1438,19 +1438,21 @@ Parameter Key Words sslcompression - If set to 1 (default), data sent over SSL connections will be - compressed. - If set to 0, compression will be disabled (this requires - OpenSSL 1.0.0 or later). - This parameter is ignored if a connection without SSL is made, - or if the version of OpenSSL used does not support - it. + If set to 1, data sent over SSL connections will be compressed. If + set to 0, compression will be disabled. The default is 0. This + parameter is ignored if a connection without SSL is made. + - Compression uses CPU time, but can improve throughput if - the network is the bottleneck. - Disabling compression can improve response time and throughput - if CPU performance is the limiting factor. + SSL compression is nowadays considered insecure and its use is no + longer recommended. OpenSSL 1.1.0 disables + compression by default, and many operating system distributions + disable it in prior versions as well, so setting this parameter to on + will not have any effect if the server does not accept compression. + On the other hand, OpenSSL before 1.0.0 + does not support disabling compression, so this parameter is ignored + with those versions, and whether compression is used depends on the + server. diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c index 77eebb0ba1..39c19998c2 100644 --- a/src/interfaces/libpq/fe-connect.c +++ b/src/interfaces/libpq/fe-connect.c @@ -279,7 +279,7 @@ static const internalPQconninfoOption PQconninfoOptions[] = { "SSL-Mode", "", 12, /* sizeof("verify-full") == 12 */ offsetof(struct pg_conn, sslmode)}, - {"sslcompression", "PGSSLCOMPRESSION", "1", NULL, + {"sslcompression", "PGSSLCOMPRESSION", "0", NULL, "SSL-Compression", "", 1, offsetof(struct pg_conn, sslcompression)}, diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c index cade4e157c..25aa7a21bf 100644 --- a/src/interfaces/libpq/fe-secure-openssl.c +++ b/src/interfaces/libpq/fe-secure-openssl.c @@ -1188,14 +1188,14 @@ initialize_SSL(PGconn *conn) SSL_set_verify(conn->ssl, SSL_VERIFY_PEER, verify_cb); /* - * If the OpenSSL version used supports it (from 1.0.0 on) and the user - * requested it, disable SSL compression. + * Set compression option if the OpenSSL version used supports it (from + * 1.0.0 on). */ #ifdef SSL_OP_NO_COMPRESSION if (conn->sslcompression && conn->sslcompression[0] == '0') - { SSL_set_options(conn->ssl, SSL_OP_NO_COMPRESSION); - } + else + SSL_clear_options(conn->ssl, SSL_OP_NO_COMPRESSION); #endif return 0; base-commit: b6e132ddc8601c99ac5466792f6128ee859f4128 -- 2.16.2