From 444b2ebee97fdbabbb32ec7b4ebd1b6f40638ec5 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Tue, 28 Jul 2015 21:39:40 +0200 Subject: [PATCH] Disable ssl renegotiation by default. While postgres' use of SSL renegotiation is a good idea in theory, it turned out to not work well in practice. The specification and openssl's implementation of it have lead to several security issues. Postgres' use of renegotiation also had its share of bugs. Additionally OpenSSL has a bunch of bugs around renegotiation, reported and open for years, that regularly lead to connections breaking with obscure error messages. We tried increasingly complex workarounds to get around these bugs, but we didn't find anything complete. Since these connection breakages often lead to hard to debug problems, e.g. spuriously failing base backups and significant latency spikes when synchronous replication is used, we have decided to change the default setting for ssl renegotiation to 0 (disabled) in the released backbranches and remove it entirely in 9.5 and master.. Author: Michael Paquier, with changes by me Discussion: 20150624144148.GQ4797@alap3.anarazel.de Backpatch: 9.0-9.4; 9.5 and master get a different patch --- doc/src/sgml/config.sgml | 10 +++++++++- src/backend/utils/misc/guc.c | 2 +- src/backend/utils/misc/postgresql.conf.sample | 2 +- 3 files changed, 11 insertions(+), 3 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 2f37a29f5e4..412e4eb2fc7 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -670,7 +670,7 @@ SET ENABLE_SEQSCAN TO OFF; cryptanalysis when large amounts of traffic can be examined, but it also carries a large performance penalty. The sum of sent and received traffic is used to check the limit. If this parameter is set to 0, - renegotiation is disabled. The default is 512MB. + renegotiation is disabled. The default is 0. @@ -682,6 +682,14 @@ SET ENABLE_SEQSCAN TO OFF; disabled. + + + + Due to bugs in OpenSSL enabling ssl renegotiation, by + configuring a non-zero ssl_renegotiation_limit, is likely + to lead to problems like long-lived connections breaking. + + diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index c171539209e..203f2026633 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -2012,7 +2012,7 @@ static struct config_int ConfigureNamesInt[] = GUC_UNIT_KB, }, &ssl_renegotiation_limit, - 512 * 1024, 0, MAX_KILOBYTES, NULL, NULL + 0, 0, MAX_KILOBYTES, NULL, NULL }, { diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 155af1cb988..1ebe72d723e 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -80,7 +80,7 @@ #ssl = off # (change requires restart) #ssl_ciphers = 'ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH' # allowed SSL ciphers # (change requires restart) -#ssl_renegotiation_limit = 512MB # amount of data between renegotiations +#ssl_renegotiation_limit = 0 # amount of data between renegotiations #password_encryption = on #db_user_namespace = off -- 2.39.5