postgres.git / summary / log / commit / refs
commit 444b2ebee97fdbabbb32ec7b4ebd1b6f40638ec5
Author: Andres Freund <andres@anarazel.de>
Date: Tue Jul 28 19:39:40 2015 +0000
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 <literal>512MB</>.
+ renegotiation is disabled. The default is <literal>0</>.
</para>
<note>
<para>
@@ -682,6 +682,14 @@ SET ENABLE_SEQSCAN TO OFF;
disabled.
</para>
</note>
+
+ <warning>
+ <para>
+ Due to bugs in <productname>OpenSSL</> enabling ssl renegotiation, by
+ configuring a non-zero <varname>ssl_renegotiation_limit</>, is likely
+ to lead to problems like long-lived connections breaking.
+ </para>
+ </warning>
</listitem>
</varlistentry>
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
[parent: f87bf8480674]