From 413d34be4e1f47ce52b02a6c60858ef6f1285578 Mon Sep 17 00:00:00 2001 From: Magnus Hagander Date: Thu, 25 Feb 2010 13:26:16 +0000 Subject: [PATCH] Add configuration parameter ssl_renegotiation_limit to control how often we do SSL session key renegotiation. Can be set to 0 to disable renegotiation completely, which is required if a broken SSL library is used (broken patches to CVE-2009-3555 a known cause) or when using a client library that can't do renegotiation. --- doc/src/sgml/config.sgml | 28 ++++++++++++++++++++++++++- src/backend/libpq/be-secure.c | 9 +++++---- src/backend/utils/misc/guc.c | 13 ++++++++++++- src/backend/utils/misc/postgresql.conf.sample | 1 + 4 files changed, 45 insertions(+), 6 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 4d7119fed2..e14dbfdbd7 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -1,4 +1,4 @@ - + Server Configuration @@ -606,6 +606,32 @@ SET ENABLE_SEQSCAN TO OFF; + + ssl_renegotiation_limit (int) + + ssl_renegotiation_limit configuration parameter + + + + Specifies how much data can flow over an SSL encrypted connection + before renegotiation of the session will take place. Renegotiation of the + session decreases the chance of doing cryptanalysis when large amounts of data + are sent, but it also carries a large performance penalty. The sum of + sent and received traffic is used to check the limit. If the parameter is + set to 0, renegotiation is disabled. The default is 512MB. + + + + SSL libraries from before November 2009 are insecure when using SSL + renegotiation, due to a vulnerability in the SSL protocol. As a stop-gap fix + for this vulnerability, some vendors also shipped SSL libraries incapable + of doing renegotiation. If any of these libraries are in use on the client + or server, SSL renegotiation should be disabled. + + + + + ssl_ciphers (string) diff --git a/src/backend/libpq/be-secure.c b/src/backend/libpq/be-secure.c index 9499899950..6dac77bff7 100644 --- a/src/backend/libpq/be-secure.c +++ b/src/backend/libpq/be-secure.c @@ -11,7 +11,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.97 2010/02/18 11:13:45 heikki Exp $ + * $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.98 2010/02/25 13:26:15 mha Exp $ * * Since the server static private key ($DataDir/server.key) * will normally be stored unencrypted so that the database @@ -93,13 +93,14 @@ static void close_SSL(Port *); static const char *SSLerrmessage(void); #endif -#ifdef USE_SSL /* * How much data can be sent across a secure connection * (total in both directions) before we require renegotiation. + * Set to 0 to disable renegotiation completely. */ -#define RENEGOTIATION_LIMIT (512 * 1024 * 1024) +int ssl_renegotiation_limit; +#ifdef USE_SSL static SSL_CTX *SSL_context = NULL; static bool ssl_loaded_verify_locations = false; @@ -320,7 +321,7 @@ secure_write(Port *port, void *ptr, size_t len) { int err; - if (port->count > RENEGOTIATION_LIMIT) + if (ssl_renegotiation_limit && port->count > ssl_renegotiation_limit * 1024L) { SSL_set_session_id_context(port->ssl, (void *) &SSL_context, sizeof(SSL_context)); diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index bde3be91cf..d533078845 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -10,7 +10,7 @@ * Written by Peter Eisentraut . * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.541 2010/02/17 04:19:40 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.542 2010/02/25 13:26:15 mha Exp $ * *-------------------------------------------------------------------- */ @@ -117,6 +117,7 @@ extern char *temp_tablespaces; extern bool synchronize_seqscans; extern bool fullPageWrites; extern int vacuum_defer_cleanup_age; +extern int ssl_renegotiation_limit; int trace_recovery_messages = LOG; @@ -1969,6 +1970,16 @@ static struct config_int ConfigureNamesInt[] = }, { + {"ssl_renegotiation_limit", PGC_USERSET, CONN_AUTH_SECURITY, + gettext_noop("Set the amount of traffic to send and receive before renegotiating the encryption keys."), + NULL, + GUC_UNIT_KB, + }, + &ssl_renegotiation_limit, + 512 * 1024, 0, MAX_KILOBYTES, NULL, NULL + }, + + { {"tcp_keepalives_count", PGC_USERSET, CLIENT_CONN_OTHER, gettext_noop("Maximum number of TCP keepalive retransmits."), gettext_noop("This controls the number of consecutive keepalive retransmits that can be " diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 1d2b9f0f67..b550132d11 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -80,6 +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 #password_encryption = on #db_user_namespace = off -- 2.11.0