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Re: OpenLDAP and DH parameter size / LogJam vulnerability
On Wed, Jul 15, 2015 at 05:58:47PM +0200, Jens Vagelpohl wrote:
> Since that ITS is several years old I guess the fix is not in OPENLDAP_REL_ENG_2_4?
Attached is the change backported to 2.4.40 if that helps you.
--
Emmanuel Dreyfus
manu@netbsd.org
>From 6f120920d359d3b880c5c56bde4c1b91c3bedb01 Mon Sep 17 00:00:00 2001
From: Ben Jencks <ben@bjencks.net>
Date: Sun, 27 Jan 2013 18:27:03 -0500
Subject: [PATCH] ITS#7506 tls_o.c: Fix Diffie-Hellman parameter usage.
If a DHParamFile or olcDHParamFile is specified, then it will be used,
otherwise a hardcoded 1024 bit parameter will be used. This allows the use of
larger parameters; previously only 512 or 1024 bit parameters would ever be
used.
>From cfeb28412c28ce9feeea6e6c055286f201bd0a34 Mon Sep 17 00:00:00 2001
From: Howard Chu <hyc@openldap.org>
Date: Sat, 7 Sep 2013 06:39:53 -0700
Subject: [PATCH] ITS#7506 fix prev commit
The patch unconditionally enabled DHparams, which is a significant
change of behavior. Reverting to previous behavior, which only enables
DH use if a DHparam file was configured.
--- libraries/libldap/tls_o.c.orig 2015-07-15 18:14:17.000000000 +0200
+++ libraries/libldap/tls_o.c 2015-07-15 18:14:41.000000000 +0200
@@ -58,26 +58,15 @@
static int tlso_verify_cb( int ok, X509_STORE_CTX *ctx );
static int tlso_verify_ok( int ok, X509_STORE_CTX *ctx );
static RSA * tlso_tmp_rsa_cb( SSL *ssl, int is_export, int key_length );
-static DH * tlso_tmp_dh_cb( SSL *ssl, int is_export, int key_length );
-
-typedef struct dhplist {
- struct dhplist *next;
- int keylength;
- DH *param;
-} dhplist;
-
-static dhplist *tlso_dhparams;
-
static int tlso_seed_PRNG( const char *randfile );
#ifdef LDAP_R_COMPILE
/*
* provide mutexes for the OpenSSL library.
*/
static ldap_pvt_thread_mutex_t tlso_mutexes[CRYPTO_NUM_LOCKS];
-static ldap_pvt_thread_mutex_t tlso_dh_mutex;
static void tlso_locking_cb( int mode, int type, const char *file, int line )
{
if ( mode & CRYPTO_LOCK ) {
@@ -106,9 +95,8 @@
for( i=0; i< CRYPTO_NUM_LOCKS ; i++ ) {
ldap_pvt_thread_mutex_init( &tlso_mutexes[i] );
}
- ldap_pvt_thread_mutex_init( &tlso_dh_mutex );
CRYPTO_set_locking_callback( tlso_locking_cb );
CRYPTO_set_id_callback( tlso_thread_self );
}
#endif /* LDAP_R_COMPILE */
@@ -310,27 +298,27 @@
if ( lo->ldo_tls_dhfile ) {
DH *dh = NULL;
BIO *bio;
- dhplist *p;
+ SSL_CTX_set_options( ctx, SSL_OP_SINGLE_DH_USE );
if (( bio=BIO_new_file( lt->lt_dhfile,"r" )) == NULL ) {
Debug( LDAP_DEBUG_ANY,
"TLS: could not use DH parameters file `%s'.\n",
lo->ldo_tls_dhfile,0,0);
tlso_report_error();
return -1;
}
- while (( dh=PEM_read_bio_DHparams( bio, NULL, NULL, NULL ))) {
- p = LDAP_MALLOC( sizeof(dhplist) );
- if ( p != NULL ) {
- p->keylength = DH_size( dh ) * 8;
- p->param = dh;
- p->next = tlso_dhparams;
- tlso_dhparams = p;
- }
+ if (!( dh=PEM_read_bio_DHparams( bio, NULL, NULL, NULL ))) {
+ Debug( LDAP_DEBUG_ANY,
+ "TLS: could not read DH parameters file `%s'.\n",
+ lo->ldo_tls_dhfile,0,0);
+ tlso_report_error();
+ BIO_free( bio );
+ return -1;
}
BIO_free( bio );
+ SSL_CTX_set_tmp_dh( ctx, dh );
}
if ( tlso_opt_trace ) {
SSL_CTX_set_info_callback( ctx, tlso_info_cb );
@@ -348,11 +336,8 @@
SSL_CTX_set_verify( ctx, i,
lo->ldo_tls_require_cert == LDAP_OPT_X_TLS_ALLOW ?
tlso_verify_ok : tlso_verify_cb );
SSL_CTX_set_tmp_rsa_callback( ctx, tlso_tmp_rsa_cb );
- if ( lo->ldo_tls_dhfile ) {
- SSL_CTX_set_tmp_dh_callback( ctx, tlso_tmp_dh_cb );
- }
#ifdef HAVE_OPENSSL_CRL
if ( lo->ldo_tls_crlcheck ) {
X509_STORE *x509_s = SSL_CTX_get_cert_store( ctx );
if ( lo->ldo_tls_crlcheck == LDAP_OPT_X_TLS_CRL_PEER ) {
@@ -1159,110 +1144,8 @@
return 0;
}
-struct dhinfo {
- int keylength;
- const char *pem;
- size_t size;
-};
-
-
-/* From the OpenSSL 0.9.7 distro */
-static const char tlso_dhpem512[] =
-"-----BEGIN DH PARAMETERS-----\n\
-MEYCQQDaWDwW2YUiidDkr3VvTMqS3UvlM7gE+w/tlO+cikQD7VdGUNNpmdsp13Yn\n\
-a6LT1BLiGPTdHghM9tgAPnxHdOgzAgEC\n\
------END DH PARAMETERS-----\n";
-
-static const char tlso_dhpem1024[] =
-"-----BEGIN DH PARAMETERS-----\n\
-MIGHAoGBAJf2QmHKtQXdKCjhPx1ottPb0PMTBH9A6FbaWMsTuKG/K3g6TG1Z1fkq\n\
-/Gz/PWk/eLI9TzFgqVAuPvr3q14a1aZeVUMTgo2oO5/y2UHe6VaJ+trqCTat3xlx\n\
-/mNbIK9HA2RgPC3gWfVLZQrY+gz3ASHHR5nXWHEyvpuZm7m3h+irAgEC\n\
------END DH PARAMETERS-----\n";
-
-static const char tlso_dhpem2048[] =
-"-----BEGIN DH PARAMETERS-----\n\
-MIIBCAKCAQEA7ZKJNYJFVcs7+6J2WmkEYb8h86tT0s0h2v94GRFS8Q7B4lW9aG9o\n\
-AFO5Imov5Jo0H2XMWTKKvbHbSe3fpxJmw/0hBHAY8H/W91hRGXKCeyKpNBgdL8sh\n\
-z22SrkO2qCnHJ6PLAMXy5fsKpFmFor2tRfCzrfnggTXu2YOzzK7q62bmqVdmufEo\n\
-pT8igNcLpvZxk5uBDvhakObMym9mX3rAEBoe8PwttggMYiiw7NuJKO4MqD1llGkW\n\
-aVM8U2ATsCun1IKHrRxynkE1/MJ86VHeYYX8GZt2YA8z+GuzylIOKcMH6JAWzMwA\n\
-Gbatw6QwizOhr9iMjZ0B26TE3X8LvW84wwIBAg==\n\
------END DH PARAMETERS-----\n";
-
-static const char tlso_dhpem4096[] =
-"-----BEGIN DH PARAMETERS-----\n\
-MIICCAKCAgEA/urRnb6vkPYc/KEGXWnbCIOaKitq7ySIq9dTH7s+Ri59zs77zty7\n\
-vfVlSe6VFTBWgYjD2XKUFmtqq6CqXMhVX5ElUDoYDpAyTH85xqNFLzFC7nKrff/H\n\
-TFKNttp22cZE9V0IPpzedPfnQkE7aUdmF9JnDyv21Z/818O93u1B4r0szdnmEvEF\n\
-bKuIxEHX+bp0ZR7RqE1AeifXGJX3d6tsd2PMAObxwwsv55RGkn50vHO4QxtTARr1\n\
-rRUV5j3B3oPMgC7Offxx+98Xn45B1/G0Prp11anDsR1PGwtaCYipqsvMwQUSJtyE\n\
-EOQWk+yFkeMe4vWv367eEi0Sd/wnC+TSXBE3pYvpYerJ8n1MceI5GQTdarJ77OW9\n\
-bGTHmxRsLSCM1jpLdPja5jjb4siAa6EHc4qN9c/iFKS3PQPJEnX7pXKBRs5f7AF3\n\
-W3RIGt+G9IVNZfXaS7Z/iCpgzgvKCs0VeqN38QsJGtC1aIkwOeyjPNy2G6jJ4yqH\n\
-ovXYt/0mc00vCWeSNS1wren0pR2EiLxX0ypjjgsU1mk/Z3b/+zVf7fZSIB+nDLjb\n\
-NPtUlJCVGnAeBK1J1nG3TQicqowOXoM6ISkdaXj5GPJdXHab2+S7cqhKGv5qC7rR\n\
-jT6sx7RUr0CNTxzLI7muV2/a4tGmj0PSdXQdsZ7tw7gbXlaWT1+MM2MCAQI=\n\
------END DH PARAMETERS-----\n";
-
-static const struct dhinfo tlso_dhpem[] = {
- { 512, tlso_dhpem512, sizeof(tlso_dhpem512) },
- { 1024, tlso_dhpem1024, sizeof(tlso_dhpem1024) },
- { 2048, tlso_dhpem2048, sizeof(tlso_dhpem2048) },
- { 4096, tlso_dhpem4096, sizeof(tlso_dhpem4096) },
- { 0, NULL, 0 }
-};
-
-static DH *
-tlso_tmp_dh_cb( SSL *ssl, int is_export, int key_length )
-{
- struct dhplist *p = NULL;
- BIO *b = NULL;
- DH *dh = NULL;
- int i;
-
- /* Do we have params of this length already? */
- LDAP_MUTEX_LOCK( &tlso_dh_mutex );
- for ( p = tlso_dhparams; p; p=p->next ) {
- if ( p->keylength == key_length ) {
- LDAP_MUTEX_UNLOCK( &tlso_dh_mutex );
- return p->param;
- }
- }
-
- /* No - check for hardcoded params */
-
- for (i=0; tlso_dhpem[i].keylength; i++) {
- if ( tlso_dhpem[i].keylength == key_length ) {
- b = BIO_new_mem_buf( (char *)tlso_dhpem[i].pem, tlso_dhpem[i].size );
- break;
- }
- }
-
- if ( b ) {
- dh = PEM_read_bio_DHparams( b, NULL, NULL, NULL );
- BIO_free( b );
- }
-
- /* Generating on the fly is expensive/slow... */
- if ( !dh ) {
- dh = DH_generate_parameters( key_length, DH_GENERATOR_2, NULL, NULL );
- }
- if ( dh ) {
- p = LDAP_MALLOC( sizeof(struct dhplist) );
- if ( p != NULL ) {
- p->keylength = key_length;
- p->param = dh;
- p->next = tlso_dhparams;
- tlso_dhparams = p;
- }
- }
-
- LDAP_MUTEX_UNLOCK( &tlso_dh_mutex );
- return dh;
-}
tls_impl ldap_int_tls_impl = {
"OpenSSL",