www/apache
1
0
Fork 0
mirror of https://github.com/apache/httpd.git synced 2025-08-07 04:02:58 +03:00
Code Activity

Streamline ephemeral key handling:

Browse Source 
- drop support for ephemeral RSA keys (only allowed/needed
  for export ciphers)

- drop pTmpKeys from the per-process SSLModConfigRec, and remove
  the temp key generation at startup (unnecessary for DHE/ECDHE)

- unconditionally disable null and export-grade ciphers by always
  prepending "!aNULL:!eNULL:!EXP:" to any cipher suite string

- do not configure per-connection SSL_tmp_*_callbacks, as it is
  sufficient to set them for the SSL_CTX

- set default curve for ECDHE at startup, obviating the need
  for a per-handshake callback, for the time being (and also
  configure SSL_OP_SINGLE_ECDH_USE, previously left out)

For additional background, see
https://mail-archives.apache.org/mod_mbox/httpd-dev/201309.mbox/%3C52358ED1.2070704@velox.ch%3E


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1526168 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Kaspar Brand
2013-09-25 12:52:35 +00:00
parent 6a062fcc84
commit a6a324f9bb
7 changed files with 30 additions and 310 deletions
Download Patch File Download Diff File Expand all files Collapse all files

104
modules/ssl/ssl_engine_kernel.c
View File

@@ -1299,119 +1299,19 @@ const authz_provider ssl_authz_provider_verify_client =
** _________________________________________________________________
*/
/*
* Handle out temporary RSA private keys on demand
*
* The background of this as the TLSv1 standard explains it:
*
* | D.1. Temporary RSA keys
* |
* | US Export restrictions limit RSA keys used for encryption to 512
* | bits, but do not place any limit on lengths of RSA keys used for
* | signing operations. Certificates often need to be larger than 512
* | bits, since 512-bit RSA keys are not secure enough for high-value
* | transactions or for applications requiring long-term security. Some
* | certificates are also designated signing-only, in which case they
* | cannot be used for key exchange.
* |
* | When the public key in the certificate cannot be used for encryption,
* | the server signs a temporary RSA key, which is then exchanged. In
* | exportable applications, the temporary RSA key should be the maximum
* | allowable length (i.e., 512 bits). Because 512-bit RSA keys are
* | relatively insecure, they should be changed often. For typical
* | electronic commerce applications, it is suggested that keys be
* | changed daily or every 500 transactions, and more often if possible.
* | Note that while it is acceptable to use the same temporary key for
* | multiple transactions, it must be signed each time it is used.
* |
* | RSA key generation is a time-consuming process. In many cases, a
* | low-priority process can be assigned the task of key generation.
* | Whenever a new key is completed, the existing temporary key can be
* | replaced with the new one.
*
* XXX: base on comment above, if thread support is enabled,
* we should spawn a low-priority thread to generate new keys
* on the fly.
*
* So we generated 512 and 1024 bit temporary keys on startup
* which we now just hand out on demand....
*/
RSA *ssl_callback_TmpRSA(SSL *ssl, int export, int keylen)
{
conn_rec *c = (conn_rec *)SSL_get_app_data(ssl);
SSLModConfigRec *mc = myModConfigFromConn(c);
int idx;
ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, c,
"handing out temporary %d bit RSA key", keylen);
/* doesn't matter if export flag is on,
* we won't be asked for keylen > 512 in that case.
* if we are asked for a keylen > 1024, it is too expensive
* to generate on the fly.
* XXX: any reason not to generate 2048 bit keys at startup?
*/
switch (keylen) {
case 512:
idx = SSL_TMP_KEY_RSA_512;
break;
case 1024:
default:
idx = SSL_TMP_KEY_RSA_1024;
}
return (RSA *)mc->pTmpKeys[idx];
}
/*
* Hand out the already generated DH parameters...
*/
DH *ssl_callback_TmpDH(SSL *ssl, int export, int keylen)
{
conn_rec *c = (conn_rec *)SSL_get_app_data(ssl);
SSLModConfigRec *mc = myModConfigFromConn(c);
int idx;
ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, c,
"handing out temporary %d bit DH key", keylen);
"handing out parameters for temporary %d bit DH key", keylen);
switch (keylen) {
case 512:
idx = SSL_TMP_KEY_DH_512;
break;
case 1024:
default:
idx = SSL_TMP_KEY_DH_1024;
}
return (DH *)mc->pTmpKeys[idx];
return ssl_dh_GetTmpParam(keylen);
}
#ifndef OPENSSL_NO_EC
EC_KEY *ssl_callback_TmpECDH(SSL *ssl, int export, int keylen)
{
conn_rec *c = (conn_rec *)SSL_get_app_data(ssl);
SSLModConfigRec *mc = myModConfigFromConn(c);
int idx;
/* XXX Uses 256-bit key for now. TODO: support other sizes. */
ap_log_cerror(APLOG_MARK, APLOG_TRACE2, 0, c,
"handing out temporary 256 bit ECC key");
switch (keylen) {
case 256:
default:
idx = SSL_TMP_KEY_EC_256;
}
return (EC_KEY *)mc->pTmpKeys[idx];
}
#endif
/*
* This OpenSSL callback function is called when OpenSSL
* does client authentication and verifies the certificate chain.