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/*++
/* NAME
/* tls_rsa
/* SUMMARY
/* RSA support
/* SYNOPSIS
/* #define TLS_INTERNAL
/* #include <tls.h>
/*
/* RSA *tls_tmp_rsa_cb(ssl, export, keylength)
/* SSL *ssl; /* unused */
/* int export;
/* int keylength;
/* DESCRIPTION
/* tls_tmp_rsa_cb() is a call-back routine for the
/* SSL_CTX_set_tmp_rsa_callback() function.
/*
/* This implementation will generate only 512-bit ephemeral
/* RSA keys for export ciphersuites. It will log a warning in
/* all other usage contexts.
/* LICENSE
/* .ad
/* .fi
/* This software is free. You can do with it whatever you want.
/* The original author kindly requests that you acknowledge
/* the use of his software.
/* AUTHOR(S)
/* Originally written by:
/* Lutz Jaenicke
/* BTU Cottbus
/* Allgemeine Elektrotechnik
/* Universitaetsplatz 3-4
/* D-03044 Cottbus, Germany
/*
/* Updated by:
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*
/* Viktor Dukhovni.
/*--*/
/* System library. */
#include <sys_defs.h>
#include <msg.h>
#ifdef USE_TLS
/* TLS library. */
#define TLS_INTERNAL
#include <tls.h>
#include <openssl/rsa.h>
/*
* 2015-12-05: Ephemeral RSA removed from OpenSSL 1.1.0-dev
*/
#if OPENSSL_VERSION_NUMBER < 0x10100000L
/* tls_tmp_rsa_cb - call-back to generate ephemeral RSA key */
RSA *tls_tmp_rsa_cb(SSL *unused_ssl, int export, int keylength)
{
static RSA *rsa_tmp;
/*
* We generate ephemeral RSA keys only for export ciphersuites. In all
* other contexts use of ephemeral RSA keys violates the SSL/TLS
* protocol, and only takes place when applications ask for trouble and
* set the SSL_OP_EPHEMERAL_RSA option. Postfix should never do that.
*/
if (!export || keylength != 512) {
msg_warn("%sexport %d-bit ephemeral RSA key requested",
export ? "" : "non-", keylength);
return 0;
}
if (rsa_tmp == 0) {
BIGNUM *e = BN_new();
if (e != 0 && BN_set_word(e, RSA_F4) && (rsa_tmp = RSA_new()) != 0)
if (!RSA_generate_key_ex(rsa_tmp, keylength, e, 0)) {
RSA_free(rsa_tmp);
rsa_tmp = 0;
}
if (e)
BN_free(e);
}
return (rsa_tmp);
}
#endif /* OPENSSL_VERSION_NUMBER */
#ifdef TEST
#include <msg_vstream.h>
int main(int unused_argc, char *const argv[])
{
int ok = 0;
/*
* 2015-12-05: Ephemeral RSA removed from OpenSSL 1.1.0-dev
*/
#if OPENSSL_VERSION_NUMBER < 0x10100000L
RSA *rsa;
msg_vstream_init(argv[0], VSTREAM_ERR);
/* Export at 512-bits should work */
rsa = tls_tmp_rsa_cb(0, 1, 512);
ok = rsa != 0 && RSA_size(rsa) == 512 / 8;
ok = ok && PEM_write_RSAPrivateKey(stdout, rsa, 0, 0, 0, 0, 0);
tls_print_errors();
/* Non-export or unexpected bit length should fail */
ok = ok && tls_tmp_rsa_cb(0, 0, 512) == 0;
ok = ok && tls_tmp_rsa_cb(0, 1, 1024) == 0;
#endif
return ok ? 0 : 1;
}
#endif
#endif
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