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Security framework.

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Security callback: selects which parameters are permitted including
sensible defaults based on bits of security.

The "parameters" which can be selected include: ciphersuites,
curves, key sizes, certificate signature algorithms, supported
signature algorithms, DH parameters, SSL/TLS version, session tickets
and compression.

In some cases prohibiting the use of a parameters will mean they are
not advertised to the peer: for example cipher suites and ECC curves.
In other cases it will abort the handshake: e.g DH parameters or the
peer key size.

Documentation to follow...
This commit is contained in:
Dr. Stephen Henson
2013-12-15 13:32:24 +00:00
parent 66f96fe2d5
commit b362ccab5c
16 changed files with 827 additions and 202 deletions
Download Patch File Download Diff File Expand all files Collapse all files

175
ssl/ssl_cert.c
View File

@@ -132,6 +132,8 @@
#include <openssl/bn.h>
#include "ssl_locl.h"
static int ssl_security_default_callback(SSL *s, SSL_CTX *ctx, int op, int bits, int nid, void *other, void *ex);
int SSL_get_ex_data_X509_STORE_CTX_idx(void)
{
static volatile int ssl_x509_store_ctx_idx= -1;
@@ -190,6 +192,9 @@ CERT *ssl_cert_new(void)
ret->key= &(ret->pkeys[SSL_PKEY_RSA_ENC]);
ret->references=1;
ssl_cert_set_default_md(ret);
ret->sec_cb = ssl_security_default_callback;
ret->sec_level = OPENSSL_TLS_SECURITY_LEVEL;
ret->sec_ex = NULL;
return(ret);
}
@@ -414,6 +419,10 @@ CERT *ssl_cert_dup(CERT *cert)
ret->ciphers_raw = NULL;
ret->sec_cb = cert->sec_cb;
ret->sec_level = cert->sec_level;
ret->sec_ex = cert->sec_ex;
return(ret);
#if !defined(OPENSSL_NO_DH) || !defined(OPENSSL_NO_ECDH)
@@ -553,26 +562,36 @@ int ssl_cert_inst(CERT **o)
return(1);
}
int ssl_cert_set0_chain(CERT *c, STACK_OF(X509) *chain)
int ssl_cert_set0_chain(SSL *s, SSL_CTX *ctx, STACK_OF(X509) *chain)
{
CERT_PKEY *cpk = c->key;
int i, r;
CERT_PKEY *cpk = s ? s->cert->key : ctx->cert->key;
if (!cpk)
return 0;
if (cpk->chain)
sk_X509_pop_free(cpk->chain, X509_free);
for (i = 0; i < sk_X509_num(chain); i++)
{
r = ssl_security_cert(s, ctx, sk_X509_value(chain, i), 0, 0);
if (r != 1)
{
SSLerr(SSL_F_SSL_CERT_SET0_CHAIN, r);
return 0;
}
}
cpk->chain = chain;
return 1;
}
int ssl_cert_set1_chain(CERT *c, STACK_OF(X509) *chain)
int ssl_cert_set1_chain(SSL *s, SSL_CTX *ctx, STACK_OF(X509) *chain)
{
STACK_OF(X509) *dchain;
if (!chain)
return ssl_cert_set0_chain(c, NULL);
return ssl_cert_set0_chain(s, ctx, NULL);
dchain = X509_chain_up_ref(chain);
if (!dchain)
return 0;
if (!ssl_cert_set0_chain(c, dchain))
if (!ssl_cert_set0_chain(s, ctx, dchain))
{
sk_X509_pop_free(dchain, X509_free);
return 0;
@@ -580,11 +599,18 @@ int ssl_cert_set1_chain(CERT *c, STACK_OF(X509) *chain)
return 1;
}
int ssl_cert_add0_chain_cert(CERT *c, X509 *x)
int ssl_cert_add0_chain_cert(SSL *s, SSL_CTX *ctx, X509 *x)
{
CERT_PKEY *cpk = c->key;
int r;
CERT_PKEY *cpk = s ? s->cert->key : ctx->cert->key;
if (!cpk)
return 0;
r = ssl_security_cert(s, ctx, x, 0, 0);
if (r != 1)
{
SSLerr(SSL_F_SSL_CERT_ADD0_CHAIN_CERT, r);
return 0;
}
if (!cpk->chain)
cpk->chain = sk_X509_new_null();
if (!cpk->chain || !sk_X509_push(cpk->chain, x))
@@ -592,9 +618,9 @@ int ssl_cert_add0_chain_cert(CERT *c, X509 *x)
return 1;
}
int ssl_cert_add1_chain_cert(CERT *c, X509 *x)
int ssl_cert_add1_chain_cert(SSL *s, SSL_CTX *ctx, X509 *x)
{
if (!ssl_cert_add0_chain_cert(c, x))
if (!ssl_cert_add0_chain_cert(s, ctx, x))
return 0;
CRYPTO_add(&x->references, 1, CRYPTO_LOCK_X509);
return 1;
@@ -790,6 +816,14 @@ int ssl_verify_cert_chain(SSL *s,STACK_OF(X509) *sk)
{
#ifndef OPENSSL_NO_X509_VERIFY
i=X509_verify_cert(&ctx);
#if 0
/* Dummy error calls so mkerr generates them */
SSLerr(SSL_F_SSL_VERIFY_CERT_CHAIN,SSL_R_EE_KEY_TOO_SMALL);
SSLerr(SSL_F_SSL_VERIFY_CERT_CHAIN,SSL_R_CA_KEY_TOO_SMALL);
SSLerr(SSL_F_SSL_VERIFY_CERT_CHAIN,SSL_R_CA_MD_TOO_WEAK);
#endif
if (i > 0)
i = ssl_security_cert_chain(s, ctx.chain, NULL, 1);
#else
i=0;
ctx.error=X509_V_ERR_APPLICATION_VERIFICATION;
@@ -1159,6 +1193,13 @@ int ssl_add_cert_chain(SSL *s, CERT_PKEY *cpk, unsigned long *l)
X509_verify_cert(&xs_ctx);
/* Don't leave errors in the queue */
ERR_clear_error();
i = ssl_security_cert_chain(s, xs_ctx.chain, NULL, 0);
if (i != 1)
{
X509_STORE_CTX_cleanup(&xs_ctx);
SSLerr(SSL_F_SSL_ADD_CERT_CHAIN, i);
return 0;
}
for (i=0; i < sk_X509_num(xs_ctx.chain); i++)
{
x = sk_X509_value(xs_ctx.chain, i);
@@ -1173,6 +1214,12 @@ int ssl_add_cert_chain(SSL *s, CERT_PKEY *cpk, unsigned long *l)
}
else
{
i = ssl_security_cert_chain(s, extra_certs, x, 0);
if (i != 1)
{
SSLerr(SSL_F_SSL_ADD_CERT_CHAIN, i);
return 0;
}
if (!ssl_add_cert_to_buf(buf, l, x))
return 0;
for (i=0; i<sk_X509_num(extra_certs); i++)
@@ -1186,9 +1233,11 @@ int ssl_add_cert_chain(SSL *s, CERT_PKEY *cpk, unsigned long *l)
}
/* Build a certificate chain for current certificate */
int ssl_build_cert_chain(CERT *c, X509_STORE *chain_store, int flags)
int ssl_build_cert_chain(SSL *s, SSL_CTX *ctx, int flags)
{
CERT *c = s ? s->cert : ctx->cert;
CERT_PKEY *cpk = c->key;
X509_STORE *chain_store = NULL;
X509_STORE_CTX xs_ctx;
STACK_OF(X509) *chain = NULL, *untrusted = NULL;
X509 *x;
@@ -1232,6 +1281,10 @@ int ssl_build_cert_chain(CERT *c, X509_STORE *chain_store, int flags)
{
if (c->chain_store)
chain_store = c->chain_store;
else if (s)
chain_store = s->ctx->cert_store;
else
chain_store = ctx->cert_store;
if (flags & SSL_BUILD_CHAIN_FLAG_UNTRUSTED)
untrusted = cpk->chain;
@@ -1266,8 +1319,6 @@ int ssl_build_cert_chain(CERT *c, X509_STORE *chain_store, int flags)
goto err;
}
X509_STORE_CTX_cleanup(&xs_ctx);
if (cpk->chain)
sk_X509_pop_free(cpk->chain, X509_free);
/* Remove EE certificate from chain */
x = sk_X509_shift(chain);
X509_free(x);
@@ -1285,6 +1336,23 @@ int ssl_build_cert_chain(CERT *c, X509_STORE *chain_store, int flags)
}
}
}
/* Check security level of all CA certificates: EE will have been
* checked already.
*/
for (i = 0; i < sk_X509_num(chain); i++)
{
x = sk_X509_value(chain, i);
rv = ssl_security_cert(s, ctx, x, 0, 0);
if (rv != 1)
{
SSLerr(SSL_F_SSL_BUILD_CERT_CHAIN, rv);
sk_X509_pop_free(chain, X509_free);
rv = 0;
goto err;
}
}
if (cpk->chain)
sk_X509_pop_free(cpk->chain, X509_free);
cpk->chain = chain;
if (rv == 0)
rv = 1;
@@ -1310,3 +1378,86 @@ int ssl_cert_set_cert_store(CERT *c, X509_STORE *store, int chain, int ref)
return 1;
}
static int ssl_security_default_callback(SSL *s, SSL_CTX *ctx, int op, int bits, int nid, void *other, void *ex)
{
int level, minbits;
static const int minbits_table[5] = {80, 112, 128, 192, 256};
if (ctx)
level = SSL_CTX_get_security_level(ctx);
else
level = SSL_get_security_level(s);
/* Level 0: anything goes */
if (level <= 0)
return 1;
if (level > 5)
level = 5;
minbits = minbits_table[level - 1];
switch (op)
{
case SSL_SECOP_CIPHER_SUPPORTED:
case SSL_SECOP_CIPHER_SHARED:
case SSL_SECOP_CIPHER_CHECK:
{
const SSL_CIPHER *c = other;
/* No ciphers below security level */
if (bits < minbits)
return 0;
/* No SSLv2 ciphers */
if ((SSL_CIPHER_get_id(c) >> 24) == 0x2)
return 0;
/* No unauthenticated ciphersuites */
if (c->algorithm_auth & SSL_aNULL)
return 0;
/* No MD5 mac ciphersuites */
if (c->algorithm_mac & SSL_MD5)
return 0;
/* Level 2: no RC4 */
if (level >= 2 && c->algorithm_enc == SSL_RC4)
return 0;
/* Level 3: forward secure ciphersuites only */
if (level >= 3 && !(c->algorithm_mkey & (SSL_kEDH|SSL_kEECDH)))
return 0;
break;
}
case SSL_SECOP_VERSION:
/* SSLv2 allowed only on level zero */
if (nid == SSL2_VERSION)
return 0;
/* SSLv3 not allowed on level 2 */
if (nid <= SSL3_VERSION && level >= 2)
return 0;
/* TLS v1.1 and above only for level 3 */
if (nid <= TLS1_VERSION && level >= 3)
return 0;
/* TLS v1.2 only for level 4 and above */
if (nid <= TLS1_1_VERSION && level >= 4)
return 0;
break;
case SSL_SECOP_COMPRESSION:
if (level >= 2)
return 0;
break;
case SSL_SECOP_TICKET:
if (level >= 3)
return 0;
break;
case SSL_SECOP_SSL2_COMPAT:
/* SSLv2 compatible client hello only for level zero */
return 0;
default:
if (bits < minbits)
return 0;
}
return 1;
}
int ssl_security(SSL *s, int op, int bits, int nid, void *other)
{
return s->cert->sec_cb(s, NULL, op, bits, nid, other, s->cert->sec_ex);
}
int ssl_ctx_security(SSL_CTX *ctx, int op, int bits, int nid, void *other)
{
return ctx->cert->sec_cb(NULL, ctx, op, bits, nid, other, ctx->cert->sec_ex);
}