wbrawner/openssl
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Update the example in proxy_certificates.txt

Browse source 
Reviewed-by: Rich Salz <rsalz@openssl.org>
This commit is contained in:
Richard Levitte 2016-07-25 18:55:28 +02:00
parent 9d7bfb14dd
commit 61d81f0ac9
1 changed files with 111 additions and 98 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

209
doc/HOWTO/proxy_certificates.txt
View file

@ -164,138 +164,151 @@ You need the following ingredients:
Here is some skeleton code you can fill in:
/* In this example, I will use a view of granted rights as a bit
array, one bit for each possible right. */
#include <string.h>
#include <netdb.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#define total_rights 25
/*
* In this example, I will use a view of granted rights as a bit
* array, one bit for each possible right.
*/
typedef struct your_rights {
unsigned char rights[total_rights / 8];
unsigned char rights[(total_rights + 7) / 8];
} YOUR_RIGHTS;
/* The following procedure will create an index for the ex_data
store in the X509 validation context the first time it's called.
Subsequent calls will return the same index. */
static int get_proxy_auth_ex_data_idx(void)
/*
* The following procedure will create an index for the ex_data
* store in the X509 validation context the first time it's called.
* Subsequent calls will return the same index. */
static int get_proxy_auth_ex_data_idx(X509_STORE_CTX *ctx)
{
static volatile int idx = -1;
if (idx < 0)
{
CRYPTO_w_lock(CRYPTO_LOCK_X509_STORE);
if (idx < 0)
{
idx = X509_STORE_CTX_get_ex_new_index(0,
"for verify callback",
NULL,NULL,NULL);
static volatile int idx = -1;
if (idx < 0) {
X509_STORE_lock(X509_STORE_CTX_get0_store(ctx));
if (idx < 0) {
idx = X509_STORE_CTX_get_ex_new_index(0,
"for verify callback",
NULL,NULL,NULL);
}
CRYPTO_w_unlock(CRYPTO_LOCK_X509_STORE);
X509_STORE_unlock(X509_STORE_CTX_get0_store(ctx));
}
return idx;
return idx;
}
/* Callback to be given to the X509 validation procedure. */
static int verify_callback(int ok, X509_STORE_CTX *ctx)
{
if (ok == 1) /* It's REALLY important you keep the proxy policy
check within this section. It's important to know
that when ok is 1, the certificates are checked
from top to bottom. You get the CA root first,
followed by the possible chain of intermediate
CAs, followed by the EE certificate, followed by
the possible proxy certificates. */
{
X509 *xs = ctx->current_cert;
if (ok == 1) {
/*
* It's REALLY important you keep the proxy policy
* check within this section. It's important to know
* that when ok is 1, the certificates are checked
* from top to bottom. You get the CA root first,
* followed by the possible chain of intermediate
* CAs, followed by the EE certificate, followed by
* the possible proxy certificates.
*/
X509 *xs = X509_STORE_CTX_get_current_cert(ctx);
if (xs->ex_flags & EXFLAG_PROXY)
{
YOUR_RIGHTS *rights =
(YOUR_RIGHTS *)X509_STORE_CTX_get_ex_data(ctx,
get_proxy_auth_ex_data_idx());
PROXY_CERT_INFO_EXTENSION *pci =
X509_get_ext_d2i(xs, NID_proxyCertInfo, NULL, NULL);
if (X509_get_extension_flags(xs) & EXFLAG_PROXY) {
YOUR_RIGHTS *rights =
(YOUR_RIGHTS *)X509_STORE_CTX_get_ex_data(ctx,
get_proxy_auth_ex_data_idx(ctx));
PROXY_CERT_INFO_EXTENSION *pci =
X509_get_ext_d2i(xs, NID_proxyCertInfo, NULL, NULL);
switch (OBJ_obj2nid(pci->proxyPolicy->policyLanguage))
{
switch (OBJ_obj2nid(pci->proxyPolicy->policyLanguage)) {
case NID_Independent:
/* Do whatever you need to grant explicit rights to
this particular proxy certificate, usually by
pulling them from some database. If there are none
to be found, clear all rights (making this and any
subsequent proxy certificate void of any rights).
*/
memset(rights->rights, 0, sizeof(rights->rights));
break;
/*
* Do whatever you need to grant explicit rights to
* this particular proxy certificate, usually by
* pulling them from some database. If there are none
* to be found, clear all rights (making this and any
* subsequent proxy certificate void of any rights).
*/
memset(rights->rights, 0, sizeof(rights->rights));
break;
case NID_id_ppl_inheritAll:
/* This is basically a NOP, we simply let the current
rights stand as they are. */
break;
/*
* This is basically a NOP, we simply let the current
* rights stand as they are.
*/
break;
default:
/* This is usually the most complex section of code.
You really do whatever you want as long as you
follow RFC 3820. In the example we use here, the
simplest thing to do is to build another, temporary
bit array and fill it with the rights granted by
the current proxy certificate, then use it as a
mask on the accumulated rights bit array, and
voilà, you now have a new accumulated rights bit
array. */
{
int i;
YOUR_RIGHTS tmp_rights;
memset(tmp_rights.rights, 0, sizeof(tmp_rights.rights));
/* This is usually the most complex section of code.
* You really do whatever you want as long as you
* follow RFC 3820. In the example we use here, the
* simplest thing to do is to build another, temporary
* bit array and fill it with the rights granted by
* the current proxy certificate, then use it as a
* mask on the accumulated rights bit array, and
* voilà, you now have a new accumulated rights bit
* array.
*/
{
int i;
YOUR_RIGHTS tmp_rights;
memset(tmp_rights.rights, 0, sizeof(tmp_rights.rights));
/* process_rights() is supposed to be a procedure
that takes a string and it's length, interprets
it and sets the bits in the YOUR_RIGHTS pointed
at by the third argument. */
process_rights((char *) pci->proxyPolicy->policy->data,
pci->proxyPolicy->policy->length,
&tmp_rights);
/*
* process_rights() is supposed to be a procedure
* that takes a string and it's length, interprets
* it and sets the bits in the YOUR_RIGHTS pointed
* at by the third argument.
*/
process_rights((char *) pci->proxyPolicy->policy->data,
pci->proxyPolicy->policy->length,
&tmp_rights);
for(i = 0; i < total_rights / 8; i++)
rights->rights[i] &= tmp_rights.rights[i];
}
break;
for(i = 0; i < total_rights / 8; i++)
rights->rights[i] &= tmp_rights.rights[i];
}
break;
}
PROXY_CERT_INFO_EXTENSION_free(pci);
}
else if (!(xs->ex_flags & EXFLAG_CA))
{
/* We have an EE certificate, let's use it to set default!
*/
YOUR_RIGHTS *rights =
(YOUR_RIGHTS *)X509_STORE_CTX_get_ex_data(ctx,
get_proxy_auth_ex_data_idx());
PROXY_CERT_INFO_EXTENSION_free(pci);
} else if (!(X509_get_extension_flags(xs) & EXFLAG_CA)) {
/* We have an EE certificate, let's use it to set default! */
YOUR_RIGHTS *rights =
(YOUR_RIGHTS *)X509_STORE_CTX_get_ex_data(ctx,
get_proxy_auth_ex_data_idx(ctx));
/* The following procedure finds out what rights the owner
of the current certificate has, and sets them in the
YOUR_RIGHTS structure pointed at by the second
argument. */
set_default_rights(xs, rights);
/* The following procedure finds out what rights the owner
* of the current certificate has, and sets them in the
* YOUR_RIGHTS structure pointed at by the second
* argument.
*/
set_default_rights(xs, rights);
}
}
return ok;
return ok;
}
static int my_X509_verify_cert(X509_STORE_CTX *ctx,
YOUR_RIGHTS *needed_rights)
{
int i;
int (*save_verify_cb)(int ok,X509_STORE_CTX *ctx) = ctx->verify_cb;
YOUR_RIGHTS rights;
int ok;
int (*save_verify_cb)(int ok,X509_STORE_CTX *ctx) =
X509_STORE_CTX_get_verify_cb(ctx);
YOUR_RIGHTS rights;
X509_STORE_CTX_set_verify_cb(ctx, verify_callback);
X509_STORE_CTX_set_ex_data(ctx, get_proxy_auth_ex_data_idx(), &rights);
X509_STORE_CTX_set_flags(ctx, X509_V_FLAG_ALLOW_PROXY_CERTS);
ok = X509_verify_cert(ctx);
X509_STORE_CTX_set_verify_cb(ctx, verify_callback);
X509_STORE_CTX_set_ex_data(ctx, get_proxy_auth_ex_data_idx(ctx), &rights);
X509_STORE_CTX_set_flags(ctx, X509_V_FLAG_ALLOW_PROXY_CERTS);
ok = X509_verify_cert(ctx);
if (ok == 1)
{
ok = check_needed_rights(rights, needed_rights);
if (ok == 1) {
ok = check_needed_rights(rights, needed_rights);
}
X509_STORE_CTX_set_verify_cb(ctx, save_verify_cb);
X509_STORE_CTX_set_verify_cb(ctx, save_verify_cb);
return ok;
return ok;
}
If you use SSL or TLS, you can easily set up a callback to have the
certificates checked properly, using the code above: