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gh-114572: Fix locking in cert_store_stats and get_ca_certs (#114573) 

* gh-114572: Fix locking in cert_store_stats and get_ca_certs

cert_store_stats and get_ca_certs query the SSLContext's X509_STORE with
X509_STORE_get0_objects, but reading the result requires a lock. See
https://github.com/openssl/openssl/pull/23224 for details.

Instead, use X509_STORE_get1_objects, newly added in that PR.
X509_STORE_get1_objects does not exist in current OpenSSLs, but we can
polyfill it with X509_STORE_lock and X509_STORE_unlock.

* Work around const-correctness problem

* Add missing X509_STORE_get1_objects failure check

* Add blurb
This commit is contained in:
David Benjamin 2024-02-15 19:24:51 -05:00 committed by GitHub
parent 58cb634632
commit bce693111b
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2 changed files with 64 additions and 5 deletions
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4
Misc/NEWS.d/next/Security/2024-01-26-22-14-09.gh-issue-114572.t1QMQD.rst Normal file
View File

@ -0,0 +1,4 @@
:meth:`ssl.SSLContext.cert_store_stats` and
:meth:`ssl.SSLContext.get_ca_certs` now correctly lock access to the
certificate store, when the :class:`ssl.SSLContext` is shared across
multiple threads.

65
Modules/_ssl.c
View File

@ -4553,6 +4553,50 @@ set_sni_callback(PySSLContext *self, PyObject *arg, void *c)
return 0;
}
#if OPENSSL_VERSION_NUMBER < 0x30300000L
static X509_OBJECT *x509_object_dup(const X509_OBJECT *obj)
{
int ok;
X509_OBJECT *ret = X509_OBJECT_new();
if (ret == NULL) {
return NULL;
}
switch (X509_OBJECT_get_type(obj)) {
case X509_LU_X509:
ok = X509_OBJECT_set1_X509(ret, X509_OBJECT_get0_X509(obj));
break;
case X509_LU_CRL:
/* X509_OBJECT_get0_X509_CRL was not const-correct prior to 3.0.*/
ok = X509_OBJECT_set1_X509_CRL(
ret, X509_OBJECT_get0_X509_CRL((X509_OBJECT *)obj));
break;
default:
/* We cannot duplicate unrecognized types in a polyfill, but it is
* safe to leave an empty object. The caller will ignore it. */
ok = 1;
break;
}
if (!ok) {
X509_OBJECT_free(ret);
return NULL;
}
return ret;
}
static STACK_OF(X509_OBJECT) *
X509_STORE_get1_objects(X509_STORE *store)
{
STACK_OF(X509_OBJECT) *ret;
if (!X509_STORE_lock(store)) {
return NULL;
}
ret = sk_X509_OBJECT_deep_copy(X509_STORE_get0_objects(store),
x509_object_dup, X509_OBJECT_free);
X509_STORE_unlock(store);
return ret;
}
#endif
PyDoc_STRVAR(PySSLContext_sni_callback_doc,
"Set a callback that will be called when a server name is provided by the SSL/TLS client in the SNI extension.\n\
\n\
@ -4582,7 +4626,12 @@ _ssl__SSLContext_cert_store_stats_impl(PySSLContext *self)
int x509 = 0, crl = 0, ca = 0, i;
store = SSL_CTX_get_cert_store(self->ctx);
objs = X509_STORE_get0_objects(store);
objs = X509_STORE_get1_objects(store);
if (objs == NULL) {
PyErr_SetString(PyExc_MemoryError, "failed to query cert store");
return NULL;
}
for (i = 0; i < sk_X509_OBJECT_num(objs); i++) {
obj = sk_X509_OBJECT_value(objs, i);
switch (X509_OBJECT_get_type(obj)) {
@ -4596,12 +4645,11 @@ _ssl__SSLContext_cert_store_stats_impl(PySSLContext *self)
crl++;
break;
default:
/* Ignore X509_LU_FAIL, X509_LU_RETRY, X509_LU_PKEY.
* As far as I can tell they are internal states and never
* stored in a cert store */
/* Ignore unrecognized types. */
break;
}
}
sk_X509_OBJECT_pop_free(objs, X509_OBJECT_free);
return Py_BuildValue("{sisisi}", "x509", x509, "crl", crl,
"x509_ca", ca);
}
@ -4633,7 +4681,12 @@ _ssl__SSLContext_get_ca_certs_impl(PySSLContext *self, int binary_form)
}
store = SSL_CTX_get_cert_store(self->ctx);
objs = X509_STORE_get0_objects(store);
objs = X509_STORE_get1_objects(store);
if (objs == NULL) {
PyErr_SetString(PyExc_MemoryError, "failed to query cert store");
goto error;
}
for (i = 0; i < sk_X509_OBJECT_num(objs); i++) {
X509_OBJECT *obj;
X509 *cert;
@ -4661,9 +4714,11 @@ _ssl__SSLContext_get_ca_certs_impl(PySSLContext *self, int binary_form)
}
Py_CLEAR(ci);
}
sk_X509_OBJECT_pop_free(objs, X509_OBJECT_free);
return rlist;
error:
sk_X509_OBJECT_pop_free(objs, X509_OBJECT_free);
Py_XDECREF(ci);
Py_XDECREF(rlist);
return NULL;