File CVE-2024-0397-memrace_ssl.SSLContext_cert_store.patch of Package python3.36158
From e7011813a2b8f078182d29c252ea728b1ef163d8 Mon Sep 17 00:00:00 2001
From: Seth Michael Larson <seth@python.org>
Date: Fri, 19 Apr 2024 11:21:40 -0700
Subject: [PATCH] [CVE-2024-0397] 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 gh#openssl/openssl#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.
From-PR: gh#python/cpython!114573
Fixes: gh#python/cpython#114572
Fixes: bsc#1226447 (CVE-2024-0397)
Patch: CVE-2024-0397-memrace_ssl.SSLContext_cert_store.patch
---
...-04-19-11-21-13.gh-issue-114572.t1QMQD.rst | 4 +
Modules/_ssl.c | 98 ++++++++++++++++++-
2 files changed, 99 insertions(+), 3 deletions(-)
create mode 100644 Misc/NEWS.d/next/Security/2024-04-19-11-21-13.gh-issue-114572.t1QMQD.rst
diff --git a/Misc/NEWS.d/next/Security/2024-04-19-11-21-13.gh-issue-114572.t1QMQD.rst b/Misc/NEWS.d/next/Security/2024-04-19-11-21-13.gh-issue-114572.t1QMQD.rst
new file mode 100644
index 00000000000..b4f9fe64db0
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2024-04-19-11-21-13.gh-issue-114572.t1QMQD.rst
@@ -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.
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index 7365630a5ea..aafca11016e 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -124,6 +124,10 @@ struct py_ssl_library_code {
# define HAVE_TLSv1_2 0
#endif
+#if (OPENSSL_VERSION_NUMBER >= 0x30300000L) && !defined(LIBRESSL_VERSION_NUMBER)
+# define OPENSSL_VERSION_3_3 1
+#endif
+
/* SNI support (client- and server-side) appeared in OpenSSL 1.0.0 and 0.9.8f
* This includes the SSL_set_SSL_CTX() function.
*/
@@ -164,6 +168,16 @@ struct py_ssl_library_code {
#define HAVE_OPENSSL_CRYPTO_LOCK
#endif
+/* OpenSSL 1.1+ allows locking X509_STORE, 1.0.2 doesn't. */
+#ifdef OPENSSL_VERSION_1_1
+#define HAVE_OPENSSL_X509_STORE_LOCK
+#endif
+
+/* OpenSSL 3.3 added the X509_STORE_get1_objects API */
+#ifdef OPENSSL_VERSION_3_3
+#define HAVE_OPENSSL_X509_STORE_GET1_OBJECTS 1
+#endif
+
#if defined(OPENSSL_VERSION_1_1) && !defined(OPENSSL_NO_SSL2)
#define OPENSSL_NO_SSL2
#endif
@@ -4096,6 +4110,61 @@ _ssl__SSLContext_set_servername_callback(PySSLContext *self, PyObject *cb)
#endif
}
+/* Shim of X509_STORE_get1_objects API from OpenSSL 3.3
+ * Only available with the X509_STORE_lock() API */
+#if defined(HAVE_OPENSSL_X509_STORE_LOCK) && !defined(OPENSSL_VERSION_3_3)
+#define HAVE_OPENSSL_X509_STORE_GET1_OBJECTS 1
+
+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\
+If the argument is None then the callback is disabled. The method is called\n\
+with the SSLSocket, the server name as a string, and the SSLContext object.\n\
+See RFC 6066 for details of the SNI extension.");
+
/*[clinic input]
_ssl._SSLContext.cert_store_stats
@@ -4118,7 +4187,15 @@ _ssl__SSLContext_cert_store_stats_impl(PySSLContext *self)
int x509 = 0, crl = 0, ca = 0, i;
store = SSL_CTX_get_cert_store(self->ctx);
+#if HAVE_OPENSSL_X509_STORE_GET1_OBJECTS
+ objs = X509_STORE_get1_objects(store);
+ if (objs == NULL) {
+ PyErr_SetString(PyExc_MemoryError, "failed to query cert store");
+ return NULL;
+ }
+#else
objs = X509_STORE_get0_objects(store);
+#endif
for (i = 0; i < sk_X509_OBJECT_num(objs); i++) {
obj = sk_X509_OBJECT_value(objs, i);
switch (X509_OBJECT_get_type(obj)) {
@@ -4132,12 +4209,13 @@ _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;
}
}
+#if HAVE_OPENSSL_X509_STORE_GET1_OBJECTS
+ sk_X509_OBJECT_pop_free(objs, X509_OBJECT_free);
+#endif
return Py_BuildValue("{sisisi}", "x509", x509, "crl", crl,
"x509_ca", ca);
}
@@ -4169,7 +4247,15 @@ _ssl__SSLContext_get_ca_certs_impl(PySSLContext *self, int binary_form)
}
store = SSL_CTX_get_cert_store(self->ctx);
+#if HAVE_OPENSSL_X509_STORE_GET1_OBJECTS
+ objs = X509_STORE_get1_objects(store);
+ if (objs == NULL) {
+ PyErr_SetString(PyExc_MemoryError, "failed to query cert store");
+ return NULL;
+ }
+#else
objs = X509_STORE_get0_objects(store);
+#endif
for (i = 0; i < sk_X509_OBJECT_num(objs); i++) {
X509_OBJECT *obj;
X509 *cert;
@@ -4197,9 +4283,15 @@ _ssl__SSLContext_get_ca_certs_impl(PySSLContext *self, int binary_form)
}
Py_CLEAR(ci);
}
+#if HAVE_OPENSSL_X509_STORE_GET1_OBJECTS
+ sk_X509_OBJECT_pop_free(objs, X509_OBJECT_free);
+#endif
return rlist;
error:
+#if HAVE_OPENSSL_X509_STORE_GET1_OBJECTS
+ sk_X509_OBJECT_pop_free(objs, X509_OBJECT_free);
+#endif
Py_XDECREF(ci);
Py_XDECREF(rlist);
return NULL;
--
2.45.2
