python311/CVE-2024-0397-memrace_ssl.SSLContext_cert_store.patch

146 lines
4.9 KiB
Diff

From fa5c6d1c4b3e6556cddf663d7b36ed7cdbbde18c Mon Sep 17 00:00:00 2001
From: David Benjamin <davidben@google.com>
Date: Thu, 15 Feb 2024 19:24:51 -0500
Subject: [PATCH] gh-114572: Fix locking in cert_store_stats and get_ca_certs
(GH-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
(cherry picked from commit bce693111bff906ccf9281c22371331aaff766ab)
Co-authored-by: David Benjamin <davidben@google.com>
---
Misc/NEWS.d/next/Security/2024-01-26-22-14-09.gh-issue-114572.t1QMQD.rst | 4
Modules/_ssl.c | 65 +++++++++-
2 files changed, 64 insertions(+), 5 deletions(-)
create mode 100644 Misc/NEWS.d/next/Security/2024-01-26-22-14-09.gh-issue-114572.t1QMQD.rst
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2024-01-26-22-14-09.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.
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -4529,6 +4529,50 @@ set_sni_callback(PySSLContext *self, PyO
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\
@@ -4558,7 +4602,12 @@ _ssl__SSLContext_cert_store_stats_impl(P
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)) {
@@ -4572,12 +4621,11 @@ _ssl__SSLContext_cert_store_stats_impl(P
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);
}
@@ -4609,7 +4657,12 @@ _ssl__SSLContext_get_ca_certs_impl(PySSL
}
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;
@@ -4637,9 +4690,11 @@ _ssl__SSLContext_get_ca_certs_impl(PySSL
}
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;