bpo-41056: Fix a NULL pointer dereference on MemoryError within the ssl module. (GH-21009)
Detected by Coverity.
diff --git a/Misc/NEWS.d/next/Library/2020-06-20-18-35-43.bpo-41056.Garcle.rst b/Misc/NEWS.d/next/Library/2020-06-20-18-35-43.bpo-41056.Garcle.rst
new file mode 100644
index 0000000..1776f0d
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-06-20-18-35-43.bpo-41056.Garcle.rst
@@ -0,0 +1 @@
+Fix a NULL pointer dereference within the ssl module during a MemoryError in the keylog callback. (discovered by Coverity)
\ No newline at end of file
diff --git a/Modules/_ssl/debughelpers.c b/Modules/_ssl/debughelpers.c
index 858b3d7..b840da2 100644
--- a/Modules/_ssl/debughelpers.c
+++ b/Modules/_ssl/debughelpers.c
@@ -125,6 +125,12 @@
threadstate = PyGILState_Ensure();
+ ssl_obj = (PySSLSocket *)SSL_get_app_data(ssl);
+ assert(PySSLSocket_Check(ssl_obj));
+ if (ssl_obj->ctx->keylog_bio == NULL) {
+ return;
+ }
+
/* Allocate a static lock to synchronize writes to keylog file.
* The lock is neither released on exit nor on fork(). The lock is
* also shared between all SSLContexts although contexts may write to
@@ -141,12 +147,6 @@
}
}
- ssl_obj = (PySSLSocket *)SSL_get_app_data(ssl);
- assert(PySSLSocket_Check(ssl_obj));
- if (ssl_obj->ctx->keylog_bio == NULL) {
- return;
- }
-
PySSL_BEGIN_ALLOW_THREADS
PyThread_acquire_lock(lock, 1);
res = BIO_printf(ssl_obj->ctx->keylog_bio, "%s\n", line);