From 10bf6e482328f622f4b2659e4ad5e3d88f57ba58 Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Sun, 21 Jun 2020 12:11:29 -0700 Subject: [PATCH] bpo-41056: Fix a NULL pointer dereference on MemoryError within the ssl module. (GH-21009) Detected by Coverity. (cherry picked from commit eb0d5c38de7f970d8cd8524f4163d831c7720f51) Co-authored-by: Gregory P. Smith --- .../Library/2020-06-20-18-35-43.bpo-41056.Garcle.rst | 1 + Modules/_ssl/debughelpers.c | 12 ++++++------ 2 files changed, 7 insertions(+), 6 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2020-06-20-18-35-43.bpo-41056.Garcle.rst 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 00000000000..1776f0d1cf8 --- /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 858b3d7955c..b840da2f663 100644 --- a/Modules/_ssl/debughelpers.c +++ b/Modules/_ssl/debughelpers.c @@ -125,6 +125,12 @@ _PySSL_keylog_callback(const SSL *ssl, const char *line) 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 @@ _PySSL_keylog_callback(const SSL *ssl, const char *line) } } - 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);