From 9668d260a197207b440c8e65f09f4cc24b9cd566 Mon Sep 17 00:00:00 2001 From: petervanvugt <65050545+petervanvugt@users.noreply.github.com> Date: Fri, 1 May 2026 08:37:36 -0700 Subject: [PATCH] gh-148850: Fix memory sanitizer false positive in os.getrandom (GH-148851) Co-authored-by: Petr Viktorin --- Include/pyport.h | 4 ++++ .../2026-04-21-19-29-29.gh-issue-148850.MSH0J_.rst | 1 + Modules/posixmodule.c | 2 ++ 3 files changed, 7 insertions(+) create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2026-04-21-19-29-29.gh-issue-148850.MSH0J_.rst diff --git a/Include/pyport.h b/Include/pyport.h index c975921beafb..73a3e6cdaf09 100644 --- a/Include/pyport.h +++ b/Include/pyport.h @@ -553,6 +553,7 @@ extern "C" { # if !defined(_Py_MEMORY_SANITIZER) # define _Py_MEMORY_SANITIZER # define _Py_NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory)) +# define _Py_MSAN_UNPOISON(PTR, SIZE) (__msan_unpoison(PTR, SIZE)) # endif # endif # if __has_feature(address_sanitizer) @@ -591,6 +592,9 @@ extern "C" { #ifndef _Py_NO_SANITIZE_MEMORY # define _Py_NO_SANITIZE_MEMORY #endif +#ifndef _Py_MSAN_UNPOISON +# define _Py_MSAN_UNPOISON(PTR, SIZE) +#endif /* AIX has __bool__ redefined in it's system header file. */ #if defined(_AIX) && defined(__bool__) diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-04-21-19-29-29.gh-issue-148850.MSH0J_.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-04-21-19-29-29.gh-issue-148850.MSH0J_.rst new file mode 100644 index 000000000000..324d16103101 --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-04-21-19-29-29.gh-issue-148850.MSH0J_.rst @@ -0,0 +1 @@ +Fix the memory sanitizer false positive in :func:`os.getrandom`. diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c index e5ce487723b2..3bdbf2ef8167 100644 --- a/Modules/posixmodule.c +++ b/Modules/posixmodule.c @@ -17195,6 +17195,8 @@ os_getrandom_impl(PyObject *module, Py_ssize_t size, int flags) goto error; } + _Py_MSAN_UNPOISON(data, size); + return PyBytesWriter_FinishWithSize(writer, n); error: -- 2.47.3