From 99e339946d831cca5ddf8808e8985c47405a3754 Mon Sep 17 00:00:00 2001 From: Orson Peters Date: Fri, 26 Apr 2024 17:12:10 +0200 Subject: [PATCH] fix: avoid WRITE+EXEC for CPUID check (#15912) --- py-polars/polars/_cpu_check.py | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/py-polars/polars/_cpu_check.py b/py-polars/polars/_cpu_check.py index 77a343befe60..f4abd982fe87 100644 --- a/py-polars/polars/_cpu_check.py +++ b/py-polars/polars/_cpu_check.py @@ -24,6 +24,7 @@ from __future__ import annotations import ctypes +import ctypes.util import os from ctypes import CFUNCTYPE, POINTER, c_long, c_size_t, c_uint32, c_ulong, c_void_p from typing import ClassVar @@ -159,15 +160,26 @@ def __init__(self) -> None: else: import mmap # Only import if necessary. + # On some platforms PROT_WRITE + PROT_EXEC is forbidden, so we first + # only write and then mprotect into PROT_EXEC. + libc = ctypes.CDLL(ctypes.util.find_library("c"), use_errno=True) + mprotect = libc.mprotect + mprotect.argtypes = (ctypes.c_void_p, ctypes.c_size_t, ctypes.c_int) + mprotect.restype = ctypes.c_int + self.mmap = mmap.mmap( -1, size, mmap.MAP_PRIVATE | mmap.MAP_ANONYMOUS, - mmap.PROT_READ | mmap.PROT_WRITE | mmap.PROT_EXEC, + mmap.PROT_READ | mmap.PROT_WRITE, ) self.addr = ctypes.addressof(ctypes.c_void_p.from_buffer(self.mmap)) self.mmap.write(code) + if mprotect(self.addr, size, mmap.PROT_READ | mmap.PROT_EXEC) != 0: + msg = "could not execute mprotect for CPUID check" + raise RuntimeError(msg) + func_type = CFUNCTYPE(None, POINTER(CPUID_struct), c_uint32, c_uint32) self.func_ptr = func_type(self.addr)