From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f53.google.com (mail-wm1-f53.google.com [209.85.128.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD90F3B531D for ; Wed, 19 Aug 2026 08:39:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787128792; cv=none; b=Q5DvexuP4txa44K2QRp7wwnifh+VYTe+tKfR0V68kWMJ9J4UCt8Ym3s1WKdPVPENmOenuXl9b/rDFENUaM1JIBvfuP7rRuF64PuC10IWx4j/sOtzs/ivNouMwDFKtxQROF9MPL7Mx8E4uv6muk2c6RwIoXU71RDWtGxCU66c/SQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787128792; c=relaxed/simple; bh=lV3H2tb2qiMnCClXMs0+wmrc43ydlEATktuhAe9EyR8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=kAk+SKhr+2Tz5G98QeN/BWrYFF0rigbHXE2ViGL8mNQU7rLhYf/bNWtbKrEEb/Uxuj/Qn+Ps3TqImpZWk4Sa24GwVXsxL06fopP0/o7f2+mzbr19pm27YZL+tXN1pTlYHAVOk7vexOfYAZzbirCX8+s1+1NVSg438AAeI7U5mDo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=mw1r3Suu; arc=none smtp.client-ip=209.85.128.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mw1r3Suu" Received: by mail-wm1-f53.google.com with SMTP id 5b1f17b1804b1-499a4d1d7f1so5996145e9.3 for ; Wed, 19 Aug 2026 01:39:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787128789; x=1787733589; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=UORZ+icp2lmX+P7JbOJDudH0GncJTos6NcrZjknca28=; b=mw1r3SuuP8K1aEv2+l0aFJWKdsOR7wnG00iyyvUrnMyyCTjC9rps9yYGHE51st70Xm JujOYkZnfPAMvc/AQXBozcWiDeSnyh6J9srZ0d1Q8ejxRr4/MjpKGHiH/ErQkkUNXYzK 0r9sXW38ZblraA8B2TQz4brEU1UQ/HqGuHCwTvFdXnubyHgUj2nMwntUXUFFIh1hQiex 6iPB8EjYr/S5/hNyUUiYaq7Qnctt0pTQlbbnn73+wNeIBjed/zd3XtJv9Xl36QiApK/B 0CKiaNHCILIFB2ENz3XbPpG+eeD15X5nZTZOgfUzsD9delARqgYT39nA3M+tRaxtok6a 6wjg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787128789; x=1787733589; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=UORZ+icp2lmX+P7JbOJDudH0GncJTos6NcrZjknca28=; b=gbExz2OMgkxDUxDVGh79vozKiZXRPTWWhLjVwztGTsktMLI0oSzZ7E6uPC88eV5/6u BBfHYQVy3zEkyBNk+wiYA0rgV1uaXbY5cRhg8ZoJNJigRhx9Pkq4iD/5INWydetfiuFs anQQcNJcHg9bV+TCBx0+Bm4+fuS8+6Qx5poAV7+X9aibocpRmwxTdqw6PUQsJIl9eeSw feFBvB4LcA+M3Q50xZRfkivlTGSWEbCV8Tej30eAF+bPdQxMzJgAN2GdXe0zn3E0vAY+ c4yK0t4ENzdZkFqpM6F732UY1sr+nwF0mtaYZ9A1YyTVcttu7ur1qfXtu/KHnNgZjCSb yLNg== X-Gm-Message-State: AOJu0Yxnh3z2kJpiXs5axuTpFyDDEO/SIpmSv0RvtdN2JocH7dYQgmq6 cbvJCG2BrITvU9KaQ8Jd6a/AwoF+5WMXljKCBOSXiESjCh/3YalXifjm X-Gm-Gg: AR+sD11S+ftWT6mzTIjjFNXRIPoITA45p4WONsrUik+8CI+zu3PVUSk3RdGKGSLcJk/ hRm5z7MqWOPTR60lGKfD1XGZ8NuiqVRIDnC20OOZdMmHcRXGz6oB0LWQmhWv2Srfn4/1HO31860 C9pDsG661hl11QVP/5NPJXcb5peuCSBSHGBuiSdwnlLlob1Z0svlxJjVjLsDOE1BL14W0QtOig7 guOnMTdew9PlpDIzOp7uu8oG2BjV0gVEiL3+O7PBTG7K/JecgvxPD1Q37CPnR1KZmqp4VfTXjk4 zYsYK2dLPwZF5+1eS5z0nnRJ6qjvenGcNRNDjH7gNxJ4I2XqsuVmuXX0IXeRmUECM9pqOmxdTS7 sdTv4B14l4J1vu/MipSXaqdVW4DQinLKbQCEPC3Mf/w+W8KIA6vSgpHCqaSxYhhpjuHZS9235kQ PpHEM3RS+Mj5u7BsTniQCf5FBDZKOFkNWe7u9LRXC2OhvQZGJCL6NnGBXjNFMngCzCqvok X-Received: by 2002:a05:600c:6748:b0:497:fecd:5b00 with SMTP id 5b1f17b1804b1-499aa1d0670mr56106685e9.9.1787128788828; Wed, 19 Aug 2026 01:39:48 -0700 (PDT) Received: from SurHub.localdomain ([196.188.112.82]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-499aa0dd3c9sm44758655e9.12.2026.08.19.01.39.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Aug 2026 01:39:48 -0700 (PDT) From: Abdifatah Suruur To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, nipun.gupta@amd.com, nikhil.agarwal@amd.com Subject: [PATCH] vfio/cdx: prevent read-only region mappings from becoming writable Date: Wed, 19 Aug 2026 11:39:43 +0300 Message-ID: <20260819083943.1391-1-suruurism@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit vfio_cdx_mmap() rejects writable mappings of regions without the WRITE flag, but leaves VM_MAYWRITE set. Userspace can map such a region read-only and then upgrade the mapping to writable with mprotect(), writing to MMIO regions the device marks read-only. Clear VM_MAYWRITE for regions without the WRITE flag, as i915 does for its read-only objects and as fixed in drm/vc4 (CVE-2026-68445) and drm/panthor (CVE-2024-53071) and ptp: vmclock (commit a5edadbae57e2298a56cf7a4e774a027905a331f). Fixes: 234489ac56130 ("vfio/cdx: add support for CDX bus") Cc: stable@vger.kernel.org Signed-off-by: Abdifatah Suruur --- --- a/drivers/vfio/cdx/main.c +++ b/drivers/vfio/cdx/main.c @@ -284,5 +284,9 @@ if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_WRITE) && (vma->vm_flags & VM_WRITE)) return -EPERM; + /* Prevent read-only region mappings from being upgraded with mprotect() */ + if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_WRITE)) + vm_flags_clear(vma, VM_MAYWRITE); + return vfio_cdx_mmap_mmio(vdev->regions[index], vma); }