From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793829319; b=TykhkNyttmKDwfxNMbYFb6NbzrDlfqs5IXnrUA9ZR7JmIUtgrJj3vWFSEjt8tdcmlQ+Z qgLrHxvim62RW4i6s3dKtr4Tjyl0JzfI/GtC0aqHY2Z/sb6pG72o7kAdmQA6uGuWcixb+ ZjOou7CdaZX6kB9jMIs2wLwNixd3pdwj/Q/CrQyt7JaUxzq9GAgYEFcrSHd5zsaz3+Gt3 mHZuYiRCvy6IlMUZ9kepfOFjPa7jd4ejslGI2fC/Hl72KLLhE/XqYhE3lb91ZsEiw6kEg unIWuvBpiUiD+bjGvvY1+YSDz7MN2Rf55qDJQlKTGLFZtowfv8pnbLIvfhkNcWSVsnA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793829319; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=GZP8/kcsLsUEjTtM4gAYAMvJuvrNKt+3CCqPIlo954w=; b=vzfumrRAt50sVQKg0Wa/wivSvB+bcddnksYy5TE4tJRM2wgaLPAaRSwnpcpHdXnr95L5 aA8Xwuvpdq+zX0VyoHrRZd543r6xpRYs+OH/WP7Prwv8eRI0LlfdAdryHPPc5ada8KZ6n sTkq5QjgXAdDWy21D0yW47kkkP1Aq/5h1W6T7bNqCIvK+Xr7pe+dO3wmtK4HD/9Pb2dWb 2Euyx/A7qIAgHZkXXwoEJ1B8zmyqxCnZj4lC07T6+wFdS7nXVD8VRfc7NxiCmOLDkJRP4 4EHVHpLbzcE0am43uVRLK2jJQi2gEcz8nuGh5Sk0Nx6YozV3owQiHPKyhyhWzvR+1TA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=GdJUq7EU; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 053B16074917; Wed, 4 Nov 2026 21:55:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=GdJUq7EU Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A3891F000C1; Wed, 4 Nov 2026 21:55:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793829318; bh=GZP8/kcsLsUEjTtM4gAYAMvJuvrNKt+3CCqPIlo954w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GdJUq7EUmOVtK9s851Q2RviftiXFY6+ES046NGSyrdQKSiw6T+OqFPtOw/z7npMRl 9DVOvMwMJx6IKwvE7jAHH/UZAb1g2M9CWP5neaVvZdhNRK2RHTYICLdz3enuYeJJi0 ArJ6AAnyd5be9Dkr/rpPvqz/X/1uMLTJ4vf5wTWQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Asad Kamal , Lijo Lazar , Alex Deucher , Sasha Levin Subject: [PATCH 6.18 0020/1005] drm/amdgpu: Gate debugfs MMIO access on kernel lockdown Date: Wed, 4 Nov 2026 15:55:53 -0500 Message-ID: <20261104211044.117663998@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Asad Kamal [ Upstream commit 17ac73b24006700f50972d37e297dec1f523c14a ] amdgpu_regs, amdgpu_regs2, and related debugfs nodes allow arbitrary MMIO read/write via RREG32/WREG32 without checking security_locked_down(). On kernel_lockdown=integrity systems this bypasses the same restrictions as /dev/mem and PCI config space sysfs. Check LOCKDOWN_PCI_ACCESS (matching pci-sysfs) at the entry of every debugfs handler that performs direct register access. v2: Use consistent check as per previous check to use LOCKDOWN_DEBUGFS(Lijo) v3: Do not create any entry from amdgpu_debugfs_regs_init() if LOCKDOWN_PCI_ACCESS is active and log once. (Lijo) Signed-off-by: Asad Kamal Reviewed-by: Lijo Lazar Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c index 04939a9711e95..c7535ef0ae401 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include "amdgpu.h" @@ -1646,6 +1647,12 @@ int amdgpu_debugfs_regs_init(struct amdgpu_device *adev) struct dentry *ent, *root = minor->debugfs_root; unsigned int i; + if (security_locked_down(LOCKDOWN_PCI_ACCESS)) { + drm_info(adev_to_drm(adev), + "amdgpu: HW debugfs nodes disabled (kernel lockdown)\n"); + return 0; + } + for (i = 0; i < ARRAY_SIZE(debugfs_regs); i++) { ent = debugfs_create_file(debugfs_regs_names[i], S_IFREG | 0400, root, -- 2.53.0