From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D92D3188A3A; Thu, 3 Apr 2025 15:27:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743694021; cv=none; b=iY9OBzKHDIVyQp3GaNGBaXtua1QdOWm+cT0gy9f8EG9DwO0F4eUoGzGf5kyP2YA5VSxOY1CTeG/tqz60dhyqEmvHLkS77x1sz6qR+ZN37j4ssJ4GtGZ2Np2PNuiA0TYp23w8KNWZhgBLSBnB7ZxCkwegkZocy+VBccCYnNF9hSI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743694021; c=relaxed/simple; bh=kjYe3Efpepfsnv/dl7n86aP47rLOVYOWZwcmApiikYM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KmuvjXAGNRZznet+ik9GNXySY593PBEzUAP6D7bPvUglG/P9cg/PJHDg2EEEHZKtjWEkAHDs5sT79TSprXjLXutzcAoN4Tv+6yGZjF2j8p73+h5qUXp7JHtb0R0N2u81btsn+ME0wXpsIvceTlf7WmW2D2+4CZnOsPuUGswodfc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=f3wtWsyY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="f3wtWsyY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DBFAC4CEE3; Thu, 3 Apr 2025 15:27:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1743694021; bh=kjYe3Efpepfsnv/dl7n86aP47rLOVYOWZwcmApiikYM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f3wtWsyYT3oILFBi98oYA69XS5/LWk9PHDwAtvItDk6m66+diWQ5OkNgLZWf9cm0p AecJOgm0Kn5sASxKgGD0YEV0YlL0iKNppgjvhRsMCRiF2eUrf7xTOeJ6GbTXD2+VA7 1zuLJSfw5mkgCxNPqQxI/r1sPUiNzmSxytK/Bi18= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mark Brown , "Russell King (Oracle)" , Ard Biesheuvel , Wang Kefeng , Andrew Morton , Ben Hutchings , linux-arm-kernel@lists.infradead.org, Kees Cook Subject: [PATCH 6.6 04/26] ARM: 9350/1: fault: Implement copy_from_kernel_nofault_allowed() Date: Thu, 3 Apr 2025 16:20:25 +0100 Message-ID: <20250403151622.542513914@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250403151622.415201055@linuxfoundation.org> References: <20250403151622.415201055@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit 169f9102f9198b04afffa6164372a4ba4070f412 upstream. Under PAN emulation when dumping backtraces from things like the LKDTM EXEC_USERSPACE test[1], a double fault (which would hang a CPU) would happen because of dump_instr() attempting to read a userspace address. Make sure copy_from_kernel_nofault() does not attempt this any more. Closes: https://lava.sirena.org.uk/scheduler/job/497571 Link: https://lore.kernel.org/all/202401181125.D48DCB4C@keescook/ [1] Reported-by: Mark Brown Suggested-by: Russell King (Oracle) Reviewed-by: Ard Biesheuvel Tested-by: Mark Brown Cc: Wang Kefeng Cc: Andrew Morton Cc: Ben Hutchings Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Kees Cook Signed-off-by: Russell King (Oracle) Signed-off-by: Greg Kroah-Hartman --- arch/arm/mm/fault.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -25,6 +25,13 @@ #include "fault.h" +bool copy_from_kernel_nofault_allowed(const void *unsafe_src, size_t size) +{ + unsigned long addr = (unsigned long)unsafe_src; + + return addr >= TASK_SIZE && ULONG_MAX - addr >= size; +} + #ifdef CONFIG_MMU /*