From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (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 0B7DF7E1; Sat, 20 Jul 2024 02:52:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721443939; cv=none; b=SFz2ZSH8V063y5zQjiWGVvizIhOdLQDmm4OY5IYeGbXi9p6ZgpyfF1vUWM5DYXB6DIF888UoIWOkq7uHB65kVpt9BZlvFVBBucj5m/vJD1qRsnWdKbWCllbqQeyzuZqLmDrrUoxJ4VKI+X++twknUSqgpP/mCxUvZN3lLOTuMTw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721443939; c=relaxed/simple; bh=rXWQ+aYhcvCvsxoqQktWoi6QYVfimbAyisHo0NWeYk8=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=PYklG3Bddza5C/PwHSdSrAux9h/UfzhDwAKbNT3bkdifhDKtkm0JqctysyYnWwNs8hmALtjJjgbKCcuGqqbpKVooGcDd/MFWuWJdZGyCfEyG16DufI2B0HHpYyTeI15qWvsQdU457zqEDxhxWSLOjakLBcnTe3a3a2hO08ydWUw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.174]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4WQrYQ30XvzyN2x; Sat, 20 Jul 2024 10:47:22 +0800 (CST) Received: from kwepemi100008.china.huawei.com (unknown [7.221.188.57]) by mail.maildlp.com (Postfix) with ESMTPS id 38353140121; Sat, 20 Jul 2024 10:52:08 +0800 (CST) Received: from [10.67.109.254] (10.67.109.254) by kwepemi100008.china.huawei.com (7.221.188.57) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Sat, 20 Jul 2024 10:52:07 +0800 Message-ID: Date: Sat, 20 Jul 2024 10:52:06 +0800 Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.2.0 Subject: Re: [PATCH v2] loongarch: Support RANDOMIZE_KSTACK_OFFSET Content-Language: en-US To: Kees Cook CC: , , , , , , , References: <20240719031427.119274-1-ruanjinjie@huawei.com> <202407190858.3097E9AF98@keescook> From: Jinjie Ruan In-Reply-To: <202407190858.3097E9AF98@keescook> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemi100008.china.huawei.com (7.221.188.57) On 2024/7/20 0:01, Kees Cook wrote: > On Fri, Jul 19, 2024 at 11:14:27AM +0800, Jinjie Ruan wrote: >> Add support of kernel stack offset randomization while handling syscall, >> the offset is defaultly limited by KSTACK_OFFSET_MAX(). >> >> In order to avoid trigger stack canaries (due to __builtin_alloca) and >> slowing down the entry path, use __no_stack_protector attribute to >> disable stack protector for do_syscall() at function level. >> >> With this patch, the REPORT_STACK test show that: >> `loongarch64 bits of stack entropy: 7` > > I suspect this will report the correct "6" after now that this commit > has landed: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=872bb37f6829d4f7f3ed5afe2786add3d4384b4b Hi, Kees I noticed your patch, and I reconfirm that I have updated to the latest mainline and that your patch is in the code. However，the following REPORT_STACK test of your below script has the same result (run multiple times). And riscv64, arm64, x86 also has the 7 bit of stack entropy. for i in $(seq 1 1000); do echo "REPORT_STACK" >/sys/kernel/debug/provoke-crash/DIRECT done offsets=$(dmesg | grep 'Stack offset' | cut -d: -f3 | sort | uniq -c | sort -n | wc -l) echo "$(uname -m) bits of stack entropy: $(echo "obase=2; $offsets" | bc | wc -L)" > >> >> Signed-off-by: Jinjie Ruan >> Suggested-by: Huacai Chen > > Thanks for adding this and getting it tested! > > Reviewed-by: Kees Cook >