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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 26 Feb 2020 06:38:32 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 01Q6cVmq35979592 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Feb 2020 06:38:31 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4BDA24C044; Wed, 26 Feb 2020 06:38:31 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 014B64C050; Wed, 26 Feb 2020 06:38:31 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 26 Feb 2020 06:38:30 +0000 (GMT) Received: from [10.61.2.125] (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id 52577A00F1; Wed, 26 Feb 2020 17:38:26 +1100 (AEDT) Subject: Re: [PATCH v5 8/8] powerpc/mm: Disable set_memory() routines when strict RWX isn't enabled To: Russell Currey , linuxppc-dev@lists.ozlabs.org References: <20200226063551.65363-1-ruscur@russell.cc> <20200226063551.65363-9-ruscur@russell.cc> From: Andrew Donnellan Date: Wed, 26 Feb 2020 17:38:29 +1100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200226063551.65363-9-ruscur@russell.cc> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 20022606-0008-0000-0000-000003567CAB X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20022606-0009-0000-0000-00004A779A5A Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.572 definitions=2020-02-26_01:2020-02-25, 2020-02-26 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 phishscore=0 spamscore=0 suspectscore=0 impostorscore=0 clxscore=1015 mlxscore=0 bulkscore=0 malwarescore=0 priorityscore=1501 mlxlogscore=923 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002260047 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kernel-hardening@lists.openwall.com, jniethe5@gmail.com, npiggin@gmail.com, joel@jms.id.au, dja@axtens.net Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 26/2/20 5:35 pm, Russell Currey wrote: > There are a couple of reasons that the set_memory() functions are > problematic when STRICT_KERNEL_RWX isn't enabled: > > - The linear mapping is a different size and apply_to_page_range() > may modify a giant section, breaking everything > - patch_instruction() doesn't know to work around a page being marked > RO, and will subsequently crash > > The latter can be replicated by building a kernel with the set_memory() > patches but with STRICT_KERNEL_RWX off and running ftracetest. > > Reported-by: Jordan Niethe > Signed-off-by: Russell Currey Can we squash this in earlier in the series for the sake of bisectability? -- Andrew Donnellan OzLabs, ADL Canberra ajd@linux.ibm.com IBM Australia Limited