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Tue, 30 Dec 2025 20:35:52 GMT Received: from smtpav01.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 26C2E58058; Tue, 30 Dec 2025 20:35:52 +0000 (GMT) Received: from smtpav01.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A5F6658057; Tue, 30 Dec 2025 20:35:50 +0000 (GMT) Received: from li-43857255-d5e6-4659-90f1-fc5cee4750ad.ibm.com (unknown [9.61.14.46]) by smtpav01.dal12v.mail.ibm.com (Postfix) with ESMTP; Tue, 30 Dec 2025 20:35:50 +0000 (GMT) Message-ID: <29879a797996a14547c1274c45a4e7b824ab95d3.camel@linux.ibm.com> Subject: Re: [PATCH v2 1/3] ima: Add ima_validate_range() for previous kernel IMA buffer From: Mimi Zohar To: Harshit Mogalapalli Cc: akpm@linux-foundation.org, ardb@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, graf@amazon.com, guoweikang.kernel@gmail.com, henry.willard@oracle.com, hpa@zytor.com, jbohac@suse.cz, joel.granados@kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, noodles@fb.com, paul.x.webb@oracle.com, rppt@kernel.org, sohil.mehta@intel.com, sourabhjain@linux.ibm.com, stable@vger.kernel.org, tglx@linutronix.de, x86@kernel.org, yifei.l.liu@oracle.com In-Reply-To: <20251229081523.622515-2-harshit.m.mogalapalli@oracle.com> References: <20251229081523.622515-1-harshit.m.mogalapalli@oracle.com> <20251229081523.622515-2-harshit.m.mogalapalli@oracle.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Date: Tue, 30 Dec 2025 15:35:50 -0500 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Evolution 3.54.3 (3.54.3-2.fc41) X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: waATqpdTwZIoCRN7iD1mqXx0j3ZaZVXP X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMjMwMDE4MiBTYWx0ZWRfX7m8Ak9TfMvdF kHpGf8wLoEnGqjPWuW9W75khE7c5O0rs8MsrCQkPdIHeIYmU4r4gmlXvzEhYvcIo+MxoKz2XpLb 6SH3VgL5ou/03MQA0YEGXhyp8ZgUafAjT2nVraLxtAGAN1TrubLZtml3eTiM4jPZ0+OnMmkUVbX yNAXBiB7B58BTVaZvsO7n3hPZXBFTlnYcxSpfrQPFPBDYCCYq+t9LZab7iHn5Tpzlh5805VYMpm N7ORSod7Qm9g9LKvIzzo/CQmlDDIRbIG08fBjDuoxK67j5JUc+6Vxh2mldwaeQP3k8Yb9EeAvV3 ZNSK2j3+ES5n0uQMZBksX8/JHOTsbJlbkmljLXSYuKwj4CD7w6XV1K06rk0dfbHH3+RLMZpY/L2 OBr0jsR3Ue9uTRUP2wVQBeRnd2cjrpPSQNkXj9Deytvug/72xPaeHogdzSBbGo4MW4h68mXFQi3 yFqPKyClfWxn+zcbhBA== X-Authority-Analysis: v=2.4 cv=AN8t5o3d c=1 sm=1 tr=0 ts=695437aa cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=wP3pNCr1ah4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=yPCof4ZbAAAA:8 a=i_rEbNLS2gNQOS-lV44A:9 a=QEXdDO2ut3YA:10 a=zZCYzV9kfG8A:10 X-Proofpoint-GUID: 0v-ueOVDUDvI9LEJziQSSfAjTNUZklzE X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-12-30_03,2025-12-30_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 impostorscore=0 adultscore=0 suspectscore=0 malwarescore=0 bulkscore=0 priorityscore=1501 lowpriorityscore=0 phishscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2512120000 definitions=main-2512300182 Hi Harshit, The subject line could be written at a higher level. Perhaps base it on th= e ima_validate_range() function comment "verify a physical buffer lies in addressable RAM" (e.g. ima: verify the previous kernel's IMA buffer lies in addressable RAM).=20 On Mon, 2025-12-29 at 00:15 -0800, Harshit Mogalapalli wrote: > When the second-stage kernel is booted with a limiting command line > (e.g. "mem=3D"), the IMA measurement buffer handed over from the > previous kernel may fall outside the addressable RAM of the new kernel. > Accessing such a buffer can fault during early restore. >=20 > Introduce a small generic helper, ima_validate_range(), which verifies > that a physical [start, end] range for the previous-kernel IMA buffer > lies within addressable memory: > - On x86, use pfn_range_is_mapped(). > - On OF based architectures, use page_is_ram(). >=20 > Cc: stable@vger.kernel.org > Signed-off-by: Harshit Mogalapalli --=20 thanks, Mimi