From nobody Fri Dec 19 07:17:37 2025 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 267E2226CE4; Mon, 21 Apr 2025 22:25:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745274342; cv=none; b=YnTUbnC1IkIWygGOgfEVJ2b1DKxU/GtfxpUiXg0WOR94TFN/K17w4eDm35dj1eA8Ay7P+RMQPS3m0kL4bF6g+M18ijQU03asCkmBb6FupbX6G8p4Cabo1y9cGScdnCGW8iGqY2sIxwuakMFbD97k1zLRWKrAXz/7NSW60fuyIHQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745274342; c=relaxed/simple; bh=nUzvZlz0kFXK8f1OkHwJrlCdXsKIoFQO2tX7gzLN4uw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ly+dSAY0xAq4XEXXhAodl4g6pxKyM5pApxDkLCC4VF8ATzWitEOQqtNmfi5ZuOeJj6laoEgCyzk+N1TerOKRH8GqA80lI75dRqTtcqLvzU4ksMTYWAAC/Q7WYleYs8gj4RNcyLXahM0jzgA0PCi9XOYwWhZI6HYNS32zWopOB5s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=W2Y7nmAn; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="W2Y7nmAn" Received: from DESKTOP-VOT081N.hsd1.ga.comcast.net (unknown [20.110.218.7]) by linux.microsoft.com (Postfix) with ESMTPSA id AA275203B86C; Mon, 21 Apr 2025 15:25:37 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com AA275203B86C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1745274339; bh=MiqAzXObv2omepy5lJKLE7NO586d6ZTiSnYnz65g+4c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=W2Y7nmAnS3KpbaCexVvhfgKrjhuXhSRxhW6Nx9OK7e8KcwlK1O2eM6GJysuHFpbBy 2jIW27G0oYJ4I206uTnUuMHHBwope7RoBFLvB98jx4HhjABI22q4RUdGCreg+3u+vK ouM2YTJr2PqHDKbk4TFv3V3H4F2PoJpxq3vunK6g= From: steven chen To: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com Subject: [PATCH v13 4/9] ima: kexec: skip IMA segment validation after kexec soft reboot Date: Mon, 21 Apr 2025 15:25:10 -0700 Message-ID: <20250421222516.9830-5-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250421222516.9830-1-chenste@linux.microsoft.com> References: <20250421222516.9830-1-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Steven Chen Currently, the function kexec_calculate_store_digests() calculates and stores the digest of the segment during the kexec_file_load syscall, where the IMA segment is also allocated. Later, the IMA segment will be updated with the measurement log at the kexec execute stage when a kexec reboot is initiated. Therefore, the digests should be updated for the IMA segment in the normal case. The problem is that the content of memory segments carried over to the new kernel during the kexec systemcall can be changed at kexec 'execute' stage, but the size and the location of the memory segments cannot be changed at kexec 'execute' stage. To address this, skip the calculation and storage of the digest for the IMA segment in kexec_calculate_store_digests() so that it is not added=20 to the purgatory_sha_regions. With this change, the IMA segment is not included in the digest calculation, storage, and verification. Cc: Eric Biederman Cc: Baoquan He =20 Cc: Vivek Goyal Cc: Dave Young Co-developed-by: Tushar Sugandhi Signed-off-by: Tushar Sugandhi Signed-off-by: Steven Chen Reviewed-by: Stefan Berger Reviewed-by: Mimi Zohar Acked-by: Baoquan He --- include/linux/kexec.h | 3 +++ kernel/kexec_file.c | 22 ++++++++++++++++++++++ security/integrity/ima/ima_kexec.c | 3 +++ 3 files changed, 28 insertions(+) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 7d6b12f8b8d0..107e726f2ef3 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -362,6 +362,9 @@ struct kimage { =20 phys_addr_t ima_buffer_addr; size_t ima_buffer_size; + + unsigned long ima_segment_index; + bool is_ima_segment_index_set; #endif =20 /* Core ELF header buffer */ diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 3eedb8c226ad..606132253c79 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -38,6 +38,21 @@ void set_kexec_sig_enforced(void) } #endif =20 +#ifdef CONFIG_IMA_KEXEC +static bool check_ima_segment_index(struct kimage *image, int i) +{ + if (image->is_ima_segment_index_set && i =3D=3D image->ima_segment_index) + return true; + else + return false; +} +#else +static bool check_ima_segment_index(struct kimage *image, int i) +{ + return false; +} +#endif + static int kexec_calculate_store_digests(struct kimage *image); =20 /* Maximum size in bytes for kernel/initrd files. */ @@ -764,6 +779,13 @@ static int kexec_calculate_store_digests(struct kimage= *image) if (ksegment->kbuf =3D=3D pi->purgatory_buf) continue; =20 + /* + * Skip the segment if ima_segment_index is set and matches + * the current index + */ + if (check_ima_segment_index(image, i)) + continue; + ret =3D crypto_shash_update(desc, ksegment->kbuf, ksegment->bufsz); if (ret) diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/im= a_kexec.c index b12ac3619b8f..7e0a19c3483f 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -145,6 +145,7 @@ void ima_add_kexec_buffer(struct kimage *image) kbuf.buffer =3D kexec_buffer; kbuf.bufsz =3D kexec_buffer_size; kbuf.memsz =3D kexec_segment_size; + image->is_ima_segment_index_set =3D false; ret =3D kexec_add_buffer(&kbuf); if (ret) { pr_err("Error passing over kexec measurement buffer.\n"); @@ -155,6 +156,8 @@ void ima_add_kexec_buffer(struct kimage *image) image->ima_buffer_addr =3D kbuf.mem; image->ima_buffer_size =3D kexec_segment_size; image->ima_buffer =3D kexec_buffer; + image->ima_segment_index =3D image->nr_segments - 1; + image->is_ima_segment_index_set =3D true; =20 kexec_dprintk("kexec measurement buffer for the loaded kernel at 0x%lx.\n= ", kbuf.mem); --=20 2.43.0