From patchwork Wed Feb 14 15:38:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 13556700 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D482D5A4E1 for ; Wed, 14 Feb 2024 15:38:35 +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=1707925117; cv=none; b=gvTdchQbITPOaijErGOyfe6adZUfai2VXCIwoREOHbv9c3HPrqjdV46MIrKLRFJDkDLfhuKDh2ZlhllqPYDNEK+pwj7uO5jyzD9quq5gDfA0hxmDni+b9KPZQZ8OKu2dAI0vVhmbkXHItWAclqSCQsfZc0VKNAo78RF2cWt/WVU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707925117; c=relaxed/simple; bh=m4gCm3J16zB805fp6gH1DCk1yV7y2jB5xxHkWeop2Lk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=HFgZrqwj/WLrOnUQoIJgBx2prY4wzAen7g0wxZs+o9/18373AvqgjlwzsXzufdHgnC4m40OV6+2kD3djNT4WEK6niG+26CaqNGc0ABQgJY30kvGeaQXKNKIAsFgpm1/I5uGOhGRgAUY45RR4TZseFYk7m1jZ2Ok7gh0FwNy9K/o= 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=KJ9JAEoj; 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="KJ9JAEoj" Received: from tushar-HP-Pavilion-Laptop-15-eg0xxx.lan (unknown [50.46.228.62]) by linux.microsoft.com (Postfix) with ESMTPSA id 4D8A620B2003; Wed, 14 Feb 2024 07:38:35 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 4D8A620B2003 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1707925115; bh=7AfuizgJ5ElWTHZgEiEhqrG4GwZkXPqkkrHChqJjnRk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KJ9JAEojMDPIpCYEicWI2Hvf0bgAdnLVRsk0Jo3mrdAf52Wi8BCW/dWl9YKie8pUK 8dbavId1j6BOTH15o/t+X7gfydphHDfI4qTuTBJK9GQ+cc0wY1+/nn6zlwzMwv1TWf iuctBCpIy27AhGJWW34NKDsC7pQDBGQn0dX+Y2ZQ= From: Tushar Sugandhi To: zohar@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, stefanb@linux.ibm.com, ebiederm@xmission.com, noodles@fb.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org Cc: code@tyhicks.com, nramas@linux.microsoft.com, paul@paul-moore.com Subject: [PATCH v5 3/8] ima: kexec: skip IMA segment validation after kexec soft reboot Date: Wed, 14 Feb 2024 07:38:22 -0800 Message-Id: <20240214153827.1087657-4-tusharsu@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240214153827.1087657-1-tusharsu@linux.microsoft.com> References: <20240214153827.1087657-1-tusharsu@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 kexec_calculate_store_digests() calculates and stores the digest of the segment at kexec_file_load syscall where the IMA segment is also allocated. With this series, the IMA segment will be updated with the measurement log at kexec soft reboot. Therefore, it may fail digest verification in verify_sha256_digest() after kexec soft reboot into the new Kernel. Therefore, the digest calculation, storage, and verification of the IMA segment needs to be skipped. Skip IMA segment from calculating and storing digest in function kexec_calculate_store_digests() so that it is not added to the 'purgatory_sha_regions'. Since verify_sha256_digest() only verifies 'purgatory_sha_regions', no change is needed in verify_sha256_digest() in this context. With this change, the IMA segment is not included in the digest calculation, storage, and verification. Signed-off-by: Tushar Sugandhi --- include/linux/kexec.h | 3 +++ kernel/kexec_file.c | 8 ++++++++ security/integrity/ima/ima_kexec.c | 3 +++ 3 files changed, 14 insertions(+) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 3145447eb77a..73f0dd0e1787 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -358,6 +358,9 @@ struct kimage { phys_addr_t ima_buffer_addr; size_t ima_buffer_size; + + unsigned long ima_segment_index; + bool is_ima_segment_index_set; #endif /* Core ELF header buffer */ diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index bef2f6f2571b..0e3689bfb0bb 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -750,6 +750,14 @@ static int kexec_calculate_store_digests(struct kimage *image) if (ksegment->kbuf == pi->purgatory_buf) continue; + /* + * Skip the segment if ima_segment_index is set and matches + * the current index + */ + if (image->is_ima_segment_index_set && + i == image->ima_segment_index) + continue; + ret = crypto_shash_update(desc, ksegment->kbuf, ksegment->bufsz); if (ret) diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index a9cb5e882e2e..ccb072617c2d 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -161,6 +161,7 @@ void ima_add_kexec_buffer(struct kimage *image) kbuf.buffer = kexec_buffer; kbuf.bufsz = kexec_buffer_size; kbuf.memsz = kexec_segment_size; + image->is_ima_segment_index_set = false; ret = kexec_add_buffer(&kbuf); if (ret) { pr_err("Error passing over kexec measurement buffer.\n"); @@ -171,6 +172,8 @@ void ima_add_kexec_buffer(struct kimage *image) image->ima_buffer_addr = kbuf.mem; image->ima_buffer_size = kexec_segment_size; image->ima_buffer = kexec_buffer; + image->ima_segment_index = image->nr_segments - 1; + image->is_ima_segment_index_set = true; /* * kexec owns kexec_buffer after kexec_add_buffer() is called