From patchwork Fri Jan 24 22:42:35 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: steven chen X-Patchwork-Id: 13949992 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 3306D1E7C34; Fri, 24 Jan 2025 22:43:55 +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=1737758637; cv=none; b=lc0WTOoFLhmtMWhId1m/6t8T7LAnIgAtYXs/BChmHaAmqn+Nyv/6D5l88Ewa20GyVWXKP3h40EDhr55/pf7+IUKlKduuVuA+r/YOaMb98251DLPx/D86hGaUIkGQ0s6/xkiCJ0NIPy2Mt4ZCelSjW/pYd8/Tij0XLSq4lMwJ7L8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737758637; c=relaxed/simple; bh=+/vM8Wp0in6MfYqVPUlNCdxA+Ip9RDetizxsc5AYjso=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=AfxuS2NyZ2qaNs0YWu3stb0lQZBJNbi7lCEzAGyd8f7gxrEAjC4hgj8dw9MwSTttws+gHps5/BuisrferxAucUCC//iPpbs0bLTAE1oCR5eF34Ed0vShEd/DpIxBBwU45SmJxR0Gcq1oTV0P715T+sg8Jn/BgsX5J9P3pJf2zsY= 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=MIHYYHVd; 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="MIHYYHVd" Received: from localhost.localdomain (unknown [167.220.59.4]) by linux.microsoft.com (Postfix) with ESMTPSA id 9101D210D0CA; Fri, 24 Jan 2025 14:43:55 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 9101D210D0CA DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1737758635; bh=bmgLmYsYlhYHbjbOJ7FsAVpXQjF5XYvbaC/P+6RVs/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MIHYYHVdvHhDoyS5mr7/GCJk1RVU2krxQ2Psp2hcplXEXtEih4JJuGrIiwctVoDlM aPDv988eCSoCtgrwYckZ0SVkm6CkIbAFG8939JP20QlsyVbrENLWybrsGuNnXG32vB qquu57rF1NZQZcKdcrL1WcOjmEgy/Apj3ky3MHiU= From: steven chen To: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, petr@tesarici.cz, eric.snowberg@oracle.com, paul@paul-moore.com, code@tyhicks.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, madvenka@linux.microsoft.com Cc: linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, chenste@linux.microsoft.com Subject: [PATCH v6 3/7] ima: kexec: skip IMA segment validation after kexec soft reboot Date: Fri, 24 Jan 2025 14:42:35 -0800 Message-Id: <20250124224239.22335-4-chenste@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250124224239.22335-1-chenste@linux.microsoft.com> References: <20250124224239.22335-1-chenste@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/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. Author: Tushar Sugandhi Signed-off-by: Tushar Sugandhi Signed-off-by: steven chen --- include/linux/kexec.h | 3 +++ kernel/kexec_file.c | 10 ++++++++++ security/integrity/ima/ima_kexec.c | 3 +++ 3 files changed, 16 insertions(+) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index f8413ea5c8c8..f3246e881ac8 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -362,6 +362,9 @@ 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 3eedb8c226ad..4ff3ba0f3e8e 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -764,6 +764,16 @@ static int kexec_calculate_store_digests(struct kimage *image) if (ksegment->kbuf == pi->purgatory_buf) continue; +#ifdef CONFIG_IMA_KEXEC + /* + * 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; +#endif + 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 b60a902460e2..283860d20521 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -162,6 +162,7 @@ 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"); @@ -172,6 +173,8 @@ 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