From patchwork Wed Feb 14 15:38:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tushar Sugandhi X-Patchwork-Id: 13556705 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 607225D47F for ; Wed, 14 Feb 2024 15:38:37 +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=1707925118; cv=none; b=iF8S7FoWJgGcHKV8ugoi3NmjYU44aXwKuqxfWQPALLO1xKHPDfD/NY3Lg/Vv/DoswwPTwJdsrXX+qaQnYbXJcxEFmYX2ZDjSsfrwH9/GvjJJvWNxtftih+5D+xlCitLadDnuor4oHevR2RluHf9+ip5ptD1zFPS2gXCTVfNUqp0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707925118; c=relaxed/simple; bh=Xz/+z5gr8HifANxnPt07MWN2+HV0YL5BY94izlFqzuQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=iKTRLyz7tiZZPcyMEQke+tS4b76zPWKdu63KNlFd1XVDWgt7MzTtuUpcH+MUGNNjHysU9HEUXaE7BaG1Nc+mytA8D62ct5l8F5SMOWjsNDSaBgzsYMVdG+X2A2BW2hAlQTPJ03s4ehy82Nd1C++dv/mx2nKSh3B3Yt9YVPFK14g= 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=CwcSJxEj; 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="CwcSJxEj" Received: from tushar-HP-Pavilion-Laptop-15-eg0xxx.lan (unknown [50.46.228.62]) by linux.microsoft.com (Postfix) with ESMTPSA id A72D720B2008; Wed, 14 Feb 2024 07:38:36 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com A72D720B2008 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1707925116; bh=S9UPRKSI8CaypUVC1iW3GsRtiy2NP5QedIfKvKIgtkE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CwcSJxEjSO3aOk2cfjVq2nAr5tWEi4lkIw/dfuT8gZHa3sgbAQQcspcW9byYZ3ZAN /thdUY/PcC43kJZmltp1yb+WU7yKgbXt3XEaPw3lD0a3CM7JMfia0wVo0QfgaFLlSu 4mVXPshTUUh9s1HNZyOwzx9ddDBkkSDZf0msx11A= 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 8/8] ima: measure kexec load and exec events as critical data Date: Wed, 14 Feb 2024 07:38:27 -0800 Message-Id: <20240214153827.1087657-9-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 The amount of memory allocated at kexec load, even with the extra memory allocated, might not be large enough for the entire measurement list. The indeterminate interval between kexec 'load' and 'execute' could exacerbate this problem. Define two new IMA events, 'kexec_load' and 'kexec_execute', to be measured as critical data at kexec 'load' and 'execute' respectively. Report the allocated kexec segment size, IMA binary log size and the runtime measurements count as part of those events. These events, and the values reported through them, serve as markers in the IMA log to verify the IMA events are captured during kexec soft reboot. The presence of a 'kexec_load' event in between the last two 'boot_aggregate' events in the IMA log implies this is a kexec soft reboot, and not a cold-boot. And the absence of 'kexec_execute' event after kexec soft reboot implies missing events in that window which results in inconsistency with TPM PCR quotes, necessitating a cold boot for a successful remote attestation. Signed-off-by: Tushar Sugandhi --- security/integrity/ima/ima_kexec.c | 34 +++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index 50903d4ce880..31495a043959 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -17,6 +17,8 @@ #include "ima.h" #ifdef CONFIG_IMA_KEXEC +#define IMA_KEXEC_EVENT_LEN 256 + static struct seq_file ima_kexec_file; static void *ima_kexec_buffer; static size_t kexec_segment_size; @@ -38,6 +40,10 @@ static void ima_free_kexec_file_buf(struct seq_file *sf) static int ima_alloc_kexec_file_buf(size_t segment_size) { + char ima_kexec_event[IMA_KEXEC_EVENT_LEN]; + size_t buf_size; + long len; + /* * kexec 'load' may be called multiple times. * Free and realloc the buffer only if the segment_size is @@ -47,7 +53,7 @@ static int ima_alloc_kexec_file_buf(size_t segment_size) ima_kexec_file.size == segment_size && ima_kexec_file.read_pos == 0 && ima_kexec_file.count == sizeof(struct ima_kexec_hdr)) - return 0; + goto out; ima_free_kexec_file_buf(&ima_kexec_file); @@ -60,6 +66,18 @@ static int ima_alloc_kexec_file_buf(size_t segment_size) ima_kexec_file.read_pos = 0; ima_kexec_file.count = sizeof(struct ima_kexec_hdr); /* reserved space */ +out: + buf_size = ima_get_binary_runtime_size(); + len = atomic_long_read(&ima_htable.len); + + scnprintf(ima_kexec_event, IMA_KEXEC_EVENT_LEN, + "kexec_segment_size=%lu;ima_binary_runtime_size=%lu;" + "ima_runtime_measurements_count=%ld;", + segment_size, buf_size, len); + + ima_measure_critical_data("ima_kexec", "kexec_load", ima_kexec_event, + strlen(ima_kexec_event), false, NULL, 0); + return 0; } @@ -186,10 +204,12 @@ void ima_add_kexec_buffer(struct kimage *image) static int ima_update_kexec_buffer(struct notifier_block *self, unsigned long action, void *data) { + char ima_kexec_event[IMA_KEXEC_EVENT_LEN]; void *buf = NULL; size_t buf_size; int ret = NOTIFY_OK; bool resume = false; + long len; if (!kexec_in_progress) { pr_info("%s: No kexec in progress.\n", __func__); @@ -201,6 +221,18 @@ static int ima_update_kexec_buffer(struct notifier_block *self, return ret; } + buf_size = ima_get_binary_runtime_size(); + len = atomic_long_read(&ima_htable.len); + + scnprintf(ima_kexec_event, IMA_KEXEC_EVENT_LEN, + "kexec_segment_size=%lu;ima_binary_runtime_size=%lu;" + "ima_runtime_measurements_count=%ld;", + kexec_segment_size, buf_size, len); + + ima_measure_critical_data("ima_kexec", "kexec_execute", + ima_kexec_event, strlen(ima_kexec_event), + false, NULL, 0); + ima_measurements_suspend(); ret = ima_dump_measurement_list(&buf_size, &buf,