Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754944AbcJUCpr (ORCPT ); Thu, 20 Oct 2016 22:45:47 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:49661 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754805AbcJUCpl (ORCPT ); Thu, 20 Oct 2016 22:45:41 -0400 From: Thiago Jung Bauermann To: linux-security-module Cc: Mimi Zohar , "Eric W. Biederman" , linux-ima-devel@lists.sourceforge.net, Dave Young , kexec@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Andrew Morton Subject: [PATCH v6 04/10] ima: maintain memory size needed for serializing the measurement list Date: Fri, 21 Oct 2016 00:44:52 -0200 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1477017898-10375-1-git-send-email-bauerman@linux.vnet.ibm.com> References: <1477017898-10375-1-git-send-email-bauerman@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16102102-0032-0000-0000-0000029E63F7 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16102102-0033-0000-0000-00000F173069 Message-Id: <1477017898-10375-5-git-send-email-bauerman@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-10-21_01:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1610210048 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4781 Lines: 143 From: Mimi Zohar In preparation for serializing the binary_runtime_measurements, this patch maintains the amount of memory required. Changelog v5: - replace CONFIG_KEXEC_FILE with architecture CONFIG_HAVE_IMA_KEXEC (Thiago) Changelog v3: - include the ima_kexec_hdr size in the binary_runtime_measurement size. Signed-off-by: Mimi Zohar --- security/integrity/ima/Kconfig | 12 +++++++++ security/integrity/ima/ima.h | 1 + security/integrity/ima/ima_queue.c | 53 ++++++++++++++++++++++++++++++++++++-- 3 files changed, 64 insertions(+), 2 deletions(-) diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 5487827fa86c..370eb2f4dd37 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -27,6 +27,18 @@ config IMA to learn more about IMA. If unsure, say N. +config IMA_KEXEC + bool "Enable carrying the IMA measurement list across a soft boot" + depends on IMA && TCG_TPM && HAVE_IMA_KEXEC + default n + help + TPM PCRs are only reset on a hard reboot. In order to validate + a TPM's quote after a soft boot, the IMA measurement list of the + running kernel must be saved and restored on boot. + + Depending on the IMA policy, the measurement list can grow to + be very large. + config IMA_MEASURE_PCR_IDX int depends on IMA diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 51dc8d57d64d..ea1dcc452911 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -143,6 +143,7 @@ void ima_print_digest(struct seq_file *m, u8 *digest, u32 size); struct ima_template_desc *ima_template_desc_current(void); int ima_restore_measurement_entry(struct ima_template_entry *entry); int ima_restore_measurement_list(loff_t bufsize, void *buf); +unsigned long ima_get_binary_runtime_size(void); int ima_init_template(void); /* diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c index 12d1b040bca9..3a3cc2a45645 100644 --- a/security/integrity/ima/ima_queue.c +++ b/security/integrity/ima/ima_queue.c @@ -29,6 +29,11 @@ #define AUDIT_CAUSE_LEN_MAX 32 LIST_HEAD(ima_measurements); /* list of all measurements */ +#ifdef CONFIG_IMA_KEXEC +static unsigned long binary_runtime_size; +#else +static unsigned long binary_runtime_size = ULONG_MAX; +#endif /* key: inode (before secure-hashing a file) */ struct ima_h_table ima_htable = { @@ -64,6 +69,24 @@ static struct ima_queue_entry *ima_lookup_digest_entry(u8 *digest_value, return ret; } +/* + * Calculate the memory required for serializing a single + * binary_runtime_measurement list entry, which contains a + * couple of variable length fields (e.g template name and data). + */ +static int get_binary_runtime_size(struct ima_template_entry *entry) +{ + int size = 0; + + size += sizeof(u32); /* pcr */ + size += sizeof(entry->digest); + size += sizeof(int); /* template name size field */ + size += strlen(entry->template_desc->name); + size += sizeof(entry->template_data_len); + size += entry->template_data_len; + return size; +} + /* ima_add_template_entry helper function: * - Add template entry to the measurement list and hash table, for * all entries except those carried across kexec. @@ -90,9 +113,30 @@ static int ima_add_digest_entry(struct ima_template_entry *entry, int flags) key = ima_hash_key(entry->digest); hlist_add_head_rcu(&qe->hnext, &ima_htable.queue[key]); } + + if (binary_runtime_size != ULONG_MAX) { + int size; + + size = get_binary_runtime_size(entry); + binary_runtime_size = (binary_runtime_size < ULONG_MAX - size) ? + binary_runtime_size + size : ULONG_MAX; + } return 0; } +/* + * Return the amount of memory required for serializing the + * entire binary_runtime_measurement list, including the ima_kexec_hdr + * structure. + */ +unsigned long ima_get_binary_runtime_size(void) +{ + if (binary_runtime_size >= (ULONG_MAX - sizeof(struct ima_kexec_hdr))) + return ULONG_MAX; + else + return binary_runtime_size + sizeof(struct ima_kexec_hdr); +}; + static int ima_pcr_extend(const u8 *hash, int pcr) { int result = 0; @@ -106,8 +150,13 @@ static int ima_pcr_extend(const u8 *hash, int pcr) return result; } -/* Add template entry to the measurement list and hash table, - * and extend the pcr. +/* + * Add template entry to the measurement list and hash table, and + * extend the pcr. + * + * On systems which support carrying the IMA measurement list across + * kexec, maintain the total memory size required for serializing the + * binary_runtime_measurements. */ int ima_add_template_entry(struct ima_template_entry *entry, int violation, const char *op, struct inode *inode, -- 2.7.4