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Fri, 11 Dec 2020 18:58:28 -0500 X-MC-Unique: MtWGb6DvMC-hAyNEkkyJRQ-1 Received: from tusharsu-Ubuntu.lan (c-71-197-163-6.hsd1.wa.comcast.net [71.197.163.6]) by linux.microsoft.com (Postfix) with ESMTPSA id 44CCC20B7189; Fri, 11 Dec 2020 15:58:21 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 44CCC20B7189 From: Tushar Sugandhi To: zohar@linux.ibm.com, stephen.smalley.work@gmail.com, casey@schaufler-ca.com, agk@redhat.com, snitzer@redhat.com, gmazyland@gmail.com, paul@paul-moore.com Date: Fri, 11 Dec 2020 15:58:03 -0800 Message-Id: <20201211235807.30815-5-tusharsu@linux.microsoft.com> In-Reply-To: <20201211235807.30815-1-tusharsu@linux.microsoft.com> References: <20201211235807.30815-1-tusharsu@linux.microsoft.com> X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-loop: dm-devel@redhat.com Cc: sashal@kernel.org, dm-devel@redhat.com, selinux@vger.kernel.org, jmorris@namei.org, linux-kernel@vger.kernel.org, nramas@linux.microsoft.com, linux-security-module@vger.kernel.org, tyhicks@linux.microsoft.com, linux-integrity@vger.kernel.org Subject: [dm-devel] [PATCH v8 4/8] IMA: add policy rule to measure critical data X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com A new IMA policy rule is needed for the IMA hook ima_measure_critical_data() and the corresponding func CRITICAL_DATA for measuring the input buffer. The policy rule should ensure the buffer would get measured only when the policy rule allows the action. The policy rule should also support the necessary constraints (flags etc.) for integrity critical buffer data measurements. Add a policy rule to define the constraints for restricting integrity critical data measurements. Signed-off-by: Tushar Sugandhi --- Documentation/ABI/testing/ima_policy | 2 +- security/integrity/ima/ima_policy.c | 34 ++++++++++++++++++++++++---- 2 files changed, 31 insertions(+), 5 deletions(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index e35263f97fc1..6ec7daa87cba 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -32,7 +32,7 @@ Description: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK]MODULE_CHECK] [FIRMWARE_CHECK] [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] - [KEXEC_CMDLINE] [KEY_CHECK] + [KEXEC_CMDLINE] [KEY_CHECK] [CRITICAL_DATA] mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] [[^]MAY_EXEC] fsmagic:= hex value diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index a09d1a41a290..07116ff35c25 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -85,6 +85,7 @@ struct ima_rule_entry { } lsm[MAX_LSM_RULES]; char *fsname; struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */ + struct ima_rule_opt_list *data_source; /* Measure data from this source */ struct ima_template_desc *template; }; @@ -479,6 +480,12 @@ static bool ima_match_rule_data(struct ima_rule_entry *rule, opt_list = rule->keyrings; break; + case CRITICAL_DATA: + if (!rule->data_source) + return true; + + opt_list = rule->data_source; + break; default: return false; } @@ -515,13 +522,19 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, { int i; - if (func == KEY_CHECK) { - return (rule->flags & IMA_FUNC) && (rule->func == func) && - ima_match_rule_data(rule, func_data, cred); - } if ((rule->flags & IMA_FUNC) && (rule->func != func && func != POST_SETATTR)) return false; + + switch (func) { + case KEY_CHECK: + case CRITICAL_DATA: + return ((rule->func == func) && + ima_match_rule_data(rule, func_data, cred)); + default: + break; + } + if ((rule->flags & IMA_MASK) && (rule->mask != mask && func != POST_SETATTR)) return false; @@ -1116,6 +1129,17 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) if (ima_rule_contains_lsm_cond(entry)) return false; + break; + case CRITICAL_DATA: + if (entry->action & ~(MEASURE | DONT_MEASURE)) + return false; + + if (entry->flags & ~(IMA_FUNC | IMA_UID | IMA_PCR)) + return false; + + if (ima_rule_contains_lsm_cond(entry)) + return false; + break; default: return false; @@ -1248,6 +1272,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) else if (IS_ENABLED(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) && strcmp(args[0].from, "KEY_CHECK") == 0) entry->func = KEY_CHECK; + else if (strcmp(args[0].from, "CRITICAL_DATA") == 0) + entry->func = CRITICAL_DATA; else result = -EINVAL; if (!result)