From patchwork Fri Jun 26 22:39:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tyler Hicks X-Patchwork-Id: 11629055 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 72EA414E3 for ; Fri, 26 Jun 2020 22:39:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 503A32100A for ; Fri, 26 Jun 2020 22:39:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="GAK98Rzg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725970AbgFZWjs (ORCPT ); Fri, 26 Jun 2020 18:39:48 -0400 Received: from linux.microsoft.com ([13.77.154.182]:37972 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726530AbgFZWjr (ORCPT ); Fri, 26 Jun 2020 18:39:47 -0400 Received: from sequoia.work.tihix.com (162-237-133-238.lightspeed.rcsntx.sbcglobal.net [162.237.133.238]) by linux.microsoft.com (Postfix) with ESMTPSA id 8A46220B4901; Fri, 26 Jun 2020 15:39:44 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 8A46220B4901 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1593211185; bh=WG1KYGxBabmnas+RFIfamDI2zDei+OK4HHl8rZcS7h4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GAK98Rzg5DPdMyh/1Z+jC5yie/1+3Vl3BHrABfDdHoMgPHmZntawK49gcBxGsF+S1 mRoc2Qp0AQGqi0skLOllegODkRgM3EJIN3QfVzgWYL1q1LAFhZxHTkoHx6x41KlwzH JZusT10BIaZxBrd83W23/7jSR6UJ2rqc373ad980= From: Tyler Hicks To: Mimi Zohar , Dmitry Kasatkin Cc: James Morris , "Serge E . Hallyn" , Lakshmi Ramasubramanian , Prakhar Srivastava , linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, Eric Biederman , kexec@lists.infradead.org Subject: [PATCH v2 11/11] ima: Support additional conditionals in the KEXEC_CMDLINE hook function Date: Fri, 26 Jun 2020 17:39:00 -0500 Message-Id: <20200626223900.253615-12-tyhicks@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200626223900.253615-1-tyhicks@linux.microsoft.com> References: <20200626223900.253615-1-tyhicks@linux.microsoft.com> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Take the properties of the kexec kernel's inode and the current task ownership into consideration when matching a KEXEC_CMDLINE operation to the rules in the IMA policy. This allows for some uniformity when writing IMA policy rules for KEXEC_KERNEL_CHECK, KEXEC_INITRAMFS_CHECK, and KEXEC_CMDLINE operations. Prior to this patch, it was not possible to write a set of rules like this: dont_measure func=KEXEC_KERNEL_CHECK obj_type=foo_t dont_measure func=KEXEC_INITRAMFS_CHECK obj_type=foo_t dont_measure func=KEXEC_CMDLINE obj_type=foo_t measure func=KEXEC_KERNEL_CHECK measure func=KEXEC_INITRAMFS_CHECK measure func=KEXEC_CMDLINE The inode information associated with the kernel being loaded by a kexec_kernel_load(2) syscall can now be included in the decision to measure or not Additonally, the uid, euid, and subj_* conditionals can also now be used in KEXEC_CMDLINE rules. There was no technical reason as to why those conditionals weren't being considered previously other than ima_match_rules() didn't have a valid inode to use so it immediately bailed out for KEXEC_CMDLINE operations rather than going through the full list of conditional comparisons. Signed-off-by: Tyler Hicks Cc: Eric Biederman Cc: kexec@lists.infradead.org Reviewed-by: Lakshmi Ramasubramanian --- * v2 - Moved the inode parameter of process_buffer_measurement() to be the first parameter so that it more closely matches process_masurement() include/linux/ima.h | 4 ++-- kernel/kexec_file.c | 2 +- security/integrity/ima/ima.h | 2 +- security/integrity/ima/ima_api.c | 2 +- security/integrity/ima/ima_appraise.c | 2 +- security/integrity/ima/ima_asymmetric_keys.c | 2 +- security/integrity/ima/ima_main.c | 23 +++++++++++++++----- security/integrity/ima/ima_policy.c | 17 +++++---------- security/integrity/ima/ima_queue_keys.c | 2 +- 9 files changed, 31 insertions(+), 25 deletions(-) diff --git a/include/linux/ima.h b/include/linux/ima.h index 9164e1534ec9..d15100de6cdd 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -25,7 +25,7 @@ extern int ima_post_read_file(struct file *file, void *buf, loff_t size, enum kernel_read_file_id id); extern void ima_post_path_mknod(struct dentry *dentry); extern int ima_file_hash(struct file *file, char *buf, size_t buf_size); -extern void ima_kexec_cmdline(const void *buf, int size); +extern void ima_kexec_cmdline(int kernel_fd, const void *buf, int size); #ifdef CONFIG_IMA_KEXEC extern void ima_add_kexec_buffer(struct kimage *image); @@ -103,7 +103,7 @@ static inline int ima_file_hash(struct file *file, char *buf, size_t buf_size) return -EOPNOTSUPP; } -static inline void ima_kexec_cmdline(const void *buf, int size) {} +static inline void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) {} #endif /* CONFIG_IMA */ #ifndef CONFIG_IMA_KEXEC diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index bb05fd52de85..07df431c1f21 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -287,7 +287,7 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, goto out; } - ima_kexec_cmdline(image->cmdline_buf, + ima_kexec_cmdline(kernel_fd, image->cmdline_buf, image->cmdline_buf_len - 1); } diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 59ec28f5c117..ff2bf57ff0c7 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -265,7 +265,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file, struct evm_ima_xattr_data *xattr_value, int xattr_len, const struct modsig *modsig, int pcr, struct ima_template_desc *template_desc); -void process_buffer_measurement(const void *buf, int size, +void process_buffer_measurement(struct inode *inode, const void *buf, int size, const char *eventname, enum ima_hooks func, int pcr, const char *keyring); void ima_audit_measurement(struct integrity_iint_cache *iint, diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index bf22de8b7ce0..4f39fb93f278 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -162,7 +162,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename, /** * ima_get_action - appraise & measure decision based on policy. - * @inode: pointer to inode to measure + * @inode: pointer to the inode associated with the object being validated * @cred: pointer to credentials structure to validate * @secid: secid of the task being validated * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXEC, diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index a9649b04b9f1..6c52bf7ea7f0 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -328,7 +328,7 @@ int ima_check_blacklist(struct integrity_iint_cache *iint, rc = is_binary_blacklisted(digest, digestsize); if ((rc == -EPERM) && (iint->flags & IMA_MEASURE)) - process_buffer_measurement(digest, digestsize, + process_buffer_measurement(NULL, digest, digestsize, "blacklisted-hash", NONE, pcr, NULL); } diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c index aaae80c4e376..1c68c500c26f 100644 --- a/security/integrity/ima/ima_asymmetric_keys.c +++ b/security/integrity/ima/ima_asymmetric_keys.c @@ -58,7 +58,7 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, * if the IMA policy is configured to measure a key linked * to the given keyring. */ - process_buffer_measurement(payload, payload_len, + process_buffer_measurement(NULL, payload, payload_len, keyring->description, KEY_CHECK, 0, keyring->description); } diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 8351b2fd48e0..8a91711ca79b 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -726,6 +726,7 @@ int ima_load_data(enum kernel_load_data_id id) /* * process_buffer_measurement - Measure the buffer to ima log. + * @inode: inode associated with the object being measured (NULL for KEY_CHECK) * @buf: pointer to the buffer that needs to be added to the log. * @size: size of buffer(in bytes). * @eventname: event name to be used for the buffer entry. @@ -735,7 +736,7 @@ int ima_load_data(enum kernel_load_data_id id) * * Based on policy, the buffer is measured into the ima log. */ -void process_buffer_measurement(const void *buf, int size, +void process_buffer_measurement(struct inode *inode, const void *buf, int size, const char *eventname, enum ima_hooks func, int pcr, const char *keyring) { @@ -768,7 +769,7 @@ void process_buffer_measurement(const void *buf, int size, */ if (func) { security_task_getsecid(current, &secid); - action = ima_get_action(NULL, current_cred(), secid, 0, func, + action = ima_get_action(inode, current_cred(), secid, 0, func, &pcr, &template, keyring); if (!(action & IMA_MEASURE)) return; @@ -823,16 +824,26 @@ void process_buffer_measurement(const void *buf, int size, /** * ima_kexec_cmdline - measure kexec cmdline boot args + * @kernel_fd: file descriptor of the kexec kernel being loaded * @buf: pointer to buffer * @size: size of buffer * * Buffers can only be measured, not appraised. */ -void ima_kexec_cmdline(const void *buf, int size) +void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) { - if (buf && size != 0) - process_buffer_measurement(buf, size, "kexec-cmdline", - KEXEC_CMDLINE, 0, NULL); + struct fd f; + + if (!buf || !size) + return; + + f = fdget(kernel_fd); + if (!f.file) + return; + + process_buffer_measurement(file_inode(f.file), buf, size, + "kexec-cmdline", KEXEC_CMDLINE, 0, NULL); + fdput(f); } static int __init init_ima(void) diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 5eb14b567a31..294323b36d06 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -443,13 +443,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, { int i; - if ((func == KEXEC_CMDLINE) || (func == KEY_CHECK)) { - if ((rule->flags & IMA_FUNC) && (rule->func == func)) { - if (func == KEY_CHECK) - return ima_match_keyring(rule, keyring, cred); - return true; - } - return false; + if (func == KEY_CHECK) { + return (rule->flags & IMA_FUNC) && (rule->func == func) && + ima_match_keyring(rule, keyring, cred); } if ((rule->flags & IMA_FUNC) && (rule->func != func && func != POST_SETATTR)) @@ -1007,10 +1003,9 @@ static bool ima_validate_rule(struct ima_rule_entry *entry) if (entry->action & ~(MEASURE | DONT_MEASURE)) return false; - if (entry->flags & ~(IMA_FUNC | IMA_PCR)) - return false; - - if (ima_rule_contains_lsm_cond(entry)) + if (entry->flags & ~(IMA_FUNC | IMA_FSMAGIC | IMA_UID | + IMA_FOWNER | IMA_FSUUID | + IMA_EUID | IMA_PCR | IMA_FSNAME)) return false; break; diff --git a/security/integrity/ima/ima_queue_keys.c b/security/integrity/ima/ima_queue_keys.c index 56ce24a18b66..69a8626a35c0 100644 --- a/security/integrity/ima/ima_queue_keys.c +++ b/security/integrity/ima/ima_queue_keys.c @@ -158,7 +158,7 @@ void ima_process_queued_keys(void) list_for_each_entry_safe(entry, tmp, &ima_keys, list) { if (!timer_expired) - process_buffer_measurement(entry->payload, + process_buffer_measurement(NULL, entry->payload, entry->payload_len, entry->keyring_name, KEY_CHECK, 0,