From 19f8a84713edc1d27ea05be00effb97b8f1ef207 Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Fri, 15 Jan 2016 10:17:12 -0500 Subject: [PATCH] ima: measure and appraise the IMA policy itself Add support for measuring and appraising the IMA policy itself. Changelog v4: - use braces on both if/else branches, even if single line on one of the branches - Dmitry - Use the id mapping - Dmitry Signed-off-by: Mimi Zohar Acked-by: Petko Manolov Acked-by: Dmitry Kasatkin --- security/integrity/ima/ima.h | 2 ++ security/integrity/ima/ima_fs.c | 12 ++++++++++-- security/integrity/ima/ima_main.c | 1 + security/integrity/ima/ima_policy.c | 12 +++++++++++- 4 files changed, 24 insertions(+), 3 deletions(-) diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index bd97e0d290de..5d0f61163d98 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -149,6 +149,7 @@ enum ima_hooks { FIRMWARE_CHECK, KEXEC_KERNEL_CHECK, KEXEC_INITRAMFS_CHECK, + POLICY_CHECK, MAX_CHECK }; @@ -191,6 +192,7 @@ int ima_policy_show(struct seq_file *m, void *v); #define IMA_APPRAISE_LOG 0x04 #define IMA_APPRAISE_MODULES 0x08 #define IMA_APPRAISE_FIRMWARE 0x10 +#define IMA_APPRAISE_POLICY 0x20 #ifdef CONFIG_IMA_APPRAISE int ima_appraise_measurement(enum ima_hooks func, diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index a6c61b351f36..60d011aaec38 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -325,10 +325,18 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf, if (result < 0) goto out_free; - if (data[0] == '/') + if (data[0] == '/') { result = ima_read_policy(data); - else + } else if (ima_appraise & IMA_APPRAISE_POLICY) { + pr_err("IMA: signed policy file (specified as an absolute pathname) required\n"); + integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL, + "policy_update", "signed policy required", + 1, 0); + if (ima_appraise & IMA_APPRAISE_ENFORCE) + result = -EACCES; + } else { result = ima_parse_add_rule(data); + } mutex_unlock(&ima_write_mutex); out_free: kfree(data); diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index f76488162c1e..391f41751021 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -344,6 +344,7 @@ static int read_idmap[READING_MAX_ID] = { [READING_MODULE] = MODULE_CHECK, [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK, [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK, + [READING_POLICY] = POLICY_CHECK }; /** diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 646134cdf3e8..c1b5d00fe5d4 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -114,6 +114,7 @@ static struct ima_rule_entry default_measurement_rules[] = { .uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_INMASK | IMA_UID}, {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC}, {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC}, + {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC}, }; static struct ima_rule_entry default_appraise_rules[] = { @@ -618,6 +619,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK") == 0) entry->func = KEXEC_INITRAMFS_CHECK; + else if (strcmp(args[0].from, "POLICY_CHECK") == 0) + entry->func = POLICY_CHECK; else result = -EINVAL; if (!result) @@ -776,6 +779,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) temp_ima_appraise |= IMA_APPRAISE_MODULES; else if (entry->func == FIRMWARE_CHECK) temp_ima_appraise |= IMA_APPRAISE_FIRMWARE; + else if (entry->func == POLICY_CHECK) + temp_ima_appraise |= IMA_APPRAISE_POLICY; audit_log_format(ab, "res=%d", !result); audit_log_end(ab); return result; @@ -862,7 +867,8 @@ static char *mask_tokens[] = { enum { func_file = 0, func_mmap, func_bprm, func_module, func_firmware, func_post, - func_kexec_kernel, func_kexec_initramfs + func_kexec_kernel, func_kexec_initramfs, + func_policy }; static char *func_tokens[] = { @@ -873,6 +879,7 @@ static char *func_tokens[] = { "FIRMWARE_CHECK", "KEXEC_KERNEL_CHECK", "KEXEC_INITRAMFS_CHECK", + "POLICY_CHECK", "POST_SETATTR" }; @@ -944,6 +951,9 @@ static void policy_func_show(struct seq_file *m, enum ima_hooks func) case KEXEC_INITRAMFS_CHECK: seq_printf(m, pt(Opt_func), ft(func_kexec_initramfs)); break; + case POLICY_CHECK: + seq_printf(m, pt(Opt_func), ft(func_policy)); + break; default: snprintf(tbuf, sizeof(tbuf), "%d", func); seq_printf(m, pt(Opt_func), tbuf); -- 2.20.1