From 24fd03c87695a76f0517df42a37e51b1597d2c8a Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Thu, 11 Jun 2015 20:48:33 -0400 Subject: ima: update builtin policies This patch defines a builtin measurement policy "tcb", similar to the existing "ima_tcb", but with additional rules to also measure files based on the effective uid and to measure files opened with the "read" mode bit set (eg. read, read-write). Changing the builtin "ima_tcb" policy could potentially break existing users. Instead of defining a new separate boot command line option each time the builtin measurement policy is modified, this patch defines a single generic boot command line option "ima_policy=" to specify the builtin policy and deprecates the use of the builtin ima_tcb policy. [The "ima_policy=" boot command line option is based on Roberto Sassu's "ima: added new policy type exec" patch.] Signed-off-by: Mimi Zohar Signed-off-by: Dr. Greg Wettstein Cc: stable@vger.kernel.org --- security/integrity/ima/ima_policy.c | 65 ++++++++++++++++++++++++++++++++----- 1 file changed, 56 insertions(+), 9 deletions(-) (limited to 'security') diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index b3a2038ed424..3997e206f82d 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -44,6 +44,8 @@ enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE, LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE }; +enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB }; + struct ima_rule_entry { struct list_head list; int action; @@ -72,7 +74,7 @@ struct ima_rule_entry { * normal users can easily run the machine out of memory simply building * and running executables. */ -static struct ima_rule_entry default_rules[] = { +static struct ima_rule_entry dont_measure_rules[] = { {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC}, {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC}, {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC}, @@ -83,13 +85,29 @@ static struct ima_rule_entry default_rules[] = { {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC}, {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC}, - {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC}, + {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC} +}; + +static struct ima_rule_entry original_measurement_rules[] = { + {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC, + .flags = IMA_FUNC | IMA_MASK}, + {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC, + .flags = IMA_FUNC | IMA_MASK}, + {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, + .uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_MASK | IMA_UID}, + {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC}, + {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC}, +}; + +static struct ima_rule_entry default_measurement_rules[] = { {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC, .flags = IMA_FUNC | IMA_MASK}, {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC, .flags = IMA_FUNC | IMA_MASK}, - {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, .uid = GLOBAL_ROOT_UID, - .flags = IMA_FUNC | IMA_MASK | IMA_UID}, + {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, + .uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_INMASK | IMA_EUID}, + {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, + .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}, }; @@ -121,14 +139,29 @@ static struct list_head *ima_rules; static DEFINE_MUTEX(ima_rules_mutex); -static bool ima_use_tcb __initdata; +static int ima_policy __initdata; static int __init default_measure_policy_setup(char *str) { - ima_use_tcb = 1; + if (ima_policy) + return 1; + + ima_policy = ORIGINAL_TCB; return 1; } __setup("ima_tcb", default_measure_policy_setup); +static int __init policy_setup(char *str) +{ + if (ima_policy) + return 1; + + if (strcmp(str, "tcb") == 0) + ima_policy = DEFAULT_TCB; + + return 1; +} +__setup("ima_policy=", policy_setup); + static bool ima_use_appraise_tcb __initdata; static int __init default_appraise_policy_setup(char *str) { @@ -352,13 +385,27 @@ void __init ima_init_policy(void) { int i, measure_entries, appraise_entries; - /* if !ima_use_tcb set entries = 0 so we load NO default rules */ - measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0; + /* if !ima_policy set entries = 0 so we load NO default rules */ + measure_entries = ima_policy ? ARRAY_SIZE(dont_measure_rules) : 0; appraise_entries = ima_use_appraise_tcb ? ARRAY_SIZE(default_appraise_rules) : 0; for (i = 0; i < measure_entries; i++) - list_add_tail(&default_rules[i].list, &ima_default_rules); + list_add_tail(&dont_measure_rules[i].list, &ima_default_rules); + + switch (ima_policy) { + case ORIGINAL_TCB: + for (i = 0; i < ARRAY_SIZE(original_measurement_rules); i++) + list_add_tail(&original_measurement_rules[i].list, + &ima_default_rules); + break; + case DEFAULT_TCB: + for (i = 0; i < ARRAY_SIZE(default_measurement_rules); i++) + list_add_tail(&default_measurement_rules[i].list, + &ima_default_rules); + default: + break; + } for (i = 0; i < appraise_entries; i++) { list_add_tail(&default_appraise_rules[i].list, -- cgit v1.2.3-59-g8ed1b