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Diffstat (limited to 'security/integrity/ima/ima_policy.c')
-rw-r--r--security/integrity/ima/ima_policy.c124
1 files changed, 100 insertions, 24 deletions
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index d1eefb9d65fb..3997e206f82d 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -27,6 +27,8 @@
#define IMA_UID 0x0008
#define IMA_FOWNER 0x0010
#define IMA_FSUUID 0x0020
+#define IMA_INMASK 0x0040
+#define IMA_EUID 0x0080
#define UNKNOWN 0
#define MEASURE 0x0001 /* same as IMA_MEASURE */
@@ -42,6 +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;
@@ -70,7 +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},
@@ -79,12 +83,31 @@ static struct ima_rule_entry default_rules[] = {
{.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
{.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}
+};
+
+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 = 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_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},
};
@@ -99,6 +122,7 @@ static struct ima_rule_entry default_appraise_rules[] = {
{.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
+ {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
#ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER},
@@ -115,14 +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)
{
@@ -182,6 +221,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
if ((rule->flags & IMA_MASK) &&
(rule->mask != mask && func != POST_SETATTR))
return false;
+ if ((rule->flags & IMA_INMASK) &&
+ (!(rule->mask & mask) && func != POST_SETATTR))
+ return false;
if ((rule->flags & IMA_FSMAGIC)
&& rule->fsmagic != inode->i_sb->s_magic)
return false;
@@ -190,6 +232,16 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
return false;
if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
return false;
+ if (rule->flags & IMA_EUID) {
+ if (has_capability_noaudit(current, CAP_SETUID)) {
+ if (!uid_eq(rule->uid, cred->euid)
+ && !uid_eq(rule->uid, cred->suid)
+ && !uid_eq(rule->uid, cred->uid))
+ return false;
+ } else if (!uid_eq(rule->uid, cred->euid))
+ return false;
+ }
+
if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
return false;
for (i = 0; i < MAX_LSM_RULES; i++) {
@@ -333,21 +385,31 @@ 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 + appraise_entries; i++) {
- if (i < measure_entries)
- list_add_tail(&default_rules[i].list,
- &ima_default_rules);
- else {
- int j = i - measure_entries;
+ for (i = 0; i < measure_entries; i++)
+ list_add_tail(&dont_measure_rules[i].list, &ima_default_rules);
- list_add_tail(&default_appraise_rules[j].list,
+ 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,
+ &ima_default_rules);
}
ima_rules = &ima_default_rules;
@@ -373,7 +435,8 @@ enum {
Opt_audit,
Opt_obj_user, Opt_obj_role, Opt_obj_type,
Opt_subj_user, Opt_subj_role, Opt_subj_type,
- Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner,
+ Opt_func, Opt_mask, Opt_fsmagic,
+ Opt_uid, Opt_euid, Opt_fowner,
Opt_appraise_type, Opt_fsuuid, Opt_permit_directio
};
@@ -394,6 +457,7 @@ static match_table_t policy_tokens = {
{Opt_fsmagic, "fsmagic=%s"},
{Opt_fsuuid, "fsuuid=%s"},
{Opt_uid, "uid=%s"},
+ {Opt_euid, "euid=%s"},
{Opt_fowner, "fowner=%s"},
{Opt_appraise_type, "appraise_type=%s"},
{Opt_permit_directio, "permit_directio"},
@@ -435,6 +499,7 @@ static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
{
struct audit_buffer *ab;
+ char *from;
char *p;
int result = 0;
@@ -525,18 +590,23 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
if (entry->mask)
result = -EINVAL;
- if ((strcmp(args[0].from, "MAY_EXEC")) == 0)
+ from = args[0].from;
+ if (*from == '^')
+ from++;
+
+ if ((strcmp(from, "MAY_EXEC")) == 0)
entry->mask = MAY_EXEC;
- else if (strcmp(args[0].from, "MAY_WRITE") == 0)
+ else if (strcmp(from, "MAY_WRITE") == 0)
entry->mask = MAY_WRITE;
- else if (strcmp(args[0].from, "MAY_READ") == 0)
+ else if (strcmp(from, "MAY_READ") == 0)
entry->mask = MAY_READ;
- else if (strcmp(args[0].from, "MAY_APPEND") == 0)
+ else if (strcmp(from, "MAY_APPEND") == 0)
entry->mask = MAY_APPEND;
else
result = -EINVAL;
if (!result)
- entry->flags |= IMA_MASK;
+ entry->flags |= (*args[0].from == '^')
+ ? IMA_INMASK : IMA_MASK;
break;
case Opt_fsmagic:
ima_log_string(ab, "fsmagic", args[0].from);
@@ -566,6 +636,9 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
break;
case Opt_uid:
ima_log_string(ab, "uid", args[0].from);
+ case Opt_euid:
+ if (token == Opt_euid)
+ ima_log_string(ab, "euid", args[0].from);
if (uid_valid(entry->uid)) {
result = -EINVAL;
@@ -574,11 +647,14 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
result = kstrtoul(args[0].from, 10, &lnum);
if (!result) {
- entry->uid = make_kuid(current_user_ns(), (uid_t)lnum);
- if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum))
+ entry->uid = make_kuid(current_user_ns(),
+ (uid_t) lnum);
+ if (!uid_valid(entry->uid) ||
+ (uid_t)lnum != lnum)
result = -EINVAL;
else
- entry->flags |= IMA_UID;
+ entry->flags |= (token == Opt_uid)
+ ? IMA_UID : IMA_EUID;
}
break;
case Opt_fowner:
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.