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Diffstat (limited to 'security/integrity/ima/ima_policy.c')
-rw-r--r--security/integrity/ima/ima_policy.c138
1 files changed, 93 insertions, 45 deletions
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 07f033634b27..ea224f00b305 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -59,6 +59,11 @@ enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
enum policy_rule_list { IMA_DEFAULT_POLICY = 1, IMA_CUSTOM_POLICY };
+struct ima_rule_opt_list {
+ size_t count;
+ char *items[];
+};
+
struct ima_rule_entry {
struct list_head list;
int action;
@@ -78,7 +83,7 @@ struct ima_rule_entry {
int type; /* audit type */
} lsm[MAX_LSM_RULES];
char *fsname;
- char *keyrings; /* Measure keys added to these keyrings */
+ struct ima_rule_opt_list *keyrings; /* Measure keys added to these keyrings */
struct ima_template_desc *template;
};
@@ -206,10 +211,6 @@ static LIST_HEAD(ima_policy_rules);
static LIST_HEAD(ima_temp_rules);
static struct list_head *ima_rules = &ima_default_rules;
-/* Pre-allocated buffer used for matching keyrings. */
-static char *ima_keyrings;
-static size_t ima_keyrings_len;
-
static int ima_policy __initdata;
static int __init default_measure_policy_setup(char *str)
@@ -253,6 +254,72 @@ static int __init default_appraise_policy_setup(char *str)
}
__setup("ima_appraise_tcb", default_appraise_policy_setup);
+static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src)
+{
+ struct ima_rule_opt_list *opt_list;
+ size_t count = 0;
+ char *src_copy;
+ char *cur, *next;
+ size_t i;
+
+ src_copy = match_strdup(src);
+ if (!src_copy)
+ return ERR_PTR(-ENOMEM);
+
+ next = src_copy;
+ while ((cur = strsep(&next, "|"))) {
+ /* Don't accept an empty list item */
+ if (!(*cur)) {
+ kfree(src_copy);
+ return ERR_PTR(-EINVAL);
+ }
+ count++;
+ }
+
+ /* Don't accept an empty list */
+ if (!count) {
+ kfree(src_copy);
+ return ERR_PTR(-EINVAL);
+ }
+
+ opt_list = kzalloc(struct_size(opt_list, items, count), GFP_KERNEL);
+ if (!opt_list) {
+ kfree(src_copy);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ /*
+ * strsep() has already replaced all instances of '|' with '\0',
+ * leaving a byte sequence of NUL-terminated strings. Reference each
+ * string with the array of items.
+ *
+ * IMPORTANT: Ownership of the allocated buffer is transferred from
+ * src_copy to the first element in the items array. To free the
+ * buffer, kfree() must only be called on the first element of the
+ * array.
+ */
+ for (i = 0, cur = src_copy; i < count; i++) {
+ opt_list->items[i] = cur;
+ cur = strchr(cur, '\0') + 1;
+ }
+ opt_list->count = count;
+
+ return opt_list;
+}
+
+static void ima_free_rule_opt_list(struct ima_rule_opt_list *opt_list)
+{
+ if (!opt_list)
+ return;
+
+ if (opt_list->count) {
+ kfree(opt_list->items[0]);
+ opt_list->count = 0;
+ }
+
+ kfree(opt_list);
+}
+
static void ima_lsm_free_rule(struct ima_rule_entry *entry)
{
int i;
@@ -274,7 +341,7 @@ static void ima_free_rule(struct ima_rule_entry *entry)
* the defined_templates list and cannot be freed here
*/
kfree(entry->fsname);
- kfree(entry->keyrings);
+ ima_free_rule_opt_list(entry->keyrings);
ima_lsm_free_rule(entry);
kfree(entry);
}
@@ -394,8 +461,8 @@ int ima_lsm_policy_change(struct notifier_block *nb, unsigned long event,
static bool ima_match_keyring(struct ima_rule_entry *rule,
const char *keyring, const struct cred *cred)
{
- char *next_keyring, *keyrings_ptr;
bool matched = false;
+ size_t i;
if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid))
return false;
@@ -406,15 +473,8 @@ static bool ima_match_keyring(struct ima_rule_entry *rule,
if (!keyring)
return false;
- strcpy(ima_keyrings, rule->keyrings);
-
- /*
- * "keyrings=" is specified in the policy in the format below:
- * keyrings=.builtin_trusted_keys|.ima|.evm
- */
- keyrings_ptr = ima_keyrings;
- while ((next_keyring = strsep(&keyrings_ptr, "|")) != NULL) {
- if (!strcmp(next_keyring, keyring)) {
+ for (i = 0; i < rule->keyrings->count; i++) {
+ if (!strcmp(rule->keyrings->items[i], keyring)) {
matched = true;
break;
}
@@ -1065,7 +1125,6 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
bool uid_token;
struct ima_template_desc *template_desc;
int result = 0;
- size_t keyrings_len;
ab = integrity_audit_log_start(audit_context(), GFP_KERNEL,
AUDIT_INTEGRITY_POLICY_RULE);
@@ -1231,37 +1290,18 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
case Opt_keyrings:
ima_log_string(ab, "keyrings", args[0].from);
- keyrings_len = strlen(args[0].from) + 1;
-
- if ((entry->keyrings) ||
- (keyrings_len < 2)) {
+ if (entry->keyrings) {
result = -EINVAL;
break;
}
- if (keyrings_len > ima_keyrings_len) {
- char *tmpbuf;
-
- tmpbuf = krealloc(ima_keyrings, keyrings_len,
- GFP_KERNEL);
- if (!tmpbuf) {
- result = -ENOMEM;
- break;
- }
-
- ima_keyrings = tmpbuf;
- ima_keyrings_len = keyrings_len;
- }
-
- entry->keyrings = kstrdup(args[0].from, GFP_KERNEL);
- if (!entry->keyrings) {
- kfree(ima_keyrings);
- ima_keyrings = NULL;
- ima_keyrings_len = 0;
- result = -ENOMEM;
+ entry->keyrings = ima_alloc_rule_opt_list(args);
+ if (IS_ERR(entry->keyrings)) {
+ result = PTR_ERR(entry->keyrings);
+ entry->keyrings = NULL;
break;
}
- result = 0;
+
entry->flags |= IMA_KEYRINGS;
break;
case Opt_fsuuid:
@@ -1574,6 +1614,15 @@ static void policy_func_show(struct seq_file *m, enum ima_hooks func)
seq_printf(m, "func=%d ", func);
}
+static void ima_show_rule_opt_list(struct seq_file *m,
+ const struct ima_rule_opt_list *opt_list)
+{
+ size_t i;
+
+ for (i = 0; i < opt_list->count; i++)
+ seq_printf(m, "%s%s", i ? "|" : "", opt_list->items[i]);
+}
+
int ima_policy_show(struct seq_file *m, void *v)
{
struct ima_rule_entry *entry = v;
@@ -1630,9 +1679,8 @@ int ima_policy_show(struct seq_file *m, void *v)
}
if (entry->flags & IMA_KEYRINGS) {
- if (entry->keyrings != NULL)
- snprintf(tbuf, sizeof(tbuf), "%s", entry->keyrings);
- seq_printf(m, pt(Opt_keyrings), tbuf);
+ seq_puts(m, "keyrings=");
+ ima_show_rule_opt_list(m, entry->keyrings);
seq_puts(m, " ");
}