EVM: Allow runtime modification of the set of verified xattrs

security/integrity/evm/evm_main.c +8 -2

index 9ea9c19a545c..86b1632d6b5b 100644
@@ -35,7 +35,7 @@ static const char * const integrity_status_msg[] = {
 };
 int evm_hmac_attrs;
 
-char *evm_config_xattrnames[] = {
+char *evm_config_default_xattrnames[] = {
 #ifdef CONFIG_SECURITY_SELINUX
 	XATTR_NAME_SELINUX,
 #endif

@@ -57,6 +57,8 @@ char *evm_config_xattrnames[] = {
 	NULL
 };
 
+LIST_HEAD(evm_config_xattrnames);
+
 static int evm_fixmode;
 static int __init evm_set_fixmode(char *str)
 {

@@ -66,12 +68,30 @@ static int __init evm_set_fixmode(char *str)
 }
 __setup("evm=", evm_set_fixmode);
 
-static void __init evm_init_config(void)
+static int __init evm_init_config(void)
 {
+	struct xattr_list *tmp;
+	char **xattrname;
+
+	for (xattrname = evm_config_default_xattrnames; *xattrname != NULL;

security/integrity/evm/evm_main.c +4 -0

+	}
+
 #ifdef CONFIG_EVM_ATTR_FSUUID
 	evm_hmac_attrs |= EVM_ATTR_FSUUID;
 #endif
 	pr_info("HMAC attrs: 0x%x\n", evm_hmac_attrs);
+
+	return 0;
 }
 
 static bool evm_key_loaded(void)

Quoted 1 line · Matthew Garrett

+ for (xattrname = evm_config_default_xattrnames; *xattrname !=

security/integrity/evm/evm_main.c static int __init evm_set_fixmode(char *str) · line 86

Quoted 10 lines

security/integrity/evm/evm_main.c +10 -0

+          xattrname++) {
+             tmp = kmalloc(sizeof(struct xattr_list), GFP_KERNEL);
+             if (!tmp)
+                     return -ENOMEM;
+             tmp->name = kstrdup(*xattrname, GFP_KERNEL);
+             if (!tmp->name) {
+                     kfree(tmp);
+                     return -ENOMEM;
+             }
+             list_add_tail(&tmp->list, &evm_config_xattrnames);

If evm_config_xattrnames[] is defined as struct xattr_list, there's no need for allocating memory for the xattr_list and name. Something like in ima_init_policy() would work.

Could we break this patch up to simplify review? The first patch would create and use the xattrname list. The subsequent patch(es) would add the new functionality.

Quoted 2 lines · Mimi Zohar

Quoted 1 line · Matthew Garrett

+ for (xattrname = evm_config_default_xattrnames; *xattrname !=

NULL;

Quoted 10 lines

Quoted 10 lines

security/integrity/evm/evm_main.c +10 -0

+          xattrname++) {
+             tmp = kmalloc(sizeof(struct xattr_list), GFP_KERNEL);
+             if (!tmp)
+                     return -ENOMEM;
+             tmp->name = kstrdup(*xattrname, GFP_KERNEL);
+             if (!tmp->name) {
+                     kfree(tmp);
+                     return -ENOMEM;
+             }
+             list_add_tail(&tmp->list, &evm_config_xattrnames);

Quoted 3 lines

If evm_config_xattrnames[] is defined as struct xattr_list, there's no need for allocating memory for the xattr_list and name. Something like in ima_init_policy() would work.

Hm. Do you mean evm_config_default_xattrnames?

Quoted 4 lines

Could we break this patch up to simplify review? The first patch would create and use the xattrname list. The subsequent patch(es) would add the new functionality.

Sure, I'll do that.