Use a list of xattrs rather than an array - this makes it easier to
extend the list at runtime.
Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxx>
---
security/integrity/evm/evm.h | 7 ++-
security/integrity/evm/evm_crypto.c | 10 ++--
security/integrity/evm/evm_main.c | 79 +++++++++++++++++------------
3 files changed, 57 insertions(+), 39 deletions(-)
diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h
index 45c4a89c02ff..1257c3c24723 100644
--- a/security/integrity/evm/evm.h
+++ b/security/integrity/evm/evm.h
@@ -30,6 +30,11 @@
#define EVM_INIT_MASK (EVM_INIT_HMAC | EVM_INIT_X509 | EVM_SETUP_COMPLETE | \
EVM_ALLOW_METADATA_WRITES)
+struct xattr_list {
+ struct list_head list;
+ char *name;
+};
+
extern int evm_initialized;
#define EVM_ATTR_FSUUID 0x0001
@@ -40,7 +45,7 @@ extern struct crypto_shash *hmac_tfm;
extern struct crypto_shash *hash_tfm;
/* List of EVM protected security xattrs */
-extern char *evm_config_xattrnames[];
+extern struct list_head evm_config_xattrnames;
int evm_init_key(void);
int evm_update_evmxattr(struct dentry *dentry,
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index a46fba322340..caeea20670cc 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -192,8 +192,8 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
char type, char *digest)
{
struct inode *inode = d_backing_inode(dentry);
+ struct xattr_list *xattr;
struct shash_desc *desc;
- char **xattrname;
size_t xattr_size = 0;
char *xattr_value = NULL;
int error;
@@ -208,14 +208,14 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
return PTR_ERR(desc);
error = -ENODATA;
- for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) {
+ list_for_each_entry(xattr, &evm_config_xattrnames, list) {
bool is_ima = false;
- if (strcmp(*xattrname, XATTR_NAME_IMA) == 0)
+ if (strcmp(xattr->name, XATTR_NAME_IMA) == 0)
is_ima = true;
if ((req_xattr_name && req_xattr_value)
- && !strcmp(*xattrname, req_xattr_name)) {
+ && !strcmp(xattr->name, req_xattr_name)) {
error = 0;
crypto_shash_update(desc, (const u8 *)req_xattr_value,
req_xattr_value_len);
@@ -223,7 +223,7 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry,
ima_present = true;
continue;
}
- size = vfs_getxattr_alloc(dentry, *xattrname,
+ size = vfs_getxattr_alloc(dentry, xattr->name,
&xattr_value, xattr_size, GFP_NOFS);
if (size == -ENOMEM) {
error = -ENOMEM;
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index 9ea9c19a545c..09582d4fc4a8 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -35,28 +35,29 @@ static const char * const integrity_status_msg[] = {
};
int evm_hmac_attrs;
-char *evm_config_xattrnames[] = {
+static struct xattr_list evm_config_default_xattrnames[] __ro_after_init = {
#ifdef CONFIG_SECURITY_SELINUX
- XATTR_NAME_SELINUX,
+ {.name = XATTR_NAME_SELINUX},
#endif
#ifdef CONFIG_SECURITY_SMACK
- XATTR_NAME_SMACK,
+ {.name = XATTR_NAME_SMACK},
#ifdef CONFIG_EVM_EXTRA_SMACK_XATTRS
- XATTR_NAME_SMACKEXEC,
- XATTR_NAME_SMACKTRANSMUTE,
- XATTR_NAME_SMACKMMAP,
+ {.name = XATTR_NAME_SMACKEXEC},
+ {.name = XATTR_NAME_SMACKTRANSMUTE},
+ {.name = XATTR_NAME_SMACKMMAP},
#endif
#endif
#ifdef CONFIG_SECURITY_APPARMOR
- XATTR_NAME_APPARMOR,
+ {.name = XATTR_NAME_APPARMOR},
#endif
#ifdef CONFIG_IMA_APPRAISE
- XATTR_NAME_IMA,
+ {.name = XATTR_NAME_IMA},
#endif
- XATTR_NAME_CAPS,
- NULL
+ {.name = XATTR_NAME_CAPS},
};
+LIST_HEAD(evm_config_xattrnames);
+
static int evm_fixmode;
static int __init evm_set_fixmode(char *str)
{
@@ -68,6 +69,17 @@ __setup("evm=", evm_set_fixmode);
static void __init evm_init_config(void)
{
+ int i, xattrs;
+
+ xattrs = ARRAY_SIZE(evm_config_default_xattrnames);
+
+ pr_info("Initialising EVM extended attributes:\n");
+ for (i = 0; i < xattrs; i++) {
+ pr_info("%s\n", evm_config_default_xattrnames[i].name);
+ list_add_tail(&evm_config_default_xattrnames[i].list,
+ &evm_config_xattrnames);
+ }
+
#ifdef CONFIG_EVM_ATTR_FSUUID
evm_hmac_attrs |= EVM_ATTR_FSUUID;
#endif
@@ -82,15 +94,15 @@ static bool evm_key_loaded(void)
static int evm_find_protected_xattrs(struct dentry *dentry)
{
struct inode *inode = d_backing_inode(dentry);
- char **xattr;
+ struct xattr_list *xattr;
int error;
int count = 0;
if (!(inode->i_opflags & IOP_XATTR))
return -EOPNOTSUPP;
- for (xattr = evm_config_xattrnames; *xattr != NULL; xattr++) {
- error = __vfs_getxattr(dentry, inode, *xattr, NULL, 0);
+ list_for_each_entry(xattr, &evm_config_xattrnames, list) {
+ error = __vfs_getxattr(dentry, inode, xattr->name, NULL, 0);
if (error < 0) {
if (error == -ENODATA)
continue;
@@ -211,24 +223,25 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry,
static int evm_protected_xattr(const char *req_xattr_name)
{
- char **xattrname;
int namelen;
int found = 0;
+ struct xattr_list *xattr;
namelen = strlen(req_xattr_name);
- for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) {
- if ((strlen(*xattrname) == namelen)
- && (strncmp(req_xattr_name, *xattrname, namelen) == 0)) {
+ list_for_each_entry(xattr, &evm_config_xattrnames, list) {
+ if ((strlen(xattr->name) == namelen)
+ && (strncmp(req_xattr_name, xattr->name, namelen) == 0)) {
found = 1;
break;
}
if (strncmp(req_xattr_name,
- *xattrname + XATTR_SECURITY_PREFIX_LEN,
+ xattr->name + XATTR_SECURITY_PREFIX_LEN,
strlen(req_xattr_name)) == 0) {
found = 1;
break;
}
}
+
return found;
}
@@ -544,35 +557,35 @@ void __init evm_load_x509(void)
static int __init init_evm(void)
{
int error;
+ struct list_head *pos, *q;
+ struct xattr_list *xattr;
evm_init_config();
error = integrity_init_keyring(INTEGRITY_KEYRING_EVM);
if (error)
- return error;
+ goto error;
error = evm_init_secfs();
if (error < 0) {
pr_info("Error registering secfs\n");
- return error;
+ goto error;
}
- return 0;
-}
-
-/*
- * evm_display_config - list the EVM protected security extended attributes
- */
-static int __init evm_display_config(void)
-{
- char **xattrname;
+error:
+ if (error != 0) {
+ if (!list_empty(&evm_config_xattrnames)) {
+ list_for_each_safe(pos, q, &evm_config_xattrnames) {
+ xattr = list_entry(pos, struct xattr_list,
+ list);
+ list_del(pos);
+ }
+ }
+ }
- for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++)
- pr_info("%s\n", *xattrname);
- return 0;
+ return error;
}
-pure_initcall(evm_display_config);
late_initcall(init_evm);
MODULE_DESCRIPTION("Extended Verification Module");
--
2.17.0.441.gb46fe60e1d-goog
