[PATCH v3 24/25] integrity: Move integrity functions to the LSM infrastructure

Roberto Sassu
2023-09-04T13:43:04Z

From: Roberto Sassu <roberto.sassu@huawei.com>

Remove hardcoded calls to integrity functions from the LSM infrastructure.
Also move the global declaration of integrity_inode_get() to
security/integrity/integrity.h, so that the function can be still called by
IMA.

Register integrity functions as hook implementations in
integrity_lsm_init().

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
---
include/linux/integrity.h | 26 --------------------------
security/integrity/iint.c | 11 ++++++++++-
security/integrity/integrity.h | 7 +++++++
security/security.c | 9 +--------
4 files changed, 18 insertions(+), 35 deletions(-)

diff --git a/include/linux/integrity.h b/include/linux/integrity.h
index 2ea0f2f65ab6..afaae7ad26f4 100644
--- a/include/linux/integrity.h
+++ b/include/linux/integrity.h
@@ -21,38 +21,12 @@ enum integrity_status {

/* List of EVM protected security xattrs */
#ifdef CONFIG_INTEGRITY
-extern struct integrity_iint_cache *integrity_inode_get(struct inode *inode);
-extern void integrity_inode_free(struct inode *inode);
extern void __init integrity_load_keys(void);

#else
-static inline struct integrity_iint_cache *
- integrity_inode_get(struct inode *inode)
-{
- return NULL;
-}
-
-static inline void integrity_inode_free(struct inode *inode)
-{
- return;
-}
-
static inline void integrity_load_keys(void)
{
}
#endif /* CONFIG_INTEGRITY */

-#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
-
-extern int integrity_kernel_module_request(char *kmod_name);
-
-#else
-
-static inline int integrity_kernel_module_request(char *kmod_name)
-{
- return 0;
-}
-
-#endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */
-
#endif /* _LINUX_INTEGRITY_H */
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index dd03f978b45c..70ee803a33ea 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -138,7 +138,7 @@ struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
*
* Free the integrity information(iint) associated with an inode.
*/
-void integrity_inode_free(struct inode *inode)
+static void integrity_inode_free(struct inode *inode)
{
struct integrity_iint_cache *iint;

@@ -167,12 +167,21 @@ static void init_once(void *foo)
mutex_init(&iint->mutex);
}

+static struct security_hook_list integrity_hooks[] __ro_after_init = {
+ LSM_HOOK_INIT(inode_free_security, integrity_inode_free),
+#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
+ LSM_HOOK_INIT(kernel_module_request, integrity_kernel_module_request),
+#endif
+};
+
static int __init integrity_lsm_init(void)
{
iint_cache =
kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
0, SLAB_PANIC, init_once);

+ security_add_hooks(integrity_hooks, ARRAY_SIZE(integrity_hooks),
+ "integrity");
init_ima_lsm();
init_evm_lsm();
return 0;
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 83a465ac9013..e020c365997b 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -178,6 +178,7 @@ struct integrity_iint_cache {
* integrity data associated with an inode.
*/
struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
+struct integrity_iint_cache *integrity_inode_get(struct inode *inode);

int integrity_kernel_read(struct file *file, loff_t offset,
void *addr, unsigned long count);
@@ -251,12 +252,18 @@ static inline int __init integrity_load_cert(const unsigned int id,
#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
int asymmetric_verify(struct key *keyring, const char *sig,
int siglen, const char *data, int datalen);
+int integrity_kernel_module_request(char *kmod_name);
#else
static inline int asymmetric_verify(struct key *keyring, const char *sig,
int siglen, const char *data, int datalen)
{
return -EOPNOTSUPP;
}
+
+static inline int integrity_kernel_module_request(char *kmod_name)
+{
+ return 0;
+}
#endif

#ifdef CONFIG_IMA_APPRAISE_MODSIG
diff --git a/security/security.c b/security/security.c
index 5e700557e434..5f26a0c16d48 100644
--- a/security/security.c
+++ b/security/security.c
@@ -19,7 +19,6 @@
#include <linux/kernel.h>
#include <linux/kernel_read_file.h>
#include <linux/lsm_hooks.h>
-#include <linux/integrity.h>
#include <linux/fsnotify.h>
#include <linux/mman.h>
#include <linux/mount.h>
@@ -1497,7 +1496,6 @@ static void inode_free_by_rcu(struct rcu_head *head)
*/
void security_inode_free(struct inode *inode)
{
- integrity_inode_free(inode);
call_void_hook(inode_free_security, inode);
/*
* The inode may still be referenced in a path walk and
@@ -3090,12 +3088,7 @@ int security_kernel_create_files_as(struct cred *new, struct inode *inode)
*/
int security_kernel_module_request(char *kmod_name)
{
- int ret;
-
- ret = call_int_hook(kernel_module_request, 0, kmod_name);
- if (ret)
- return ret;
- return integrity_kernel_module_request(kmod_name);
+ return call_int_hook(kernel_module_request, 0, kmod_name);
}

/**
--
2.34.1