[PATCH v3 21/25] ima: Move to LSM infrastructure

Roberto Sassu
2023-09-04T13:42:37Z

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

Remove hardcoded IMA function calls (not for appraisal) from the LSM
infrastructure, the VFS, NFS and the key subsystem.

Make those functions as static (except for ima_file_check() which is
exported, and ima_post_key_create_or_update(), which is not in ima_main.c),
and register them as implementation of the respective hooks in the new
function init_ima_lsm().

Call init_ima_lsm() from integrity_lsm_init() (renamed from
integrity_iintcache_init()), to make sure that the integrity subsystem is
ready at the time IMA hooks are registered. The same will be done for EVM,
by calling init_evm_lsm() just after init_ima_lsm().

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
---
fs/file_table.c | 2 -
fs/namei.c | 7 ---
fs/nfsd/vfs.c | 7 ---
fs/open.c | 1 -
include/linux/ima.h | 94 -------------------------------
security/integrity/iint.c | 7 ++-
security/integrity/ima/ima.h | 6 ++
security/integrity/ima/ima_main.c | 63 ++++++++++++++-------
security/integrity/integrity.h | 9 +++
security/keys/key.c | 9 +--
security/security.c | 53 +++--------------
11 files changed, 72 insertions(+), 186 deletions(-)

diff --git a/fs/file_table.c b/fs/file_table.c
index 964e24120684..7b9c756a42df 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -26,7 +26,6 @@
#include <linux/percpu_counter.h>
#include <linux/percpu.h>
#include <linux/task_work.h>
-#include <linux/ima.h>
#include <linux/swap.h>
#include <linux/kmemleak.h>

@@ -376,7 +375,6 @@ static void __fput(struct file *file)
locks_remove_file(file);

security_file_pre_free(file);
- ima_file_free(file);
if (unlikely(file->f_flags & FASYNC)) {
if (file->f_op->fasync)
file->f_op->fasync(-1, file, 0);
diff --git a/fs/namei.c b/fs/namei.c
index efed0e1e93f5..a200021209c3 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -27,7 +27,6 @@
#include <linux/fsnotify.h>
#include <linux/personality.h>
#include <linux/security.h>
-#include <linux/ima.h>
#include <linux/syscalls.h>
#include <linux/mount.h>
#include <linux/audit.h>
@@ -3636,8 +3635,6 @@ static int do_open(struct nameidata *nd,
error = vfs_open(&nd->path, file);
if (!error)
error = security_file_post_open(file, op->acc_mode);
- if (!error)
- error = ima_file_check(file, op->acc_mode);
if (!error && do_truncate)
error = handle_truncate(idmap, file);
if (unlikely(error > 0)) {
@@ -3701,7 +3698,6 @@ static int vfs_tmpfile(struct mnt_idmap *idmap,
spin_unlock(&inode->i_lock);
}
security_inode_post_create_tmpfile(idmap, dir, file, mode);
- ima_post_create_tmpfile(idmap, dir, file, mode);
return 0;
}

@@ -4049,9 +4045,6 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode,
case 0: case S_IFREG:
error = vfs_create(idmap, path.dentry->d_inode,
dentry, mode, true);
- if (!error)
- ima_post_path_mknod(idmap, &path, dentry,
- mode_stripped, dev);
break;
case S_IFCHR: case S_IFBLK:
error = vfs_mknod(idmap, path.dentry->d_inode,
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 3450bb1c8a18..94bbd7ac8b68 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -25,7 +25,6 @@
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
#include <linux/jhash.h>
-#include <linux/ima.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
@@ -868,12 +867,6 @@ __nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
goto out_nfserr;
}

- host_err = ima_file_check(file, may_flags);
- if (host_err) {
- fput(file);
- goto out_nfserr;
- }
-
if (may_flags & NFSD_MAY_64BIT_COOKIE)
file->f_mode |= FMODE_64BITHASH;
else
diff --git a/fs/open.c b/fs/open.c
index 0c55c8e7f837..6825ac1d07a9 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -29,7 +29,6 @@
#include <linux/audit.h>
#include <linux/falloc.h>
#include <linux/fs_struct.h>
-#include <linux/ima.h>
#include <linux/dnotify.h>
#include <linux/compat.h>
#include <linux/mnt_idmapping.h>
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 6e4d060ff378..58591b5cbdb4 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -16,26 +16,7 @@ struct linux_binprm;

#ifdef CONFIG_IMA
extern enum hash_algo ima_get_current_hash_algo(void);
-extern int ima_bprm_check(struct linux_binprm *bprm);
extern int ima_file_check(struct file *file, int mask);
-extern void ima_post_create_tmpfile(struct mnt_idmap *idmap,
- struct inode *dir, struct file *file,
- umode_t mode);
-extern void ima_file_free(struct file *file);
-extern int ima_file_mmap(struct file *file, unsigned long reqprot,
- unsigned long prot, unsigned long flags);
-int ima_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
- unsigned long prot);
-extern int ima_load_data(enum kernel_load_data_id id, bool contents);
-extern int ima_post_load_data(char *buf, loff_t size,
- enum kernel_load_data_id id, char *description);
-extern int ima_read_file(struct file *file, enum kernel_read_file_id id,
- bool contents);
-int ima_post_read_file(struct file *file, char *buf, loff_t size,
- enum kernel_read_file_id id);
-extern void ima_post_path_mknod(struct mnt_idmap *idmap,
- const struct path *dir, struct dentry *dentry,
- umode_t mode, unsigned int dev);
extern int ima_file_hash(struct file *file, char *buf, size_t buf_size);
extern int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size);
extern void ima_kexec_cmdline(int kernel_fd, const void *buf, int size);
@@ -60,72 +41,11 @@ static inline enum hash_algo ima_get_current_hash_algo(void)
return HASH_ALGO__LAST;
}

-static inline int ima_bprm_check(struct linux_binprm *bprm)
-{
- return 0;
-}
-
static inline int ima_file_check(struct file *file, int mask)
{
return 0;
}

-static inline void ima_post_create_tmpfile(struct mnt_idmap *idmap,
- struct inode *dir,
- struct file *file,
- umode_t mode)
-{
-}
-
-static inline void ima_file_free(struct file *file)
-{
- return;
-}
-
-static inline int ima_file_mmap(struct file *file, unsigned long reqprot,
- unsigned long prot, unsigned long flags)
-{
- return 0;
-}
-
-static inline int ima_file_mprotect(struct vm_area_struct *vma,
- unsigned long reqprot, unsigned long prot)
-{
- return 0;
-}
-
-static inline int ima_load_data(enum kernel_load_data_id id, bool contents)
-{
- return 0;
-}
-
-static inline int ima_post_load_data(char *buf, loff_t size,
- enum kernel_load_data_id id,
- char *description)
-{
- return 0;
-}
-
-static inline int ima_read_file(struct file *file, enum kernel_read_file_id id,
- bool contents)
-{
- return 0;
-}
-
-static inline int ima_post_read_file(struct file *file, char *buf, loff_t size,
- enum kernel_read_file_id id)
-{
- return 0;
-}
-
-static inline void ima_post_path_mknod(struct mnt_idmap *idmap,
- const struct path *dir,
- struct dentry *dentry,
- umode_t mode, unsigned int dev)
-{
- return;
-}
-
static inline int ima_file_hash(struct file *file, char *buf, size_t buf_size)
{
return -EOPNOTSUPP;
@@ -176,20 +96,6 @@ static inline void ima_add_kexec_buffer(struct kimage *image)
{}
#endif

-#ifdef CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS
-extern void ima_post_key_create_or_update(struct key *keyring,
- struct key *key,
- const void *payload, size_t plen,
- unsigned long flags, bool create);
-#else
-static inline void ima_post_key_create_or_update(struct key *keyring,
- struct key *key,
- const void *payload,
- size_t plen,
- unsigned long flags,
- bool create) {}
-#endif /* CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS */
-
#ifdef CONFIG_IMA_APPRAISE
extern bool is_ima_appraise_enabled(void);
extern void ima_inode_post_setattr(struct mnt_idmap *idmap,
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index a462df827de2..32f0f3c5c4dd 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -167,20 +167,21 @@ static void init_once(void *foo)
mutex_init(&iint->mutex);
}

-static int __init integrity_iintcache_init(void)
+static int __init integrity_lsm_init(void)
{
iint_cache =
kmem_cache_create("iint_cache", sizeof(struct integrity_iint_cache),
0, SLAB_PANIC, init_once);
+
+ init_ima_lsm();
return 0;
}
DEFINE_LSM(integrity) = {
.name = "integrity",
- .init = integrity_iintcache_init,
+ .init = integrity_lsm_init,
.order = LSM_ORDER_LAST,
};

-
/*
* integrity_kernel_read - read data from the file
*
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index c29db699c996..c0412100023e 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -127,6 +127,12 @@ void ima_load_kexec_buffer(void);
static inline void ima_load_kexec_buffer(void) {}
#endif /* CONFIG_HAVE_IMA_KEXEC */

+#ifdef CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS
+void ima_post_key_create_or_update(struct key *keyring, struct key *key,
+ const void *payload, size_t plen,
+ unsigned long flags, bool create);
+#endif
+
/*
* The default binary_runtime_measurements list format is defined as the
* platform native format. The canonical format is defined as little-endian.
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index f8581032e62c..0e4f882fcdce 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -188,7 +188,7 @@ static void ima_check_last_writer(struct integrity_iint_cache *iint,
*
* Flag files that changed, based on i_version
*/
-void ima_file_free(struct file *file)
+static void ima_file_free(struct file *file)
{
struct inode *inode = file_inode(file);
struct integrity_iint_cache *iint;
@@ -413,8 +413,8 @@ static int process_measurement(struct file *file, const struct cred *cred,
* On success return 0. On integrity appraisal error, assuming the file
* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
*/
-int ima_file_mmap(struct file *file, unsigned long reqprot,
- unsigned long prot, unsigned long flags)
+static int ima_file_mmap(struct file *file, unsigned long reqprot,
+ unsigned long prot, unsigned long flags)
{
u32 secid;
int ret;
@@ -452,8 +452,8 @@ int ima_file_mmap(struct file *file, unsigned long reqprot,
*
* On mprotect change success, return 0. On failure, return -EACESS.
*/
-int ima_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
- unsigned long prot)
+static int ima_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
+ unsigned long prot)
{
struct ima_template_desc *template = NULL;
struct file *file;
@@ -511,7 +511,7 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
* On success return 0. On integrity appraisal error, assuming the file
* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
*/
-int ima_bprm_check(struct linux_binprm *bprm)
+static int ima_bprm_check(struct linux_binprm *bprm)
{
int ret;
u32 secid;
@@ -673,9 +673,8 @@ EXPORT_SYMBOL_GPL(ima_inode_hash);
* Skip calling process_measurement(), but indicate which newly, created
* tmpfiles are in policy.
*/
-void ima_post_create_tmpfile(struct mnt_idmap *idmap,
- struct inode *dir, struct file *file,
- umode_t mode)
+static void ima_post_create_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
+ struct file *file, umode_t mode)
{
struct integrity_iint_cache *iint;
struct inode *inode = file_inode(file);
@@ -710,9 +709,9 @@ void ima_post_create_tmpfile(struct mnt_idmap *idmap,
* Mark files created via the mknodat syscall as new, so that the
* file data can be written later.
*/
-void ima_post_path_mknod(struct mnt_idmap *idmap,
- const struct path *dir, struct dentry *dentry,
- umode_t mode, unsigned int dev)
+static void __maybe_unused
+ima_post_path_mknod(struct mnt_idmap *idmap, const struct path *dir,
+ struct dentry *dentry, umode_t mode, unsigned int dev)
{
struct integrity_iint_cache *iint;
struct inode *inode = dentry->d_inode;
@@ -751,8 +750,8 @@ void ima_post_path_mknod(struct mnt_idmap *idmap,
*
* For permission return 0, otherwise return -EACCES.
*/
-int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
- bool contents)
+static int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
+ bool contents)
{
enum ima_hooks func;
u32 secid;
@@ -801,8 +800,8 @@ const int read_idmap[READING_MAX_ID] = {
* On success return 0. On integrity appraisal error, assuming the file
* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
*/
-int ima_post_read_file(struct file *file, char *buf, loff_t size,
- enum kernel_read_file_id read_id)
+static int ima_post_read_file(struct file *file, char *buf, loff_t size,
+ enum kernel_read_file_id read_id)
{
enum ima_hooks func;
u32 secid;
@@ -835,7 +834,7 @@ int ima_post_read_file(struct file *file, char *buf, loff_t size,
*
* For permission return 0, otherwise return -EACCES.
*/
-int ima_load_data(enum kernel_load_data_id id, bool contents)
+static int ima_load_data(enum kernel_load_data_id id, bool contents)
{
bool ima_enforce, sig_enforce;

@@ -889,9 +888,9 @@ int ima_load_data(enum kernel_load_data_id id, bool contents)
* On success return 0. On integrity appraisal error, assuming the file
* is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
*/
-int ima_post_load_data(char *buf, loff_t size,
- enum kernel_load_data_id load_id,
- char *description)
+static int ima_post_load_data(char *buf, loff_t size,
+ enum kernel_load_data_id load_id,
+ char *description)
{
if (load_id == LOADING_FIRMWARE) {
if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
@@ -1120,4 +1119,28 @@ static int __init init_ima(void)
return error;
}

+static struct security_hook_list ima_hooks[] __ro_after_init = {
+ LSM_HOOK_INIT(bprm_check_security, ima_bprm_check),
+ LSM_HOOK_INIT(file_post_open, ima_file_check),
+ LSM_HOOK_INIT(inode_post_create_tmpfile, ima_post_create_tmpfile),
+ LSM_HOOK_INIT(file_pre_free_security, ima_file_free),
+ LSM_HOOK_INIT(mmap_file, ima_file_mmap),
+ LSM_HOOK_INIT(file_mprotect, ima_file_mprotect),
+ LSM_HOOK_INIT(kernel_load_data, ima_load_data),
+ LSM_HOOK_INIT(kernel_post_load_data, ima_post_load_data),
+ LSM_HOOK_INIT(kernel_read_file, ima_read_file),
+ LSM_HOOK_INIT(kernel_post_read_file, ima_post_read_file),
+#ifdef CONFIG_SECURITY_PATH
+ LSM_HOOK_INIT(path_post_mknod, ima_post_path_mknod),
+#endif
+#ifdef CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS
+ LSM_HOOK_INIT(key_post_create_or_update, ima_post_key_create_or_update),
+#endif
+};
+
+void __init init_ima_lsm(void)
+{
+ security_add_hooks(ima_hooks, ARRAY_SIZE(ima_hooks), "integrity");
+}
+
late_initcall(init_ima); /* Start IMA after the TPM is available */
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 7167a6e99bdc..7adc7d6c4f9f 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -18,6 +18,7 @@
#include <crypto/hash.h>
#include <linux/key.h>
#include <linux/audit.h>
+#include <linux/lsm_hooks.h>

/* iint action cache flags */
#define IMA_MEASURE 0x00000001
@@ -191,6 +192,14 @@ extern struct dentry *integrity_dir;

struct modsig;

+#ifdef CONFIG_IMA
+void __init init_ima_lsm(void);
+#else
+static inline void __init init_ima_lsm(void)
+{
+}
+#endif
+
#ifdef CONFIG_INTEGRITY_SIGNATURE

int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
diff --git a/security/keys/key.c b/security/keys/key.c
index 0f9c6faf3491..2acf9fa80735 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -13,7 +13,6 @@
#include <linux/security.h>
#include <linux/workqueue.h>
#include <linux/random.h>
-#include <linux/ima.h>
#include <linux/err.h>
#include "internal.h"

@@ -936,8 +935,6 @@ static key_ref_t __key_create_or_update(key_ref_t keyring_ref,

security_key_post_create_or_update(keyring, key, payload, plen, flags,
true);
- ima_post_key_create_or_update(keyring, key, payload, plen,
- flags, true);

key_ref = make_key_ref(key, is_key_possessed(keyring_ref));

@@ -969,13 +966,9 @@ static key_ref_t __key_create_or_update(key_ref_t keyring_ref,

key_ref = __key_update(key_ref, &prep);

- if (!IS_ERR(key_ref)) {
+ if (!IS_ERR(key_ref))
security_key_post_create_or_update(keyring, key, payload, plen,
flags, false);
- ima_post_key_create_or_update(keyring, key,
- payload, plen,
- flags, false);
- }

goto error_free_prep;
}
diff --git a/security/security.c b/security/security.c
index 957e53ba904f..0b196d3f01b8 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1098,12 +1098,7 @@ int security_bprm_creds_from_file(struct linux_binprm *bprm, struct file *file)
*/
int security_bprm_check(struct linux_binprm *bprm)
{
- int ret;
-
- ret = call_int_hook(bprm_check_security, 0, bprm);
- if (ret)
- return ret;
- return ima_bprm_check(bprm);
+ return call_int_hook(bprm_check_security, 0, bprm);
}

/**
@@ -2793,13 +2788,8 @@ static inline unsigned long mmap_prot(struct file *file, unsigned long prot)
int security_mmap_file(struct file *file, unsigned long prot,
unsigned long flags)
{
- unsigned long prot_adj = mmap_prot(file, prot);
- int ret;
-
- ret = call_int_hook(mmap_file, 0, file, prot, prot_adj, flags);
- if (ret)
- return ret;
- return ima_file_mmap(file, prot, prot_adj, flags);
+ return call_int_hook(mmap_file, 0, file, prot, mmap_prot(file, prot),
+ flags);
}

/**
@@ -2828,12 +2818,7 @@ int security_mmap_addr(unsigned long addr)
int security_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
unsigned long prot)
{
- int ret;
-
- ret = call_int_hook(file_mprotect, 0, vma, reqprot, prot);
- if (ret)
- return ret;
- return ima_file_mprotect(vma, reqprot, prot);
+ return call_int_hook(file_mprotect, 0, vma, reqprot, prot);
}

/**
@@ -3163,12 +3148,7 @@ int security_kernel_module_request(char *kmod_name)
int security_kernel_read_file(struct file *file, enum kernel_read_file_id id,
bool contents)
{
- int ret;
-
- ret = call_int_hook(kernel_read_file, 0, file, id, contents);
- if (ret)
- return ret;
- return ima_read_file(file, id, contents);
+ return call_int_hook(kernel_read_file, 0, file, id, contents);
}
EXPORT_SYMBOL_GPL(security_kernel_read_file);

@@ -3188,12 +3168,7 @@ EXPORT_SYMBOL_GPL(security_kernel_read_file);
int security_kernel_post_read_file(struct file *file, char *buf, loff_t size,
enum kernel_read_file_id id)
{
- int ret;
-
- ret = call_int_hook(kernel_post_read_file, 0, file, buf, size, id);
- if (ret)
- return ret;
- return ima_post_read_file(file, buf, size, id);
+ return call_int_hook(kernel_post_read_file, 0, file, buf, size, id);
}
EXPORT_SYMBOL_GPL(security_kernel_post_read_file);

@@ -3208,12 +3183,7 @@ EXPORT_SYMBOL_GPL(security_kernel_post_read_file);
*/
int security_kernel_load_data(enum kernel_load_data_id id, bool contents)
{
- int ret;
-
- ret = call_int_hook(kernel_load_data, 0, id, contents);
- if (ret)
- return ret;
- return ima_load_data(id, contents);
+ return call_int_hook(kernel_load_data, 0, id, contents);
}
EXPORT_SYMBOL_GPL(security_kernel_load_data);

@@ -3235,13 +3205,8 @@ int security_kernel_post_load_data(char *buf, loff_t size,
enum kernel_load_data_id id,
char *description)
{
- int ret;
-
- ret = call_int_hook(kernel_post_load_data, 0, buf, size, id,
- description);
- if (ret)
- return ret;
- return ima_post_load_data(buf, size, id, description);
+ return call_int_hook(kernel_post_load_data, 0, buf, size, id,
+ description);
}
EXPORT_SYMBOL_GPL(security_kernel_post_load_data);

--
2.34.1