ima: define '.ima' as a builtin 'trusted' keyring

Require all keys added to the IMA keyring be signed by an
existing trusted key on the system trusted keyring.

Changelog v6:
- remove ifdef CONFIG_IMA_TRUSTED_KEYRING in C code - Dmitry
- update Kconfig dependency and help
- select KEYS_DEBUG_PROC_KEYS - Dmitry

Changelog v5:
- Move integrity_init_keyring() to init_ima() - Dmitry
- reset keyring[id] on failure - Dmitry

Changelog v1:
- don't link IMA trusted keyring to user keyring

Changelog:
- define stub integrity_init_keyring() function (reported-by Fengguang Wu)
- differentiate between regular and trusted keyring names.
- replace printk with pr_info (D. Kasatkin)
- only make the IMA keyring a trusted keyring (reported-by D. Kastatkin)
- define stub integrity_init_keyring() definition based on
  CONFIG_INTEGRITY_SIGNATURE, not CONFIG_INTEGRITY_ASYMMETRIC_KEYS.
  (reported-by Jim Davis)

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Acked-by: David Howells <dhowells@redhat.com>
This commit is contained in:
Mimi Zohar 2013-08-13 08:47:43 -04:00
Родитель 32c4741cb6
Коммит 7d2ce2320e
5 изменённых файлов: 63 добавлений и 2 удалений

Просмотреть файл

@ -13,7 +13,9 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/rbtree.h>
#include <linux/cred.h>
#include <linux/key-type.h>
#include <linux/digsig.h>
@ -24,7 +26,11 @@ static struct key *keyring[INTEGRITY_KEYRING_MAX];
static const char *keyring_name[INTEGRITY_KEYRING_MAX] = {
"_evm",
"_module",
#ifndef CONFIG_IMA_TRUSTED_KEYRING
"_ima",
#else
".ima",
#endif
};
int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
@ -56,3 +62,25 @@ int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
return -EOPNOTSUPP;
}
int integrity_init_keyring(const unsigned int id)
{
const struct cred *cred = current_cred();
int err = 0;
keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0),
KGIDT_INIT(0), cred,
((KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW | KEY_USR_READ |
KEY_USR_WRITE | KEY_USR_SEARCH),
KEY_ALLOC_NOT_IN_QUOTA, NULL);
if (!IS_ERR(keyring[id]))
set_bit(KEY_FLAG_TRUSTED_ONLY, &keyring[id]->flags);
else {
err = PTR_ERR(keyring[id]);
pr_info("Can't allocate %s keyring (%d)\n",
keyring_name[id], err);
keyring[id] = NULL;
}
return err;
}

Просмотреть файл

@ -123,3 +123,13 @@ config IMA_APPRAISE
For more information on integrity appraisal refer to:
<http://linux-ima.sourceforge.net>
If unsure, say N.
config IMA_TRUSTED_KEYRING
bool "Require all keys on the .ima keyring be signed"
depends on IMA_APPRAISE && SYSTEM_TRUSTED_KEYRING
depends on INTEGRITY_ASYMMETRIC_KEYS
select KEYS_DEBUG_PROC_KEYS
default y
help
This option requires that all keys added to the .ima
keyring be signed by a key on the system trusted keyring.

Просмотреть файл

@ -249,4 +249,16 @@ static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
return -EINVAL;
}
#endif /* CONFIG_IMA_LSM_RULES */
#ifdef CONFIG_IMA_TRUSTED_KEYRING
static inline int ima_init_keyring(const unsigned int id)
{
return integrity_init_keyring(id);
}
#else
static inline int ima_init_keyring(const unsigned int id)
{
return 0;
}
#endif /* CONFIG_IMA_TRUSTED_KEYRING */
#endif

Просмотреть файл

@ -325,8 +325,14 @@ static int __init init_ima(void)
hash_setup(CONFIG_IMA_DEFAULT_HASH);
error = ima_init();
if (!error)
ima_initialized = 1;
if (error)
goto out;
error = ima_init_keyring(INTEGRITY_KEYRING_IMA);
if (error)
goto out;
ima_initialized = 1;
out:
return error;
}

Просмотреть файл

@ -124,6 +124,7 @@ struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
const char *digest, int digestlen);
int integrity_init_keyring(const unsigned int id);
#else
static inline int integrity_digsig_verify(const unsigned int id,
@ -133,6 +134,10 @@ static inline int integrity_digsig_verify(const unsigned int id,
return -EOPNOTSUPP;
}
static inline int integrity_init_keyring(const unsigned int id)
{
return 0;
}
#endif /* CONFIG_INTEGRITY_SIGNATURE */
#ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS