On Thu, 2015-09-10 at 14:17 +0300, Petko Manolov wrote:
> The .system keyring is populated at kernel build time and read-only while the
> system is running. There is no way to dynamically add other user's CA so
> .ima_root_ca was introduced as read-write keyring that stores these
> certificates. CA hierarchy is achieved by allowing import of key material
> that
> has been signed by CA already present in the .system keyring.
>
> The new .ima_blacklist is a keyring that holds all revoked IMA keys. It is
> consulted first, then the .ima keyring.
A couple of minor comments inline below...
>
> Signed-off-by: Petko Manolov <pet...@mip-labs.com>
> ---
> crypto/asymmetric_keys/x509_public_key.c | 2 ++
> include/keys/system_keyring.h | 13 ++++++++
> security/integrity/digsig_asymmetric.c | 13 ++++++++
> security/integrity/ima/Kconfig | 11 +++++++
> security/integrity/ima/Makefile | 1 +
> security/integrity/ima/ima_root_ca.c | 56
> ++++++++++++++++++++++++++++++++
> security/integrity/integrity.h | 13 ++++++++
> 7 files changed, 109 insertions(+)
> create mode 100644 security/integrity/ima/ima_root_ca.c
>
> diff --git a/crypto/asymmetric_keys/x509_public_key.c
> b/crypto/asymmetric_keys/x509_public_key.c
> index 6d88dd1..e39ca38 100644
> --- a/crypto/asymmetric_keys/x509_public_key.c
> +++ b/crypto/asymmetric_keys/x509_public_key.c
> @@ -319,6 +319,8 @@ static int x509_key_preparse(struct key_preparsed_payload
> *prep)
> goto error_free_cert;
> } else if (!prep->trusted) {
> ret = x509_validate_trust(cert, get_system_trusted_keyring());
> + if (ret)
> + ret = x509_validate_trust(cert,
> get_ima_root_ca_keyring());
> if (!ret)
> prep->trusted = 1;
> }
> diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
> index b20cd88..774de6c 100644
> --- a/include/keys/system_keyring.h
> +++ b/include/keys/system_keyring.h
> @@ -35,4 +35,17 @@ extern int system_verify_data(const void *data, unsigned
> long len,
> enum key_being_used_for usage);
> #endif
>
> +#ifdef CONFIG_IMA_ROOT_CA_KEYRING
> +extern struct key *ima_root_ca_keyring;
> +static inline struct key *get_ima_root_ca_keyring(void)
> +{
> + return ima_root_ca_keyring;
> +}
> +#else
> +static inline struct key *get_ima_root_ca_keyring(void)
> +{
> + return NULL;
> +}
> +#endif /* CONFIG_IMA_ROOT_CA_KEYRING */
> +
> #endif /* _KEYS_SYSTEM_KEYRING_H */
> diff --git a/security/integrity/digsig_asymmetric.c
> b/security/integrity/digsig_asymmetric.c
> index 4fec181..52377d9 100644
> --- a/security/integrity/digsig_asymmetric.c
> +++ b/security/integrity/digsig_asymmetric.c
> @@ -32,9 +32,22 @@ static struct key *request_asymmetric_key(struct key
> *keyring, uint32_t keyid)
>
> pr_debug("key search: \"%s\"\n", name);
>
> + key = get_ima_blacklist_keyring();
> + if (key) {
> + key_ref_t kref;
> +
> + kref = keyring_search(make_key_ref(key, 1),
> + &key_type_asymmetric, name);
> + if (!IS_ERR(kref)) {
> + pr_err("Key '%s' is in ima_blacklist_keyring\n", name);
> + return ERR_PTR(-EKEYREJECTED);
> + }
> + }
> +
> if (keyring) {
> /* search in specific keyring */
> key_ref_t kref;
> +
> kref = keyring_search(make_key_ref(keyring, 1),
> &key_type_asymmetric, name);
> if (IS_ERR(kref))
> diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
> index ebe7a907..69426ce 100644
> --- a/security/integrity/ima/Kconfig
> +++ b/security/integrity/ima/Kconfig
> @@ -146,6 +146,17 @@ config IMA_TRUSTED_KEYRING
> This option requires that all keys added to the .ima
> keyring be signed by a key on the system trusted keyring.
>
> +config IMA_ROOT_CA_KEYRING
> + bool "Create IMA Root CA keyring"
> + depends on IMA_TRUSTED_KEYRING
> + default y
> + help
> + This option creates IMA Root CA keyring. This is intermediate
> + keyring which sits between the .system and .ima keyrings, effectively
> + creating a simple CA hierarchy. All keys in it must be signed either
> + by a key in the .system keyring or one which is already in
> + .ima_root_ca_keyring.
> +
> config IMA_LOAD_X509
> bool "Load X509 certificate onto the '.ima' trusted keyring"
> depends on IMA_TRUSTED_KEYRING
> diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
> index d79263d..b2f9aa0 100644
> --- a/security/integrity/ima/Makefile
> +++ b/security/integrity/ima/Makefile
> @@ -8,3 +8,4 @@ obj-$(CONFIG_IMA) += ima.o
> ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
> ima_policy.o ima_template.o ima_template_lib.o
> ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o
> +obj-$(CONFIG_IMA_ROOT_CA_KEYRING) += ima_root_ca.o
> diff --git a/security/integrity/ima/ima_root_ca.c
> b/security/integrity/ima/ima_root_ca.c
> new file mode 100644
> index 0000000..23fccdc
> --- /dev/null
> +++ b/security/integrity/ima/ima_root_ca.c
> @@ -0,0 +1,56 @@
> +/*
> + * Copyright (C) 2015 Juniper Networks, Inc.
> + *
> + * Author:
> + * Petko Manolov <petko.mano...@konsulko.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation, version 2 of the
> + * License.
> + *
> + */
> +
> +#include <linux/export.h>
> +#include <linux/kernel.h>
> +#include <linux/sched.h>
> +#include <linux/cred.h>
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <keys/asymmetric-type.h>
> +
> +
> +struct key *ima_root_ca_keyring;
> +EXPORT_SYMBOL_GPL(ima_root_ca_keyring);
> +struct key *ima_blacklist_keyring;
> +EXPORT_SYMBOL_GPL(ima_blacklist_keyring);
Do these keyrings need to be exported?
> +/*
> + * Allocate the IMA Root CA keyring
> + */
> +__init int ima_root_ca_init(void)
> +{
> + pr_notice("Initialise IMA Root CA keyring.\n");
> +
> + ima_root_ca_keyring = keyring_alloc(".ima_root_ca",
> + KUIDT_INIT(0), KGIDT_INIT(0), current_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);
> +
> + ima_blacklist_keyring = keyring_alloc(".ima_blacklist",
> + KUIDT_INIT(0), KGIDT_INIT(0), current_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(ima_root_ca_keyring) || IS_ERR(ima_blacklist_keyring))
> + panic("Can't allocate IMA Root CA or blacklist keyrings.");
> + set_bit(KEY_FLAG_TRUSTED_ONLY, &ima_root_ca_keyring->flags);
> + set_bit(KEY_FLAG_TRUSTED_ONLY, &ima_blacklist_keyring->flags);
Why not use the existing ima/integrity_init_keyring() function?
Mimi
> + return 0;
> +}
> +
> +module_init(ima_root_ca_init);
> diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
> index 9c61687..79d4a33 100644
> --- a/security/integrity/integrity.h
> +++ b/security/integrity/integrity.h
> @@ -184,3 +184,16 @@ static inline void integrity_audit_msg(int audit_msgno,
> struct inode *inode,
> {
> }
> #endif
> +
> +#ifdef CONFIG_IMA_ROOT_CA_KEYRING
> +extern struct key *ima_blacklist_keyring;
> +static inline struct key *get_ima_blacklist_keyring(void)
> +{
> + return ima_blacklist_keyring;
> +}
> +#else
> +static inline struct key *get_ima_blacklist_keyring(void)
> +{
> + return NULL;
> +}
> +#endif
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