Currently, UBIFS auth_key can only be a logon key: This is a user key
that's provided to the kernel in plaintext and that then remains within
the kernel. Linux also supports trusted and encrypted keys, which have
stronger guarantees: They are only exposed to userspace in encrypted
form and, in the case of trusted keys, can be directly rooted to a trust
source like a TPM chip.
Add support for auth_key to be either a logon, encrypted or trusted key.
At mount time, the keyring will be searched for a key with the supplied
name in that order.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
To: David Howells <dhowells@xxxxxxxxxx>
To: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
To: James Morris <jmorris@xxxxxxxxx>
To: "Serge E. Hallyn" <serge@xxxxxxxxxx>
To: Alasdair Kergon <agk@xxxxxxxxxx>
To: Mike Snitzer <snitzer@xxxxxxxxxx>
To: dm-devel@xxxxxxxxxx
To: Song Liu <song@xxxxxxxxxx>
To: Richard Weinberger <richard@xxxxxx>
To: Jonathan Corbet <corbet@xxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-raid@xxxxxxxxxxxxxxx
Cc: keyrings@xxxxxxxxxxxxxxx
Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx
Cc: linux-security-module@xxxxxxxxxxxxxxx
Cc: linux-integrity@xxxxxxxxxxxxxxx
---
Documentation/filesystems/ubifs.rst | 2 +-
fs/ubifs/auth.c | 19 ++++++++++++-------
2 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/Documentation/filesystems/ubifs.rst b/Documentation/filesystems/ubifs.rst
index e6ee99762534..12d08458b3d7 100644
--- a/Documentation/filesystems/ubifs.rst
+++ b/Documentation/filesystems/ubifs.rst
@@ -101,7 +101,7 @@ compr=zlib override default compressor and set it to "zlib"
auth_key= specify the key used for authenticating the filesystem.
Passing this option makes authentication mandatory.
The passed key must be present in the kernel keyring
- and must be of type 'logon'
+ and must be of type 'logon', 'encrypted' or 'trusted'.
auth_hash_name= The hash algorithm used for authentication. Used for
both hashing and for creating HMACs. Typical values
include "sha256" or "sha512"
diff --git a/fs/ubifs/auth.c b/fs/ubifs/auth.c
index 6a0b8d858d81..af8e9eb58a60 100644
--- a/fs/ubifs/auth.c
+++ b/fs/ubifs/auth.c
@@ -14,6 +14,8 @@
#include <crypto/hash.h>
#include <crypto/algapi.h>
#include <keys/user-type.h>
+#include <keys/trusted-type.h>
+#include <keys/encrypted-type.h>
#include <keys/asymmetric-type.h>
#include "ubifs.h"
@@ -256,9 +258,10 @@ out_destroy:
int ubifs_init_authentication(struct ubifs_info *c)
{
struct key *keyring_key;
- const struct user_key_payload *ukp;
int err;
+ unsigned int len;
char hmac_name[CRYPTO_MAX_ALG_NAME];
+ const void *key_material;
if (!c->auth_hash_name) {
ubifs_err(c, "authentication hash name needed with authentication");
@@ -277,6 +280,10 @@ int ubifs_init_authentication(struct ubifs_info *c)
c->auth_hash_name);
keyring_key = request_key(&key_type_logon, c->auth_key_name, NULL);
+ if (IS_ERR(keyring_key) && IS_REACHABLE(CONFIG_ENCRYPTED_KEYS))
+ keyring_key = request_key(&key_type_encrypted, c->auth_key_name, NULL);
+ if (IS_ERR(keyring_key) && IS_REACHABLE(CONFIG_TRUSTED_KEYS))
+ keyring_key = request_key(&key_type_trusted, c->auth_key_name, NULL);
if (IS_ERR(keyring_key)) {
ubifs_err(c, "Failed to request key: %ld",
@@ -286,12 +293,10 @@ int ubifs_init_authentication(struct ubifs_info *c)
down_read(&keyring_key->sem);
- ukp = user_key_payload_locked(keyring_key);
- if (!ukp) {
- /* key was revoked before we acquired its semaphore */
- err = -EKEYREVOKED;
+ key_material = key_extract_material(keyring_key, &len);
+ err = PTR_ERR_OR_ZERO(key_material);
+ if (err < 0)
goto out;
- }
c->hash_tfm = crypto_alloc_shash(c->auth_hash_name, 0, 0);
if (IS_ERR(c->hash_tfm)) {
@@ -324,7 +329,7 @@ int ubifs_init_authentication(struct ubifs_info *c)
goto out_free_hmac;
}
- err = crypto_shash_setkey(c->hmac_tfm, ukp->data, ukp->datalen);
+ err = crypto_shash_setkey(c->hmac_tfm, key_material, len);
if (err)
goto out_free_hmac;
--
git-series 0.9.1
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