[PATCH v2 1/3] keys, trusted: select the hash algorithm

Jarkko Sakkinen
2015-10-30T11:35:29Z

Added 'hash=' option for selecting the hash algorithm for add_key()
syscall and documentation for it.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
Documentation/security/keys-trusted-encrypted.txt | 3 +++
include/keys/trusted-type.h | 1 +
security/keys/Kconfig | 1 +
security/keys/trusted.c | 20 +++++++++++++++++++-
4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/Documentation/security/keys-trusted-encrypted.txt b/Documentation/security/keys-trusted-encrypted.txt
index e105ae9..fd2565b 100644
--- a/Documentation/security/keys-trusted-encrypted.txt
+++ b/Documentation/security/keys-trusted-encrypted.txt
@@ -38,6 +38,9 @@ Usage:
pcrlock= pcr number to be extended to "lock" blob
migratable= 0|1 indicating permission to reseal to new PCR values,
default 1 (resealing allowed)
+ hash= hash algorithm name as a string. For TPM 1.x the only
+ allowed value is sha1. For TPM 2.x the allowed values
+ are sha1, sha256, sha384, sha512 and sm3-256.

"keyctl print" returns an ascii hex copy of the sealed key, which is in standard
TPM_STORED_DATA format. The key length for new keys are always in bytes.
diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
index f91ecd9..a6a1008 100644
--- a/include/keys/trusted-type.h
+++ b/include/keys/trusted-type.h
@@ -36,6 +36,7 @@ struct trusted_key_options {
uint32_t pcrinfo_len;
unsigned char pcrinfo[MAX_PCRINFO_SIZE];
int pcrlock;
+ uint32_t hash;
};

extern struct key_type key_type_trusted;
diff --git a/security/keys/Kconfig b/security/keys/Kconfig
index 72483b8..fe4d74e 100644
--- a/security/keys/Kconfig
+++ b/security/keys/Kconfig
@@ -54,6 +54,7 @@ config TRUSTED_KEYS
select CRYPTO
select CRYPTO_HMAC
select CRYPTO_SHA1
+ select CRYPTO_HASH_INFO
help
This option provides support for creating, sealing, and unsealing
keys in the kernel. Trusted keys are random number symmetric keys,
diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index d3633cf..7a87bcd 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -11,6 +11,7 @@
* See Documentation/security/keys-trusted-encrypted.txt
*/

+#include <crypto/hash_info.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/init.h>
@@ -710,7 +711,8 @@ enum {
Opt_err = -1,
Opt_new, Opt_load, Opt_update,
Opt_keyhandle, Opt_keyauth, Opt_blobauth,
- Opt_pcrinfo, Opt_pcrlock, Opt_migratable
+ Opt_pcrinfo, Opt_pcrlock, Opt_migratable,
+ Opt_hash,
};

static const match_table_t key_tokens = {
@@ -723,6 +725,7 @@ static const match_table_t key_tokens = {
{Opt_pcrinfo, "pcrinfo=%s"},
{Opt_pcrlock, "pcrlock=%s"},
{Opt_migratable, "migratable=%s"},
+ {Opt_hash, "hash=%s"},
{Opt_err, NULL}
};

@@ -736,6 +739,7 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
int res;
unsigned long handle;
unsigned long lock;
+ int i;

while ((p = strsep(&c, " \t"))) {
if (*p == '\0' || *p == ' ' || *p == '\t')
@@ -787,6 +791,20 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
return -EINVAL;
opt->pcrlock = lock;
break;
+ case Opt_hash:
+ for (i = 0; i < HASH_ALGO__LAST; i++) {
+ if (!strcmp(args[0].from, hash_algo_name[i])) {
+ opt->hash = i;
+ break;
+ }
+ }
+ res = tpm_is_tpm2(TPM_ANY_NUM);
+ if (res < 0)
+ return res;
+ if (i == HASH_ALGO__LAST ||
+ (!res && i != HASH_ALGO_SHA1))
+ return -EINVAL;
+ break;
default:
return -EINVAL;
}
--
2.5.0