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SubjectRe: [PATCH] keys, trusted: select TPM2 hash algorithm
On Sat, Oct 24, 2015 at 03:42:42PM +0300, Jarkko Sakkinen wrote:
> Added 'hashalg=' option for selecting the hash algorithm.
>
> Currently available options are:
>
> * sha1
> * sha256
> * sha384
> * sha512
> * sm3_256
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Things that came to mind after sending this:

* Documentation update is needed.
* Maybe it would be a good idea to return -EINVAL in the following
conditions:
* TPM1 chip
* Explicit hashalg option where hashalg is something different than
sha1.

Also one question: should I split this into three patches:

* Support for 'hashalg' in drivers/char/tpm.
* Parsing of hashalg in security/keys.
* Documentation update.

Anyway, this patch is good for testing. No functional updates are
needed except maybe that update for TPM1 chips.

/Jarkko

> ---
> drivers/char/tpm/tpm.h | 5 ++++-
> drivers/char/tpm/tpm2-cmd.c | 34 ++++++++++++++++++++++++++++++++++
> include/keys/trusted-type.h | 2 ++
> security/keys/trusted.c | 8 +++++++-
> 4 files changed, 47 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index a4257a3..4c18f46 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -92,7 +92,10 @@ enum tpm2_algorithms {
> TPM2_ALG_SHA1 = 0x0004,
> TPM2_ALG_KEYEDHASH = 0x0008,
> TPM2_ALG_SHA256 = 0x000B,
> - TPM2_ALG_NULL = 0x0010
> + TPM2_ALG_SHA384 = 0x000C,
> + TPM2_ALG_SHA512 = 0x000D,
> + TPM2_ALG_NULL = 0x0010,
> + TPM2_ALG_SM3_256 = 0x0012,
> };
>
> enum tpm2_command_codes {
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index bd7039f..0704bd6 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -104,6 +104,22 @@ struct tpm2_cmd {
> union tpm2_cmd_params params;
> } __packed;
>
> +struct tpm2_hashalg {
> + char name[MAX_HASHALG_SIZE];
> + u32 id;
> +};
> +
> +struct tpm2_hashalg tpm2_hashalg_map[] = {
> + {"sha1", TPM2_ALG_SHA1},
> + {"sha256", TPM2_ALG_SHA256},
> + {"sm3_256", TPM2_ALG_SM3_256},
> + {"sha384", TPM2_ALG_SHA384},
> + {"sha512", TPM2_ALG_SHA512},
> +};
> +
> +#define TPM2_HASHALG_COUNT \
> + (sizeof(tpm2_hashalg_map) / sizeof(tpm2_hashalg_map[1]))
> +
> /*
> * Array with one entry per ordinal defining the maximum amount
> * of time the chip could take to return the result. The values
> @@ -429,8 +445,26 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
> {
> unsigned int blob_len;
> struct tpm_buf buf;
> + u32 hashalg = TPM2_ALG_SHA256;
> + int i;
> int rc;
>
> + if (strlen(options->hashalg) > 0) {
> + for (i = 0; i < TPM2_HASHALG_COUNT; i++) {
> + if (!strcmp(options->hashalg,
> + tpm2_hashalg_map[i].name)) {
> + hashalg = tpm2_hashalg_map[i].id;
> + dev_dbg(chip->pdev, "%s: hashalg: %s 0x%08X\n",
> + __func__, tpm2_hashalg_map[i].name,
> + hashalg);
> + break;
> + }
> + }
> +
> + if (i == TPM2_HASHALG_COUNT)
> + return -EINVAL;
> + }
> +
> rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
> if (rc)
> return rc;
> diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
> index f91ecd9..a545733 100644
> --- a/include/keys/trusted-type.h
> +++ b/include/keys/trusted-type.h
> @@ -18,6 +18,7 @@
> #define MAX_KEY_SIZE 128
> #define MAX_BLOB_SIZE 512
> #define MAX_PCRINFO_SIZE 64
> +#define MAX_HASHALG_SIZE 16
>
> struct trusted_key_payload {
> struct rcu_head rcu;
> @@ -36,6 +37,7 @@ struct trusted_key_options {
> uint32_t pcrinfo_len;
> unsigned char pcrinfo[MAX_PCRINFO_SIZE];
> int pcrlock;
> + unsigned char hashalg[MAX_HASHALG_SIZE];
> };
>
> extern struct key_type key_type_trusted;
> diff --git a/security/keys/trusted.c b/security/keys/trusted.c
> index d3633cf..9e7564d 100644
> --- a/security/keys/trusted.c
> +++ b/security/keys/trusted.c
> @@ -710,7 +710,8 @@ 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_hashalg,
> };
>
> static const match_table_t key_tokens = {
> @@ -723,6 +724,7 @@ static const match_table_t key_tokens = {
> {Opt_pcrinfo, "pcrinfo=%s"},
> {Opt_pcrlock, "pcrlock=%s"},
> {Opt_migratable, "migratable=%s"},
> + {Opt_hashalg, "hashalg=%s"},
> {Opt_err, NULL}
> };
>
> @@ -787,6 +789,10 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
> return -EINVAL;
> opt->pcrlock = lock;
> break;
> + case Opt_hashalg:
> + strncpy(opt->hashalg, args[0].from,
> + MAX_HASHALG_SIZE - 1);
> + break;
> default:
> return -EINVAL;
> }
> --
> 2.5.0
>


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