diff options
author | Tomas Winkler <tomas.winkler@intel.com> | 2018-10-19 21:22:55 +0300 |
---|---|---|
committer | Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> | 2018-11-13 13:46:30 +0200 |
commit | 433d390f005d3a89dba5a03a87b5a6c242748de3 (patch) | |
tree | 2a19263f8baba11d681c24bb12eea9c36e612ac7 /drivers/char/tpm/tpm1-cmd.c | |
parent | f4d916b72feafd70967994f4f5a5d7f371a77ba0 (diff) |
tpm: factor out tpm1_get_random into tpm1-cmd.c
Factor out get random implementation from tpm-interface.c
into tpm1_get_random function in tpm1-cmd.c.
No functional changes.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Diffstat (limited to 'drivers/char/tpm/tpm1-cmd.c')
-rw-r--r-- | drivers/char/tpm/tpm1-cmd.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c index 3bd079587ef5..e02f0c1c822f 100644 --- a/drivers/char/tpm/tpm1-cmd.c +++ b/drivers/char/tpm/tpm1-cmd.c @@ -469,3 +469,58 @@ ssize_t tpm1_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap, return rc; } EXPORT_SYMBOL_GPL(tpm1_getcap); + +#define TPM_ORD_GET_RANDOM 70 +#define TPM_GETRANDOM_RESULT_SIZE 18 +static const struct tpm_input_header tpm_getrandom_header = { + .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND), + .length = cpu_to_be32(14), + .ordinal = cpu_to_be32(TPM_ORD_GET_RANDOM) +}; + +int tpm1_get_random(struct tpm_chip *chip, u8 *out, size_t max) +{ + struct tpm_cmd_t tpm_cmd; + u32 recd; + u32 num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA); + u32 rlength; + int err, total = 0, retries = 5; + u8 *dest = out; + + if (!out || !num_bytes || max > TPM_MAX_RNG_DATA) + return -EINVAL; + + do { + tpm_cmd.header.in = tpm_getrandom_header; + tpm_cmd.params.getrandom_in.num_bytes = cpu_to_be32(num_bytes); + + err = tpm_transmit_cmd(chip, NULL, &tpm_cmd, + TPM_GETRANDOM_RESULT_SIZE + num_bytes, + offsetof(struct tpm_getrandom_out, + rng_data), + 0, "attempting get random"); + if (err) + break; + + recd = be32_to_cpu(tpm_cmd.params.getrandom_out.rng_data_len); + if (recd > num_bytes) { + total = -EFAULT; + break; + } + + rlength = be32_to_cpu(tpm_cmd.header.out.length); + if (rlength < TPM_HEADER_SIZE + + offsetof(struct tpm_getrandom_out, rng_data) + + recd) { + total = -EFAULT; + break; + } + memcpy(dest, tpm_cmd.params.getrandom_out.rng_data, recd); + + dest += recd; + total += recd; + num_bytes -= recd; + } while (retries-- && (size_t)total < max); + + return total ? total : -EIO; +} |