Implemented TPM2 support for tpm_get_random().
Signed-off-by: Jarkko Sakkinen <[email protected]>
---
drivers/char/tpm/tpm-interface.c | 6 ++++++
drivers/char/tpm/tpm.h | 11 ++++++++++
drivers/char/tpm/tpm2-commands.c | 45 ++++++++++++++++++++++++++++++++++++++++
drivers/char/tpm/tpm2.h | 2 ++
4 files changed, 64 insertions(+)
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index ed23ba3..3d4a664 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -1002,6 +1002,12 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
if (chip == NULL)
return -ENODEV;
+ if (chip->tpm2) {
+ err = tpm2_get_random(chip, out, max);
+ tpm_chip_put(chip);
+ return err;
+ }
+
do {
tpm_cmd.header.in = tpm_getrandom_header;
tpm_cmd.params.getrandom_in.num_bytes = cpu_to_be32(num_bytes);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 4637342..b4c0d5d 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -351,6 +351,15 @@ struct tpm2_get_tpm_pt_out {
__be32 value;
} __packed;
+struct tpm2_get_random_in {
+ __be16 size;
+} __packed;
+
+struct tpm2_get_random_out {
+ __be16 size;
+ u8 buffer[TPM_MAX_RNG_DATA];
+} __packed;
+
typedef union {
struct tpm_getcap_params_out getcap_out;
struct tpm_readpubek_params_out readpubek_out;
@@ -368,6 +377,8 @@ typedef union {
struct tpm2_self_test_in tpm2_selftest_in;
struct tpm2_get_tpm_pt_in tpm2_get_tpm_pt_in;
struct tpm2_get_tpm_pt_out tpm2_get_tpm_pt_out;
+ struct tpm2_get_random_in tpm2_getrandom_in;
+ struct tpm2_get_random_out tpm2_getrandom_out;
} tpm_cmd_params;
struct tpm_cmd_t {
diff --git a/drivers/char/tpm/tpm2-commands.c b/drivers/char/tpm/tpm2-commands.c
index b69999e..90cebb2 100644
--- a/drivers/char/tpm/tpm2-commands.c
+++ b/drivers/char/tpm/tpm2-commands.c
@@ -349,3 +349,48 @@ int tpm2_do_selftest(struct tpm_chip *chip)
return rc;
}
+
+static struct tpm_input_header tpm2_getrandom_header = {
+ .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
+ .length = cpu_to_be32(sizeof(struct tpm_input_header) +
+ sizeof(struct tpm2_get_random_in)),
+ .ordinal = cpu_to_be32(TPM2_CC_GET_RANDOM)
+};
+
+/**
+ * tpm2_get_random() - get random bytes from the TPM RNG
+ * @chip: TPM chip to use
+ * @out: destination buffer for the random bytes
+ * @max: the max number of bytes to write to @out
+ *
+ * Returns < 0 on error and the number of bytes read on success
+ */
+int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
+{
+ struct tpm_cmd_t tpm_cmd;
+ u32 recd, num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA);
+ 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 = tpm2_getrandom_header;
+ tpm_cmd.params.tpm2_getrandom_in.size = cpu_to_be16(num_bytes);
+
+ err = tpm_transmit_cmd(chip, &tpm_cmd, sizeof(tpm_cmd),
+ "attempting get random");
+ if (err)
+ break;
+
+ recd = be16_to_cpu(tpm_cmd.params.tpm2_getrandom_out.size);
+ memcpy(dest, tpm_cmd.params.tpm2_getrandom_out.buffer, recd);
+
+ dest += recd;
+ total += recd;
+ num_bytes -= recd;
+ } while (retries-- && total < max);
+
+ return total ? total : -EIO;
+}
diff --git a/drivers/char/tpm/tpm2.h b/drivers/char/tpm/tpm2.h
index e4ed2e5..6ec84bc 100644
--- a/drivers/char/tpm/tpm2.h
+++ b/drivers/char/tpm/tpm2.h
@@ -38,6 +38,7 @@ enum tpm2_algorithms {
enum tpm2_command_codes {
TPM2_CC_SELF_TEST = 0x0143,
TPM2_CC_GET_CAPABILITY = 0x017A,
+ TPM2_CC_GET_RANDOM = 0x017B,
TPM2_CC_PCR_READ = 0x017E,
TPM2_CC_PCR_EXTEND = 0x0182,
};
@@ -61,5 +62,6 @@ ssize_t tpm2_get_tpm_pt(struct device *dev, u32 property_id,
u32* value,
int tpm2_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash);
int tpm2_do_selftest(struct tpm_chip *chip);
+int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max);
#endif /* __DRIVERS_CHAR_TPM2_H__ */
--
2.1.0
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