[PATCH 3/4] tpm2-sessions: Remove unnecessary wrapper

Jarkko Sakkinen
2025-09-22T16:43:41Z

From: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>

Open code tpm_buf_append_hmac_session_opt() because it adds unnecessary
disperancy to the call sites (and reduces the amount of code).

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>
---
drivers/char/tpm/tpm2-cmd.c | 14 +++++++++++---
security/keys/trusted-keys/trusted_tpm2.c | 12 ++++++++++--
2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 61a4daaef292..0a795adbdc11 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -257,9 +257,17 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)

do {
tpm_buf_reset(&buf, TPM2_ST_SESSIONS, TPM2_CC_GET_RANDOM);
- tpm_buf_append_hmac_session_opt(chip, &buf, TPM2_SA_ENCRYPT
- | TPM2_SA_CONTINUE_SESSION,
- NULL, 0);
+ if (tpm2_chip_auth(chip)) {
+ tpm_buf_append_hmac_session(chip, &buf,
+ TPM2_SA_ENCRYPT |
+ TPM2_SA_CONTINUE_SESSION,
+ NULL, 0);
+ } else {
+ offset = buf.handles * 4 + TPM_HEADER_SIZE;
+ head = (struct tpm_header *)buf.data;
+ if (tpm_buf_length(&buf) == offset)
+ head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
+ }
tpm_buf_append_u16(&buf, num_bytes);
tpm_buf_fill_hmac_session(chip, &buf);
err = tpm_transmit_cmd(chip, &buf,
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index e165b117bbca..c414a7006d78 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -482,8 +482,10 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
struct trusted_key_options *options,
u32 blob_handle)
{
+ struct tpm_header *head;
struct tpm_buf buf;
u16 data_len;
+ int offset;
u8 *data;
int rc;

@@ -518,8 +520,14 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
tpm2_buf_append_auth(&buf, options->policyhandle,
NULL /* nonce */, 0, 0,
options->blobauth, options->blobauth_len);
- tpm_buf_append_hmac_session_opt(chip, &buf, TPM2_SA_ENCRYPT,
- NULL, 0);
+ if (tpm2_chip_auth(chip)) {
+ tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT, NULL, 0);
+ } else {
+ offset = buf.handles * 4 + TPM_HEADER_SIZE;
+ head = (struct tpm_header *)buf.data;
+ if (tpm_buf_length(&buf) == offset)
+ head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
+ }
}

tpm_buf_fill_hmac_session(chip, &buf);
--
2.39.5