[PATCH 1/4] tpm: Use -EPERM as fallback error code in tpm_ret_to_err

Jarkko Sakkinen
2025-09-22T16:43:33Z

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

Using -EFAULT here was not the best idea for tpm_ret_to_err as the fallback
error code as it is no concise with trusted keys.

Change the fallback as -EPERM, process TPM_RC_HASH also in tpm_ret_to_err,
and by these changes make the helper applicable for trusted keys.

Fixes: 539fbab37881 ("tpm: Mask TPM RC in tpm2_start_auth_session()")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>
---
include/linux/tpm.h | 9 +++++---
security/keys/trusted-keys/trusted_tpm2.c | 26 ++++++-----------------
2 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index dc0338a783f3..667d290789ca 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -449,13 +449,16 @@ static inline ssize_t tpm_ret_to_err(ssize_t ret)
if (ret < 0)
return ret;

- switch (tpm2_rc_value(ret)) {
- case TPM2_RC_SUCCESS:
+ if (!ret)
return 0;
+
+ switch (tpm2_rc_value(ret)) {
case TPM2_RC_SESSION_MEMORY:
return -ENOMEM;
+ case TPM2_RC_HASH:
+ return -EINVAL;
default:
- return -EFAULT;
+ return -EPERM;
}
}

diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 024be262702f..e165b117bbca 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -348,25 +348,19 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
}

blob_len = tpm2_key_encode(payload, options, &buf.data[offset], blob_len);
+ if (blob_len < 0)
+ rc = blob_len;

out:
tpm_buf_destroy(&sized);
tpm_buf_destroy(&buf);

- if (rc > 0) {
- if (tpm2_rc_value(rc) == TPM2_RC_HASH)
- rc = -EINVAL;
- else
- rc = -EPERM;
- }
- if (blob_len < 0)
- rc = blob_len;
- else
+ if (!rc)
payload->blob_len = blob_len;

out_put:
tpm_put_ops(chip);
- return rc;
+ return tpm_ret_to_err(rc);
}

/**
@@ -468,10 +462,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip,
kfree(blob);
tpm_buf_destroy(&buf);

- if (rc > 0)
- rc = -EPERM;
-
- return rc;
+ return tpm_ret_to_err(rc);
}

/**
@@ -534,8 +525,6 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
tpm_buf_fill_hmac_session(chip, &buf);
rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
rc = tpm_buf_check_hmac_response(chip, &buf, rc);
- if (rc > 0)
- rc = -EPERM;

if (!rc) {
data_len = be16_to_cpup(
@@ -568,7 +557,7 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,

out:
tpm_buf_destroy(&buf);
- return rc;
+ return tpm_ret_to_err(rc);
}

/**
@@ -600,6 +589,5 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,

out:
tpm_put_ops(chip);
-
- return rc;
+ return tpm_ret_to_err(rc);
}
--
2.39.5