[PATCH v2] KEYS: trusted: allow trusted.ko to initialize w/o a TPM

From: Jarkko Sakkinen
Date: Tue Mar 26 2019 - 08:09:32 EST


Allow trusted.ko to initialize w/o a TPM. This commit adds checks to the
key type callbacks and exported functions to fail when a TPM is not
available.

Cc: James Morris <jmorris@xxxxxxxxx>
Reported-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Tested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Fixes: 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure...")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
v2:
- Remove checks from the key type callbacks because the key type will
not be registered.
- Cc to James Morris because hopefully we can land this 5.1.0.
security/keys/trusted.c | 31 +++++++++++++++++++++++++------
1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index ecec672d3a77..67c0e19a2125 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -135,6 +135,9 @@ int TSS_authhmac(unsigned char *digest, const unsigned char *key,
int ret;
va_list argp;

+ if (!chip)
+ return -ENODEV;
+
sdesc = init_sdesc(hashalg);
if (IS_ERR(sdesc)) {
pr_info("trusted_key: can't alloc %s\n", hash_alg);
@@ -196,6 +199,9 @@ int TSS_checkhmac1(unsigned char *buffer,
va_list argp;
int ret;

+ if (!chip)
+ return -ENODEV;
+
bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
tag = LOAD16(buffer, 0);
ordinal = command;
@@ -363,6 +369,9 @@ int trusted_tpm_send(unsigned char *cmd, size_t buflen)
{
int rc;

+ if (!chip)
+ return -ENODEV;
+
dump_tpm_buf(cmd);
rc = tpm_send(chip, cmd, buflen);
dump_tpm_buf(cmd);
@@ -429,6 +438,9 @@ int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
{
int ret;

+ if (!chip)
+ return -ENODEV;
+
INIT_BUF(tb);
store16(tb, TPM_TAG_RQU_COMMAND);
store32(tb, TPM_OIAP_SIZE);
@@ -1245,9 +1257,13 @@ static int __init init_trusted(void)
{
int ret;

+ /* encrypted_keys.ko depends on successful load of this module even if
+ * TPM is not used.
+ */
chip = tpm_default_chip();
if (!chip)
- return -ENOENT;
+ return 0;
+
ret = init_digests();
if (ret < 0)
goto err_put;
@@ -1263,16 +1279,19 @@ static int __init init_trusted(void)
err_free:
kfree(digests);
err_put:
- put_device(&chip->dev);
+ if (chip)
+ put_device(&chip->dev);
return ret;
}

static void __exit cleanup_trusted(void)
{
- put_device(&chip->dev);
- kfree(digests);
- trusted_shash_release();
- unregister_key_type(&key_type_trusted);
+ if (chip) {
+ put_device(&chip->dev);
+ kfree(digests);
+ trusted_shash_release();
+ unregister_key_type(&key_type_trusted);
+ }
}

late_initcall(init_trusted);
--
2.19.1