[PATCH v9 3/8] KEYS: trusted: Replace a redundant instance of tpm2_hash_map

Jarkko Sakkinen
2025-11-28T02:54:32Z

'trusted_tpm2' duplicates 'tpm2_hash_map' originally part of the TPN
driver, which is suboptimal.

Implement and export `tpm2_find_hash_alg()` in the driver, and substitute
the redundant code in 'trusted_tpm2' with a call to the new function.

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v9:
- Improved the commit message a bit.
v8:
- Remove spurious tpm2_alg_to_crypto_id.
- Check return value of tpm2_find_hash_alg correctly in trusted_tpm2.c
i.e, fail on "hash_alg < 0". Trusted keys were tested but I had my
test harness misconfigured. I bisected the failure to this patch.
- The diff was not exactly minimal. Further optimize it.
v7:
- A new patch.
---
drivers/char/tpm/tpm2-cmd.c | 14 +++++++++++++-
include/linux/tpm.h | 1 +
security/keys/trusted-keys/trusted_tpm2.c | 23 ++++-------------------
3 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index e298194883e8..a121c518ff6f 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -18,7 +18,7 @@ static bool disable_pcr_integrity;
module_param(disable_pcr_integrity, bool, 0444);
MODULE_PARM_DESC(disable_pcr_integrity, "Disable integrity protection of TPM2_PCR_Extend");

-static struct tpm2_hash tpm2_hash_map[] = {
+struct tpm2_hash tpm2_hash_map[] = {
{HASH_ALGO_SHA1, TPM_ALG_SHA1},
{HASH_ALGO_SHA256, TPM_ALG_SHA256},
{HASH_ALGO_SHA384, TPM_ALG_SHA384},
@@ -26,6 +26,18 @@ static struct tpm2_hash tpm2_hash_map[] = {
{HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
};

+int tpm2_find_hash_alg(unsigned int crypto_id)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++)
+ if (crypto_id == tpm2_hash_map[i].crypto_id)
+ return tpm2_hash_map[i].tpm_id;
+
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(tpm2_find_hash_alg);
+
int tpm2_get_timeouts(struct tpm_chip *chip)
{
chip->timeout_a = msecs_to_jiffies(TPM2_TIMEOUT_A);
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 973458a38250..cbd3a70c0378 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -477,6 +477,7 @@ extern int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
extern struct tpm_chip *tpm_default_chip(void);
void tpm2_flush_context(struct tpm_chip *chip, u32 handle);
+int tpm2_find_hash_alg(unsigned int crypto_id);

static inline void tpm_buf_append_empty_auth(struct tpm_buf *buf, u32 handle)
{
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index c414a7006d78..4467e880ebd5 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -18,14 +18,6 @@

#include "tpm2key.asn1.h"

-static struct tpm2_hash tpm2_hash_map[] = {
- {HASH_ALGO_SHA1, TPM_ALG_SHA1},
- {HASH_ALGO_SHA256, TPM_ALG_SHA256},
- {HASH_ALGO_SHA384, TPM_ALG_SHA384},
- {HASH_ALGO_SHA512, TPM_ALG_SHA512},
- {HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
-};
-
static u32 tpm2key_oid[] = { 2, 23, 133, 10, 1, 5 };

static int tpm2_key_encode(struct trusted_key_payload *payload,
@@ -244,20 +236,13 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
off_t offset = TPM_HEADER_SIZE;
struct tpm_buf buf, sized;
int blob_len = 0;
- u32 hash;
+ int hash;
u32 flags;
- int i;
int rc;

- for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
- if (options->hash == tpm2_hash_map[i].crypto_id) {
- hash = tpm2_hash_map[i].tpm_id;
- break;
- }
- }
-
- if (i == ARRAY_SIZE(tpm2_hash_map))
- return -EINVAL;
+ hash = tpm2_find_hash_alg(options->hash);
+ if (hash < 0)
+ return hash;

if (!options->keyhandle)
return -EINVAL;
--
2.52.0