On Fri, Nov 28, 2025 at 04:53:55AM +0200, Jarkko Sakkinen wrote:
'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 <[email protected]>

Reviewed-by: Jonathan McDowell <[email protected]>

---
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


J.

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