[PATCH v3 5/7] tpm-buf: Remove tpm_buf_append_handle

Jarkko Sakkinen
2025-12-10T14:40:13Z

Since the number of handles is fixed to a single handle, eliminate all uses
of buf->handles and deduce values during compile-time.

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v2:
- Streamline the code change and remove dead code.
---
drivers/char/tpm/tpm-buf.c | 25 -------------------------
drivers/char/tpm/tpm2-cmd.c | 6 ++----
drivers/char/tpm/tpm2-sessions.c | 14 ++------------
include/linux/tpm.h | 2 --
4 files changed, 4 insertions(+), 43 deletions(-)

diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index 73be8a87b472..752c69b8a4f5 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -40,7 +40,6 @@ static void __tpm_buf_reset(struct tpm_buf *buf, u16 buf_size, u16 tag, u32 ordi
buf->flags = 0;
buf->length = sizeof(*head);
buf->capacity = buf_size - sizeof(*buf);
- buf->handles = 0;
head->tag = cpu_to_be16(tag);
head->length = cpu_to_be32(sizeof(*head));
head->ordinal = cpu_to_be32(ordinal);
@@ -56,7 +55,6 @@ static void __tpm_buf_reset_sized(struct tpm_buf *buf, u16 buf_size)
buf->flags = TPM_BUF_TPM2B;
buf->length = 2;
buf->capacity = buf_size - sizeof(*buf);
- buf->handles = 0;
buf->data[0] = 0;
buf->data[1] = 0;
}
@@ -177,29 +175,6 @@ void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value)
}
EXPORT_SYMBOL_GPL(tpm_buf_append_u32);

-/**
- * tpm_buf_append_handle() - Add a handle
- * @buf: &tpm_buf instance
- * @handle: a TPM object handle
- *
- * Add a handle to the buffer, and increase the count tracking the number of
- * handles in the command buffer. Works only for command buffers.
- */
-void tpm_buf_append_handle(struct tpm_buf *buf, u32 handle)
-{
- if (buf->flags & TPM_BUF_INVALID)
- return;
-
- if (buf->flags & TPM_BUF_TPM2B) {
- WARN(1, "tpm-buf: invalid type: TPM2B\n");
- buf->flags |= TPM_BUF_INVALID;
- return;
- }
-
- tpm_buf_append_u32(buf, handle);
- buf->handles++;
-}
-
/**
* tpm_buf_read() - Read from a TPM buffer
* @buf: &tpm_buf instance
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 436ee82620e4..bc50d6b734cf 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -205,7 +205,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
return rc;
tpm_buf_append_hmac_session(chip, buf, 0, NULL, 0);
} else {
- tpm_buf_append_handle(buf, pcr_idx);
+ tpm_buf_append_u32(buf, pcr_idx);
tpm_buf_append_auth(chip, buf, NULL, 0);
}

@@ -281,10 +281,8 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
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);
+ head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
}
tpm_buf_append_u16(buf, num_bytes);
err = tpm_buf_fill_hmac_session(chip, buf);
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 62a200ae72d7..f2b8ca893e15 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -261,7 +261,7 @@ int tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
}

if (!tpm2_chip_auth(chip)) {
- tpm_buf_append_handle(buf, handle);
+ tpm_buf_append_u32(buf, handle);
return 0;
}

@@ -288,17 +288,7 @@ EXPORT_SYMBOL_GPL(tpm_buf_append_name);
void tpm_buf_append_auth(struct tpm_chip *chip, struct tpm_buf *buf,
u8 *passphrase, int passphrase_len)
{
- /* offset tells us where the sessions area begins */
- int offset = buf->handles * 4 + TPM_HEADER_SIZE;
- u32 len = 9 + passphrase_len;
-
- if (tpm_buf_length(buf) != offset) {
- /* not the first session so update the existing length */
- len += get_unaligned_be32(&buf->data[offset]);
- put_unaligned_be32(len, &buf->data[offset]);
- } else {
- tpm_buf_append_u32(buf, len);
- }
+ tpm_buf_append_u32(buf, 9 + passphrase_len);
/* auth handle */
tpm_buf_append_u32(buf, TPM2_RS_PW);
/* nonce */
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 9f684fc7ae04..e68995df8796 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -395,7 +395,6 @@ enum tpm_buf_flags {
*/
struct tpm_buf {
u8 flags;
- u8 handles;
u16 length;
u16 capacity;
u8 data[];
@@ -441,7 +440,6 @@ void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value);
u8 tpm_buf_read_u8(struct tpm_buf *buf, off_t *offset);
u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset);
u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset);
-void tpm_buf_append_handle(struct tpm_buf *buf, u32 handle);

/*
* Check if TPM device is in the firmware upgrade mode.
--
2.52.0