[PATCH v9 6/8] tpm-buf: Merge TPM_BUF_BOUNDARY_ERROR and TPM_BUF_OVERFLOW

Jarkko Sakkinen
2025-11-28T02:54:47Z

Merge TPM_BUF_BOUNDARY_ERROR and TPM_BUF_OVERFLOW into TPM_BUF_INVALID,
given that they are identical. The only difference are the log messages.

In addition, add a missing TPM_BUF_INVALID check to tpm_buf_append_handle()
following the pattern from other functions in tpm-buf.c.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@opinsys.com>
Reviewed-by: Jonathan McDowell <noodles@meta.com>
---
v9:
- Improvde the commit message.
v8:
- No changes.
v7:
- No changes.
v6:
- Change short summary to something more descriptive.
v5:
- No changes.
v4:
- No changes.
v3:
- No changes.
v2:
- A new patch.
---
drivers/char/tpm/tpm-buf.c | 14 ++++++++------
include/linux/tpm.h | 8 +++-----
security/keys/trusted-keys/trusted_tpm2.c | 6 +++---
3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index dc882fc9fa9e..69ee77400539 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -104,13 +104,12 @@ EXPORT_SYMBOL_GPL(tpm_buf_length);
*/
void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length)
{
- /* Return silently if overflow has already happened. */
- if (buf->flags & TPM_BUF_OVERFLOW)
+ if (buf->flags & TPM_BUF_INVALID)
return;

if ((buf->length + new_length) > PAGE_SIZE) {
WARN(1, "tpm_buf: write overflow\n");
- buf->flags |= TPM_BUF_OVERFLOW;
+ buf->flags |= TPM_BUF_INVALID;
return;
}

@@ -157,8 +156,12 @@ EXPORT_SYMBOL_GPL(tpm_buf_append_u32);
*/
void tpm_buf_append_handle(struct tpm_chip *chip, struct tpm_buf *buf, u32 handle)
{
+ if (buf->flags & TPM_BUF_INVALID)
+ return;
+
if (buf->flags & TPM_BUF_TPM2B) {
dev_err(&chip->dev, "Invalid buffer type (TPM2B)\n");
+ buf->flags |= TPM_BUF_INVALID;
return;
}

@@ -177,14 +180,13 @@ static void tpm_buf_read(struct tpm_buf *buf, off_t *offset, size_t count, void
{
off_t next_offset;

- /* Return silently if overflow has already happened. */
- if (buf->flags & TPM_BUF_BOUNDARY_ERROR)
+ if (buf->flags & TPM_BUF_INVALID)
return;

next_offset = *offset + count;
if (next_offset > buf->length) {
WARN(1, "tpm_buf: read out of boundary\n");
- buf->flags |= TPM_BUF_BOUNDARY_ERROR;
+ buf->flags |= TPM_BUF_INVALID;
return;
}

diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index cbd3a70c0378..2796bac2a114 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -369,12 +369,10 @@ struct tpm_header {
} __packed;

enum tpm_buf_flags {
- /* the capacity exceeded: */
- TPM_BUF_OVERFLOW = BIT(0),
/* TPM2B format: */
- TPM_BUF_TPM2B = BIT(1),
- /* read out of boundary: */
- TPM_BUF_BOUNDARY_ERROR = BIT(2),
+ TPM_BUF_TPM2B = BIT(0),
+ /* The buffer is in invalid and unusable state: */
+ TPM_BUF_INVALID = BIT(1),
};

/*
diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c
index 8e2d1a013c7e..8f3fc64c2399 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -280,7 +280,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
/* creation PCR */
tpm_buf_append_u32(&buf, 0);

- if (buf.flags & TPM_BUF_OVERFLOW) {
+ if (buf.flags & TPM_BUF_INVALID) {
rc = -E2BIG;
tpm2_end_auth_session(chip);
goto out;
@@ -293,7 +293,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
goto out;

blob_len = tpm_buf_read_u32(&buf, &offset);
- if (blob_len > MAX_BLOB_SIZE || buf.flags & TPM_BUF_BOUNDARY_ERROR) {
+ if (blob_len > MAX_BLOB_SIZE || buf.flags & TPM_BUF_INVALID) {
rc = -E2BIG;
goto out;
}
@@ -403,7 +403,7 @@ static int tpm2_load_cmd(struct tpm_chip *chip,

tpm_buf_append(&buf, blob, blob_len);

- if (buf.flags & TPM_BUF_OVERFLOW) {
+ if (buf.flags & TPM_BUF_INVALID) {
rc = -E2BIG;
tpm2_end_auth_session(chip);
goto out;
--
2.52.0