[PATCH v16 07/38] tpm-buf: Merge TPM_BUF_BOUNDARY_ERROR and TPM_BUF_OVERFLOW

[Ross Philipson]

From: Jarkko Sakkinen <jarkko.sakkinen at opinsys.com>

Merge TPM_BUF_BOUNDARY_ERROR and TPM_BUF_OVERFLOW into TPM_BUF_INVALID,
given that they are identical (the only difference being the associated
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.

Message-ID: <20260125192526.782202-11-jarkko at kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen at opinsys.com>
Reviewed-by: Jonathan McDowell <noodles at meta.com>
Signed-off-by: Ross Philipson <ross.philipson at gmail.com>
---
 drivers/char/tpm/tpm-buf.c                | 10 ++++------
 include/linux/tpm.h                       |  8 +++-----
 security/keys/trusted-keys/trusted_tpm2.c |  6 +++---
 3 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index 4c4f450630df..61833b4d81f0 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -103,13 +103,12 @@ 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;
 	}
 
@@ -176,14 +175,13 @@ 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 3630b2ea6aef..3c6a5bcc138a 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -201,12 +201,10 @@ enum tpm_chip_flags {
 #define to_tpm_chip(d) container_of(d, struct tpm_chip, dev)
 
 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 29d79c05ed6b..779a2e66ac20 100644
--- a/security/keys/trusted-keys/trusted_tpm2.c
+++ b/security/keys/trusted-keys/trusted_tpm2.c
@@ -312,7 +312,7 @@ 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;
@@ -328,7 +328,7 @@ 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;
 	}
@@ -441,7 +441,7 @@ 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;
-- 
2.47.3