tpm_buf_append_name() has the following snippet in the beginning:
if (!tpm2_chip_auth(chip)) {
tpm_buf_append_u32(buf, handle);
/* count the number of handles in the upper bits of flags */
buf->handles++;
return;
}
The claim in the comment is wrong, and the comment is in the wrong place
as alignment in this case should not anyway be a concern of the call
site. In essence the comment is lying about the code, and thus needs to
be adressed.
Further, 'handles' was incorrectly place to struct tpm_buf, as tpm-buf.c
does manage its state. It is easy to grep that only piece of code that
actually uses the field is tpm2-sessions.c.
Address the issues by moving the variable to struct tpm_chip.
Cc: stable@xxxxxxxxxxxxxxx # v6.10+
Fixes: 699e3efd6c64 ("tpm: Add HMAC session start and end functions")
Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
v3:
* Reset chip->handles in the beginning of tpm2_start_auth_session()
so that it shows correct value, when TCG_TPM2_HMAC is enabled but
tpm2_sessions_init() has never been called.
v2:
* Was a bit more broken than I first thought, as 'handles' is only
useful for tpm2-sessions.c and has zero relation to tpm-buf.c.
---
drivers/char/tpm/tpm-buf.c | 1 -
drivers/char/tpm/tpm2-cmd.c | 2 +-
drivers/char/tpm/tpm2-sessions.c | 7 ++++---
include/linux/tpm.h | 8 ++++----
4 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
index cad0048bcc3c..d06e8e063151 100644
--- a/drivers/char/tpm/tpm-buf.c
+++ b/drivers/char/tpm/tpm-buf.c
@@ -44,7 +44,6 @@ void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal)
head->tag = cpu_to_be16(tag);
head->length = cpu_to_be32(sizeof(*head));
head->ordinal = cpu_to_be32(ordinal);
- buf->handles = 0;
}
EXPORT_SYMBOL_GPL(tpm_buf_reset);
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 1e856259219e..b781e4406fc2 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -776,7 +776,7 @@ int tpm2_auto_startup(struct tpm_chip *chip)
if (rc)
goto out;
- rc = tpm2_sessions_init(chip);
+ /* rc = tpm2_sessions_init(chip); */
out:
/*
diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index d3521aadd43e..5e7c12d64ba8 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -238,8 +238,7 @@ void tpm_buf_append_name(struct tpm_chip *chip, struct tpm_buf *buf,
if (!tpm2_chip_auth(chip)) {
tpm_buf_append_u32(buf, handle);
- /* count the number of handles in the upper bits of flags */
- buf->handles++;
+ chip->handles++;
return;
}
@@ -310,7 +309,7 @@ void tpm_buf_append_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf,
if (!tpm2_chip_auth(chip)) {
/* offset tells us where the sessions area begins */
- int offset = buf->handles * 4 + TPM_HEADER_SIZE;
+ int offset = chip->handles * 4 + TPM_HEADER_SIZE;
u32 len = 9 + passphrase_len;
if (tpm_buf_length(buf) != offset) {
@@ -963,6 +962,8 @@ int tpm2_start_auth_session(struct tpm_chip *chip)
int rc;
u32 null_key;
+ chip->handles = 0;
+
if (!auth) {
dev_warn_once(&chip->dev, "auth session is not active\n");
return 0;
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index e93ee8d936a9..b664f7556494 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -202,9 +202,9 @@ struct tpm_chip {
/* active locality */
int locality;
+ /* handle count for session: */
+ u8 handles;
#ifdef CONFIG_TCG_TPM2_HMAC
- /* details for communication security via sessions */
-
/* saved context for NULL seed */
u8 null_key_context[TPM2_MAX_CONTEXT_SIZE];
/* name of NULL seed */
@@ -377,7 +377,6 @@ struct tpm_buf {
u32 flags;
u32 length;
u8 *data;
- u8 handles;
};
enum tpm2_object_attributes {
@@ -517,7 +516,7 @@ static inline void tpm_buf_append_hmac_session_opt(struct tpm_chip *chip,
if (tpm2_chip_auth(chip)) {
tpm_buf_append_hmac_session(chip, buf, attributes, passphrase, passphraselen);
} else {
- offset = buf->handles * 4 + TPM_HEADER_SIZE;
+ offset = chip->handles * 4 + TPM_HEADER_SIZE;
head = (struct tpm_header *)buf->data;
/*
@@ -541,6 +540,7 @@ void tpm2_end_auth_session(struct tpm_chip *chip);
static inline int tpm2_start_auth_session(struct tpm_chip *chip)
{
+ chip->handles = 0;
return 0;
}
static inline void tpm2_end_auth_session(struct tpm_chip *chip)
--
2.45.2
