On Tue, Sep 30, 2025 at 12:11:47PM +0100, Jonathan McDowell wrote:
> On Mon, Sep 29, 2025 at 10:48:27PM +0300, Jarkko Sakkinen wrote:
> > From: Jarkko Sakkinen <[email protected]>
> >
> > Open code tpm_buf_append_hmac_session_opt() in order to unmask the code
> > paths in the call sites of tpm_buf_append_hmac_session().
> >
> > Signed-off-by: Jarkko Sakkinen <[email protected]>
>
> Reviewed-by: Jonathan McDowell <[email protected]>
Thanks (short summary has a typo tho)
>
> > ---
> > v3:
> > - No changes.
> > v2:
> > - Uncorrupt the patch.
> > ---
> > drivers/char/tpm/tpm2-cmd.c | 14 +++++++++++---
> > include/linux/tpm.h | 23 -----------------------
> > security/keys/trusted-keys/trusted_tpm2.c | 12 ++++++++++--
> > 3 files changed, 21 insertions(+), 28 deletions(-)
> >
> > diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> > index 86b1a4d859b9..c7bfa705ea8f 100644
> > --- a/drivers/char/tpm/tpm2-cmd.c
> > +++ b/drivers/char/tpm/tpm2-cmd.c
> > @@ -257,9 +257,17 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *dest,
> > size_t max)
> >
> > do {
> > tpm_buf_reset(&buf, TPM2_ST_SESSIONS, TPM2_CC_GET_RANDOM);
> > - tpm_buf_append_hmac_session_opt(chip, &buf, TPM2_SA_ENCRYPT
> > - | TPM2_SA_CONTINUE_SESSION,
> > - NULL, 0);
> > + if (tpm2_chip_auth(chip)) {
> > + tpm_buf_append_hmac_session(chip, &buf,
> > + TPM2_SA_ENCRYPT |
> > + 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);
> > + }
> > tpm_buf_append_u16(&buf, num_bytes);
> > tpm_buf_fill_hmac_session(chip, &buf);
> > err = tpm_transmit_cmd(chip, &buf,
> > diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> > index 1fa02e18e688..e72e7657faa2 100644
> > --- a/include/linux/tpm.h
> > +++ b/include/linux/tpm.h
> > @@ -532,29 +532,6 @@ void tpm_buf_append_hmac_session(struct tpm_chip
> > *chip, struct tpm_buf *buf,
> > int passphraselen);
> > void tpm_buf_append_auth(struct tpm_chip *chip, struct tpm_buf *buf,
> > u8 *passphrase, int passphraselen);
> > -static inline void tpm_buf_append_hmac_session_opt(struct tpm_chip *chip,
> > - struct tpm_buf *buf,
> > - u8 attributes,
> > - u8 *passphrase,
> > - int passphraselen)
> > -{
> > - struct tpm_header *head;
> > - int offset;
> > -
> > - if (tpm2_chip_auth(chip)) {
> > - tpm_buf_append_hmac_session(chip, buf, attributes, passphrase,
> > passphraselen);
> > - } else {
> > - offset = buf->handles * 4 + TPM_HEADER_SIZE;
> > - head = (struct tpm_header *)buf->data;
> > -
> > - /*
> > - * If the only sessions are optional, the command tag must
> > change to
> > - * TPM2_ST_NO_SESSIONS.
> > - */
> > - if (tpm_buf_length(buf) == offset)
> > - head->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS);
> > - }
> > -}
> >
> > #ifdef CONFIG_TCG_TPM2_HMAC
> >
> > diff --git a/security/keys/trusted-keys/trusted_tpm2.c
> > b/security/keys/trusted-keys/trusted_tpm2.c
> > index e165b117bbca..c414a7006d78 100644
> > --- a/security/keys/trusted-keys/trusted_tpm2.c
> > +++ b/security/keys/trusted-keys/trusted_tpm2.c
> > @@ -482,8 +482,10 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
> > struct trusted_key_options *options,
> > u32 blob_handle)
> > {
> > + struct tpm_header *head;
> > struct tpm_buf buf;
> > u16 data_len;
> > + int offset;
> > u8 *data;
> > int rc;
> >
> > @@ -518,8 +520,14 @@ static int tpm2_unseal_cmd(struct tpm_chip *chip,
> > tpm2_buf_append_auth(&buf, options->policyhandle,
> > NULL /* nonce */, 0, 0,
> > options->blobauth, options->blobauth_len);
> > - tpm_buf_append_hmac_session_opt(chip, &buf, TPM2_SA_ENCRYPT,
> > - NULL, 0);
> > + if (tpm2_chip_auth(chip)) {
> > + tpm_buf_append_hmac_session(chip, &buf,
> > TPM2_SA_ENCRYPT, 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);
> > + }
> > }
> >
> > tpm_buf_fill_hmac_session(chip, &buf);
> > --
> > 2.39.5
> >
> >
>
> J.
>
> --
> ... I love you the way a bomb loves a crowd.
BR, Jarkko
