Address !chip->auth

Unless tpm2_sessions_init() is called, then chip->auth ends up being a null pointer, which is ignored by authenticated sessions code. These patches aim to fully address the bug, and hopefully still make into 6.10-rc7.

Tested on x86-64 with:

- TCG_TPM2_HMAC disabled.
- TCG_TPM2_HMAC enabled.
- TCG_TPM2_HMAC enabled, and "/* rc = tpm2_sessions_init(chip); */".

For drivers that do not initialize with tpm2_chip_bootstrap(), the lack of auth sessions is reported once per power cycle by:

"tpm tpm0: auth session is not active"

This is expected output for the following drivers:

* tpm_ftpm_tee.c
* tpm_i2c_nuvoton.c
* tpm_ibmvtpm.c
* tpm_tis_i2c_cr50.c
* tpm_vtpm_proxy.c

They need to later on enable auth sessions, if they eager to. This patch set only fixes any collateral damage of not doing so.

v4:
* Address:
https://lore.kernel.org/linux-integrity/CAHk-=wiM=Cyw-07EkbAH66pE50VzJiT3bVHv9CS=kYR6zz5mTQ@mail.gmail.com/
* Git: https://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd.git/log/?h=auth-null-4
v3:
* Address:
https://lore.kernel.org/linux-integrity/922603265d61011dbb23f18a04525ae973b83ffd.camel@HansenPartnership.com/
* Git: https://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd.git/log/?h=auth-null-3
* Did a full QA run given the changes in config flag handling.
v2:
* Rebase to commit 8a9c6c40432e ("Merge tag 'io_uring-6.10-20240703' of git://git.kernel.dk/linux").
* Couple of cosmetic fixes.

Jarkko Sakkinen (3):
tpm: Address !chip->auth in tpm2_*_auth_session()
tpm: Address !chip->auth in tpm_buf_append_name()
tpm: Address !chip->auth in tpm_buf_append_hmac_session*()

 drivers/char/tpm/Makefile        |   2 +-
 drivers/char/tpm/tpm2-sessions.c | 419 ++++++++++++++++++-------------
 include/linux/tpm.h              |  81 +++---
 3 files changed, 269 insertions(+), 233 deletions(-)

2.45.2