diff options
| author | Jarkko Sakkinen <jarkko@kernel.org> | 2024-11-13 07:54:12 +0200 |
|---|---|---|
| committer | Jarkko Sakkinen <jarkko@kernel.org> | 2024-11-13 21:10:45 +0200 |
| commit | 27184f8905ba680f22abf1707fbed24036a67119 (patch) | |
| tree | 41ee96a7f5cc05747216cd7401c6014dfa7280fd /Documentation | |
| parent | 14b6320953a3f856a3f93bf9a0e423395baa593d (diff) | |
tpm: Opt-in in disable PCR integrity protection
The initial HMAC session feature added TPM bus encryption and/or integrity
protection to various in-kernel TPM operations. This can cause performance
bottlenecks with IMA, as it heavily utilizes PCR extend operations.
In order to mitigate this performance issue, introduce a kernel
command-line parameter to the TPM driver for disabling the integrity
protection for PCR extend operations (i.e. TPM2_PCR_Extend).
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Link: https://lore.kernel.org/linux-integrity/20241015193916.59964-1-zohar@linux.ibm.com/
Fixes: 6519fea6fd37 ("tpm: add hmac checks to tpm2_pcr_extend()")
Tested-by: Mimi Zohar <zohar@linux.ibm.com>
Co-developed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Co-developed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 1666576acc0e..d401577b5a6a 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6727,6 +6727,15 @@ torture.verbose_sleep_duration= [KNL] Duration of each verbose-printk() sleep in jiffies. + tpm.disable_pcr_integrity= [HW,TPM] + Do not protect PCR registers from unintended physical + access, or interposers in the bus by the means of + having an integrity protected session wrapped around + TPM2_PCR_Extend command. Consider this in a situation + where TPM is heavily utilized by IMA, thus protection + causing a major performance hit, and the space where + machines are deployed is by other means guarded. + tpm_suspend_pcr=[HW,TPM] Format: integer pcr id Specify that at suspend time, the tpm driver |