6.17-stable review patch. If anyone has any objections, please let me know.
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From: Jarkko Sakkinen jarkko@kernel.org
commit 4bddf4587c131d7b8ce8952cd32b284dcda0dd1f upstream.
After reading all the feedback, right now disabling the TPM2_TCG_HMAC is the right call.
Other views discussed:
A. Having a kernel command-line parameter or refining the feature otherwise. This goes to the area of improvements. E.g., one example is my own idea where the null key specific code would be replaced with a persistent handle parameter (which can be *unambigously* defined as part of attestation process when done correctly).
B. Removing the code. I don't buy this because that is same as saying that HMAC encryption cannot work at all (if really nitpicking) in any form. Also I disagree on the view that the feature could not be refined to something more reasoable.
Also, both A and B are worst options in terms of backporting.
Thuss, this is the best possible choice.
Cc: stable@vger.kernel.or # v6.10+ Fixes: d2add27cf2b8 ("tpm: Add NULL primary creation") Suggested-by: Chris Fenner cfenn@google.com Signed-off-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/tpm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/char/tpm/Kconfig +++ b/drivers/char/tpm/Kconfig @@ -29,7 +29,7 @@ if TCG_TPM
config TCG_TPM2_HMAC bool "Use HMAC and encrypted transactions on the TPM bus" - default X86_64 + default n select CRYPTO_ECDH select CRYPTO_LIB_AESCFB select CRYPTO_LIB_SHA256