On Tue, Dec 04, 2018 at 09:21:31AM +0100, Roberto Sassu wrote: > Update > > This version of the patch set includes an additional patch (7/7) which > modifies the definition of tpm_pcr_extend() and tpm2_pcr_extend(). The new > patch has been included to facilitate the review of the changes to support > TPM 2.0 crypto agility for reading/extending PCRs. > > > Original patch set description > > The TPM driver currently relies on the crypto subsystem to determine the > digest size of supported TPM algorithms. In the future, TPM vendors might > implement new algorithms in their chips, and those algorithms might not > be supported by the crypto subsystem. > > Usually, vendors provide patches for the new hardware, and likely > the crypto subsystem will be updated before the new algorithm is > introduced. However, old kernels might be updated later, after patches > are included in the mainline kernel. This would leave the opportunity > for attackers to misuse PCRs, as PCR banks with an unknown algorithm > are not extended. > > This patch set provides a long term solution for this issue. If a TPM > algorithm is not known by the crypto subsystem, the TPM driver retrieves > the digest size from the TPM with a PCR read. All the PCR banks are > extended, even if the algorithm is not yet supported by the crypto > subsystem. > > PCR bank information (TPM algorithm ID, digest size, crypto subsystem ID) > is stored in the tpm_chip structure and available for users of the TPM > driver. > > Changelog > > v5: > - rename digest_struct variable to digest > - add _head suffix to tcg_efi_specid_event and tcg_pcr_event2 > - rename digest_size member of tpm_bank_list to extend_size > - change type of alg_id member of tpm_bank list from u8 to u16 > - add missing semi-colon in pcrlock() > > v4: > - rename active_banks to allocated_banks > - replace kmalloc_array() with kcalloc() > - increment nr_allocated_banks if at least one PCR in the bank is selected > - pass multiple digests to tpm_pcr_extend() > > v3: > - remove end marker change > - replace active_banks static array with pointer to dynamic array > - remove TPM2_ACTIVE_PCR_BANKS > > v2: > - change the end marker of the active_banks array > - check digest size from output of PCR read command > - remove count parameter from tpm_pcr_read() and tpm2_pcr_read() > > v1: > - modify definition of tpm_pcr_read() > - move hash algorithms and definition of tpm2_digest to include/linux/tpm.h > > Roberto Sassu (7): > tpm: dynamically allocate the allocated_banks array > tpm: add _head suffix to tcg_efi_specid_event and tcg_pcr_event2 > tpm: rename and export tpm2_digest and tpm2_algorithms > tpm: modify tpm_pcr_read() definition to pass a TPM hash algorithm > tpm: retrieve digest size of unknown algorithms with PCR read > tpm: ensure that the output of PCR read contains the correct digest > size > tpm: pass an array of tpm_bank_list structures to tpm_pcr_extend() > > drivers/char/tpm/eventlog/tpm2.c | 12 +-- > drivers/char/tpm/tpm-chip.c | 1 + > drivers/char/tpm/tpm-interface.c | 36 +++---- > drivers/char/tpm/tpm.h | 23 ++--- > drivers/char/tpm/tpm1-cmd.c | 26 ++++- > drivers/char/tpm/tpm2-cmd.c | 154 +++++++++++++++++++++------- > include/linux/tpm.h | 43 +++++++- > include/linux/tpm_eventlog.h | 19 +--- > security/integrity/ima/ima_crypto.c | 10 +- > security/integrity/ima/ima_queue.c | 5 +- > security/keys/trusted.c | 5 +- > 11 files changed, 220 insertions(+), 114 deletions(-) > > -- > 2.17.1 > Some generic stuff I noticed: * Use SHA1_DIGEST_SIZE, not TPM_DIGEST_SIZE. The latter is just uninforming constant that we want to get rid off. /Jarkko
