]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
tpm: check event log version before reading final events
authorLoïc Yhuel <loic.yhuel@gmail.com>
Tue, 12 May 2020 04:01:13 +0000 (06:01 +0200)
committerArd Biesheuvel <ardb@kernel.org>
Sun, 17 May 2020 09:46:50 +0000 (11:46 +0200)
commitb4f1874c62168159fdb419ced4afc77c1b51c475
tree1dd6215da30e15bd3337049384c6823a89ecb736
parente8da08a088236aff4b51d4ec97c750051f9fe417
tpm: check event log version before reading final events

This fixes the boot issues since 5.3 on several Dell models when the TPM
is enabled. Depending on the exact grub binary, booting the kernel would
freeze early, or just report an error parsing the final events log.

We get an event log in the SHA-1 format, which doesn't have a
tcg_efi_specid_event_head in the first event, and there is a final events
table which doesn't match the crypto agile format.
__calc_tpm2_event_size reads bad "count" and "efispecid->num_algs", and
either fails, or loops long enough for the machine to be appear frozen.

So we now only parse the final events table, which is per the spec always
supposed to be in the crypto agile format, when we got a event log in this
format.

Fixes: c46f3405692de ("tpm: Reserve the TPM final events table")
Fixes: 166a2809d65b2 ("tpm: Don't duplicate events from the final event log in the TCG2 log")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1779611
Signed-off-by: Loïc Yhuel <loic.yhuel@gmail.com>
Link: https://lore.kernel.org/r/20200512040113.277768-1-loic.yhuel@gmail.com
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Matthew Garrett <mjg59@google.com>
[ardb: warn when final events table is missing or in the wrong format]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
drivers/firmware/efi/libstub/tpm.c
drivers/firmware/efi/tpm.c