From b4f1874c62168159fdb419ced4afc77c1b51c475 Mon Sep 17 00:00:00 2001 From: Loïc Yhuel Date: Tue, 12 May 2020 06:01:13 +0200 Subject: tpm: check event log version before reading final events MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Link: https://lore.kernel.org/r/20200512040113.277768-1-loic.yhuel@gmail.com Reviewed-by: Javier Martinez Canillas Reviewed-by: Jerry Snitselaar Reviewed-by: Matthew Garrett [ardb: warn when final events table is missing or in the wrong format] Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/tpm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/firmware/efi/tpm.c') diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c index 31f9f0e369b9..0543fbf60222 100644 --- a/drivers/firmware/efi/tpm.c +++ b/drivers/firmware/efi/tpm.c @@ -62,8 +62,11 @@ int __init efi_tpm_eventlog_init(void) tbl_size = sizeof(*log_tbl) + log_tbl->size; memblock_reserve(efi.tpm_log, tbl_size); - if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR) + if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR || + log_tbl->version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2) { + pr_warn(FW_BUG "TPM Final Events table missing or invalid\n"); goto out; + } final_tbl = early_memremap(efi.tpm_final_log, sizeof(*final_tbl)); -- cgit