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authorJerry Snitselaar <jsnitsel@redhat.com>2019-10-02 19:59:02 +0300
committerIngo Molnar <mingo@kernel.org>2019-10-07 16:24:36 +0300
commite658c82be5561412c5e83b5e74e9da4830593f3e (patch)
tree8045655bc39e44fa29a4b1cd13b9dcb128b82896
parent05c8c1ff81ed2eb9bad7c27cf92e55c864c16df8 (diff)
downloadlinux-e658c82be5561412c5e83b5e74e9da4830593f3e.tar.xz
efi/tpm: Only set 'efi_tpm_final_log_size' after successful event log parsing
If __calc_tpm2_event_size() fails to parse an event it will return 0, resulting tpm2_calc_event_log_size() returning -1. Currently there is no check of this return value, and 'efi_tpm_final_log_size' can end up being set to this negative value resulting in a crash like this one: BUG: unable to handle page fault for address: ffffbc8fc00866ad #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page RIP: 0010:memcpy_erms+0x6/0x10 Call Trace: tpm_read_log_efi() tpm_bios_log_setup() tpm_chip_register() tpm_tis_core_init.cold.9+0x28c/0x466 tpm_tis_plat_probe() platform_drv_probe() ... Also __calc_tpm2_event_size() returns a size of 0 when it fails to parse an event, so update function documentation to reflect this. The root cause of the issue that caused the failure of event parsing in this case is resolved by Peter Jone's patchset dealing with large event logs where crossing over a page boundary causes the page with the event count to be unmapped. Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Ben Dooks <ben.dooks@codethink.co.uk> Cc: Dave Young <dyoung@redhat.com> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lukas Wunner <lukas@wunner.de> Cc: Lyude Paul <lyude@redhat.com> Cc: Matthew Garrett <mjg59@google.com> Cc: Octavian Purdila <octavian.purdila@intel.com> Cc: Peter Jones <pjones@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Scott Talbert <swt@techie.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Cc: linux-integrity@vger.kernel.org Cc: stable@vger.kernel.org Fixes: c46f3405692de ("tpm: Reserve the TPM final events table") Link: https://lkml.kernel.org/r/20191002165904.8819-6-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--drivers/firmware/efi/tpm.c9
-rw-r--r--include/linux/tpm_eventlog.h2
2 files changed, 9 insertions, 2 deletions
diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c
index b9ae5c6f9b9c..703469c1ab8e 100644
--- a/drivers/firmware/efi/tpm.c
+++ b/drivers/firmware/efi/tpm.c
@@ -85,11 +85,18 @@ int __init efi_tpm_eventlog_init(void)
final_tbl->nr_events,
log_tbl->log);
}
+
+ if (tbl_size < 0) {
+ pr_err(FW_BUG "Failed to parse event in TPM Final Events Log\n");
+ goto out_calc;
+ }
+
memblock_reserve((unsigned long)final_tbl,
tbl_size + sizeof(*final_tbl));
- early_memunmap(final_tbl, sizeof(*final_tbl));
efi_tpm_final_log_size = tbl_size;
+out_calc:
+ early_memunmap(final_tbl, sizeof(*final_tbl));
out:
early_memunmap(log_tbl, sizeof(*log_tbl));
return ret;
diff --git a/include/linux/tpm_eventlog.h b/include/linux/tpm_eventlog.h
index b50cc3adca18..131ea1bad458 100644
--- a/include/linux/tpm_eventlog.h
+++ b/include/linux/tpm_eventlog.h
@@ -152,7 +152,7 @@ struct tcg_algorithm_info {
* total. Once we've done this we know the offset of the data length field,
* and can calculate the total size of the event.
*
- * Return: size of the event on success, <0 on failure
+ * Return: size of the event on success, 0 on failure
*/
static inline int __calc_tpm2_event_size(struct tcg_pcr_event2_head *event,