This is a note to let you know that I've just added the patch titled tpm: fix handling of the TPM 2.0 event logs to the 4.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tpm-fix-handling-of-the-tpm-2.0-event-logs.patch and it can be found in the queue-4.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From fd5c78694f3f1c875e293de7a641ba8a3d60d00d Mon Sep 17 00:00:00 2001 From: Petr Vandrovec <petr@xxxxxxxxxx> Date: Wed, 29 Mar 2017 00:43:30 -0700 Subject: tpm: fix handling of the TPM 2.0 event logs From: Petr Vandrovec <petr@xxxxxxxxxx> commit fd5c78694f3f1c875e293de7a641ba8a3d60d00d upstream. When TPM2 log has entries with more than 3 digests, or with digests not listed in the log header, log gets misparsed, eventually leading to kernel complaint that code tried to vmalloc 512MB of memory (I have no idea what would happen on bigger system). So code should not parse only first 3 digests: both event header and event itself are already in memory, so we can parse any number of digests, as long as we do not try to parse whole memory when given count of 0xFFFFFFFF. So this change: * Rejects event entry with more digests than log header describes. Digest types should be unique, and all should be described in log header, so there cannot be more digests in the event than in the header. * Reject event entry with digest that is not described in the log header. In theory code could hardcode information about digest IDs already assigned by TCG, but if firmware authors cannot get event log format right, why should anyone believe that they got event log content right. Fixes: 4d23cc323cdb ("tpm: add securityfs support for TPM 2.0 firmware event log") Signed-off-by: Petr Vandrovec <petr@xxxxxxxxxx> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/char/tpm/tpm2_eventlog.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) --- a/drivers/char/tpm/tpm2_eventlog.c +++ b/drivers/char/tpm/tpm2_eventlog.c @@ -56,18 +56,24 @@ static int calc_tpm2_event_size(struct t efispecid = (struct tcg_efi_specid_event *)event_header->event; - for (i = 0; (i < event->count) && (i < TPM2_ACTIVE_PCR_BANKS); - i++) { + /* Check if event is malformed. */ + if (event->count > efispecid->num_algs) + return 0; + + for (i = 0; i < event->count; i++) { halg_size = sizeof(event->digests[i].alg_id); memcpy(&halg, marker, halg_size); marker = marker + halg_size; - for (j = 0; (j < efispecid->num_algs); j++) { + for (j = 0; j < efispecid->num_algs; j++) { if (halg == efispecid->digest_sizes[j].alg_id) { - marker = marker + + marker += efispecid->digest_sizes[j].digest_size; break; } } + /* Algorithm without known length. Such event is unparseable. */ + if (j == efispecid->num_algs) + return 0; } event_field = (struct tcg_event_field *)marker; Patches currently in stable-queue which might be from petr@xxxxxxxxxx are queue-4.11/tpm-fix-handling-of-the-tpm-2.0-event-logs.patch