On Tue, Jun 23, 2020 at 02:01:22PM -0400, Maurizio Drocco wrote:
> From: Maurizio <maurizio.drocco@xxxxxxx>
>
> If PCRs 8 - 9 are set (i.e. not all-zeros), cal_bootaggr should include
> them into the digest.
>
> Signed-off-by: Maurizio Drocco <maurizio.drocco@xxxxxxx>
> ---
> Changelog:
> v2:
> - Always include PCRs 8 & 9 to non-sha1 hashes
> v1:
> - Include non-zero PCRs 8 & 9 to boot aggregates
>
> src/evmctl.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/src/evmctl.c b/src/evmctl.c
> index 1d065ce..46b7092 100644
> --- a/src/evmctl.c
> +++ b/src/evmctl.c
> @@ -1930,6 +1930,16 @@ static void calc_bootaggr(struct tpm_bank_info *bank)
> }
> }
>
> + if (strcmp(bank->algo_name, "sha1") != 0) {
> + for (i = 8; i < 10; i++) {
> + err = EVP_DigestUpdate(pctx, bank->pcr[i], bank->digest_size);
> + if (!err) {
> + log_err("EVP_DigestUpdate() failed\n");
> + return;
> + }
> + }
> + }
> +
> err = EVP_DigestFinal(pctx, bank->digest, &mdlen);
> if (!err) {
> log_err("EVP_DigestFinal() failed\n");
> @@ -1972,8 +1982,9 @@ static int append_bootaggr(char *bootaggr, struct tpm_bank_info *tpm_banks)
> /*
> * The IMA measurement list boot_aggregate is the link between the preboot
> * event log and the IMA measurement list. Read and calculate all the
> - * possible per TPM bank boot_aggregate digests based on the existing
> - * PCRs 0 - 7 to validate against the IMA boot_aggregate record.
> + * possible per TPM bank boot_aggregate digests based on the existing PCRs
> + * 0 - 9 to validate against the IMA boot_aggregate record. If the digest
> + * algorithm is SHA1, only PCRs 0 - 7 are considered to avoid ambiguity.
> */
> static int cmd_ima_bootaggr(struct command *cmd)
> {
> --
> 2.17.1
>
Reviewed-by: Bruno Meneguele <bmeneg@xxxxxxxxxx>
--
bmeneg
PGP Key: http://bmeneg.com/pubkey.txt
Attachment:
signature.asc
Description: PGP signature
