Re: [PATCH v1] dm verity: Add support for signature verification with 2nd keyring
From: Mickaël Salaün
Date: Fri Oct 09 2020 - 05:50:06 EST
Hi,
What do you think about this patch?
Regards,
Mickaël
On 02/10/2020 09:18, Mickaël Salaün wrote:
> From: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx>
>
> Add a new DM_VERITY_VERIFY_ROOTHASH_SIG_SECONDARY_KEYRING configuration
> to enable dm-verity signatures to be verified against the secondary
> trusted keyring. This allows certificate updates without kernel update
> and reboot, aligning with module and kernel (kexec) signature
> verifications.
>
> Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxxxxxxxxxx>
> Cc: Jaskaran Khurana <jaskarankhurana@xxxxxxxxxxxxxxxxxxx>
> Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
> Cc: Milan Broz <gmazyland@xxxxxxxxx>
> ---
> drivers/md/Kconfig | 13 ++++++++++++-
> drivers/md/dm-verity-verify-sig.c | 9 +++++++--
> 2 files changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
> index 30ba3573626c..63870fdfe8ce 100644
> --- a/drivers/md/Kconfig
> +++ b/drivers/md/Kconfig
> @@ -530,11 +530,22 @@ config DM_VERITY_VERIFY_ROOTHASH_SIG
> bool "Verity data device root hash signature verification support"
> depends on DM_VERITY
> select SYSTEM_DATA_VERIFICATION
> - help
> + ---help---
> Add ability for dm-verity device to be validated if the
> pre-generated tree of cryptographic checksums passed has a pkcs#7
> signature file that can validate the roothash of the tree.
>
> + By default, rely on the builtin trusted keyring.
> +
> + If unsure, say N.
> +
> +config DM_VERITY_VERIFY_ROOTHASH_SIG_SECONDARY_KEYRING
> + bool "Verity data device root hash signature verification with secondary keyring"
> + depends on DM_VERITY_VERIFY_ROOTHASH_SIG
> + depends on SECONDARY_TRUSTED_KEYRING
> + ---help---
> + Rely on the secondary trusted keyring to verify dm-verity signatures.
> +
> If unsure, say N.
>
> config DM_VERITY_FEC
> diff --git a/drivers/md/dm-verity-verify-sig.c b/drivers/md/dm-verity-verify-sig.c
> index 614e43db93aa..29385dc470d5 100644
> --- a/drivers/md/dm-verity-verify-sig.c
> +++ b/drivers/md/dm-verity-verify-sig.c
> @@ -119,8 +119,13 @@ int verity_verify_root_hash(const void *root_hash, size_t root_hash_len,
> }
>
> ret = verify_pkcs7_signature(root_hash, root_hash_len, sig_data,
> - sig_len, NULL, VERIFYING_UNSPECIFIED_SIGNATURE,
> - NULL, NULL);
> + sig_len,
> +#ifdef CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG_SECONDARY_KEYRING
> + VERIFY_USE_SECONDARY_KEYRING,
> +#else
> + NULL,
> +#endif
> + VERIFYING_UNSPECIFIED_SIGNATURE, NULL, NULL);
>
> return ret;
> }
>