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path: root/drivers/md/dm-verity-verify-sig.c
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2024-09-26dm verity: fallback to platform keyring also if key in trusted keyring is ↵Luca Boccassi
rejected If enabled, we fallback to the platform keyring if the trusted keyring doesn't have the key used to sign the roothash. But if pkcs7_verify() rejects the key for other reasons, such as usage restrictions, we do not fallback. Do so. Follow-up for 6fce1f40e95182ebbfe1ee3096b8fc0b37903269 Suggested-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Luca Boccassi <bluca@debian.org> Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2024-07-03dm verity: add support for signature verification with platform keyringLuca Boccassi
Add a new configuration CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG_PLATFORM_KEYRING that enables verifying dm-verity signatures using the platform keyring, which is populated using the UEFI DB certificates. This is useful for self-enrolled systems that do not use MOK, as the secondary keyring which is already used for verification, if the relevant kconfig is enabled, is linked to the machine keyring, which gets its certificates loaded from MOK. On datacenter/virtual/cloud deployments it is more common to deploy one's own certificate chain directly in DB on first boot in unattended mode, rather than relying on MOK, as the latter typically requires interactive authentication to enroll, and is more suited for personal machines. Default to the same value as DM_VERITY_VERIFY_ROOTHASH_SIG_SECONDARY_KEYRING if not otherwise specified, as it is likely that if one wants to use MOK certificates to verify dm-verity volumes, DB certificates are going to be used too. Keys in DB are allowed to load a full kernel already anyway, so they are already highly privileged. Signed-off-by: Luca Boccassi <bluca@debian.org> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2023-02-14dm: add missing SPDX-License-IndentifiersHeinz Mauelshagen
'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has deprecated its use. Suggested-by: John Wiele <jwiele@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2021-05-25dm verity: fix require_signatures module_param permissionsJohn Keeping
The third parameter of module_param() is permissions for the sysfs node but it looks like it is being used as the initial value of the parameter here. In fact, false here equates to omitting the file from sysfs and does not affect the value of require_signatures. Making the parameter writable is not simple because going from false->true is fine but it should not be possible to remove the requirement to verify a signature. But it can be useful to inspect the value of this parameter from userspace, so change the permissions to make a read-only file in sysfs. Signed-off-by: John Keeping <john@metanate.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-12-04dm verity: Add support for signature verification with 2nd keyringMickaël Salaün
Add a new configuration DM_VERITY_VERIFY_ROOTHASH_SIG_SECONDARY_KEYRING to enable dm-verity signatures to be verified against the secondary trusted keyring. Instead of relying on the builtin trusted keyring (with hard-coded certificates), the second trusted keyring can include certificate authorities from the builtin trusted keyring and child certificates loaded at run time. Using the secondary trusted keyring enables to use dm-verity disks (e.g. loop devices) signed by keys which did not exist at kernel build time, leveraging the certificate chain of trust model. In practice, this makes it possible to update certificates without kernel update and reboot, aligning with module and kernel (kexec) signature verification which already use the secondary trusted keyring. Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-08-23dm verity: add root hash pkcs#7 signature verificationJaskaran Khurana
The verification is to support cases where the root hash is not secured by Trusted Boot, UEFI Secureboot or similar technologies. One of the use cases for this is for dm-verity volumes mounted after boot, the root hash provided during the creation of the dm-verity volume has to be secure and thus in-kernel validation implemented here will be used before we trust the root hash and allow the block device to be created. The signature being provided for verification must verify the root hash and must be trusted by the builtin keyring for verification to succeed. The hash is added as a key of type "user" and the description is passed to the kernel so it can look it up and use it for verification. Adds CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG which can be turned on if root hash verification is needed. Kernel commandline dm_verity module parameter 'require_signatures' will indicate whether to force root hash signature verification (for all dm verity volumes). Signed-off-by: Jaskaran Khurana <jaskarankhurana@linux.microsoft.com> Tested-and-Reviewed-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>