On 5/21/19 7:54 AM, Jaskaran Khurana wrote:
> Adds in-kernel pkcs7 signature checking for the roothash of
> the dm-verity hash tree.
>
> The verification is to support cases where the roothash 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 first patch was your cover letter, I'd suggest name it that way in
the subject.
> The signature being provided for verification must verify the root hash and
> must be trusted by the builtin keyring for verification to succeed.
>
> Adds DM_VERITY_VERIFY_ROOTHASH_SIG: roothash verification
> against the roothash signature file *if* specified, if signature file is
> specified verification must succeed prior to creation of device mapper
> block device.
>
> Adds DM_VERITY_VERIFY_ROOTHASH_SIG_FORCE: roothash signature *must* be
> specified for all dm verity volumes and verification must succeed prior
> to creation of device mapper block device.
>
> Signed-off-by: Jaskaran Khurana
> ---
> drivers/md/Kconfig| 23 ++
> drivers/md/Makefile | 2 +-
> drivers/md/dm-verity-target.c | 44 --
> drivers/md/dm-verity-verify-sig.c | 129 ++
> drivers/md/dm-verity-verify-sig.h | 32
> 5 files changed, 222 insertions(+), 8 deletions(-)
> create mode 100644 drivers/md/dm-verity-verify-sig.c
> create mode 100644 drivers/md/dm-verity-verify-sig.h
>
> diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
> index db269a348b20..da4115753f25 100644
> --- a/drivers/md/Kconfig
> +++ b/drivers/md/Kconfig
> @@ -489,6 +489,29 @@ config DM_VERITY
>
> If unsure, say N.
>
> +config DM_VERITY_VERIFY_ROOTHASH_SIG
> + def_bool n
> + bool "Verity data device root hash signature verification support"
> + depends on DM_VERITY
> + select SYSTEM_DATA_VERIFICATION
> + help
> + The device mapper target created by DM-VERITY can 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.
> +
> + If unsure, say N.
> +
> +config DM_VERITY_VERIFY_ROOTHASH_SIG_FORCE
> + def_bool n
> + bool "Forces all dm verity data device root hash should be signed"
> + depends on DM_VERITY_VERIFY_ROOTHASH_SIG
> + help
> + The device mapper target created by DM-VERITY will succeed only if the
> + pre-generated tree of cryptographic checksums passed also has a pkcs#7
> + signature file that can validate the roothash of the tree.
> +
> + If unsure, say N.
> +
> config DM_VERITY_FEC
> bool "Verity forward error correction support"
> depends on DM_VERITY
> diff --git a/drivers/md/Makefile b/drivers/md/Makefile
> index be7a6eb92abc..8a8c142bcfe1 100644
> --- a/drivers/md/Makefile
> +++ b/drivers/md/Makefile
> @@ -61,7 +61,7 @@ obj-$(CONFIG_DM_LOG_USERSPACE) += dm-log-userspace.o
> obj-$(CONFIG_DM_ZERO)+= dm-zero.o
> obj-$(CONFIG_DM_RAID)+= dm-raid.o
> obj-$(CONFIG_DM_THIN_PROVISIONING) += dm-thin-pool.o
> -obj-$(CONFIG_DM_VERITY) += dm-verity.o
> +obj-$(CONFIG_DM_VERITY) += dm-verity.o dm-verity-verify-sig.o
> obj-$(CONFIG_DM_CACHE) += dm-cache.o
> obj-$(CONFIG_DM_CACHE_SMQ) += dm-cache-smq.o
> obj-$(CONFIG_DM_ERA) += dm-era.o
> diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
> index f4c31ffaa88e..53aebfa8bc38 100644
> --- a/drivers/md/dm-verity-target.c
> +++ b/drivers/md/dm-verity-target.c
> @@ -16,7 +16,7 @@
>
> #include "dm-verity.h"
> #include "dm-verity-fec.h"
> -
> +#include "dm-verity-verify-sig.h"
> #include
> #include
>
> @@ -34,7 +34,11 @@
> #define DM_VERITY_OPT_IGN_ZEROES "ignore_zero_blocks"
> #define DM_VERITY_OPT_AT_MOST_ONCE "check_at_most_once"
>
> -#define DM_VERITY_OPTS_MAX (2 + DM_VERITY_OPTS_FEC)
> +#define DM_VERITY_OPTS_MAX (2 + DM_VERITY_OPTS_FEC + \
> + DM_VERITY_ROOT_HASH_VERIFICATION_OPTS)
> +
> +#define DM_VERITY_MANDATORY_ARGS10
> +
>
> static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE;
>
> @@ -855,7 +859,8 @@ static int verity_alloc_zero_digest(struct dm_verity *v)
> return r;
> }
>
> -static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
> +static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
> + struct dm_verity_sig_opts *verify_args)
> {
> int r;
> unsigned argc;
> @@ -904,6 +909,15 @@ static int verity_parse_opt_args(struct dm_arg_set *as,
> struct
