Re: [PATCH v8 08/22] protectors: Add key protectors framework

[Vladimir 'phcoder' Serbinenko]

Any strong reason to have it in kernel? It doesn't seem to be
necessary in non-crypto cases. Separate module or cryptodisk looks
like better places

On Tue, Jan 16, 2024 at 12:22 PM Gary Lin via Grub-devel
<grub-devel@gnu.org> wrote:
>
> From: Hernan Gatta <hegatta@linux.microsoft.com>
>
> A key protector encapsulates functionality to retrieve an unlocking key
> for a fully-encrypted disk from a specific source. A key protector
> module registers itself with the key protectors framework when it is
> loaded and unregisters when unloaded. Additionally, a key protector may
> accept parameters that describe how it should operate.
>
> The key protectors framework, besides offering registration and
> unregistration functions, also offers a one-stop routine for finding and
> invoking a key protector by name. If a key protector with the specified
> name exists and if an unlocking key is successfully retrieved by it, the
> function returns to the caller the retrieved key and its length.
>
> Signed-off-by: Hernan Gatta <hegatta@linux.microsoft.com>
> Signed-off-by: Gary Lin <glin@suse.com>
> ---
>  grub-core/Makefile.am       |  1 +
>  grub-core/Makefile.core.def |  1 +
>  grub-core/kern/protectors.c | 75 +++++++++++++++++++++++++++++++++++++
>  include/grub/protector.h    | 48 ++++++++++++++++++++++++
>  4 files changed, 125 insertions(+)
>  create mode 100644 grub-core/kern/protectors.c
>  create mode 100644 include/grub/protector.h
>
> diff --git a/grub-core/Makefile.am b/grub-core/Makefile.am
> index f18550c1c..af21fc72d 100644
> --- a/grub-core/Makefile.am
> +++ b/grub-core/Makefile.am
> @@ -90,6 +90,7 @@ endif
>  KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/mm.h
>  KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/parser.h
>  KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/partition.h
> +KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/protector.h
>  KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/stack_protector.h
>  KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/term.h
>  KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/time.h
> diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
> index c9d81b56a..70d5e0e00 100644
> --- a/grub-core/Makefile.core.def
> +++ b/grub-core/Makefile.core.def
> @@ -149,6 +149,7 @@ kernel = {
>    common = kern/misc.c;
>    common = kern/parser.c;
>    common = kern/partition.c;
> +  common = kern/protectors.c;
>    common = kern/rescue_parser.c;
>    common = kern/rescue_reader.c;
>    common = kern/term.c;
> diff --git a/grub-core/kern/protectors.c b/grub-core/kern/protectors.c
> new file mode 100644
> index 000000000..5ee059565
> --- /dev/null
> +++ b/grub-core/kern/protectors.c
> @@ -0,0 +1,75 @@
> +/*
> + *  GRUB  --  GRand Unified Bootloader
> + *  Copyright (C) 2022 Microsoft Corporation
> + *
> + *  GRUB is free software: you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation, either version 3 of the License, or
> + *  (at your option) any later version.
> + *
> + *  GRUB is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <grub/list.h>
> +#include <grub/misc.h>
> +#include <grub/mm.h>
> +#include <grub/protector.h>
> +
> +struct grub_key_protector *grub_key_protectors = NULL;
> +
> +grub_err_t
> +grub_key_protector_register (struct grub_key_protector *protector)
> +{
> +  if (protector == NULL || protector->name == NULL || 
> grub_strlen(protector->name) == 0)
> +    return GRUB_ERR_BAD_ARGUMENT;
> +
> +  if (grub_key_protectors &&
> +      grub_named_list_find (GRUB_AS_NAMED_LIST (grub_key_protectors),
> +                           protector->name))
> +    return GRUB_ERR_BAD_ARGUMENT;
> +
> +  grub_list_push (GRUB_AS_LIST_P (&grub_key_protectors),
> +                 GRUB_AS_LIST (protector));
> +
> +  return GRUB_ERR_NONE;
> +}
> +
> +grub_err_t
> +grub_key_protector_unregister (struct grub_key_protector *protector)
> +{
> +  if (protector == NULL)
> +    return GRUB_ERR_BAD_ARGUMENT;
> +
> +  grub_list_remove (GRUB_AS_LIST (protector));
> +
> +  return GRUB_ERR_NONE;
> +}
> +
> +grub_err_t
> +grub_key_protector_recover_key (const char *protector, grub_uint8_t **key,
> +                               grub_size_t *key_size)
> +{
> +  struct grub_key_protector *kp = NULL;
> +
> +  if (grub_key_protectors == NULL)
> +    return GRUB_ERR_OUT_OF_RANGE;
> +
> +  if (protector == NULL || grub_strlen (protector) == 0)
> +    return GRUB_ERR_BAD_ARGUMENT;
> +
> +  kp = grub_named_list_find (GRUB_AS_NAMED_LIST (grub_key_protectors),
> +                            protector);
> +  if (kp == NULL)
> +    return grub_error (GRUB_ERR_OUT_OF_RANGE,
> +                      N_("A key protector with name '%s' could not be found. 
> "
> +                         "Is the name spelled correctly and is the "
> +                         "corresponding module loaded?"), protector);
> +
> +  return kp->recover_key (key, key_size);
> +}
> diff --git a/include/grub/protector.h b/include/grub/protector.h
> new file mode 100644
> index 000000000..3d9f69bce
> --- /dev/null
> +++ b/include/grub/protector.h
> @@ -0,0 +1,48 @@
> +/*
> + *  GRUB  --  GRand Unified Bootloader
> + *  Copyright (C) 2022 Microsoft Corporation
> + *
> + *  GRUB is free software: you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation, either version 3 of the License, or
> + *  (at your option) any later version.
> + *
> + *  GRUB is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef GRUB_PROTECTOR_HEADER
> +#define GRUB_PROTECTOR_HEADER 1
> +
> +#include <grub/err.h>
> +#include <grub/types.h>
> +
> +struct grub_key_protector
> +{
> +  struct grub_key_protector *next;
> +  struct grub_key_protector **prev;
> +
> +  const char *name;
> +
> +  grub_err_t (*recover_key) (grub_uint8_t **key, grub_size_t *key_size);
> +};
> +
> +extern struct grub_key_protector *EXPORT_VAR (grub_key_protectors);
> +
> +grub_err_t
> +EXPORT_FUNC (grub_key_protector_register) (struct grub_key_protector 
> *protector);
> +
> +grub_err_t
> +EXPORT_FUNC (grub_key_protector_unregister) (struct grub_key_protector 
> *protector);
> +
> +grub_err_t
> +EXPORT_FUNC (grub_key_protector_recover_key) (const char *protector,
> +                                             grub_uint8_t **key,
> +                                             grub_size_t *key_size);
> +
> +#endif /* ! GRUB_PROTECTOR_HEADER */
> --
> 2.35.3
>
>
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-- 
Regards
Vladimir 'phcoder' Serbinenko