Subject: Re: [PATCH v3 3/4] x86/efi: move common keyring handler functions to new file

From: Michael Ellerman <[email-masked]>
Date: Mon, 02 Sep 2019 21:55:36 +1000

Nayna Jain <[email-masked]> writes:

> The handlers to add the keys to the .platform keyring and blacklisted
> hashes to the .blacklist keyring is common for both the uefi and powerpc
> mechanisms of loading the keys/hashes from the firmware.
>
> This patch moves the common code from load_uefi.c to keyring_handler.c
>
> Signed-off-by: Nayna Jain <[email-masked]>
> ---
>  security/integrity/Makefile                   |  3 +-
>  .../platform_certs/keyring_handler.c          | 80 +++++++++++++++++++
>  .../platform_certs/keyring_handler.h          | 32 ++++++++
>  security/integrity/platform_certs/load_uefi.c | 67 +---------------
>  4 files changed, 115 insertions(+), 67 deletions(-)
>  create mode 100644 security/integrity/platform_certs/keyring_handler.c
>  create mode 100644 security/integrity/platform_certs/keyring_handler.h

This has no acks from security folks, though I'm not really clear on who
maintains those files.

Do I take it because it's mostly just code movement people are OK with
it going in via the powerpc tree?

cheers

> diff --git a/security/integrity/Makefile b/security/integrity/Makefile
> index 19faace69644..525bf1d6e0db 100644
> --- a/security/integrity/Makefile
> +++ b/security/integrity/Makefile
> @@ -11,7 +11,8 @@ integrity-$(CONFIG_INTEGRITY_SIGNATURE) += digsig.o
>  integrity-$(CONFIG_INTEGRITY_ASYMMETRIC_KEYS) += digsig_asymmetric.o
>  integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyring.o
>  integrity-$(CONFIG_LOAD_UEFI_KEYS) += platform_certs/efi_parser.o \
> -					platform_certs/load_uefi.o
> +				      platform_certs/load_uefi.o \
> +				      platform_certs/keyring_handler.o
>  integrity-$(CONFIG_LOAD_IPL_KEYS) += platform_certs/load_ipl_s390.o
>  $(obj)/load_uefi.o: KBUILD_CFLAGS += -fshort-wchar
>  
> diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c
> new file mode 100644
> index 000000000000..c5ba695c10e3
> --- /dev/null
> +++ b/security/integrity/platform_certs/keyring_handler.c
> @@ -0,0 +1,80 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/kernel.h>
> +#include <linux/sched.h>
> +#include <linux/cred.h>
> +#include <linux/err.h>
> +#include <linux/efi.h>
> +#include <linux/slab.h>
> +#include <keys/asymmetric-type.h>
> +#include <keys/system_keyring.h>
> +#include "../integrity.h"
> +
> +static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID;
> +static efi_guid_t efi_cert_x509_sha256_guid __initdata =
> +	EFI_CERT_X509_SHA256_GUID;
> +static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID;
> +
> +/*
> + * Blacklist a hash.
> + */
> +static __init void uefi_blacklist_hash(const char *source, const void *data,
> +				       size_t len, const char *type,
> +				       size_t type_len)
> +{
> +	char *hash, *p;
> +
> +	hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL);
> +	if (!hash)
> +		return;
> +	p = memcpy(hash, type, type_len);
> +	p += type_len;
> +	bin2hex(p, data, len);
> +	p += len * 2;
> +	*p = 0;
> +
> +	mark_hash_blacklisted(hash);
> +	kfree(hash);
> +}
> +
> +/*
> + * Blacklist an X509 TBS hash.
> + */
> +static __init void uefi_blacklist_x509_tbs(const char *source,
> +					   const void *data, size_t len)
> +{
> +	uefi_blacklist_hash(source, data, len, "tbs:", 4);
> +}
> +
> +/*
> + * Blacklist the hash of an executable.
> + */
> +static __init void uefi_blacklist_binary(const char *source,
> +					 const void *data, size_t len)
> +{
> +	uefi_blacklist_hash(source, data, len, "bin:", 4);
> +}
> +
> +/*
> + * Return the appropriate handler for particular signature list types found in
> + * the UEFI db and MokListRT tables.
> + */
> +__init efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type)
> +{
> +	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
> +		return add_to_platform_keyring;
> +	return 0;
> +}
> +
> +/*
> + * Return the appropriate handler for particular signature list types found in
> + * the UEFI dbx and MokListXRT tables.
> + */
> +__init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type)
> +{
> +	if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0)
> +		return uefi_blacklist_x509_tbs;
> +	if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
> +		return uefi_blacklist_binary;
> +	return 0;
> +}
> diff --git a/security/integrity/platform_certs/keyring_handler.h b/security/integrity/platform_certs/keyring_handler.h
> new file mode 100644
> index 000000000000..2462bfa08fe3
> --- /dev/null
> +++ b/security/integrity/platform_certs/keyring_handler.h
> @@ -0,0 +1,32 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef PLATFORM_CERTS_INTERNAL_H
> +#define PLATFORM_CERTS_INTERNAL_H
> +
> +#include <linux/efi.h>
> +
> +void blacklist_hash(const char *source, const void *data,
> +		    size_t len, const char *type,
> +		    size_t type_len);
> +
> +/*
> + * Blacklist an X509 TBS hash.
> + */
> +void blacklist_x509_tbs(const char *source, const void *data, size_t len);
> +
> +/*
> + * Blacklist the hash of an executable.
> + */
> +void blacklist_binary(const char *source, const void *data, size_t len);
> +
> +/*
> + * Return the handler for particular signature list types found in the db.
> + */
> +efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type);
> +
> +/*
> + * Return the handler for particular signature list types found in the dbx.
> + */
> +efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type);
> +
> +#endif
> diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
> index 81b19c52832b..4369204a19cd 100644
> --- a/security/integrity/platform_certs/load_uefi.c
> +++ b/security/integrity/platform_certs/load_uefi.c
> @@ -9,6 +9,7 @@
>  #include <keys/asymmetric-type.h>
>  #include <keys/system_keyring.h>
>  #include "../integrity.h"
> +#include "keyring_handler.h"
>  
>  static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID;
>  static efi_guid_t efi_cert_x509_sha256_guid __initdata =
> @@ -67,72 +68,6 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
>  	return db;
>  }
>  
> -/*
> - * Blacklist a hash.
> - */
> -static __init void uefi_blacklist_hash(const char *source, const void *data,
> -				       size_t len, const char *type,
> -				       size_t type_len)
> -{
> -	char *hash, *p;
> -
> -	hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL);
> -	if (!hash)
> -		return;
> -	p = memcpy(hash, type, type_len);
> -	p += type_len;
> -	bin2hex(p, data, len);
> -	p += len * 2;
> -	*p = 0;
> -
> -	mark_hash_blacklisted(hash);
> -	kfree(hash);
> -}
> -
> -/*
> - * Blacklist an X509 TBS hash.
> - */
> -static __init void uefi_blacklist_x509_tbs(const char *source,
> -					   const void *data, size_t len)
> -{
> -	uefi_blacklist_hash(source, data, len, "tbs:", 4);
> -}
> -
> -/*
> - * Blacklist the hash of an executable.
> - */
> -static __init void uefi_blacklist_binary(const char *source,
> -					 const void *data, size_t len)
> -{
> -	uefi_blacklist_hash(source, data, len, "bin:", 4);
> -}
> -
> -/*
> - * Return the appropriate handler for particular signature list types found in
> - * the UEFI db and MokListRT tables.
> - */
> -static __init efi_element_handler_t get_handler_for_db(const efi_guid_t *
> -						       sig_type)
> -{
> -	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
> -		return add_to_platform_keyring;
> -	return 0;
> -}
> -
> -/*
> - * Return the appropriate handler for particular signature list types found in
> - * the UEFI dbx and MokListXRT tables.
> - */
> -static __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *
> -							sig_type)
> -{
> -	if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0)
> -		return uefi_blacklist_x509_tbs;
> -	if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
> -		return uefi_blacklist_binary;
> -	return 0;
> -}
> -
>  /*
>   * Load the certs contained in the UEFI databases into the platform trusted
>   * keyring and the UEFI blacklisted X.509 cert SHA256 hashes into the blacklist
> -- 
> 2.20.1