MODSIGN: Export module signature definitions

IMA will use the module_signature format for append signatures, so export
the relevant definitions and factor out the code which verifies that the
appended signature trailer is valid.

Also, create a CONFIG_MODULE_SIG_FORMAT option so that IMA can select it
and be able to use mod_check_sig() without having to depend on either
CONFIG_MODULE_SIG or CONFIG_MODULES.

s390 duplicated the definition of struct module_signature so now they can
use the new <linux/module_signature.h> header instead.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Acked-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
This commit is contained in:
Thiago Jung Bauermann 2019-07-04 15:57:34 -03:00 committed by Mimi Zohar
parent b36f281f4a
commit c8424e776b
10 changed files with 108 additions and 77 deletions

View file

@ -10,7 +10,7 @@
#include <linux/elf.h>
#include <linux/errno.h>
#include <linux/kexec.h>
#include <linux/module.h>
#include <linux/module_signature.h>
#include <linux/verification.h>
#include <asm/boot_data.h>
#include <asm/ipl.h>
@ -23,28 +23,6 @@ const struct kexec_file_ops * const kexec_file_loaders[] = {
};
#ifdef CONFIG_KEXEC_VERIFY_SIG
/*
* Module signature information block.
*
* The constituents of the signature section are, in order:
*
* - Signer's name
* - Key identifier
* - Signature data
* - Information block
*/
struct module_signature {
u8 algo; /* Public-key crypto algorithm [0] */
u8 hash; /* Digest algorithm [0] */
u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */
u8 signer_len; /* Length of signer's name [0] */
u8 key_id_len; /* Length of key identifier [0] */
u8 __pad[3];
__be32 sig_len; /* Length of signature data */
};
#define PKEY_ID_PKCS7 2
int s390_verify_sig(const char *kernel, unsigned long kernel_len)
{
const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1;