xref: /linux/security/integrity/platform_certs/keyring_handler.c (revision e7d759f31ca295d589f7420719c311870bb3166f)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include <linux/kernel.h>
4 #include <linux/sched.h>
5 #include <linux/cred.h>
6 #include <linux/err.h>
7 #include <linux/efi.h>
8 #include <linux/slab.h>
9 #include <keys/asymmetric-type.h>
10 #include <keys/system_keyring.h>
11 #include "../integrity.h"
12 #include "keyring_handler.h"
13 
14 static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID;
15 static efi_guid_t efi_cert_x509_sha256_guid __initdata =
16 	EFI_CERT_X509_SHA256_GUID;
17 static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID;
18 
19 /*
20  * Blacklist an X509 TBS hash.
21  */
22 static __init void uefi_blacklist_x509_tbs(const char *source,
23 					   const void *data, size_t len)
24 {
25 	mark_hash_blacklisted(data, len, BLACKLIST_HASH_X509_TBS);
26 }
27 
28 /*
29  * Blacklist the hash of an executable.
30  */
31 static __init void uefi_blacklist_binary(const char *source,
32 					 const void *data, size_t len)
33 {
34 	mark_hash_blacklisted(data, len, BLACKLIST_HASH_BINARY);
35 }
36 
37 /*
38  * Add an X509 cert to the revocation list.
39  */
40 static __init void uefi_revocation_list_x509(const char *source,
41 					     const void *data, size_t len)
42 {
43 	add_key_to_revocation_list(data, len);
44 }
45 
46 /*
47  * Return the appropriate handler for particular signature list types found in
48  * the UEFI db tables.
49  */
50 __init efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type)
51 {
52 	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
53 		return add_to_platform_keyring;
54 	return NULL;
55 }
56 
57 /*
58  * Return the appropriate handler for particular signature list types found in
59  * the MokListRT tables.
60  */
61 __init efi_element_handler_t get_handler_for_mok(const efi_guid_t *sig_type)
62 {
63 	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0) {
64 		if (IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING) &&
65 		    imputed_trust_enabled())
66 			return add_to_machine_keyring;
67 		else
68 			return add_to_platform_keyring;
69 	}
70 	return NULL;
71 }
72 
73 __init efi_element_handler_t get_handler_for_ca_keys(const efi_guid_t *sig_type)
74 {
75 	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
76 		return add_to_machine_keyring;
77 
78 	return NULL;
79 }
80 
81 __init efi_element_handler_t get_handler_for_code_signing_keys(const efi_guid_t *sig_type)
82 {
83 	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
84 		return add_to_secondary_keyring;
85 
86 	return NULL;
87 }
88 
89 /*
90  * Return the appropriate handler for particular signature list types found in
91  * the UEFI dbx and MokListXRT tables.
92  */
93 __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type)
94 {
95 	if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0)
96 		return uefi_blacklist_x509_tbs;
97 	if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
98 		return uefi_blacklist_binary;
99 	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
100 		return uefi_revocation_list_x509;
101 	return NULL;
102 }
103