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 
13 static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID;
14 static efi_guid_t efi_cert_x509_sha256_guid __initdata =
15 	EFI_CERT_X509_SHA256_GUID;
16 static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID;
17 
18 /*
19  * Blacklist a hash.
20  */
21 static __init void uefi_blacklist_hash(const char *source, const void *data,
22 				       size_t len, const char *type,
23 				       size_t type_len)
24 {
25 	char *hash, *p;
26 
27 	hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL);
28 	if (!hash)
29 		return;
30 	p = memcpy(hash, type, type_len);
31 	p += type_len;
32 	bin2hex(p, data, len);
33 	p += len * 2;
34 	*p = 0;
35 
36 	mark_hash_blacklisted(hash);
37 	kfree(hash);
38 }
39 
40 /*
41  * Blacklist an X509 TBS hash.
42  */
43 static __init void uefi_blacklist_x509_tbs(const char *source,
44 					   const void *data, size_t len)
45 {
46 	uefi_blacklist_hash(source, data, len, "tbs:", 4);
47 }
48 
49 /*
50  * Blacklist the hash of an executable.
51  */
52 static __init void uefi_blacklist_binary(const char *source,
53 					 const void *data, size_t len)
54 {
55 	uefi_blacklist_hash(source, data, len, "bin:", 4);
56 }
57 
58 /*
59  * Add an X509 cert to the revocation list.
60  */
61 static __init void uefi_revocation_list_x509(const char *source,
62 					     const void *data, size_t len)
63 {
64 	add_key_to_revocation_list(data, len);
65 }
66 
67 /*
68  * Return the appropriate handler for particular signature list types found in
69  * the UEFI db and MokListRT tables.
70  */
71 __init efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type)
72 {
73 	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
74 		return add_to_platform_keyring;
75 	return 0;
76 }
77 
78 /*
79  * Return the appropriate handler for particular signature list types found in
80  * the UEFI dbx and MokListXRT tables.
81  */
82 __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type)
83 {
84 	if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0)
85 		return uefi_blacklist_x509_tbs;
86 	if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
87 		return uefi_blacklist_binary;
88 	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
89 		return uefi_revocation_list_x509;
90 	return 0;
91 }
92