1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2011 Intel Corporation 4 * 5 * Author: 6 * Dmitry Kasatkin <dmitry.kasatkin@intel.com> 7 */ 8 9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10 11 #include <linux/err.h> 12 #include <linux/sched.h> 13 #include <linux/slab.h> 14 #include <linux/cred.h> 15 #include <linux/key-type.h> 16 #include <linux/digsig.h> 17 #include <linux/vmalloc.h> 18 #include <crypto/public_key.h> 19 #include <keys/system_keyring.h> 20 21 #include "integrity.h" 22 23 static struct key *keyring[INTEGRITY_KEYRING_MAX]; 24 25 static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = { 26 #ifndef CONFIG_INTEGRITY_TRUSTED_KEYRING 27 "_evm", 28 "_ima", 29 #else 30 ".evm", 31 ".ima", 32 #endif 33 ".platform", 34 }; 35 36 #ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY 37 #define restrict_link_to_ima restrict_link_by_builtin_and_secondary_trusted 38 #else 39 #define restrict_link_to_ima restrict_link_by_builtin_trusted 40 #endif 41 42 int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen, 43 const char *digest, int digestlen) 44 { 45 if (id >= INTEGRITY_KEYRING_MAX || siglen < 2) 46 return -EINVAL; 47 48 if (!keyring[id]) { 49 keyring[id] = 50 request_key(&key_type_keyring, keyring_name[id], NULL); 51 if (IS_ERR(keyring[id])) { 52 int err = PTR_ERR(keyring[id]); 53 pr_err("no %s keyring: %d\n", keyring_name[id], err); 54 keyring[id] = NULL; 55 return err; 56 } 57 } 58 59 switch (sig[1]) { 60 case 1: 61 /* v1 API expect signature without xattr type */ 62 return digsig_verify(keyring[id], sig + 1, siglen - 1, 63 digest, digestlen); 64 case 2: 65 return asymmetric_verify(keyring[id], sig, siglen, 66 digest, digestlen); 67 } 68 69 return -EOPNOTSUPP; 70 } 71 72 static int __integrity_init_keyring(const unsigned int id, key_perm_t perm, 73 struct key_restriction *restriction) 74 { 75 const struct cred *cred = current_cred(); 76 int err = 0; 77 78 keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0), 79 KGIDT_INIT(0), cred, perm, 80 KEY_ALLOC_NOT_IN_QUOTA, restriction, NULL); 81 if (IS_ERR(keyring[id])) { 82 err = PTR_ERR(keyring[id]); 83 pr_info("Can't allocate %s keyring (%d)\n", 84 keyring_name[id], err); 85 keyring[id] = NULL; 86 } else { 87 if (id == INTEGRITY_KEYRING_PLATFORM) 88 set_platform_trusted_keys(keyring[id]); 89 } 90 91 return err; 92 } 93 94 int __init integrity_init_keyring(const unsigned int id) 95 { 96 struct key_restriction *restriction; 97 key_perm_t perm; 98 99 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW 100 | KEY_USR_READ | KEY_USR_SEARCH; 101 102 if (id == INTEGRITY_KEYRING_PLATFORM) { 103 restriction = NULL; 104 goto out; 105 } 106 107 if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING)) 108 return 0; 109 110 restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL); 111 if (!restriction) 112 return -ENOMEM; 113 114 restriction->check = restrict_link_to_ima; 115 perm |= KEY_USR_WRITE; 116 117 out: 118 return __integrity_init_keyring(id, perm, restriction); 119 } 120 121 int __init integrity_add_key(const unsigned int id, const void *data, 122 off_t size, key_perm_t perm) 123 { 124 key_ref_t key; 125 int rc = 0; 126 127 if (!keyring[id]) 128 return -EINVAL; 129 130 key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric", 131 NULL, data, size, perm, 132 KEY_ALLOC_NOT_IN_QUOTA); 133 if (IS_ERR(key)) { 134 rc = PTR_ERR(key); 135 pr_err("Problem loading X.509 certificate %d\n", rc); 136 } else { 137 pr_notice("Loaded X.509 cert '%s'\n", 138 key_ref_to_ptr(key)->description); 139 key_ref_put(key); 140 } 141 142 return rc; 143 144 } 145 146 int __init integrity_load_x509(const unsigned int id, const char *path) 147 { 148 void *data; 149 loff_t size; 150 int rc; 151 key_perm_t perm; 152 153 rc = kernel_read_file_from_path(path, &data, &size, 0, 154 READING_X509_CERTIFICATE); 155 if (rc < 0) { 156 pr_err("Unable to open file: %s (%d)", path, rc); 157 return rc; 158 } 159 160 perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ; 161 162 pr_info("Loading X.509 certificate: %s\n", path); 163 rc = integrity_add_key(id, (const void *)data, size, perm); 164 165 vfree(data); 166 return rc; 167 } 168 169 int __init integrity_load_cert(const unsigned int id, const char *source, 170 const void *data, size_t len, key_perm_t perm) 171 { 172 if (!data) 173 return -EINVAL; 174 175 pr_info("Loading X.509 certificate: %s\n", source); 176 return integrity_add_key(id, data, len, perm); 177 } 178