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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 | // SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2019 Microsoft Corporation. * * Author: Jaskaran Singh Khurana <jaskarankhurana@linux.microsoft.com> * */ #include <linux/device-mapper.h> #include <linux/verification.h> #include <keys/user-type.h> #include <linux/module.h> #include "dm-verity.h" #include "dm-verity-verify-sig.h" #define DM_VERITY_VERIFY_ERR(s) DM_VERITY_ROOT_HASH_VERIFICATION " " s static bool require_signatures; module_param(require_signatures, bool, 0444); MODULE_PARM_DESC(require_signatures, "Verify the roothash of dm-verity hash tree"); #define DM_VERITY_IS_SIG_FORCE_ENABLED() \ (require_signatures != false) bool verity_verify_is_sig_opt_arg(const char *arg_name) { return (!strcasecmp(arg_name, DM_VERITY_ROOT_HASH_VERIFICATION_OPT_SIG_KEY)); } static int verity_verify_get_sig_from_key(const char *key_desc, struct dm_verity_sig_opts *sig_opts) { struct key *key; const struct user_key_payload *ukp; int ret = 0; key = request_key(&key_type_user, key_desc, NULL); if (IS_ERR(key)) return PTR_ERR(key); down_read(&key->sem); ukp = user_key_payload_locked(key); if (!ukp) { ret = -EKEYREVOKED; goto end; } sig_opts->sig = kmalloc(ukp->datalen, GFP_KERNEL); if (!sig_opts->sig) { ret = -ENOMEM; goto end; } sig_opts->sig_size = ukp->datalen; memcpy(sig_opts->sig, ukp->data, sig_opts->sig_size); end: up_read(&key->sem); key_put(key); return ret; } int verity_verify_sig_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v, struct dm_verity_sig_opts *sig_opts, unsigned int *argc, const char *arg_name) { struct dm_target *ti = v->ti; int ret = 0; const char *sig_key = NULL; if (!*argc) { ti->error = DM_VERITY_VERIFY_ERR("Signature key not specified"); return -EINVAL; } sig_key = dm_shift_arg(as); (*argc)--; ret = verity_verify_get_sig_from_key(sig_key, sig_opts); if (ret < 0) ti->error = DM_VERITY_VERIFY_ERR("Invalid key specified"); v->signature_key_desc = kstrdup(sig_key, GFP_KERNEL); if (!v->signature_key_desc) return -ENOMEM; return ret; } /* * verify_verify_roothash - Verify the root hash of the verity hash device * using builtin trusted keys. * * @root_hash: For verity, the roothash/data to be verified. * @root_hash_len: Size of the roothash/data to be verified. * @sig_data: The trusted signature that verifies the roothash/data. * @sig_len: Size of the signature. * */ int verity_verify_root_hash(const void *root_hash, size_t root_hash_len, const void *sig_data, size_t sig_len) { int ret; if (!root_hash || root_hash_len == 0) return -EINVAL; if (!sig_data || sig_len == 0) { if (DM_VERITY_IS_SIG_FORCE_ENABLED()) return -ENOKEY; else return 0; } ret = verify_pkcs7_signature(root_hash, root_hash_len, sig_data, sig_len, #ifdef CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG_SECONDARY_KEYRING VERIFY_USE_SECONDARY_KEYRING, #else NULL, #endif VERIFYING_UNSPECIFIED_SIGNATURE, NULL, NULL); #ifdef CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG_PLATFORM_KEYRING if (ret == -ENOKEY) ret = verify_pkcs7_signature(root_hash, root_hash_len, sig_data, sig_len, VERIFY_USE_PLATFORM_KEYRING, VERIFYING_UNSPECIFIED_SIGNATURE, NULL, NULL); #endif return ret; } void verity_verify_sig_opts_cleanup(struct dm_verity_sig_opts *sig_opts) { kfree(sig_opts->sig); sig_opts->sig = NULL; sig_opts->sig_size = 0; } |