| 1 | |
| 2 | |
| 3 | * Machine keyring routines.
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| 4 | *
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| 5 | * Copyright (c) 2021, Oracle and/or its affiliates.
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| 6 |
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| 7 |
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| 8 | #include <linux/efi.h>
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| 9 | #include "../integrity.h"
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| 10 |
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| 11 | static __init int machine_keyring_init(void)
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| 12 | {
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| 13 | int rc;
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| 14 |
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| 15 | rc = integrity_init_keyring(INTEGRITY_KEYRING_MACHINE);
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| 16 | if (rc)
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| 17 | return rc;
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| 18 |
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| 19 | pr_notice("Machine keyring initialized\n");
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| 20 | return 0;
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| 21 | }
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| 22 | device_initcall(machine_keyring_init);
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| 23 |
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| 24 | void __init add_to_machine_keyring(const char *source, const void *data, size_t len)
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| 25 | {
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| 26 | key_perm_t perm;
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| 27 | int rc;
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| 28 |
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| 29 | perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW;
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| 30 | rc = integrity_load_cert(INTEGRITY_KEYRING_MACHINE, source, data, len, perm);
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| 31 |
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| 32 | |
| 33 | * Some MOKList keys may not pass the machine keyring restrictions.
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| 34 | * If the restriction check does not pass and the platform keyring
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| 35 | * is configured, try to add it into that keyring instead.
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| 36 |
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| 37 | if (rc && efi_enabled(EFI_BOOT) &&
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| 38 | IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING))
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| 39 | rc = integrity_load_cert(INTEGRITY_KEYRING_PLATFORM, source,
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| 40 | data, len, perm);
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| 41 |
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| 42 | if (rc)
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| 43 | pr_info("Error adding keys to machine keyring %s\n", source);
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| 44 | }
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| 45 |
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| 46 | |
| 47 | * Try to load the MokListTrustedRT MOK variable to see if we should trust
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| 48 | * the MOK keys within the kernel. It is not an error if this variable
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| 49 | * does not exist. If it does not exist, MOK keys should not be trusted
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| 50 | * within the machine keyring.
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| 51 |
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| 52 | static __init bool uefi_check_trust_mok_keys(void)
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| 53 | {
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| 54 | struct efi_mokvar_table_entry *mokvar_entry;
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| 55 |
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| 56 | mokvar_entry = efi_mokvar_entry_find("MokListTrustedRT");
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| 57 |
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| 58 | if (mokvar_entry)
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| 59 | return true;
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| 60 |
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| 61 | return false;
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| 62 | }
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| 63 |
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| 64 | static bool __init trust_moklist(void)
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| 65 | {
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| 66 | static bool initialized;
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| 67 | static bool trust_mok;
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| 68 |
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| 69 | if (!initialized) {
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| 70 | initialized = true;
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| 71 | trust_mok = false;
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| 72 |
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| 73 | if (uefi_check_trust_mok_keys())
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| 74 | trust_mok = true;
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| 75 | }
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| 76 |
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| 77 | return trust_mok;
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| 78 | }
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| 79 |
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| 80 | |
| 81 | * Provides platform specific check for trusting imputed keys before loading
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| 82 | * on .machine keyring. UEFI systems enable this trust based on a variable,
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| 83 | * and for other platforms, it is always enabled.
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| 84 |
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| 85 | bool __init imputed_trust_enabled(void)
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| 86 | {
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| 87 | if (efi_enabled(EFI_BOOT))
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| 88 | return trust_moklist();
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| 89 |
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| 90 | return true;
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| 91 | }
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