1# SPDX-License-Identifier: GPL-2.0 2menu "Certificates for signature checking" 3 4config MODULE_SIG_KEY 5 string "File name or PKCS#11 URI of module signing key" 6 default "certs/signing_key.pem" 7 depends on MODULE_SIG || (IMA_APPRAISE_MODSIG && MODULES) 8 help 9 Provide the file name of a private key/certificate in PEM format, 10 or a PKCS#11 URI according to RFC7512. The file should contain, or 11 the URI should identify, both the certificate and its corresponding 12 private key. 13 14 If this option is unchanged from its default "certs/signing_key.pem", 15 then the kernel will automatically generate the private key and 16 certificate as described in Documentation/admin-guide/module-signing.rst 17 18choice 19 prompt "Type of module signing key to be generated" 20 depends on MODULE_SIG || (IMA_APPRAISE_MODSIG && MODULES) 21 help 22 The type of module signing key type to generate. This option 23 does not apply if a #PKCS11 URI is used. 24 25config MODULE_SIG_KEY_TYPE_RSA 26 bool "RSA" 27 help 28 Use an RSA key for module signing. 29 30config MODULE_SIG_KEY_TYPE_ECDSA 31 bool "ECDSA" 32 select CRYPTO_ECDSA 33 depends on MODULE_SIG_SHA384 || MODULE_SIG_SHA512 34 help 35 Use an elliptic curve key (NIST P384) for module signing. Use 36 a strong hash of same or higher bit length, i.e. sha384 or 37 sha512 for hashing modules. 38 39 Note: Remove all ECDSA signing keys, e.g. certs/signing_key.pem, 40 when falling back to building Linux 5.14 and older kernels. 41 42endchoice 43 44config SYSTEM_TRUSTED_KEYRING 45 bool "Provide system-wide ring of trusted keys" 46 depends on KEYS 47 depends on ASYMMETRIC_KEY_TYPE 48 depends on X509_CERTIFICATE_PARSER = y 49 help 50 Provide a system keyring to which trusted keys can be added. Keys in 51 the keyring are considered to be trusted. Keys may be added at will 52 by the kernel from compiled-in data and from hardware key stores, but 53 userspace may only add extra keys if those keys can be verified by 54 keys already in the keyring. 55 56 Keys in this keyring are used by module signature checking. 57 58config SYSTEM_TRUSTED_KEYS 59 string "Additional X.509 keys for default system keyring" 60 depends on SYSTEM_TRUSTED_KEYRING 61 help 62 If set, this option should be the filename of a PEM-formatted file 63 containing trusted X.509 certificates to be included in the default 64 system keyring. Any certificate used for module signing is implicitly 65 also trusted. 66 67 NOTE: If you previously provided keys for the system keyring in the 68 form of DER-encoded *.x509 files in the top-level build directory, 69 those are no longer used. You will need to set this option instead. 70 71config SYSTEM_EXTRA_CERTIFICATE 72 bool "Reserve area for inserting a certificate without recompiling" 73 depends on SYSTEM_TRUSTED_KEYRING 74 help 75 If set, space for an extra certificate will be reserved in the kernel 76 image. This allows introducing a trusted certificate to the default 77 system keyring without recompiling the kernel. 78 79config SYSTEM_EXTRA_CERTIFICATE_SIZE 80 int "Number of bytes to reserve for the extra certificate" 81 depends on SYSTEM_EXTRA_CERTIFICATE 82 default 4096 83 help 84 This is the number of bytes reserved in the kernel image for a 85 certificate to be inserted. 86 87config SECONDARY_TRUSTED_KEYRING 88 bool "Provide a keyring to which extra trustable keys may be added" 89 depends on SYSTEM_TRUSTED_KEYRING 90 help 91 If set, provide a keyring to which extra keys may be added, provided 92 those keys are not blacklisted and are vouched for by a key built 93 into the kernel or already in the secondary trusted keyring. 94 95config SYSTEM_BLACKLIST_KEYRING 96 bool "Provide system-wide ring of blacklisted keys" 97 depends on KEYS 98 help 99 Provide a system keyring to which blacklisted keys can be added. 100 Keys in the keyring are considered entirely untrusted. Keys in this 101 keyring are used by the module signature checking to reject loading 102 of modules signed with a blacklisted key. 103 104config SYSTEM_BLACKLIST_HASH_LIST 105 string "Hashes to be preloaded into the system blacklist keyring" 106 depends on SYSTEM_BLACKLIST_KEYRING 107 help 108 If set, this option should be the filename of a list of hashes in the 109 form "<hash>", "<hash>", ... . This will be included into a C 110 wrapper to incorporate the list into the kernel. Each <hash> must be a 111 string starting with a prefix ("tbs" or "bin"), then a colon (":"), and 112 finally an even number of hexadecimal lowercase characters (up to 128). 113 Certificate hashes can be generated with 114 tools/certs/print-cert-tbs-hash.sh . 115 116config SYSTEM_REVOCATION_LIST 117 bool "Provide system-wide ring of revocation certificates" 118 depends on SYSTEM_BLACKLIST_KEYRING 119 depends on PKCS7_MESSAGE_PARSER=y 120 help 121 If set, this allows revocation certificates to be stored in the 122 blacklist keyring and implements a hook whereby a PKCS#7 message can 123 be checked to see if it matches such a certificate. 124 125config SYSTEM_REVOCATION_KEYS 126 string "X.509 certificates to be preloaded into the system blacklist keyring" 127 depends on SYSTEM_REVOCATION_LIST 128 help 129 If set, this option should be the filename of a PEM-formatted file 130 containing X.509 certificates to be included in the default blacklist 131 keyring. 132 133config SYSTEM_BLACKLIST_AUTH_UPDATE 134 bool "Allow root to add signed blacklist keys" 135 depends on SYSTEM_BLACKLIST_KEYRING 136 depends on SYSTEM_DATA_VERIFICATION 137 help 138 If set, provide the ability to load new blacklist keys at run time if 139 they are signed and vouched by a certificate from the builtin trusted 140 keyring. The PKCS#7 signature of the description is set in the key 141 payload. Blacklist keys cannot be removed. 142 143endmenu 144