| 1 | # SPDX-License-Identifier: GPL-2.0 |
| 2 | menu "Certificates for signature checking" |
| 3 | |
| 4 | config 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 | |
| 18 | choice |
| 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 | |
| 25 | config MODULE_SIG_KEY_TYPE_RSA |
| 26 | bool "RSA" |
| 27 | help |
| 28 | Use an RSA key for module signing. |
| 29 | |
| 30 | config MODULE_SIG_KEY_TYPE_ECDSA |
| 31 | bool "ECDSA" |
| 32 | select CRYPTO_ECDSA |
| 33 | depends on !(MODULE_SIG_SHA256 || MODULE_SIG_SHA3_256) |
| 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 | |
| 42 | config MODULE_SIG_KEY_TYPE_MLDSA_44 |
| 43 | bool "ML-DSA-44" |
| 44 | select CRYPTO_MLDSA |
| 45 | depends on OPENSSL_SUPPORTS_ML_DSA |
| 46 | help |
| 47 | Use an ML-DSA-44 key (NIST FIPS 204) for module signing. ML-DSA |
| 48 | support requires OpenSSL-3.5 minimum; preferably OpenSSL-4+. With |
| 49 | the latter, the entire module body will be signed; with the former, |
| 50 | signedAttrs will be used as it lacks support for CMS_NOATTR with |
| 51 | ML-DSA. |
| 52 | |
| 53 | config MODULE_SIG_KEY_TYPE_MLDSA_65 |
| 54 | bool "ML-DSA-65" |
| 55 | select CRYPTO_MLDSA |
| 56 | depends on OPENSSL_SUPPORTS_ML_DSA |
| 57 | help |
| 58 | Use an ML-DSA-65 key (NIST FIPS 204) for module signing. ML-DSA |
| 59 | support requires OpenSSL-3.5 minimum; preferably OpenSSL-4+. With |
| 60 | the latter, the entire module body will be signed; with the former, |
| 61 | signedAttrs will be used as it lacks support for CMS_NOATTR with |
| 62 | ML-DSA. |
| 63 | |
| 64 | config MODULE_SIG_KEY_TYPE_MLDSA_87 |
| 65 | bool "ML-DSA-87" |
| 66 | select CRYPTO_MLDSA |
| 67 | depends on OPENSSL_SUPPORTS_ML_DSA |
| 68 | help |
| 69 | Use an ML-DSA-87 key (NIST FIPS 204) for module signing. ML-DSA |
| 70 | support requires OpenSSL-3.5 minimum; preferably OpenSSL-4+. With |
| 71 | the latter, the entire module body will be signed; with the former, |
| 72 | signedAttrs will be used as it lacks support for CMS_NOATTR with |
| 73 | ML-DSA. |
| 74 | |
| 75 | endchoice |
| 76 | |
| 77 | config SYSTEM_TRUSTED_KEYRING |
| 78 | bool "Provide system-wide ring of trusted keys" |
| 79 | depends on KEYS |
| 80 | depends on ASYMMETRIC_KEY_TYPE |
| 81 | depends on X509_CERTIFICATE_PARSER = y |
| 82 | help |
| 83 | Provide a system keyring to which trusted keys can be added. Keys in |
| 84 | the keyring are considered to be trusted. Keys may be added at will |
| 85 | by the kernel from compiled-in data and from hardware key stores, but |
| 86 | userspace may only add extra keys if those keys can be verified by |
| 87 | keys already in the keyring. |
| 88 | |
| 89 | Keys in this keyring are used by module signature checking. |
| 90 | |
| 91 | config SYSTEM_TRUSTED_KEYS |
| 92 | string "Additional X.509 keys for default system keyring" |
| 93 | depends on SYSTEM_TRUSTED_KEYRING |
| 94 | help |
| 95 | If set, this option should be the filename of a PEM-formatted file |
| 96 | containing trusted X.509 certificates to be included in the default |
| 97 | system keyring. Any certificate used for module signing is implicitly |
| 98 | also trusted. |
| 99 | |
| 100 | NOTE: If you previously provided keys for the system keyring in the |
| 101 | form of DER-encoded *.x509 files in the top-level build directory, |
| 102 | those are no longer used. You will need to set this option instead. |
| 103 | |
| 104 | config SYSTEM_EXTRA_CERTIFICATE |
| 105 | bool "Reserve area for inserting a certificate without recompiling" |
| 106 | depends on SYSTEM_TRUSTED_KEYRING |
| 107 | help |
| 108 | If set, space for an extra certificate will be reserved in the kernel |
| 109 | image. This allows introducing a trusted certificate to the default |
| 110 | system keyring without recompiling the kernel. |
| 111 | |
| 112 | config SYSTEM_EXTRA_CERTIFICATE_SIZE |
| 113 | int "Number of bytes to reserve for the extra certificate" |
| 114 | depends on SYSTEM_EXTRA_CERTIFICATE |
| 115 | default 4096 |
| 116 | help |
| 117 | This is the number of bytes reserved in the kernel image for a |
| 118 | certificate to be inserted. |
| 119 | |
| 120 | config SECONDARY_TRUSTED_KEYRING |
| 121 | bool "Provide a keyring to which extra trustable keys may be added" |
| 122 | depends on SYSTEM_TRUSTED_KEYRING |
| 123 | help |
| 124 | If set, provide a keyring to which extra keys may be added, provided |
| 125 | those keys are not blacklisted and are vouched for by a key built |
| 126 | into the kernel, machine keyring (if configured), or already in the |
| 127 | secondary trusted keyring. |
| 128 | |
| 129 | config SECONDARY_TRUSTED_KEYRING_SIGNED_BY_BUILTIN |
| 130 | bool "Only allow additional certs signed by keys on the builtin trusted keyring" |
| 131 | depends on SECONDARY_TRUSTED_KEYRING |
| 132 | help |
| 133 | If set, only certificates signed by keys on the builtin trusted |
| 134 | keyring may be loaded onto the secondary trusted keyring. |
| 135 | |
| 136 | Note: The machine keyring, if configured, will be linked to the |
| 137 | secondary keyring. When enabling this option, it is recommended |
| 138 | to also configure INTEGRITY_CA_MACHINE_KEYRING_MAX to prevent |
| 139 | linking code signing keys with imputed trust to the secondary |
| 140 | trusted keyring. |
| 141 | |
| 142 | config SYSTEM_BLACKLIST_KEYRING |
| 143 | bool "Provide system-wide ring of blacklisted keys" |
| 144 | depends on KEYS |
| 145 | help |
| 146 | Provide a system keyring to which blacklisted keys can be added. |
| 147 | Keys in the keyring are considered entirely untrusted. Keys in this |
| 148 | keyring are used by the module signature checking to reject loading |
| 149 | of modules signed with a blacklisted key. |
| 150 | |
| 151 | config SYSTEM_BLACKLIST_HASH_LIST |
| 152 | string "Hashes to be preloaded into the system blacklist keyring" |
| 153 | depends on SYSTEM_BLACKLIST_KEYRING |
| 154 | help |
| 155 | If set, this option should be the filename of a list of hashes in the |
| 156 | form "<hash>", "<hash>", ... . This will be included into a C |
| 157 | wrapper to incorporate the list into the kernel. Each <hash> must be a |
| 158 | string starting with a prefix ("tbs" or "bin"), then a colon (":"), and |
| 159 | finally an even number of hexadecimal lowercase characters (up to 128). |
| 160 | Certificate hashes can be generated with |
| 161 | tools/certs/print-cert-tbs-hash.sh . |
| 162 | |
| 163 | config SYSTEM_REVOCATION_LIST |
| 164 | bool "Provide system-wide ring of revocation certificates" |
| 165 | depends on SYSTEM_BLACKLIST_KEYRING |
| 166 | depends on PKCS7_MESSAGE_PARSER=y |
| 167 | help |
| 168 | If set, this allows revocation certificates to be stored in the |
| 169 | blacklist keyring and implements a hook whereby a PKCS#7 message can |
| 170 | be checked to see if it matches such a certificate. |
| 171 | |
| 172 | config SYSTEM_REVOCATION_KEYS |
| 173 | string "X.509 certificates to be preloaded into the system blacklist keyring" |
| 174 | depends on SYSTEM_REVOCATION_LIST |
| 175 | help |
| 176 | If set, this option should be the filename of a PEM-formatted file |
| 177 | containing X.509 certificates to be included in the default blacklist |
| 178 | keyring. |
| 179 | |
| 180 | config SYSTEM_BLACKLIST_AUTH_UPDATE |
| 181 | bool "Allow root to add signed blacklist keys" |
| 182 | depends on SYSTEM_BLACKLIST_KEYRING |
| 183 | depends on SYSTEM_DATA_VERIFICATION |
| 184 | help |
| 185 | If set, provide the ability to load new blacklist keys at run time if |
| 186 | they are signed and vouched by a certificate from the builtin trusted |
| 187 | keyring. The PKCS#7 signature of the description is set in the key |
| 188 | payload. Blacklist keys cannot be removed. |
| 189 | |
| 190 | config OPENSSL_SUPPORTS_ML_DSA |
| 191 | def_bool $(success, openssl list -key-managers | grep -q ML-DSA-87) |
| 192 | help |
| 193 | Support for ML-DSA-44/65/87 was added in openssl-3.5, so as long |
| 194 | as older versions are supported, the key types may only be |
| 195 | set after testing the installed binary for support. |
| 196 | |
| 197 | endmenu |