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 help 34 Use an elliptic curve key (NIST P384) for module signing. Consider 35 using a strong hash like sha256 or sha384 for hashing modules. 36 37 Note: Remove all ECDSA signing keys, e.g. certs/signing_key.pem, 38 when falling back to building Linux 5.14 and older kernels. 39 40endchoice 41 42config SYSTEM_TRUSTED_KEYRING 43 bool "Provide system-wide ring of trusted keys" 44 depends on KEYS 45 depends on ASYMMETRIC_KEY_TYPE 46 depends on X509_CERTIFICATE_PARSER = y 47 help 48 Provide a system keyring to which trusted keys can be added. Keys in 49 the keyring are considered to be trusted. Keys may be added at will 50 by the kernel from compiled-in data and from hardware key stores, but 51 userspace may only add extra keys if those keys can be verified by 52 keys already in the keyring. 53 54 Keys in this keyring are used by module signature checking. 55 56config SYSTEM_TRUSTED_KEYS 57 string "Additional X.509 keys for default system keyring" 58 depends on SYSTEM_TRUSTED_KEYRING 59 help 60 If set, this option should be the filename of a PEM-formatted file 61 containing trusted X.509 certificates to be included in the default 62 system keyring. Any certificate used for module signing is implicitly 63 also trusted. 64 65 NOTE: If you previously provided keys for the system keyring in the 66 form of DER-encoded *.x509 files in the top-level build directory, 67 those are no longer used. You will need to set this option instead. 68 69config SYSTEM_EXTRA_CERTIFICATE 70 bool "Reserve area for inserting a certificate without recompiling" 71 depends on SYSTEM_TRUSTED_KEYRING 72 help 73 If set, space for an extra certificate will be reserved in the kernel 74 image. This allows introducing a trusted certificate to the default 75 system keyring without recompiling the kernel. 76 77config SYSTEM_EXTRA_CERTIFICATE_SIZE 78 int "Number of bytes to reserve for the extra certificate" 79 depends on SYSTEM_EXTRA_CERTIFICATE 80 default 4096 81 help 82 This is the number of bytes reserved in the kernel image for a 83 certificate to be inserted. 84 85config SECONDARY_TRUSTED_KEYRING 86 bool "Provide a keyring to which extra trustable keys may be added" 87 depends on SYSTEM_TRUSTED_KEYRING 88 help 89 If set, provide a keyring to which extra keys may be added, provided 90 those keys are not blacklisted and are vouched for by a key built 91 into the kernel or already in the secondary trusted keyring. 92 93config SYSTEM_BLACKLIST_KEYRING 94 bool "Provide system-wide ring of blacklisted keys" 95 depends on KEYS 96 help 97 Provide a system keyring to which blacklisted keys can be added. 98 Keys in the keyring are considered entirely untrusted. Keys in this 99 keyring are used by the module signature checking to reject loading 100 of modules signed with a blacklisted key. 101 102config SYSTEM_BLACKLIST_HASH_LIST 103 string "Hashes to be preloaded into the system blacklist keyring" 104 depends on SYSTEM_BLACKLIST_KEYRING 105 help 106 If set, this option should be the filename of a list of hashes in the 107 form "<hash>", "<hash>", ... . This will be included into a C 108 wrapper to incorporate the list into the kernel. Each <hash> must be a 109 string starting with a prefix ("tbs" or "bin"), then a colon (":"), and 110 finally an even number of hexadecimal lowercase characters (up to 128). 111 Certificate hashes can be generated with 112 tools/certs/print-cert-tbs-hash.sh . 113 114config SYSTEM_REVOCATION_LIST 115 bool "Provide system-wide ring of revocation certificates" 116 depends on SYSTEM_BLACKLIST_KEYRING 117 depends on PKCS7_MESSAGE_PARSER=y 118 help 119 If set, this allows revocation certificates to be stored in the 120 blacklist keyring and implements a hook whereby a PKCS#7 message can 121 be checked to see if it matches such a certificate. 122 123config SYSTEM_REVOCATION_KEYS 124 string "X.509 certificates to be preloaded into the system blacklist keyring" 125 depends on SYSTEM_REVOCATION_LIST 126 help 127 If set, this option should be the filename of a PEM-formatted file 128 containing X.509 certificates to be included in the default blacklist 129 keyring. 130 131config SYSTEM_BLACKLIST_AUTH_UPDATE 132 bool "Allow root to add signed blacklist keys" 133 depends on SYSTEM_BLACKLIST_KEYRING 134 depends on SYSTEM_DATA_VERIFICATION 135 help 136 If set, provide the ability to load new blacklist keys at run time if 137 they are signed and vouched by a certificate from the builtin trusted 138 keyring. The PKCS#7 signature of the description is set in the key 139 payload. Blacklist keys cannot be removed. 140 141endmenu 142