Kconfig (5504B)
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 help 47 Provide a system keyring to which trusted keys can be added. Keys in 48 the keyring are considered to be trusted. Keys may be added at will 49 by the kernel from compiled-in data and from hardware key stores, but 50 userspace may only add extra keys if those keys can be verified by 51 keys already in the keyring. 52 53 Keys in this keyring are used by module signature checking. 54 55config SYSTEM_TRUSTED_KEYS 56 string "Additional X.509 keys for default system keyring" 57 depends on SYSTEM_TRUSTED_KEYRING 58 help 59 If set, this option should be the filename of a PEM-formatted file 60 containing trusted X.509 certificates to be included in the default 61 system keyring. Any certificate used for module signing is implicitly 62 also trusted. 63 64 NOTE: If you previously provided keys for the system keyring in the 65 form of DER-encoded *.x509 files in the top-level build directory, 66 those are no longer used. You will need to set this option instead. 67 68config SYSTEM_EXTRA_CERTIFICATE 69 bool "Reserve area for inserting a certificate without recompiling" 70 depends on SYSTEM_TRUSTED_KEYRING 71 help 72 If set, space for an extra certificate will be reserved in the kernel 73 image. This allows introducing a trusted certificate to the default 74 system keyring without recompiling the kernel. 75 76config SYSTEM_EXTRA_CERTIFICATE_SIZE 77 int "Number of bytes to reserve for the extra certificate" 78 depends on SYSTEM_EXTRA_CERTIFICATE 79 default 4096 80 help 81 This is the number of bytes reserved in the kernel image for a 82 certificate to be inserted. 83 84config SECONDARY_TRUSTED_KEYRING 85 bool "Provide a keyring to which extra trustable keys may be added" 86 depends on SYSTEM_TRUSTED_KEYRING 87 help 88 If set, provide a keyring to which extra keys may be added, provided 89 those keys are not blacklisted and are vouched for by a key built 90 into the kernel or already in the secondary trusted keyring. 91 92config SYSTEM_BLACKLIST_KEYRING 93 bool "Provide system-wide ring of blacklisted keys" 94 depends on KEYS 95 help 96 Provide a system keyring to which blacklisted keys can be added. 97 Keys in the keyring are considered entirely untrusted. Keys in this 98 keyring are used by the module signature checking to reject loading 99 of modules signed with a blacklisted key. 100 101config SYSTEM_BLACKLIST_HASH_LIST 102 string "Hashes to be preloaded into the system blacklist keyring" 103 depends on SYSTEM_BLACKLIST_KEYRING 104 help 105 If set, this option should be the filename of a list of hashes in the 106 form "<hash>", "<hash>", ... . This will be included into a C 107 wrapper to incorporate the list into the kernel. Each <hash> must be a 108 string starting with a prefix ("tbs" or "bin"), then a colon (":"), and 109 finally an even number of hexadecimal lowercase characters (up to 128). 110 Certificate hashes can be generated with 111 tools/certs/print-cert-tbs-hash.sh . 112 113config SYSTEM_REVOCATION_LIST 114 bool "Provide system-wide ring of revocation certificates" 115 depends on SYSTEM_BLACKLIST_KEYRING 116 depends on PKCS7_MESSAGE_PARSER=y 117 help 118 If set, this allows revocation certificates to be stored in the 119 blacklist keyring and implements a hook whereby a PKCS#7 message can 120 be checked to see if it matches such a certificate. 121 122config SYSTEM_REVOCATION_KEYS 123 string "X.509 certificates to be preloaded into the system blacklist keyring" 124 depends on SYSTEM_REVOCATION_LIST 125 help 126 If set, this option should be the filename of a PEM-formatted file 127 containing X.509 certificates to be included in the default blacklist 128 keyring. 129 130config SYSTEM_BLACKLIST_AUTH_UPDATE 131 bool "Allow root to add signed blacklist keys" 132 depends on SYSTEM_BLACKLIST_KEYRING 133 depends on SYSTEM_DATA_VERIFICATION 134 help 135 If set, provide the ability to load new blacklist keys at run time if 136 they are signed and vouched by a certificate from the builtin trusted 137 keyring. The PKCS#7 signature of the description is set in the key 138 payload. Blacklist keys cannot be removed. 139 140endmenu