LXR linux/certs/Kconfig

   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        default MODULE_SIG_KEY_TYPE_RSA
  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        depends on MODULE_SIG || (IMA_APPRAISE_MODSIG && MODULES)
  28        help
  29         Use an RSA key for module signing.
  30
  31config MODULE_SIG_KEY_TYPE_ECDSA
  32        bool "ECDSA"
  33        select CRYPTO_ECDSA
  34        depends on MODULE_SIG || (IMA_APPRAISE_MODSIG && MODULES)
  35        help
  36         Use an elliptic curve key (NIST P384) for module signing. Consider
  37         using a strong hash like sha256 or sha384 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        help
  49          Provide a system keyring to which trusted keys can be added.  Keys in
  50          the keyring are considered to be trusted.  Keys may be added at will
  51          by the kernel from compiled-in data and from hardware key stores, but
  52          userspace may only add extra keys if those keys can be verified by
  53          keys already in the keyring.
  54
  55          Keys in this keyring are used by module signature checking.
  56
  57config SYSTEM_TRUSTED_KEYS
  58        string "Additional X.509 keys for default system keyring"
  59        depends on SYSTEM_TRUSTED_KEYRING
  60        help
  61          If set, this option should be the filename of a PEM-formatted file
  62          containing trusted X.509 certificates to be included in the default
  63          system keyring. Any certificate used for module signing is implicitly
  64          also trusted.
  65
  66          NOTE: If you previously provided keys for the system keyring in the
  67          form of DER-encoded *.x509 files in the top-level build directory,
  68          those are no longer used. You will need to set this option instead.
  69
  70config SYSTEM_EXTRA_CERTIFICATE
  71        bool "Reserve area for inserting a certificate without recompiling"
  72        depends on SYSTEM_TRUSTED_KEYRING
  73        help
  74          If set, space for an extra certificate will be reserved in the kernel
  75          image. This allows introducing a trusted certificate to the default
  76          system keyring without recompiling the kernel.
  77
  78config SYSTEM_EXTRA_CERTIFICATE_SIZE
  79        int "Number of bytes to reserve for the extra certificate"
  80        depends on SYSTEM_EXTRA_CERTIFICATE
  81        default 4096
  82        help
  83          This is the number of bytes reserved in the kernel image for a
  84          certificate to be inserted.
  85
  86config SECONDARY_TRUSTED_KEYRING
  87        bool "Provide a keyring to which extra trustable keys may be added"
  88        depends on SYSTEM_TRUSTED_KEYRING
  89        help
  90          If set, provide a keyring to which extra keys may be added, provided
  91          those keys are not blacklisted and are vouched for by a key built
  92          into the kernel or already in the secondary trusted keyring.
  93
  94config SYSTEM_BLACKLIST_KEYRING
  95        bool "Provide system-wide ring of blacklisted keys"
  96        depends on KEYS
  97        help
  98          Provide a system keyring to which blacklisted keys can be added.
  99          Keys in the keyring are considered entirely untrusted.  Keys in this
 100          keyring are used by the module signature checking to reject loading
 101          of modules signed with a blacklisted key.
 102
 103config SYSTEM_BLACKLIST_HASH_LIST
 104        string "Hashes to be preloaded into the system blacklist keyring"
 105        depends on SYSTEM_BLACKLIST_KEYRING
 106        help
 107          If set, this option should be the filename of a list of hashes in the
 108          form "<hash>", "<hash>", ... .  This will be included into a C
 109          wrapper to incorporate the list into the kernel.  Each <hash> should
 110          be a string of hex digits.
 111
 112config SYSTEM_REVOCATION_LIST
 113        bool "Provide system-wide ring of revocation certificates"
 114        depends on SYSTEM_BLACKLIST_KEYRING
 115        depends on PKCS7_MESSAGE_PARSER=y
 116        help
 117          If set, this allows revocation certificates to be stored in the
 118          blacklist keyring and implements a hook whereby a PKCS#7 message can
 119          be checked to see if it matches such a certificate.
 120
 121config SYSTEM_REVOCATION_KEYS
 122        string "X.509 certificates to be preloaded into the system blacklist keyring"
 123        depends on SYSTEM_REVOCATION_LIST
 124        help
 125          If set, this option should be the filename of a PEM-formatted file
 126          containing X.509 certificates to be included in the default blacklist
 127          keyring.
 128
 129endmenu
 130