Re: [PATCH v3 03/14] PGPLIB: PGP definitions (RFC 9580)

["Jarkko Sakkinen" <jarkko@kernel.org>]

On Wed Sep 11, 2024 at 3:29 PM EEST, Roberto Sassu wrote:
> From: David Howells <dhowells@redhat.com>
>
> Provide some useful PGP definitions from RFC 9580.  These describe details
> of public key crypto as used by crypto keys for things like signature
> verification.
>
> Signed-off-by: David Howells <dhowells@redhat.com>
> Co-developed-by: Roberto Sassu <roberto.sassu@huawei.com>
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
>  crypto/asymmetric_keys/pgp.h | 216 +++++++++++++++++++++++++++++++++++
>  1 file changed, 216 insertions(+)
>  create mode 100644 crypto/asymmetric_keys/pgp.h
>
> diff --git a/crypto/asymmetric_keys/pgp.h b/crypto/asymmetric_keys/pgp.h
> new file mode 100644
> index 000000000000..eaf0ab8e0373
> --- /dev/null
> +++ b/crypto/asymmetric_keys/pgp.h
> @@ -0,0 +1,216 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* PGP definitions (RFC 9580)
> + *
> + * Copyright (C) 2011 Red Hat, Inc. All Rights Reserved.
> + * Written by David Howells (dhowells@redhat.com)
> + */
> +
> +#include <linux/types.h>
> +
> +struct pgp_key_ID {
> +	u8 id[8];
> +} __packed;
> +
> +struct pgp_time {
> +	u8 time[4];
> +} __packed;
> +
> +/*
> + * PGP public-key algorithm identifiers [RFC 9580: 9.1]

Nicely done documentation, which is rare, i.e. tells what the thing is
and gives an easy to access reference. 0x1F44D for that.

> + */
> +enum pgp_pubkey_algo {
> +	PGP_PUBKEY_RSA_ENC_OR_SIG	= 1,
> +	PGP_PUBKEY_RSA_ENC_ONLY		= 2,
> +	PGP_PUBKEY_RSA_SIG_ONLY		= 3,
> +	PGP_PUBKEY_ELGAMAL		= 16,
> +	PGP_PUBKEY_DSA			= 17,
> +	PGP_PUBKEY_ECDH			= 18,
> +	PGP_PUBKEY_ECDSA		= 19,
> +	PGP_PUBKEY_EDDSA_LEGACY		= 22,
> +	PGP_PUBKEY_X25519		= 25,
> +	PGP_PUBKEY_X448			= 26,
> +	PGP_PUBKEY_ED25519		= 27,
> +	PGP_PUBKEY_ED448		= 28,
> +	PGP_PUBKEY__LAST
> +};
> +
> +/*
> + * PGP symmetric-key algorithm identifiers [RFC 9580: 9.3]
> + */
> +enum pgp_symkey_algo {
> +	PGP_SYMKEY_PLAINTEXT		= 0,
> +	PGP_SYMKEY_IDEA			= 1,
> +	PGP_SYMKEY_3DES			= 2,
> +	PGP_SYMKEY_CAST5		= 3,
> +	PGP_SYMKEY_BLOWFISH		= 4,
> +	PGP_SYMKEY_AES_128KEY		= 7,
> +	PGP_SYMKEY_AES_192KEY		= 8,
> +	PGP_SYMKEY_AES_256KEY		= 9,
> +	PGP_SYMKEY_TWOFISH_256KEY	= 10,
> +	PGP_SYMKEY_CAMELIA_128KEY	= 11,
> +	PGP_SYMKEY_CAMELIA_192KEY	= 12,
> +	PGP_SYMKEY_CAMELIA_256KEY	= 13,
> +	PGP_SYMKEY__LAST
> +};
> +
> +/*
> + * PGP compression algorithm identifiers [RFC 9580: 9.4]
> + */
> +enum pgp_compr_algo {
> +	PGP_COMPR_UNCOMPRESSED		= 0,
> +	PGP_COMPR_ZIP			= 1,
> +	PGP_COMPR_ZLIB			= 2,
> +	PGP_COMPR_BZIP2			= 3,
> +	PGP_COMPR__LAST
> +};
> +
> +/*
> + * PGP hash algorithm identifiers [RFC 9580: 9.4]
> + */
> +enum pgp_hash_algo {
> +	PGP_HASH_MD5			= 1,
> +	PGP_HASH_SHA1			= 2,
> +	PGP_HASH_RIPE_MD_160		= 3,
> +	PGP_HASH_SHA256			= 8,
> +	PGP_HASH_SHA384			= 9,
> +	PGP_HASH_SHA512			= 10,
> +	PGP_HASH_SHA224			= 11,
> +	PGP_HASH_SHA3_256		= 12,
> +	PGP_HASH_SHA3_512		= 14,
> +	PGP_HASH__LAST
> +};
> +

/*
 * doc
 */
> +extern const char *const pgp_hash_algorithms[PGP_HASH__LAST];
> +
> +/*
> + * PGP packet type tags [RFC 9580: 5].
> + */
> +enum pgp_packet_tag {
> +	PGP_PKT_RESERVED		= 0,
> +	PGP_PKT_PUBKEY_ENC_SESSION_KEY	= 1,
> +	PGP_PKT_SIGNATURE		= 2,
> +	PGP_PKT_SYMKEY_ENC_SESSION_KEY	= 3,
> +	PGP_PKT_ONEPASS_SIGNATURE	= 4,
> +	PGP_PKT_SECRET_KEY		= 5,
> +	PGP_PKT_PUBLIC_KEY		= 6,
> +	PGP_PKT_SECRET_SUBKEY		= 7,
> +	PGP_PKT_COMPRESSED_DATA		= 8,
> +	PGP_PKT_SYM_ENC_DATA		= 9,
> +	PGP_PKT_MARKER			= 10,
> +	PGP_PKT_LITERAL_DATA		= 11,
> +	PGP_PKT_TRUST			= 12,
> +	PGP_PKT_USER_ID			= 13,
> +	PGP_PKT_PUBLIC_SUBKEY		= 14,
> +	PGP_PKT_USER_ATTRIBUTE		= 17,
> +	PGP_PKT_SYM_ENC_AND_INTEG_DATA	= 18,
> +	PGP_PKT_MODIFY_DETECT_CODE	= 19,
> +	PGP_PKT_PRIVATE_0		= 60,
> +	PGP_PKT_PRIVATE_3		= 63,
> +	PGP_PKT__HIGHEST		= 63
> +};
> +
> +/*
> + * Signature (tag 2) packet [RFC 9580: 5.2].
> + */
> +enum pgp_signature_version {
> +	PGP_SIG_VERSION_3			= 3,
> +	PGP_SIG_VERSION_4			= 4,
> +};
> +
> +/*
> + * Signature types [RFC 9580: 5.2.1].
> + */
> +enum pgp_signature_type {
> +	PGP_SIG_BINARY_DOCUMENT_SIG		= 0x00,
> +	PGP_SIG_CANONICAL_TEXT_DOCUMENT_SIG	= 0x01,
> +	PGP_SIG_STANDALONE_SIG			= 0x02,
> +	PGP_SIG_GENERAL_CERT_OF_UID_PUBKEY	= 0x10,
> +	PGP_SIG_PERSONAL_CERT_OF_UID_PUBKEY	= 0x11,
> +	PGP_SIG_CASUAL_CERT_OF_UID_PUBKEY	= 0x12,
> +	PGP_SIG_POSTITIVE_CERT_OF_UID_PUBKEY	= 0x13,
> +	PGP_SIG_SUBKEY_BINDING_SIG		= 0x18,
> +	PGP_SIG_PRIMARY_KEY_BINDING_SIG		= 0x19,
> +	PGP_SIG_DIRECTLY_ON_KEY			= 0x1F,
> +	PGP_SIG_KEY_REVOCATION_SIG		= 0x20,
> +	PGP_SIG_SUBKEY_REVOCATION_SIG		= 0x28,
> +	PGP_SIG_CERT_REVOCATION_SIG		= 0x30,
> +	PGP_SIG_TIMESTAMP_SIG			= 0x40,
> +	PGP_SIG_THIRD_PARTY_CONFIRM_SIG		= 0x50,
> +};
> +

/*
 * doc
 */
> +struct pgp_signature_v3_packet {
> +	enum pgp_signature_version version : 8; /* == PGP_SIG_VERSION_3 */
> +	u8	length_of_hashed;	/* == 5 */
> +	struct {
> +		enum pgp_signature_type signature_type : 8;
> +		struct pgp_time	creation_time;
> +	} __packed hashed;
> +	struct pgp_key_ID issuer;
> +	enum pgp_pubkey_algo pubkey_algo : 8;
> +	enum pgp_hash_algo hash_algo : 8;
> +} __packed;
> +

/*
 * doc
 */
> +struct pgp_signature_v4_packet {
> +	enum pgp_signature_version version : 8;	/* == PGP_SIG_VERSION_4 */
> +	enum pgp_signature_type signature_type : 8;
> +	enum pgp_pubkey_algo pubkey_algo : 8;
> +	enum pgp_hash_algo hash_algo : 8;
> +} __packed;
> +
> +/*
> + * V4 signature subpacket types [RFC 9580: 5.2.3.7].
> + */
> +enum pgp_sig_subpkt_type {
> +	PGP_SIG_CREATION_TIME			= 2,
> +	PGP_SIG_EXPIRATION_TIME			= 3,
> +	PGP_SIG_EXPORTABLE_CERT			= 4,
> +	PGP_SIG_TRUST_SIG			= 5,
> +	PGP_SIG_REGEXP				= 6,
> +	PGP_SIG_REVOCABLE			= 7,
> +	PGP_SIG_KEY_EXPIRATION_TIME		= 9,
> +	PGP_SIG_PREF_SYM_ALGO			= 11,
> +	PGP_SIG_REVOCATION_KEY			= 12,
> +	PGP_SIG_ISSUER				= 16,
> +	PGP_SIG_NOTATION_DATA			= 20,
> +	PGP_SIG_PREF_HASH_ALGO			= 21,
> +	PGP_SIG_PREF_COMPR_ALGO			= 22,
> +	PGP_SIG_KEY_SERVER_PREFS		= 23,
> +	PGP_SIG_PREF_KEY_SERVER			= 24,
> +	PGP_SIG_PRIMARY_USER_ID			= 25,
> +	PGP_SIG_POLICY_URI			= 26,
> +	PGP_SIG_KEY_FLAGS			= 27,
> +	PGP_SIG_SIGNERS_USER_ID			= 28,
> +	PGP_SIG_REASON_FOR_REVOCATION		= 29,
> +	PGP_SIG_FEATURES			= 30,
> +	PGP_SIG_TARGET				= 31,
> +	PGP_SIG_EMBEDDED_SIG			= 32,
> +	PGP_SIG_ISSUER_FINGERPRINT		= 33,
> +	PGP_SIG_INTENDED_RECIPIENT_FINGERPRINT	= 35,
> +	PGP_SIG_PREFERRED_AEAD_CIPHERS		= 39,
> +	PGP_SIG__LAST
> +};
> +

/*
 * Documentation what is the critical mask.
 */
> +#define PGP_SIG_SUBPKT_TYPE_CRITICAL_MASK	0x80
> +
> +/*
> + * Key (tag 5, 6, 7 and 14) packet
> + */
> +enum pgp_key_version {
> +	PGP_KEY_VERSION_4			= 4,
> +};
> +

/*
 * doc
 */
> +struct pgp_key_v4_packet {
> +	enum pgp_key_version version : 8;
> +	struct pgp_time	creation_time;
> +	enum pgp_pubkey_algo pubkey_algo : 8;
> +	u8 key_material[];
> +} __packed;
> +
> +/*
> + * Literal Data (tag 11) packet
> + */
> +enum pgp_literal_data_format {
> +	PGP_LIT_FORMAT_BINARY			= 0x62,
> +	PGP_LIT_FORMAT_TEXT			= 0x74,
> +	PGP_LIT_FORMAT_TEXT_UTF8		= 0x75,
> +};


BR, Jarkko