diff options
Diffstat (limited to 'src/libstrongswan/plugins/pgp/pgp_utils.c')
| -rw-r--r-- | src/libstrongswan/plugins/pgp/pgp_utils.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/src/libstrongswan/plugins/pgp/pgp_utils.c b/src/libstrongswan/plugins/pgp/pgp_utils.c new file mode 100644 index 000000000..1658f3232 --- /dev/null +++ b/src/libstrongswan/plugins/pgp/pgp_utils.c @@ -0,0 +1,180 @@ +/* + * Copyright (C) 2009 Martin Willi + * Hochschule fuer Technik Rapperswil + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + */ + +#include "pgp_utils.h" + +#include <debug.h> + +ENUM_BEGIN(pgp_pubkey_alg_names, PGP_PUBKEY_ALG_RSA, PGP_PUBKEY_ALG_RSA_SIGN_ONLY, + "RSA", + "RSA_ENC_ONLY", + "RSA_SIGN_ONLY" +); +ENUM_NEXT(pgp_pubkey_alg_names, PGP_PUBKEY_ALG_ELGAMAL_ENC_ONLY, PGP_PUBKEY_ALG_DIFFIE_HELLMAN, PGP_PUBKEY_ALG_RSA_SIGN_ONLY, + "ELGAMAL_ENC_ONLY", + "DSA", + "ECC", + "ECDSA", + "ELGAMAL", + "DIFFIE_HELLMAN" +); +ENUM_END(pgp_pubkey_alg_names, PGP_PUBKEY_ALG_DIFFIE_HELLMAN); + +ENUM(pgp_sym_alg_names, PGP_SYM_ALG_PLAIN, PGP_SYM_ALG_TWOFISH, + "PLAINTEXT", + "IDEA", + "3DES", + "CAST5", + "BLOWFISH", + "SAFER", + "DES", + "AES_128", + "AES_192", + "AES_256", + "TWOFISH" +); + +ENUM_BEGIN(pgp_packet_tag_names, PGP_PKT_RESERVED, PGP_PKT_PUBLIC_SUBKEY, + "Reserved", + "Public-Key Encrypted Session Key Packet", + "Signature Packet", + "Symmetric-Key Encrypted Session Key Packet", + "One-Pass Signature Packet", + "Secret Key Packet", + "Public Key Packet", + "Secret Subkey Packet", + "Compressed Data Packet", + "Symmetrically Encrypted Data Packet", + "Marker Packet", + "Literal Data Packet", + "Trust Packet", + "User ID Packet", + "Public Subkey Packet" +); +ENUM_NEXT(pgp_packet_tag_names, PGP_PKT_USER_ATTRIBUTE, PGP_PKT_MOD_DETECT_CODE, PGP_PKT_PUBLIC_SUBKEY, + "User Attribute Packet", + "Sym. Encrypted and Integrity Protected Data Packet", + "Modification Detection Code Packet" +); +ENUM_END(pgp_packet_tag_names, PGP_PKT_MOD_DETECT_CODE); + +/** + * Read a PGP scalar of bytes length, advance blob + */ +bool pgp_read_scalar(chunk_t *blob, size_t bytes, u_int32_t *scalar) +{ + u_int32_t res = 0; + + if (bytes > blob->len) + { + DBG1("PGP data too short to read %d byte scalar", bytes); + return FALSE; + } + while (bytes-- > 0) + { + res = 256 * res + blob->ptr[0]; + *blob = chunk_skip(*blob, 1); + } + *scalar = res; + return TRUE; +} + +/** + * Read a PGP MPI, advance blob + */ +bool pgp_read_mpi(chunk_t *blob, chunk_t *mpi) +{ + u_int32_t bits, bytes; + + if (!pgp_read_scalar(blob, 2, &bits)) + { + DBG1("PGP data too short to read MPI length"); + return FALSE; + } + bytes = (bits + 7) / 8; + if (bytes > blob->len) + { + DBG1("PGP data too short to read %d byte MPI", bytes); + return FALSE; + } + *mpi = chunk_create(blob->ptr, bytes); + *blob = chunk_skip(*blob, bytes); + return TRUE; +} + +/** + * Read length of an PGP old packet length encoding + */ +static bool pgp_old_packet_length(chunk_t *blob, u_int32_t *length) +{ + /* bits 0 and 1 define the packet length type */ + u_char type; + + if (!blob->len) + { + return FALSE; + } + type = 0x03 & blob->ptr[0]; + *blob = chunk_skip(*blob, 1); + + if (type > 2) + { + return FALSE; + } + return pgp_read_scalar(blob, type == 0 ? 1 : type * 2, length); +} + +/** + * See header. + */ +bool pgp_read_packet(chunk_t *blob, chunk_t *data, pgp_packet_tag_t *tag) +{ + u_int32_t len; + u_char t; + + if (!blob->len) + { + DBG1("missing input"); + return FALSE; + } + t = blob->ptr[0]; + + /* bit 7 must be set */ + if (!(t & 0x80)) + { + DBG1("invalid packet tag"); + return FALSE; + } + /* bit 6 set defines new packet format */ + if (t & 0x40) + { + DBG1("new PGP packet format not supported"); + return FALSE; + } + + t = (t & 0x3C) >> 2; + if (!pgp_old_packet_length(blob, &len) || len > blob->len) + { + DBG1("invalid packet length"); + return FALSE; + } + *data = chunk_create(blob->ptr, len); + *blob = chunk_skip(*blob, len); + *tag = t; + DBG2("L1 - PGP %N (%u bytes)", pgp_packet_tag_names, t, len); + DBG3("%B", data); + return TRUE; +} + |