Moved generic PGP parsing functions to pgp_utils.[ch]

src/libstrongswan/plugins/pgp/Makefile.am

@@ -6,6 +6,7 @@ AM_CFLAGS = -rdynamic
 plugin_LTLIBRARIES = libstrongswan-pgp.la
 
 libstrongswan_pgp_la_SOURCES = pgp_plugin.h pgp_plugin.c \
+  pgp_utils.h pgp_utils.c \
   pgp_encoder.h pgp_encoder.c \
   pgp_builder.h pgp_builder.c
 

src/libstrongswan/plugins/pgp/pgp_builder.c

@@ -15,141 +15,12 @@
  */
 
 #include "pgp_builder.h"
+#include "pgp_utils.h"
 
 #include <enum.h>
 #include <debug.h>
 #include <credentials/keys/private_key.h>
 
-typedef enum pgp_pubkey_alg_t pgp_pubkey_alg_t;
-typedef enum pgp_sym_alg_t pgp_sym_alg_t;
-
-/**
- * OpenPGP public key algorithms as defined in section 9.1 of RFC 4880
- */
-enum pgp_pubkey_alg_t {
-	PGP_PUBKEY_ALG_RSA              =  1,
-	PGP_PUBKEY_ALG_RSA_ENC_ONLY     =  2,
-	PGP_PUBKEY_ALG_RSA_SIGN_ONLY    =  3,
-	PGP_PUBKEY_ALG_ELGAMAL_ENC_ONLY = 16,
-	PGP_PUBKEY_ALG_DSA              = 17,
-	PGP_PUBKEY_ALG_ECC              = 18,
-	PGP_PUBKEY_ALG_ECDSA            = 19,
-	PGP_PUBKEY_ALG_ELGAMAL          = 20,
-	PGP_PUBKEY_ALG_DIFFIE_HELLMAN   = 21,
-};
-
-/**
- * OpenPGP symmetric key algorithms as defined in section 9.2 of RFC 4880
- */
-enum pgp_sym_alg_t {
-	PGP_SYM_ALG_PLAIN    =  0,
-	PGP_SYM_ALG_IDEA     =  1,
-	PGP_SYM_ALG_3DES     =  2,
-	PGP_SYM_ALG_CAST5    =  3,
-	PGP_SYM_ALG_BLOWFISH =  4,
-	PGP_SYM_ALG_SAFER    =  5,
-	PGP_SYM_ALG_DES      =  6,
-	PGP_SYM_ALG_AES_128  =  7,
-	PGP_SYM_ALG_AES_192  =  8,
-	PGP_SYM_ALG_AES_256  =  9,
-	PGP_SYM_ALG_TWOFISH  = 10
-};
-
-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"
-);
-
-/**
- * Read a PGP scalar of bytes length, advance blob
- */
-static bool 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 length of an PGP old packet length encoding
- */
-static bool 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 read_scalar(blob, type == 0 ? 1 : type * 2, length);
-}
-
-/**
- * Read a PGP MPI, advance blob
- */
-static bool read_mpi(chunk_t *blob, chunk_t *mpi)
-{
-	u_int32_t bits, bytes;
-
-	if (!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;
-}
-
 /**
  * Load a generic public key from a PGP packet
  */
@@ -158,7 +29,7 @@ static public_key_t *parse_public_key(chunk_t blob)
 	u_int32_t alg;
 	public_key_t *key;
 
-	if (!read_scalar(&blob, 1, &alg))
+	if (!pgp_read_scalar(&blob, 1, &alg))
 	{
 		return NULL;
 	}
@@ -187,7 +58,7 @@ static public_key_t *parse_rsa_public_key(chunk_t blob)
 
 	for (i = 0; i < 2; i++)
 	{
-		if (!read_mpi(&blob, &mpi[i]))
+		if (!pgp_read_mpi(&blob, &mpi[i]))
 		{
 			return NULL;
 		}
@@ -208,12 +79,12 @@ static private_key_t *parse_rsa_private_key(chunk_t blob)
 
 	for (i = 0; i < 2; i++)
 	{
-		if (!read_mpi(&blob, &mpi[i]))
+		if (!pgp_read_mpi(&blob, &mpi[i]))
 		{
 			return NULL;
 		}
 	}
-	if (!read_scalar(&blob, 1, &s2k))
+	if (!pgp_read_scalar(&blob, 1, &s2k))
 	{
 		return NULL;
 	}
@@ -230,7 +101,7 @@ static private_key_t *parse_rsa_private_key(chunk_t blob)
 
 	for (i = 2; i < 6; i++)
 	{
-		if (!read_mpi(&blob, &mpi[i]))
+		if (!pgp_read_mpi(&blob, &mpi[i]))
 		{
 			return NULL;
 		}
@@ -270,56 +141,37 @@ static bool decrypt_not_allowed(private_key_t *this,
 static private_key_t *parse_private_key(chunk_t blob)
 {
 	chunk_t packet;
-	u_char tag, type;
+	pgp_packet_tag_t tag;
-	u_int32_t len, version, created, days, alg;
+	u_int32_t version, created, days, alg;
 	private_key_t *key;
 
-	tag = blob.ptr[0];
+	if (!pgp_read_packet(&blob, &packet, &tag))
-
-	/* bit 7 must be set */
-	if (!(tag & 0x80))
-	{
-		DBG1("invalid packet tag");
-		return NULL;
-	}
-	/* bit 6 set defines new packet format */
-	if (tag & 0x40)
-	{
-		DBG1("new PGP packet format not supported");
-		return NULL;
-	}
-
-	type = (tag & 0x3C) >> 2;
-	if (!old_packet_length(&blob, &len) || len > blob.len)
-	{
-		DBG1("invalid packet length");
-		return NULL;
-	}
-	packet.len = len;
-	packet.ptr = blob.ptr;
-	blob = chunk_skip(blob, len);
-
-	if (!read_scalar(&packet, 1, &version))
 	{
 		return NULL;
 	}
-	if (version < 3 || version > 4)
+	if (!pgp_read_scalar(&packet, 1, &version))
 	{
-		DBG1("OpenPGP packet version V%d not supported", version);
+		return FALSE;
-		return NULL;
 	}
-	if (!read_scalar(&packet, 4, &created))
+	switch (version)
+	{
+		case 3:
+			if (!pgp_read_scalar(&packet, 2, &days))
+			{
+				return NULL;
+			}
+			break;
+		case 4:
+			break;
+		default:
+			DBG1("PGP packet version V%d not supported", version);
+			return FALSE;
+	}
+	if (!pgp_read_scalar(&packet, 4, &created))
 	{
 		return NULL;
 	}
-	if (version == 3)
+	if (!pgp_read_scalar(&packet, 1, &alg))
-	{
-		if (!read_scalar(&packet, 2, &days))
-		{
-			return NULL;
-		}
-	}
-	if (!read_scalar(&packet, 1, &alg))
 	{
 		return NULL;
 	}

src/libstrongswan/plugins/pgp/pgp_utils.c

@@ -0,0 +1,178 @@
+/*
+ * 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;
+	return TRUE;
+}
+

src/libstrongswan/plugins/pgp/pgp_utils.h

@@ -0,0 +1,130 @@
+/*
+ * 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.
+ */
+
+/**
+ * @defgroup pgp_utils pgp_utils
+ * @{ @ingroup pgp
+ */
+
+#ifndef PGP_UTILS_H_
+#define PGP_UTILS_H_
+
+#include <library.h>
+
+typedef enum pgp_pubkey_alg_t pgp_pubkey_alg_t;
+typedef enum pgp_sym_alg_t pgp_sym_alg_t;
+typedef enum pgp_packet_tag_t pgp_packet_tag_t;
+
+/**
+ * OpenPGP public key algorithms as defined in section 9.1 of RFC 4880
+ */
+enum pgp_pubkey_alg_t {
+	PGP_PUBKEY_ALG_RSA              =  1,
+	PGP_PUBKEY_ALG_RSA_ENC_ONLY     =  2,
+	PGP_PUBKEY_ALG_RSA_SIGN_ONLY    =  3,
+	PGP_PUBKEY_ALG_ELGAMAL_ENC_ONLY = 16,
+	PGP_PUBKEY_ALG_DSA              = 17,
+	PGP_PUBKEY_ALG_ECC              = 18,
+	PGP_PUBKEY_ALG_ECDSA            = 19,
+	PGP_PUBKEY_ALG_ELGAMAL          = 20,
+	PGP_PUBKEY_ALG_DIFFIE_HELLMAN   = 21,
+};
+
+/**
+ * Enum names of pgp_pubkey_alg_t
+ */
+extern enum_name_t *pgp_pubkey_alg_names;
+
+/**
+ * OpenPGP symmetric key algorithms as defined in section 9.2 of RFC 4880
+ */
+enum pgp_sym_alg_t {
+	PGP_SYM_ALG_PLAIN    =  0,
+	PGP_SYM_ALG_IDEA     =  1,
+	PGP_SYM_ALG_3DES     =  2,
+	PGP_SYM_ALG_CAST5    =  3,
+	PGP_SYM_ALG_BLOWFISH =  4,
+	PGP_SYM_ALG_SAFER    =  5,
+	PGP_SYM_ALG_DES      =  6,
+	PGP_SYM_ALG_AES_128  =  7,
+	PGP_SYM_ALG_AES_192  =  8,
+	PGP_SYM_ALG_AES_256  =  9,
+	PGP_SYM_ALG_TWOFISH  = 10
+};
+
+/**
+ * Enum names of pgp_sym_alg_t
+ */
+extern enum_name_t *pgp_sym_alg_names;
+
+/**
+ * OpenPGP packet tags as defined in section 4.3 of RFC 4880
+ */
+enum pgp_packet_tag_t {
+	PGP_PKT_RESERVED               =  0,
+	PGP_PKT_PUBKEY_ENC_SESSION_KEY =  1,
+	PGP_PKT_SIGNATURE              =  2,
+	PGP_PKT_SYMKEY_ENC_SESSION_KEY =  3,
+	PGP_PKT_ONE_PASS_SIGNATURE_PKT =  4,
+	PGP_PKT_SECRET_KEY             =  5,
+	PGP_PKT_PUBLIC_KEY             =  6,
+	PGP_PKT_SECRET_SUBKEY          =  7,
+	PGP_PKT_COMPRESSED_DATA        =  8,
+	PGP_PKT_SYMKEY_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_INT_PROT_DATA  = 18,
+	PGP_PKT_MOD_DETECT_CODE        = 19
+};
+
+/**
+ * Enum names of pgp_packet_tag_t
+ */
+extern enum_name_t *pgp_packet_tag_names;
+
+/**
+ * Parse a PGP encoded MPI.
+ *
+ * @param blob		blob to read from, gets advanced
+ * @param mpi		parsed MPI value
+ * @return			TRUE if MPI parsed successfully
+ */
+bool pgp_read_mpi(chunk_t *blob, chunk_t *mpi);
+
+/**
+ * Parse a PGP encoded Scalar.
+ *
+ * @param blob		blob to read from, gets advanced
+ * @param bytes		number of bytes the scalar uses for encoding
+ * @param scalar	resultin scalar
+ * @return			TRUE if scalar parsed successfully
+ */
+bool pgp_read_scalar(chunk_t *blob, size_t bytes, u_int32_t *scalar);
+
+/**
+ * Parse a PGP packet.
+ *
+ * @param blob		blob to read from, gets advanced
+ * @param data		contained packet data
+ * @param tag		tag of the parsed PGP packet
+ * @return			TRUE if packet parsed successfully
+ */
+bool pgp_read_packet(chunk_t *blob, chunk_t *data, pgp_packet_tag_t *tag);
+
+#endif /* PGP_UTILS_ @}*/