gnupg/g10/packet.h

/* packet.h - OpenPGP packet definitions
 * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
 *               2007 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * GnuPG 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 3 of the License, or
 * (at your option) any later version.
 *
 * GnuPG 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#ifndef G10_PACKET_H
#define G10_PACKET_H

#include "types.h"
#include "../common/iobuf.h"
#include "../common/strlist.h"
#include "dek.h"
#include "filter.h"
#include "../common/openpgpdefs.h"
#include "../common/userids.h"

#define DEBUG_PARSE_PACKET 1


/* Constants to allocate static MPI arrays. */
#define PUBKEY_MAX_NPKEY  5
#define PUBKEY_MAX_NSKEY  7
#define PUBKEY_MAX_NSIG   2
#define PUBKEY_MAX_NENC   2

/* Usage flags */
#define PUBKEY_USAGE_SIG     GCRY_PK_USAGE_SIGN  /* Good for signatures. */
#define PUBKEY_USAGE_ENC     GCRY_PK_USAGE_ENCR  /* Good for encryption. */
#define PUBKEY_USAGE_CERT    GCRY_PK_USAGE_CERT  /* Also good to certify keys.*/
#define PUBKEY_USAGE_AUTH    GCRY_PK_USAGE_AUTH  /* Good for authentication. */
#define PUBKEY_USAGE_UNKNOWN GCRY_PK_USAGE_UNKN  /* Unknown usage flag. */
#define PUBKEY_USAGE_NONE    256                 /* No usage given. */
#if  (GCRY_PK_USAGE_SIGN | GCRY_PK_USAGE_ENCR | GCRY_PK_USAGE_CERT \
      | GCRY_PK_USAGE_AUTH | GCRY_PK_USAGE_UNKN) >= 256
# error Please choose another value for PUBKEY_USAGE_NONE
#endif

/* Helper macros.  */
#define is_RSA(a)     ((a)==PUBKEY_ALGO_RSA || (a)==PUBKEY_ALGO_RSA_E \
		       || (a)==PUBKEY_ALGO_RSA_S )
#define is_ELGAMAL(a) ((a)==PUBKEY_ALGO_ELGAMAL_E)
#define is_DSA(a)     ((a)==PUBKEY_ALGO_DSA)

/* A pointer to the packet object.  */
typedef struct packet_struct PACKET;

/* PKT_GPG_CONTROL types */
typedef enum {
    CTRLPKT_CLEARSIGN_START = 1,
    CTRLPKT_PIPEMODE = 2,
    CTRLPKT_PLAINTEXT_MARK =3
} ctrlpkttype_t;

typedef enum {
    PREFTYPE_NONE = 0,
    PREFTYPE_SYM = 1,
    PREFTYPE_HASH = 2,
    PREFTYPE_ZIP = 3
} preftype_t;

typedef struct {
    byte type;
    byte value;
} prefitem_t;

typedef struct
{
  int  mode;      /* Must be an integer due to the GNU modes 1001 et al.  */
  byte hash_algo;
  byte salt[8];
  u32  count;
} STRING2KEY;

typedef struct {
    byte version;
    byte cipher_algo;	 /* cipher algorithm used */
    STRING2KEY s2k;
    byte seskeylen;   /* keylength in byte or 0 for no seskey */
    byte seskey[1];
} PKT_symkey_enc;

typedef struct {
    u32     keyid[2];	    /* 64 bit keyid */
    byte    version;
    byte    pubkey_algo;    /* algorithm used for public key scheme */
    byte    throw_keyid;
    gcry_mpi_t     data[PUBKEY_MAX_NENC];
} PKT_pubkey_enc;


typedef struct {
    u32     keyid[2];	    /* 64 bit keyid */
    byte    sig_class;	    /* sig classification */
    byte    digest_algo;    /* algorithm used for digest */
    byte    pubkey_algo;    /* algorithm used for public key scheme */
    byte    last;	    /* a stupid flag */
} PKT_onepass_sig;


typedef struct {
    size_t size;  /* allocated */
    size_t len;   /* used */
    byte data[1];
} subpktarea_t;

struct revocation_key {
  byte class;
  byte algid;
  byte fpr[MAX_FINGERPRINT_LEN];
};


/* Object to keep information about a PKA DNS record. */
typedef struct
{
  int valid;    /* An actual PKA record exists for EMAIL. */
  int checked;  /* Set to true if the FPR has been checked against the
                   actual key. */
  char *uri;    /* Malloced string with the URI. NULL if the URI is
                   not available.*/
  unsigned char fpr[20]; /* The fingerprint as stored in the PKA RR. */
  char email[1];/* The email address from the notation data. */
} pka_info_t;


/* Object to keep information pertaining to a signature. */
typedef struct
{
  struct
  {
    unsigned checked:1;         /* Signature has been checked. */
    unsigned valid:1;           /* Signature is good (if checked is set). */
    unsigned chosen_selfsig:1;  /* A selfsig that is the chosen one. */
    unsigned unknown_critical:1;
    unsigned exportable:1;
    unsigned revocable:1;
    unsigned policy_url:1;  /* At least one policy URL is present */
    unsigned notation:1;    /* At least one notation is present */
    unsigned pref_ks:1;     /* At least one preferred keyserver is present */
    unsigned expired:1;
    unsigned pka_tried:1;   /* Set if we tried to retrieve the PKA record. */
  } flags;
  u32     keyid[2];	  /* 64 bit keyid */
  u32     timestamp;	  /* Signature made (seconds since Epoch). */
  u32     expiredate;     /* Expires at this date or 0 if not at all. */
  byte    version;
  byte    sig_class;	  /* Sig classification, append for MD calculation. */
  byte    pubkey_algo;    /* Algorithm used for public key scheme */
                          /* (PUBKEY_ALGO_xxx) */
  byte    digest_algo;    /* Algorithm used for digest (DIGEST_ALGO_xxxx). */
  byte    trust_depth;
  byte    trust_value;
  const byte *trust_regexp;
  struct revocation_key **revkey;
  int numrevkeys;
  pka_info_t *pka_info;      /* Malloced PKA data or NULL if not
                                available.  See also flags.pka_tried. */
  subpktarea_t *hashed;      /* All subpackets with hashed data (v4 only). */
  subpktarea_t *unhashed;    /* Ditto for unhashed data. */
  byte digest_start[2];      /* First 2 bytes of the digest. */
  gcry_mpi_t  data[PUBKEY_MAX_NSIG];
} PKT_signature;

#define ATTRIB_IMAGE 1

/* This is the cooked form of attributes.  */
struct user_attribute {
  byte type;
  const byte *data;
  u32 len;
};


/* (See also keybox-search-desc.h) */
struct gpg_pkt_user_id_s
{
  int ref;              /* reference counter */
  int len;	        /* length of the name */
  struct user_attribute *attribs;
  int numattribs;
  byte *attrib_data;    /* if this is not NULL, the packet is an attribute */
  unsigned long attrib_len;
  byte *namehash;
  int help_key_usage;
  u32 help_key_expire;
  int help_full_count;
  int help_marginal_count;
  int is_primary;       /* 2 if set via the primary flag, 1 if calculated */
  int is_revoked;
  int is_expired;
  u32 expiredate;       /* expires at this date or 0 if not at all */
  prefitem_t *prefs;    /* list of preferences (may be NULL)*/
  u32 created;          /* according to the self-signature */
  byte selfsigversion;
  struct
  {
    /* TODO: Move more flags here */
    unsigned int mdc:1;
    unsigned int ks_modify:1;
    unsigned int compacted:1;
  } flags;
  char name[1];
};
typedef struct gpg_pkt_user_id_s PKT_user_id;



struct revoke_info
{
  /* revoked at this date */
  u32 date;
  /* the keyid of the revoking key (selfsig or designated revoker) */
  u32 keyid[2];
  /* the algo of the revoking key */
  byte algo;
};


/* Information pertaining to secret keys. */
struct seckey_info
{
  int is_protected:1;	/* The secret info is protected and must */
			/* be decrypted before use, the protected */
			/* MPIs are simply (void*) pointers to memory */
			/* and should never be passed to a mpi_xxx() */
  int sha1chk:1;        /* SHA1 is used instead of a 16 bit checksum */
  u16 csum;		/* Checksum for old protection modes.  */
  byte algo;            /* Cipher used to protect the secret information. */
  STRING2KEY s2k;       /* S2K parameter.  */
  byte ivlen;           /* Used length of the IV.  */
  byte iv[16];          /* Initialization vector for CFB mode.  */
};


/****************
 * We assume that secret keys have the same number of parameters as
 * the public key and that the public parameters are the first items
 * in the PKEY array.  Thus NPKEY is always less than NSKEY and it is
 * possible to compare the secret and public keys by comparing the
 * first NPKEY elements of the PKEY array.  Note that since GnuPG 2.1
 * we don't use secret keys anymore directly because they are managed
 * by gpg-agent.  However for parsing OpenPGP key files we need a way
 * to temporary store those secret keys.  We do this by putting them
 * into the public key structure and extending the PKEY field to NSKEY
 * elements; the extra secret key information are stored in the
 * SECKEY_INFO field.
 */
typedef struct
{
  u32     timestamp;	    /* key made */
  u32     expiredate;     /* expires at this date or 0 if not at all */
  u32     max_expiredate; /* must not expire past this date */
  struct revoke_info revoked;
  byte    hdrbytes;	    /* number of header bytes */
  byte    version;
  byte    selfsigversion; /* highest version of all of the self-sigs */
  byte    pubkey_algo;    /* algorithm used for public key scheme */
  byte    pubkey_usage;   /* for now only used to pass it to getkey() */
  byte    req_usage;      /* hack to pass a request to getkey() */
  byte    req_algo;       /* Ditto */
  u32     has_expired;    /* set to the expiration date if expired */
  u32     main_keyid[2];  /* keyid of the primary key */
  u32     keyid[2];	    /* calculated by keyid_from_pk() */
  prefitem_t *prefs;      /* list of preferences (may be NULL) */
  struct
  {
    unsigned int mdc:1;           /* MDC feature set.  */
    unsigned int disabled_valid:1;/* The next flag is valid.  */
    unsigned int disabled:1;      /* The key has been disabled.  */
    unsigned int primary:1;       /* This is a primary key.  */
    unsigned int revoked:2;       /* Key has been revoked.
                                     1 = revoked by the owner
                                     2 = revoked by designated revoker.  */
    unsigned int maybe_revoked:1; /* A designated revocation is
                                     present, but without the key to
                                     check it.  */
    unsigned int valid:1;         /* Key (especially subkey) is valid.  */
    unsigned int dont_cache:1;    /* Do not cache this key.  */
    unsigned int backsig:2;       /* 0=none, 1=bad, 2=good.  */
    unsigned int serialno_valid:1;/* SERIALNO below is valid.  */
  } flags;
  PKT_user_id *user_id;   /* If != NULL: found by that uid. */
  struct revocation_key *revkey;
  int     numrevkeys;
  u32     trust_timestamp;
  byte    trust_depth;
  byte    trust_value;
  const byte *trust_regexp;
  char    *serialno;      /* Malloced hex string or NULL if it is
                             likely not on a card.  See also
                             flags.serialno_valid.  */
  struct seckey_info *seckey_info;  /* If not NULL this malloced
                                       structure describes a secret
                                       key.  */
  gcry_mpi_t  pkey[PUBKEY_MAX_NSKEY]; /* Right, NSKEY elements.  */
} PKT_public_key;

/* Evaluates as true if the pk is disabled, and false if it isn't.  If
   there is no disable value cached, fill one in. */
#define pk_is_disabled(a)                                       \
  (((a)->flags.disabled_valid)?                                 \
   ((a)->flags.disabled):(cache_disabled_value((a))))


typedef struct {
    int  len;		  /* length of data */
    char data[1];
} PKT_comment;

typedef struct {
    u32  len;		  /* reserved */
    byte  new_ctb;
    byte  algorithm;
    iobuf_t buf;	  /* IOBUF reference */
} PKT_compressed;

typedef struct {
    u32  len;		  /* Remaining length of encrypted data. */
    int  extralen;        /* This is (blocksize+2).  Used by build_packet. */
    byte new_ctb;	  /* uses a new CTB */
    byte is_partial;      /* partial length encoded */
    byte mdc_method;	  /* > 0: integrity protected encrypted data packet */
    iobuf_t buf;	  /* IOBUF reference */
} PKT_encrypted;

typedef struct {
    byte hash[20];
} PKT_mdc;

typedef struct {
    unsigned int trustval;
    unsigned int sigcache;
} PKT_ring_trust;

typedef struct {
    u32  len;		  /* length of encrypted data */
    iobuf_t buf;	  /* IOBUF reference */
    byte new_ctb;
    byte is_partial;      /* partial length encoded */
    int mode;
    u32 timestamp;
    int  namelen;
    char name[1];
} PKT_plaintext;

typedef struct {
    int  control;
    size_t datalen;
    char data[1];
} PKT_gpg_control;

/* combine all packets into a union */
struct packet_struct {
    pkttype_t pkttype;
    union {
	void *generic;
	PKT_symkey_enc	*symkey_enc;	/* PKT_SYMKEY_ENC */
	PKT_pubkey_enc	*pubkey_enc;	/* PKT_PUBKEY_ENC */
	PKT_onepass_sig *onepass_sig;	/* PKT_ONEPASS_SIG */
	PKT_signature	*signature;	/* PKT_SIGNATURE */
	PKT_public_key	*public_key;	/* PKT_PUBLIC_[SUB)KEY */
	PKT_public_key	*secret_key;	/* PKT_SECRET_[SUB]KEY */
	PKT_comment	*comment;	/* PKT_COMMENT */
	PKT_user_id	*user_id;	/* PKT_USER_ID */
	PKT_compressed	*compressed;	/* PKT_COMPRESSED */
	PKT_encrypted	*encrypted;	/* PKT_ENCRYPTED[_MDC] */
	PKT_mdc 	*mdc;		/* PKT_MDC */
	PKT_ring_trust	*ring_trust;	/* PKT_RING_TRUST */
	PKT_plaintext	*plaintext;	/* PKT_PLAINTEXT */
        PKT_gpg_control *gpg_control;   /* PKT_GPG_CONTROL */
    } pkt;
};

#define init_packet(a) do { (a)->pkttype = 0;		\
			    (a)->pkt.generic = NULL;	\
		       } while(0)


struct notation
{
  char *name;
  char *value;
  char *altvalue;
  unsigned char *bdat;
  size_t blen;
  struct
  {
    unsigned int critical:1;
    unsigned int ignore:1;
  } flags;
  struct notation *next;
};

/*-- mainproc.c --*/
void reset_literals_seen(void);
int proc_packets (ctrl_t ctrl, void *ctx, iobuf_t a );
int proc_signature_packets (ctrl_t ctrl, void *ctx, iobuf_t a,
			    strlist_t signedfiles, const char *sigfile );
int proc_signature_packets_by_fd (ctrl_t ctrl,
                                  void *anchor, IOBUF a, int signed_data_fd );
int proc_encryption_packets (ctrl_t ctrl, void *ctx, iobuf_t a);
int list_packets( iobuf_t a );

/*-- parse-packet.c --*/
int set_packet_list_mode( int mode );

#if DEBUG_PARSE_PACKET
int dbg_search_packet( iobuf_t inp, PACKET *pkt, off_t *retpos, int with_uid,
                       const char* file, int lineno  );
int dbg_parse_packet( iobuf_t inp, PACKET *ret_pkt,
                      const char* file, int lineno );
int dbg_copy_all_packets( iobuf_t inp, iobuf_t out,
                          const char* file, int lineno  );
int dbg_copy_some_packets( iobuf_t inp, iobuf_t out, off_t stopoff,
                           const char* file, int lineno  );
int dbg_skip_some_packets( iobuf_t inp, unsigned n,
                           const char* file, int lineno	);
#define search_packet( a,b,c,d )   \
             dbg_search_packet( (a), (b), (c), (d), __FILE__, __LINE__ )
#define parse_packet( a, b )  \
	     dbg_parse_packet( (a), (b), __FILE__, __LINE__ )
#define copy_all_packets( a,b )  \
             dbg_copy_all_packets((a),(b), __FILE__, __LINE__ )
#define copy_some_packets( a,b,c ) \
             dbg_copy_some_packets((a),(b),(c), __FILE__, __LINE__ )
#define skip_some_packets( a,b ) \
             dbg_skip_some_packets((a),(b), __FILE__, __LINE__ )
#else
int search_packet( iobuf_t inp, PACKET *pkt, off_t *retpos, int with_uid );
int parse_packet( iobuf_t inp, PACKET *ret_pkt);
int copy_all_packets( iobuf_t inp, iobuf_t out );
int copy_some_packets( iobuf_t inp, iobuf_t out, off_t stopoff );
int skip_some_packets( iobuf_t inp, unsigned n );
#endif

int parse_signature( iobuf_t inp, int pkttype, unsigned long pktlen,
		     PKT_signature *sig );
const byte *enum_sig_subpkt ( const subpktarea_t *subpkts,
                              sigsubpkttype_t reqtype,
                              size_t *ret_n, int *start, int *critical );
const byte *parse_sig_subpkt ( const subpktarea_t *buffer,
                               sigsubpkttype_t reqtype,
                               size_t *ret_n );
const byte *parse_sig_subpkt2 ( PKT_signature *sig,
                                sigsubpkttype_t reqtype,
                                size_t *ret_n );
int parse_one_sig_subpkt( const byte *buffer, size_t n, int type );
void parse_revkeys(PKT_signature *sig);
int parse_attribute_subpkts(PKT_user_id *uid);
void make_attribute_uidname(PKT_user_id *uid, size_t max_namelen);
PACKET *create_gpg_control ( ctrlpkttype_t type,
                             const byte *data,
                             size_t datalen );

/*-- build-packet.c --*/
int build_packet( iobuf_t inp, PACKET *pkt );
gpg_error_t gpg_mpi_write (iobuf_t out, gcry_mpi_t a);
gpg_error_t gpg_mpi_write_nohdr (iobuf_t out, gcry_mpi_t a);
u32 calc_packet_length( PACKET *pkt );
void build_sig_subpkt( PKT_signature *sig, sigsubpkttype_t type,
			const byte *buffer, size_t buflen );
void build_sig_subpkt_from_sig( PKT_signature *sig );
int  delete_sig_subpkt(subpktarea_t *buffer, sigsubpkttype_t type );
void build_attribute_subpkt(PKT_user_id *uid,byte type,
			    const void *buf,u32 buflen,
			    const void *header,u32 headerlen);
struct notation *string_to_notation(const char *string,int is_utf8);
struct notation *sig_to_notation(PKT_signature *sig);
void free_notation(struct notation *notation);

/*-- free-packet.c --*/
void free_symkey_enc( PKT_symkey_enc *enc );
void free_pubkey_enc( PKT_pubkey_enc *enc );
void free_seckey_enc( PKT_signature *enc );
int  digest_algo_from_sig( PKT_signature *sig );
void release_public_key_parts( PKT_public_key *pk );
void free_public_key( PKT_public_key *key );
void free_attributes(PKT_user_id *uid);
void free_user_id( PKT_user_id *uid );
void free_comment( PKT_comment *rem );
void free_packet( PACKET *pkt );
prefitem_t *copy_prefs (const prefitem_t *prefs);
PKT_public_key *copy_public_key( PKT_public_key *d, PKT_public_key *s );
PKT_signature *copy_signature( PKT_signature *d, PKT_signature *s );
PKT_user_id *scopy_user_id (PKT_user_id *sd );
int cmp_public_keys( PKT_public_key *a, PKT_public_key *b );
int cmp_signatures( PKT_signature *a, PKT_signature *b );
int cmp_user_ids( PKT_user_id *a, PKT_user_id *b );


/*-- sig-check.c --*/
int signature_check( PKT_signature *sig, gcry_md_hd_t digest );
int signature_check2( PKT_signature *sig, gcry_md_hd_t digest, u32 *r_expiredate,
		      int *r_expired, int *r_revoked, PKT_public_key *ret_pk );


/*-- pubkey-enc.c --*/
gpg_error_t get_session_key (PKT_pubkey_enc *k, DEK *dek);
gpg_error_t get_override_session_key (DEK *dek, const char *string);

/*-- compress.c --*/
int handle_compressed (ctrl_t ctrl, void *ctx, PKT_compressed *cd,
		       int (*callback)(iobuf_t, void *), void *passthru );

/*-- encr-data.c --*/
int decrypt_data (ctrl_t ctrl, void *ctx, PKT_encrypted *ed, DEK *dek );

/*-- plaintext.c --*/
int handle_plaintext( PKT_plaintext *pt, md_filter_context_t *mfx,
					int nooutput, int clearsig );
int ask_for_detached_datafile( gcry_md_hd_t md, gcry_md_hd_t md2,
			       const char *inname, int textmode );

/*-- sign.c --*/
int make_keysig_packet( PKT_signature **ret_sig, PKT_public_key *pk,
			PKT_user_id *uid, PKT_public_key *subpk,
			PKT_public_key *pksk, int sigclass, int digest_algo,
			u32 timestamp, u32 duration,
			int (*mksubpkt)(PKT_signature *, void *),
			void *opaque,
                        const char *cache_nonce);
int update_keysig_packet( PKT_signature **ret_sig,
                      PKT_signature *orig_sig,
                      PKT_public_key *pk,
                      PKT_user_id *uid,
                      PKT_public_key *subpk,
                      PKT_public_key *pksk,
                      int (*mksubpkt)(PKT_signature *, void *),
                      void *opaque   );

/*-- keygen.c --*/
PKT_user_id *generate_user_id (kbnode_t keyblock, const char *uidstr);

#endif /*G10_PACKET_H*/