putty/ssh.h

#include <stdio.h>
#include <string.h>

#include "puttymem.h"
#include "tree234.h"
#include "network.h"
#include "int64.h"
#include "misc.h"

struct ssh_channel;
typedef struct ssh_tag *Ssh;

extern int sshfwd_write(struct ssh_channel *c, const void *, int);
extern void sshfwd_write_eof(struct ssh_channel *c);
extern void sshfwd_unclean_close(struct ssh_channel *c, const char *err);
extern void sshfwd_unthrottle(struct ssh_channel *c, int bufsize);
Conf *sshfwd_get_conf(struct ssh_channel *c);
void sshfwd_x11_sharing_handover(struct ssh_channel *c,
                                 void *share_cs, void *share_chan,
                                 const char *peer_addr, int peer_port,
                                 int endian, int protomajor, int protominor,
                                 const void *initial_data, int initial_len);
void sshfwd_x11_is_local(struct ssh_channel *c);

extern Socket ssh_connection_sharing_init(
    const char *host, int port, Conf *conf, Ssh ssh, Plug sshplug,
    void **state);
int ssh_share_test_for_upstream(const char *host, int port, Conf *conf);
void share_got_pkt_from_server(void *ctx, int type,
                               const void *pkt, int pktlen);
void share_activate(void *state, const char *server_verstring);
void sharestate_free(void *state);
int share_ndownstreams(void *state);

void ssh_connshare_log(Ssh ssh, int event, const char *logtext,
                       const char *ds_err, const char *us_err);
unsigned ssh_alloc_sharing_channel(Ssh ssh, void *sharing_ctx);
void ssh_delete_sharing_channel(Ssh ssh, unsigned localid);
int ssh_alloc_sharing_rportfwd(Ssh ssh, const char *shost, int sport,
                               void *share_ctx);
void ssh_remove_sharing_rportfwd(Ssh ssh, const char *shost, int sport,
                                 void *share_ctx);
void ssh_sharing_queue_global_request(Ssh ssh, void *share_ctx);
struct X11FakeAuth *ssh_sharing_add_x11_display(Ssh ssh, int authtype,
                                                void *share_cs,
                                                void *share_chan);
void ssh_sharing_remove_x11_display(Ssh ssh, struct X11FakeAuth *auth);
void ssh_send_packet_from_downstream(Ssh ssh, unsigned id, int type,
                                     const void *pkt, int pktlen,
                                     const char *additional_log_text);
void ssh_sharing_downstream_connected(Ssh ssh, unsigned id,
                                      const char *peerinfo);
void ssh_sharing_downstream_disconnected(Ssh ssh, unsigned id);
void ssh_sharing_logf(Ssh ssh, unsigned id, const char *logfmt, ...);
int ssh_agent_forwarding_permitted(Ssh ssh);
void share_setup_x11_channel(void *csv, void *chanv,
                             unsigned upstream_id, unsigned server_id,
                             unsigned server_currwin, unsigned server_maxpkt,
                             unsigned client_adjusted_window,
                             const char *peer_addr, int peer_port, int endian,
                             int protomajor, int protominor,
                             const void *initial_data, int initial_len);

/*
 * Useful thing.
 */
#ifndef lenof
#define lenof(x) ( (sizeof((x))) / (sizeof(*(x))))
#endif

#define SSH_CIPHER_IDEA		1
#define SSH_CIPHER_DES		2
#define SSH_CIPHER_3DES		3
#define SSH_CIPHER_BLOWFISH	6

#ifndef BIGNUM_INTERNAL
typedef void *Bignum;
#endif

typedef struct ssh_keyalg ssh_keyalg;
typedef const struct ssh_keyalg *ssh_key;

struct RSAKey {
    int bits;
    int bytes;
    Bignum modulus;
    Bignum exponent;
    Bignum private_exponent;
    Bignum p;
    Bignum q;
    Bignum iqmp;
    char *comment;
    ssh_key sshk;
};

struct dss_key {
    Bignum p, q, g, y, x;
    ssh_key sshk;
};

struct ec_curve;

struct ec_point {
    const struct ec_curve *curve;
    Bignum x, y;
    Bignum z;  /* Jacobian denominator */
    unsigned char infinity;
};

void ec_point_free(struct ec_point *point);

/* Weierstrass form curve */
struct ec_wcurve
{
    Bignum a, b, n;
    struct ec_point G;
};

/* Montgomery form curve */
struct ec_mcurve
{
    Bignum a, b;
    struct ec_point G;
};

/* Edwards form curve */
struct ec_ecurve
{
    Bignum l, d;
    struct ec_point B;
};

struct ec_curve {
    enum { EC_WEIERSTRASS, EC_MONTGOMERY, EC_EDWARDS } type;
    /* 'name' is the identifier of the curve when it has to appear in
     * wire protocol encodings, as it does in e.g. the public key and
     * signature formats for NIST curves. Curves which do not format
     * their keys or signatures in this way just have name==NULL.
     *
     * 'textname' is non-NULL for all curves, and is a human-readable
     * identification suitable for putting in log messages. */
    const char *name, *textname;
    unsigned int fieldBits;
    Bignum p;
    union {
        struct ec_wcurve w;
        struct ec_mcurve m;
        struct ec_ecurve e;
    };
};

const ssh_keyalg *ec_alg_by_oid(int len, const void *oid,
                                        const struct ec_curve **curve);
const unsigned char *ec_alg_oid(const ssh_keyalg *alg, int *oidlen);
extern const int ec_nist_curve_lengths[], n_ec_nist_curve_lengths;
int ec_nist_alg_and_curve_by_bits(int bits,
                                  const struct ec_curve **curve,
                                  const ssh_keyalg **alg);
int ec_ed_alg_and_curve_by_bits(int bits,
                                const struct ec_curve **curve,
                                const ssh_keyalg **alg);

struct ec_key {
    struct ec_point publicKey;
    Bignum privateKey;
    ssh_key sshk;
};

struct ec_point *ec_public(const Bignum privateKey, const struct ec_curve *curve);

/*
 * SSH-1 never quite decided which order to store the two components
 * of an RSA key. During connection setup, the server sends its host
 * and server keys with the exponent first; private key files store
 * the modulus first. The agent protocol is even more confusing,
 * because the client specifies a key to the server in one order and
 * the server lists the keys it knows about in the other order!
 */
typedef enum { RSA_SSH1_EXPONENT_FIRST, RSA_SSH1_MODULUS_FIRST } RsaSsh1Order;

void BinarySource_get_rsa_ssh1_pub(
    BinarySource *src, struct RSAKey *result, RsaSsh1Order order);
void BinarySource_get_rsa_ssh1_priv(
    BinarySource *src, struct RSAKey *rsa);
int rsa_ssh1_encrypt(unsigned char *data, int length, struct RSAKey *key);
Bignum rsa_ssh1_decrypt(Bignum input, struct RSAKey *key);
void rsasanitise(struct RSAKey *key);
int rsastr_len(struct RSAKey *key);
void rsastr_fmt(char *str, struct RSAKey *key);
char *rsa_ssh1_fingerprint(struct RSAKey *key);
int rsa_verify(struct RSAKey *key);
void rsa_ssh1_public_blob(BinarySink *bs, struct RSAKey *key,
                          RsaSsh1Order order);
int rsa_ssh1_public_blob_len(void *data, int maxlen);
void freersakey(struct RSAKey *key);

typedef uint32 word32;

unsigned long crc32_compute(const void *s, size_t len);
unsigned long crc32_update(unsigned long crc_input, const void *s, size_t len);

/* SSH CRC compensation attack detector */
void *crcda_make_context(void);
void crcda_free_context(void *handle);
int detect_attack(void *handle, unsigned char *buf, uint32 len,
		  unsigned char *IV);

/*
 * SSH2 RSA key exchange functions
 */
struct ssh_hash;
struct RSAKey *ssh_rsakex_newkey(const void *data, int len);
void ssh_rsakex_freekey(struct RSAKey *key);
int ssh_rsakex_klen(struct RSAKey *key);
void ssh_rsakex_encrypt(const struct ssh_hash *h, unsigned char *in, int inlen,
                        unsigned char *out, int outlen, struct RSAKey *key);

/*
 * SSH2 ECDH key exchange functions
 */
struct ssh_kex;
const char *ssh_ecdhkex_curve_textname(const struct ssh_kex *kex);
struct ec_key *ssh_ecdhkex_newkey(const struct ssh_kex *kex);
void ssh_ecdhkex_freekey(struct ec_key *key);
void ssh_ecdhkex_getpublic(struct ec_key *key, BinarySink *bs);
Bignum ssh_ecdhkex_getkey(struct ec_key *key,
                          const void *remoteKey, int remoteKeyLen);

/*
 * Helper function for k generation in DSA, reused in ECDSA
 */
Bignum *dss_gen_k(const char *id_string, Bignum modulus, Bignum private_key,
                  unsigned char *digest, int digest_len);

typedef struct {
    uint32 h[4];
} MD5_Core_State;

struct MD5Context {
    MD5_Core_State core;
    unsigned char block[64];
    int blkused;
    uint32 lenhi, lenlo;
    BinarySink_IMPLEMENTATION;
};

void MD5Init(struct MD5Context *context);
void MD5Final(unsigned char digest[16], struct MD5Context *context);
void MD5Simple(void const *p, unsigned len, unsigned char output[16]);

void *hmacmd5_make_context(void *);
void hmacmd5_free_context(void *handle);
void hmacmd5_key(void *handle, void const *key, int len);
void hmacmd5_do_hmac(void *handle, unsigned char const *blk, int len,
		     unsigned char *hmac);

int supports_sha_ni(void);

typedef struct SHA_State {
    uint32 h[5];
    unsigned char block[64];
    int blkused;
    uint32 lenhi, lenlo;
    void (*sha1)(struct SHA_State * s, const unsigned char *p, int len);
    BinarySink_IMPLEMENTATION;
} SHA_State;
void SHA_Init(SHA_State * s);
void SHA_Final(SHA_State * s, unsigned char *output);
void SHA_Simple(const void *p, int len, unsigned char *output);

void hmac_sha1_simple(void *key, int keylen, void *data, int datalen,
		      unsigned char *output);
typedef struct SHA256_State {
    uint32 h[8];
    unsigned char block[64];
    int blkused;
    uint32 lenhi, lenlo;
    void (*sha256)(struct SHA256_State * s, const unsigned char *p, int len);
    BinarySink_IMPLEMENTATION;
} SHA256_State;
void SHA256_Init(SHA256_State * s);
void SHA256_Final(SHA256_State * s, unsigned char *output);
void SHA256_Simple(const void *p, int len, unsigned char *output);

typedef struct {
    uint64 h[8];
    unsigned char block[128];
    int blkused;
    uint32 len[4];
    BinarySink_IMPLEMENTATION;
} SHA512_State;
#define SHA384_State SHA512_State
void SHA512_Init(SHA512_State * s);
void SHA512_Final(SHA512_State * s, unsigned char *output);
void SHA512_Simple(const void *p, int len, unsigned char *output);
void SHA384_Init(SHA384_State * s);
void SHA384_Final(SHA384_State * s, unsigned char *output);
void SHA384_Simple(const void *p, int len, unsigned char *output);

struct ssh_mac;
struct ssh_cipher {
    void *(*make_context)(void);
    void (*free_context)(void *);
    void (*sesskey) (void *, const void *key);	/* for SSH-1 */
    void (*encrypt) (void *, void *blk, int len);
    void (*decrypt) (void *, void *blk, int len);
    int blksize;
    const char *text_name;
};

struct ssh2_cipher {
    void *(*make_context)(void);
    void (*free_context)(void *);
    void (*setiv) (void *, const void *iv);	/* for SSH-2 */
    void (*setkey) (void *, const void *key);/* for SSH-2 */
    void (*encrypt) (void *, void *blk, int len);
    void (*decrypt) (void *, void *blk, int len);
    /* Ignored unless SSH_CIPHER_SEPARATE_LENGTH flag set */
    void (*encrypt_length) (void *, void *blk, int len, unsigned long seq);
    void (*decrypt_length) (void *, void *blk, int len, unsigned long seq);
    const char *name;
    int blksize;
    /* real_keybits is the number of bits of entropy genuinely used by
     * the cipher scheme; it's used for deciding how big a
     * Diffie-Hellman group is needed to exchange a key for the
     * cipher. */
    int real_keybits;
    /* padded_keybytes is the number of bytes of key data expected as
     * input to the setkey function; it's used for deciding how much
     * data needs to be generated from the post-kex generation of key
     * material. In a sensible cipher which uses all its key bytes for
     * real work, this will just be real_keybits/8, but in DES-type
     * ciphers which ignore one bit in each byte, it'll be slightly
     * different. */
    int padded_keybytes;
    unsigned int flags;
#define SSH_CIPHER_IS_CBC	1
#define SSH_CIPHER_SEPARATE_LENGTH      2
    const char *text_name;
    /* If set, this takes priority over other MAC. */
    const struct ssh_mac *required_mac;
};

struct ssh2_ciphers {
    int nciphers;
    const struct ssh2_cipher *const *list;
};

struct ssh_mac {
    /* Passes in the cipher context */
    void *(*make_context)(void *);
    void (*free_context)(void *);
    void (*setkey) (void *, const void *key);
    /* whole-packet operations */
    void (*generate) (void *, void *blk, int len, unsigned long seq);
    int (*verify) (void *, const void *blk, int len, unsigned long seq);
    /* partial-packet operations */
    void (*start) (void *);
    BinarySink *(*sink) (void *);
    void (*genresult) (void *, unsigned char *);
    int (*verresult) (void *, unsigned char const *);
    const char *name, *etm_name;
    int len, keylen;
    const char *text_name;
};

struct ssh_hash {
    void *(*init)(void); /* also allocates context */
    void *(*copy)(const void *);
    BinarySink *(*sink) (void *);
    void (*final)(void *, unsigned char *); /* also frees context */
    void (*free)(void *);
    int hlen; /* output length in bytes */
    const char *text_name;
};   

struct ssh_kex {
    const char *name, *groupname;
    enum { KEXTYPE_DH, KEXTYPE_RSA, KEXTYPE_ECDH, KEXTYPE_GSS } main_type;
    const struct ssh_hash *hash;
    const void *extra;                 /* private to the kex methods */
};

struct ssh_kexes {
    int nkexes;
    const struct ssh_kex *const *list;
};

struct ssh_keyalg {
    /* Constructors that create an ssh_key */
    ssh_key *(*new_pub) (const ssh_keyalg *self, ptrlen pub);
    ssh_key *(*new_priv) (const ssh_keyalg *self, ptrlen pub, ptrlen priv);
    ssh_key *(*new_priv_openssh) (const ssh_keyalg *self, BinarySource *);

    /* Methods that operate on an existing ssh_key */
    void (*freekey) (ssh_key *key);
    void (*sign) (ssh_key *key, const void *data, int datalen, BinarySink *);
    int (*verify) (ssh_key *key, ptrlen sig, ptrlen data);
    void (*public_blob)(ssh_key *key, BinarySink *);
    void (*private_blob)(ssh_key *key, BinarySink *);
    void (*openssh_blob) (ssh_key *key, BinarySink *);
    char *(*cache_str) (ssh_key *key);

    /* 'Class methods' that don't deal with an ssh_key at all */
    int (*pubkey_bits) (const ssh_keyalg *self, ptrlen blob);

    /* Constant data fields giving information about the key type */
    const char *ssh_id;    /* string identifier in the SSH protocol */
    const char *cache_id;  /* identifier used in PuTTY's host key cache */
    const void *extra;     /* private to the public key methods */
};

#define ssh_key_new_pub(alg, data) ((alg)->new_pub(alg, data))
#define ssh_key_new_priv(alg, pub, priv) ((alg)->new_priv(alg, pub, priv))
#define ssh_key_new_priv_openssh(alg, bs) ((alg)->new_priv_openssh(alg, bs))

#define ssh_key_free(key) ((*(key))->freekey(key))
#define ssh_key_sign(key, data, len, bs) ((*(key))->sign(key, data, len, bs))
#define ssh_key_verify(key, sig, data) ((*(key))->verify(key, sig, data))
#define ssh_key_public_blob(key, bs) ((*(key))->public_blob(key, bs))
#define ssh_key_private_blob(key, bs) ((*(key))->private_blob(key, bs))
#define ssh_key_openssh_blob(key, bs) ((*(key))->openssh_blob(key, bs))
#define ssh_key_cache_str(key) ((*(key))->cache_str(key))

#define ssh_key_public_bits(alg, blob) ((alg)->pubkey_bits(alg, blob))

#define ssh_key_alg(key) (*(key))
#define ssh_key_ssh_id(key) ((*(key))->ssh_id)
#define ssh_key_cache_id(key) ((*(key))->cache_id)

struct ssh_compress {
    const char *name;
    /* For zlib@openssh.com: if non-NULL, this name will be considered once
     * userauth has completed successfully. */
    const char *delayed_name;
    void *(*compress_init) (void);
    void (*compress_cleanup) (void *);
    int (*compress) (void *, unsigned char *block, int len,
		     unsigned char **outblock, int *outlen);
    void *(*decompress_init) (void);
    void (*decompress_cleanup) (void *);
    int (*decompress) (void *, unsigned char *block, int len,
		       unsigned char **outblock, int *outlen);
    int (*disable_compression) (void *);
    const char *text_name;
};

struct ssh2_userkey {
    ssh_key *key;                      /* the key itself */
    char *comment;		       /* the key comment */
};

/* The maximum length of any hash algorithm used in kex. (bytes) */
#define SSH2_KEX_MAX_HASH_LEN (64) /* SHA-512 */

extern const struct ssh_cipher ssh_3des;
extern const struct ssh_cipher ssh_des;
extern const struct ssh_cipher ssh_blowfish_ssh1;
extern const struct ssh2_ciphers ssh2_3des;
extern const struct ssh2_ciphers ssh2_des;
extern const struct ssh2_ciphers ssh2_aes;
extern const struct ssh2_ciphers ssh2_blowfish;
extern const struct ssh2_ciphers ssh2_arcfour;
extern const struct ssh2_ciphers ssh2_ccp;
extern const struct ssh_hash ssh_sha1;
extern const struct ssh_hash ssh_sha256;
extern const struct ssh_hash ssh_sha384;
extern const struct ssh_hash ssh_sha512;
extern const struct ssh_kexes ssh_diffiehellman_group1;
extern const struct ssh_kexes ssh_diffiehellman_group14;
extern const struct ssh_kexes ssh_diffiehellman_gex;
extern const struct ssh_kexes ssh_gssk5_sha1_kex;
extern const struct ssh_kexes ssh_rsa_kex;
extern const struct ssh_kexes ssh_ecdh_kex;
extern const ssh_keyalg ssh_dss;
extern const ssh_keyalg ssh_rsa;
extern const ssh_keyalg ssh_ecdsa_ed25519;
extern const ssh_keyalg ssh_ecdsa_nistp256;
extern const ssh_keyalg ssh_ecdsa_nistp384;
extern const ssh_keyalg ssh_ecdsa_nistp521;
extern const struct ssh_mac ssh_hmac_md5;
extern const struct ssh_mac ssh_hmac_sha1;
extern const struct ssh_mac ssh_hmac_sha1_buggy;
extern const struct ssh_mac ssh_hmac_sha1_96;
extern const struct ssh_mac ssh_hmac_sha1_96_buggy;
extern const struct ssh_mac ssh_hmac_sha256;

void *aes_make_context(void);
void aes_free_context(void *handle);
void aes128_key(void *handle, const void *key);
void aes192_key(void *handle, const void *key);
void aes256_key(void *handle, const void *key);
void aes_iv(void *handle, const void *iv);
void aes_ssh2_encrypt_blk(void *handle, void *blk, int len);
void aes_ssh2_decrypt_blk(void *handle, void *blk, int len);
void aes_ssh2_sdctr(void *handle, void *blk, int len);

/*
 * PuTTY version number formatted as an SSH version string. 
 */
extern const char sshver[];

/*
 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
 * that fails. This variable is the means by which scp.c can reach
 * into the SSH code and find out which one it got.
 */
extern int ssh_fallback_cmd(void *handle);

void SHATransform(word32 * digest, word32 * data);

/*
 * Check of compiler version
 */
#ifdef _FORCE_SHA_NI
#   define COMPILER_SUPPORTS_SHA_NI
#elif defined(__clang__)
#   if __has_attribute(target) && __has_include(<shaintrin.h>) && (defined(__x86_64__) || defined(__i386))
#       define COMPILER_SUPPORTS_SHA_NI
#   endif
#elif defined(__GNUC__)
#    if ((__GNUC__ >= 5) && (defined(__x86_64__) || defined(__i386)))
#       define COMPILER_SUPPORTS_SHA_NI
#    endif
#elif defined (_MSC_VER)
#   if (defined(_M_X64) || defined(_M_IX86)) && _MSC_VER >= 1900
#      define COMPILER_SUPPORTS_SHA_NI
#   endif
#endif

#ifdef _FORCE_SOFTWARE_SHA
#   undef COMPILER_SUPPORTS_SHA_NI
#endif

int random_byte(void);
void random_add_noise(void *noise, int length);
void random_add_heavynoise(void *noise, int length);

void logevent(void *, const char *);

struct PortForwarding;

/* Allocate and register a new channel for port forwarding */
void *new_sock_channel(void *handle, struct PortForwarding *pf);
void ssh_send_port_open(void *channel, const char *hostname, int port,
                        const char *org);

/* Exports from portfwd.c */
extern char *pfd_connect(struct PortForwarding **pf, char *hostname, int port,
                         void *c, Conf *conf, int addressfamily);
extern void pfd_close(struct PortForwarding *);
extern int pfd_send(struct PortForwarding *, const void *data, int len);
extern void pfd_send_eof(struct PortForwarding *);
extern void pfd_confirm(struct PortForwarding *);
extern void pfd_unthrottle(struct PortForwarding *);
extern void pfd_override_throttle(struct PortForwarding *, int enable);
struct PortListener;
/* desthost == NULL indicates dynamic (SOCKS) port forwarding */
extern char *pfl_listen(char *desthost, int destport, char *srcaddr,
                        int port, void *backhandle, Conf *conf,
                        struct PortListener **pl, int address_family);
extern void pfl_terminate(struct PortListener *);

/* Exports from x11fwd.c */
enum {
    X11_TRANS_IPV4 = 0, X11_TRANS_IPV6 = 6, X11_TRANS_UNIX = 256
};
struct X11Display {
    /* Broken-down components of the display name itself */
    int unixdomain;
    char *hostname;
    int displaynum;
    int screennum;
    /* OSX sometimes replaces all the above with a full Unix-socket pathname */
    char *unixsocketpath;

    /* PuTTY networking SockAddr to connect to the display, and associated
     * gubbins */
    SockAddr addr;
    int port;
    char *realhost;

    /* Our local auth details for talking to the real X display. */
    int localauthproto;
    unsigned char *localauthdata;
    int localauthdatalen;
};
struct X11FakeAuth {
    /* Auth details we invented for a virtual display on the SSH server. */
    int proto;
    unsigned char *data;
    int datalen;
    char *protoname;
    char *datastring;

    /* The encrypted form of the first block, in XDM-AUTHORIZATION-1.
     * Used as part of the key when these structures are organised
     * into a tree. See x11_invent_fake_auth for explanation. */
    unsigned char *xa1_firstblock;

    /*
     * Used inside x11fwd.c to remember recently seen
     * XDM-AUTHORIZATION-1 strings, to avoid replay attacks.
     */
    tree234 *xdmseen;

    /*
     * What to do with an X connection matching this auth data.
     */
    struct X11Display *disp;
    void *share_cs, *share_chan;
};
void *x11_make_greeting(int endian, int protomajor, int protominor,
                        int auth_proto, const void *auth_data, int auth_len,
                        const char *peer_ip, int peer_port,
                        int *outlen);
int x11_authcmp(void *av, void *bv); /* for putting X11FakeAuth in a tree234 */
/*
 * x11_setup_display() parses the display variable and fills in an
 * X11Display structure. Some remote auth details are invented;
 * the supplied authtype parameter configures the preferred
 * authorisation protocol to use at the remote end. The local auth
 * details are looked up by calling platform_get_x11_auth.
 */
extern struct X11Display *x11_setup_display(const char *display, Conf *);
void x11_free_display(struct X11Display *disp);
struct X11FakeAuth *x11_invent_fake_auth(tree234 *t, int authtype);
void x11_free_fake_auth(struct X11FakeAuth *auth);
struct X11Connection;                  /* opaque outside x11fwd.c */
struct X11Connection *x11_init(tree234 *authtree, void *, const char *, int);
extern void x11_close(struct X11Connection *);
extern int x11_send(struct X11Connection *, const void *, int);
extern void x11_send_eof(struct X11Connection *s);
extern void x11_unthrottle(struct X11Connection *s);
extern void x11_override_throttle(struct X11Connection *s, int enable);
char *x11_display(const char *display);
/* Platform-dependent X11 functions */
extern void platform_get_x11_auth(struct X11Display *display, Conf *);
    /* examine a mostly-filled-in X11Display and fill in localauth* */
extern const int platform_uses_x11_unix_by_default;
    /* choose default X transport in the absence of a specified one */
SockAddr platform_get_x11_unix_address(const char *path, int displaynum);
    /* make up a SockAddr naming the address for displaynum */
char *platform_get_x_display(void);
    /* allocated local X display string, if any */
/* Callbacks in x11.c usable _by_ platform X11 functions */
/*
 * This function does the job of platform_get_x11_auth, provided
 * it is told where to find a normally formatted .Xauthority file:
 * it opens that file, parses it to find an auth record which
 * matches the display details in "display", and fills in the
 * localauth fields.
 *
 * It is expected that most implementations of
 * platform_get_x11_auth() will work by finding their system's
 * .Xauthority file, adjusting the display details if necessary
 * for local oddities like Unix-domain socket transport, and
 * calling this function to do the rest of the work.
 */
void x11_get_auth_from_authfile(struct X11Display *display,
				const char *authfilename);
int x11_identify_auth_proto(ptrlen protoname);
void *x11_dehexify(ptrlen hex, int *outlen);

Bignum copybn(Bignum b);
Bignum bn_power_2(int n);
void bn_restore_invariant(Bignum b);
Bignum bignum_from_long(unsigned long n);
void freebn(Bignum b);
Bignum modpow(Bignum base, Bignum exp, Bignum mod);
Bignum modmul(Bignum a, Bignum b, Bignum mod);
Bignum modsub(const Bignum a, const Bignum b, const Bignum n);
void decbn(Bignum n);
extern Bignum Zero, One;
Bignum bignum_from_bytes(const void *data, int nbytes);
Bignum bignum_from_bytes_le(const void *data, int nbytes);
Bignum bignum_random_in_range(const Bignum lower, const Bignum upper);
int bignum_bitcount(Bignum bn);
int bignum_byte(Bignum bn, int i);
int bignum_bit(Bignum bn, int i);
void bignum_set_bit(Bignum bn, int i, int value);
Bignum biggcd(Bignum a, Bignum b);
unsigned short bignum_mod_short(Bignum number, unsigned short modulus);
Bignum bignum_add_long(Bignum number, unsigned long addend);
Bignum bigadd(Bignum a, Bignum b);
Bignum bigsub(Bignum a, Bignum b);
Bignum bigmul(Bignum a, Bignum b);
Bignum bigmuladd(Bignum a, Bignum b, Bignum addend);
Bignum bigdiv(Bignum a, Bignum b);
Bignum bigmod(Bignum a, Bignum b);
Bignum modinv(Bignum number, Bignum modulus);
Bignum bignum_bitmask(Bignum number);
Bignum bignum_rshift(Bignum number, int shift);
Bignum bignum_lshift(Bignum number, int shift);
int bignum_cmp(Bignum a, Bignum b);
char *bignum_decimal(Bignum x);
Bignum bignum_from_decimal(const char *decimal);

void BinarySink_put_mp_ssh1(BinarySink *, Bignum);
void BinarySink_put_mp_ssh2(BinarySink *, Bignum);
Bignum BinarySource_get_mp_ssh1(BinarySource *);
Bignum BinarySource_get_mp_ssh2(BinarySource *);

#ifdef DEBUG
void diagbn(char *prefix, Bignum md);
#endif

int dh_is_gex(const struct ssh_kex *kex);
void *dh_setup_group(const struct ssh_kex *kex);
void *dh_setup_gex(Bignum pval, Bignum gval);
void dh_cleanup(void *);
Bignum dh_create_e(void *, int nbits);
const char *dh_validate_f(void *handle, Bignum f);
Bignum dh_find_K(void *, Bignum f);

int rsa_ssh1_encrypted(const Filename *filename, char **comment);
int rsa_ssh1_loadpub(const Filename *filename, BinarySink *bs,
                     char **commentptr, const char **errorstr);
int rsa_ssh1_loadkey(const Filename *filename, struct RSAKey *key,
                     const char *passphrase, const char **errorstr);
int rsa_ssh1_savekey(const Filename *filename, struct RSAKey *key,
                     char *passphrase);

extern int base64_decode_atom(const char *atom, unsigned char *out);
extern int base64_lines(int datalen);
extern void base64_encode_atom(const unsigned char *data, int n, char *out);
extern void base64_encode(FILE *fp, const unsigned char *data, int datalen,
                          int cpl);

/* ssh2_load_userkey can return this as an error */
extern struct ssh2_userkey ssh2_wrong_passphrase;
#define SSH2_WRONG_PASSPHRASE (&ssh2_wrong_passphrase)

int ssh2_userkey_encrypted(const Filename *filename, char **comment);
struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
				       const char *passphrase,
                                       const char **errorstr);
int ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
                         BinarySink *bs,
                         char **commentptr, const char **errorstr);
int ssh2_save_userkey(const Filename *filename, struct ssh2_userkey *key,
		      char *passphrase);
const ssh_keyalg *find_pubkey_alg(const char *name);
const ssh_keyalg *find_pubkey_alg_len(ptrlen name);

enum {
    SSH_KEYTYPE_UNOPENABLE,
    SSH_KEYTYPE_UNKNOWN,
    SSH_KEYTYPE_SSH1, SSH_KEYTYPE_SSH2,
    /*
     * The OpenSSH key types deserve a little explanation. OpenSSH has
     * two physical formats for private key storage: an old PEM-based
     * one largely dictated by their use of OpenSSL and full of ASN.1,
     * and a new one using the same private key formats used over the
     * wire for talking to ssh-agent. The old format can only support
     * a subset of the key types, because it needs redesign for each
     * key type, and after a while they decided to move to the new
     * format so as not to have to do that.
     *
     * On input, key files are identified as either
     * SSH_KEYTYPE_OPENSSH_PEM or SSH_KEYTYPE_OPENSSH_NEW, describing
     * accurately which actual format the keys are stored in.
     *
     * On output, however, we default to following OpenSSH's own
     * policy of writing out PEM-style keys for maximum backwards
     * compatibility if the key type supports it, and otherwise
     * switching to the new format. So the formats you can select for
     * output are SSH_KEYTYPE_OPENSSH_NEW (forcing the new format for
     * any key type), and SSH_KEYTYPE_OPENSSH_AUTO to use the oldest
     * format supported by whatever key type you're writing out.
     *
     * So we have three type codes, but only two of them usable in any
     * given circumstance. An input key file will never be identified
     * as AUTO, only PEM or NEW; key export UIs should not be able to
     * select PEM, only AUTO or NEW.
     */
    SSH_KEYTYPE_OPENSSH_AUTO,
    SSH_KEYTYPE_OPENSSH_PEM,
    SSH_KEYTYPE_OPENSSH_NEW,
    SSH_KEYTYPE_SSHCOM,
    /*
     * Public-key-only formats, which we still want to be able to read
     * for various purposes.
     */
    SSH_KEYTYPE_SSH1_PUBLIC,
    SSH_KEYTYPE_SSH2_PUBLIC_RFC4716,
    SSH_KEYTYPE_SSH2_PUBLIC_OPENSSH
};
char *ssh1_pubkey_str(struct RSAKey *ssh1key);
void ssh1_write_pubkey(FILE *fp, struct RSAKey *ssh1key);
char *ssh2_pubkey_openssh_str(struct ssh2_userkey *key);
void ssh2_write_pubkey(FILE *fp, const char *comment,
                       const void *v_pub_blob, int pub_len,
                       int keytype);
char *ssh2_fingerprint_blob(const void *blob, int bloblen);
char *ssh2_fingerprint(ssh_key *key);
int key_type(const Filename *filename);
const char *key_type_to_str(int type);

int import_possible(int type);
int import_target_type(int type);
int import_encrypted(const Filename *filename, int type, char **comment);
int import_ssh1(const Filename *filename, int type,
		struct RSAKey *key, char *passphrase, const char **errmsg_p);
struct ssh2_userkey *import_ssh2(const Filename *filename, int type,
				 char *passphrase, const char **errmsg_p);
int export_ssh1(const Filename *filename, int type,
		struct RSAKey *key, char *passphrase);
int export_ssh2(const Filename *filename, int type,
                struct ssh2_userkey *key, char *passphrase);

void des3_decrypt_pubkey(const void *key, void *blk, int len);
void des3_encrypt_pubkey(const void *key, void *blk, int len);
void des3_decrypt_pubkey_ossh(const void *key, const void *iv,
			      void *blk, int len);
void des3_encrypt_pubkey_ossh(const void *key, const void *iv,
			      void *blk, int len);
void aes256_encrypt_pubkey(const void *key, void *blk, int len);
void aes256_decrypt_pubkey(const void *key, void *blk, int len);

void des_encrypt_xdmauth(const void *key, void *blk, int len);
void des_decrypt_xdmauth(const void *key, void *blk, int len);

void openssh_bcrypt(const char *passphrase,
                    const unsigned char *salt, int saltbytes,
                    int rounds, unsigned char *out, int outbytes);

/*
 * For progress updates in the key generation utility.
 */
#define PROGFN_INITIALISE 1
#define PROGFN_LIN_PHASE 2
#define PROGFN_EXP_PHASE 3
#define PROGFN_PHASE_EXTENT 4
#define PROGFN_READY 5
#define PROGFN_PROGRESS 6
typedef void (*progfn_t) (void *param, int action, int phase, int progress);

int rsa_generate(struct RSAKey *key, int bits, progfn_t pfn,
		 void *pfnparam);
int dsa_generate(struct dss_key *key, int bits, progfn_t pfn,
		 void *pfnparam);
int ec_generate(struct ec_key *key, int bits, progfn_t pfn,
                void *pfnparam);
int ec_edgenerate(struct ec_key *key, int bits, progfn_t pfn,
                  void *pfnparam);
Bignum primegen(int bits, int modulus, int residue, Bignum factor,
		int phase, progfn_t pfn, void *pfnparam, unsigned firstbits);
void invent_firstbits(unsigned *one, unsigned *two);


/*
 * zlib compression.
 */
void *zlib_compress_init(void);
void zlib_compress_cleanup(void *);
void *zlib_decompress_init(void);
void zlib_decompress_cleanup(void *);
int zlib_compress_block(void *, unsigned char *block, int len,
			unsigned char **outblock, int *outlen);
int zlib_decompress_block(void *, unsigned char *block, int len,
			  unsigned char **outblock, int *outlen);

/*
 * Connection-sharing API provided by platforms. This function must
 * either:
 *  - return SHARE_NONE and do nothing
 *  - return SHARE_DOWNSTREAM and set *sock to a Socket connected to
 *    downplug
 *  - return SHARE_UPSTREAM and set *sock to a Socket connected to
 *    upplug.
 */
enum { SHARE_NONE, SHARE_DOWNSTREAM, SHARE_UPSTREAM };
int platform_ssh_share(const char *name, Conf *conf,
                       Plug downplug, Plug upplug, Socket *sock,
                       char **logtext, char **ds_err, char **us_err,
                       int can_upstream, int can_downstream);
void platform_ssh_share_cleanup(const char *name);

/*
 * SSH-1 message type codes.
 */
#define SSH1_MSG_DISCONNECT                       1	/* 0x1 */
#define SSH1_SMSG_PUBLIC_KEY                      2	/* 0x2 */
#define SSH1_CMSG_SESSION_KEY                     3	/* 0x3 */
#define SSH1_CMSG_USER                            4	/* 0x4 */
#define SSH1_CMSG_AUTH_RSA                        6	/* 0x6 */
#define SSH1_SMSG_AUTH_RSA_CHALLENGE              7	/* 0x7 */
#define SSH1_CMSG_AUTH_RSA_RESPONSE               8	/* 0x8 */
#define SSH1_CMSG_AUTH_PASSWORD                   9	/* 0x9 */
#define SSH1_CMSG_REQUEST_PTY                     10	/* 0xa */
#define SSH1_CMSG_WINDOW_SIZE                     11	/* 0xb */
#define SSH1_CMSG_EXEC_SHELL                      12	/* 0xc */
#define SSH1_CMSG_EXEC_CMD                        13	/* 0xd */
#define SSH1_SMSG_SUCCESS                         14	/* 0xe */
#define SSH1_SMSG_FAILURE                         15	/* 0xf */
#define SSH1_CMSG_STDIN_DATA                      16	/* 0x10 */
#define SSH1_SMSG_STDOUT_DATA                     17	/* 0x11 */
#define SSH1_SMSG_STDERR_DATA                     18	/* 0x12 */
#define SSH1_CMSG_EOF                             19	/* 0x13 */
#define SSH1_SMSG_EXIT_STATUS                     20	/* 0x14 */
#define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION        21	/* 0x15 */
#define SSH1_MSG_CHANNEL_OPEN_FAILURE             22	/* 0x16 */
#define SSH1_MSG_CHANNEL_DATA                     23	/* 0x17 */
#define SSH1_MSG_CHANNEL_CLOSE                    24	/* 0x18 */
#define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION       25	/* 0x19 */
#define SSH1_SMSG_X11_OPEN                        27	/* 0x1b */
#define SSH1_CMSG_PORT_FORWARD_REQUEST            28	/* 0x1c */
#define SSH1_MSG_PORT_OPEN                        29	/* 0x1d */
#define SSH1_CMSG_AGENT_REQUEST_FORWARDING        30	/* 0x1e */
#define SSH1_SMSG_AGENT_OPEN                      31	/* 0x1f */
#define SSH1_MSG_IGNORE                           32	/* 0x20 */
#define SSH1_CMSG_EXIT_CONFIRMATION               33	/* 0x21 */
#define SSH1_CMSG_X11_REQUEST_FORWARDING          34	/* 0x22 */
#define SSH1_CMSG_AUTH_RHOSTS_RSA                 35	/* 0x23 */
#define SSH1_MSG_DEBUG                            36	/* 0x24 */
#define SSH1_CMSG_REQUEST_COMPRESSION             37	/* 0x25 */
#define SSH1_CMSG_AUTH_TIS                        39	/* 0x27 */
#define SSH1_SMSG_AUTH_TIS_CHALLENGE              40	/* 0x28 */
#define SSH1_CMSG_AUTH_TIS_RESPONSE               41	/* 0x29 */
#define SSH1_CMSG_AUTH_CCARD                      70	/* 0x46 */
#define SSH1_SMSG_AUTH_CCARD_CHALLENGE            71	/* 0x47 */
#define SSH1_CMSG_AUTH_CCARD_RESPONSE             72	/* 0x48 */

#define SSH1_AUTH_RHOSTS                          1	/* 0x1 */
#define SSH1_AUTH_RSA                             2	/* 0x2 */
#define SSH1_AUTH_PASSWORD                        3	/* 0x3 */
#define SSH1_AUTH_RHOSTS_RSA                      4	/* 0x4 */
#define SSH1_AUTH_TIS                             5	/* 0x5 */
#define SSH1_AUTH_CCARD                           16	/* 0x10 */

#define SSH1_PROTOFLAG_SCREEN_NUMBER              1	/* 0x1 */
/* Mask for protoflags we will echo back to server if seen */
#define SSH1_PROTOFLAGS_SUPPORTED                 0	/* 0x1 */

/*
 * SSH-2 message type codes.
 */
#define SSH2_MSG_DISCONNECT                       1	/* 0x1 */
#define SSH2_MSG_IGNORE                           2	/* 0x2 */
#define SSH2_MSG_UNIMPLEMENTED                    3	/* 0x3 */
#define SSH2_MSG_DEBUG                            4	/* 0x4 */
#define SSH2_MSG_SERVICE_REQUEST                  5	/* 0x5 */
#define SSH2_MSG_SERVICE_ACCEPT                   6	/* 0x6 */
#define SSH2_MSG_KEXINIT                          20	/* 0x14 */
#define SSH2_MSG_NEWKEYS                          21	/* 0x15 */
#define SSH2_MSG_KEXDH_INIT                       30	/* 0x1e */
#define SSH2_MSG_KEXDH_REPLY                      31	/* 0x1f */
#define SSH2_MSG_KEX_DH_GEX_REQUEST_OLD           30	/* 0x1e */
#define SSH2_MSG_KEX_DH_GEX_REQUEST               34	/* 0x22 */
#define SSH2_MSG_KEX_DH_GEX_GROUP                 31	/* 0x1f */
#define SSH2_MSG_KEX_DH_GEX_INIT                  32	/* 0x20 */
#define SSH2_MSG_KEX_DH_GEX_REPLY                 33	/* 0x21 */
#define SSH2_MSG_KEXGSS_INIT                      30	/* 0x1e */
#define SSH2_MSG_KEXGSS_CONTINUE                  31	/* 0x1f */
#define SSH2_MSG_KEXGSS_COMPLETE                  32	/* 0x20 */
#define SSH2_MSG_KEXGSS_HOSTKEY                   33	/* 0x21 */
#define SSH2_MSG_KEXGSS_ERROR                     34	/* 0x22 */
#define SSH2_MSG_KEXGSS_GROUPREQ                  40	/* 0x28 */
#define SSH2_MSG_KEXGSS_GROUP                     41	/* 0x29 */
#define SSH2_MSG_KEXRSA_PUBKEY                    30    /* 0x1e */
#define SSH2_MSG_KEXRSA_SECRET                    31    /* 0x1f */
#define SSH2_MSG_KEXRSA_DONE                      32    /* 0x20 */
#define SSH2_MSG_KEX_ECDH_INIT                    30    /* 0x1e */
#define SSH2_MSG_KEX_ECDH_REPLY                   31    /* 0x1f */
#define SSH2_MSG_KEX_ECMQV_INIT                   30    /* 0x1e */
#define SSH2_MSG_KEX_ECMQV_REPLY                  31    /* 0x1f */
#define SSH2_MSG_USERAUTH_REQUEST                 50	/* 0x32 */
#define SSH2_MSG_USERAUTH_FAILURE                 51	/* 0x33 */
#define SSH2_MSG_USERAUTH_SUCCESS                 52	/* 0x34 */
#define SSH2_MSG_USERAUTH_BANNER                  53	/* 0x35 */
#define SSH2_MSG_USERAUTH_PK_OK                   60	/* 0x3c */
#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ        60	/* 0x3c */
#define SSH2_MSG_USERAUTH_INFO_REQUEST            60	/* 0x3c */
#define SSH2_MSG_USERAUTH_INFO_RESPONSE           61	/* 0x3d */
#define SSH2_MSG_GLOBAL_REQUEST                   80	/* 0x50 */
#define SSH2_MSG_REQUEST_SUCCESS                  81	/* 0x51 */
#define SSH2_MSG_REQUEST_FAILURE                  82	/* 0x52 */
#define SSH2_MSG_CHANNEL_OPEN                     90	/* 0x5a */
#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION        91	/* 0x5b */
#define SSH2_MSG_CHANNEL_OPEN_FAILURE             92	/* 0x5c */
#define SSH2_MSG_CHANNEL_WINDOW_ADJUST            93	/* 0x5d */
#define SSH2_MSG_CHANNEL_DATA                     94	/* 0x5e */
#define SSH2_MSG_CHANNEL_EXTENDED_DATA            95	/* 0x5f */
#define SSH2_MSG_CHANNEL_EOF                      96	/* 0x60 */
#define SSH2_MSG_CHANNEL_CLOSE                    97	/* 0x61 */
#define SSH2_MSG_CHANNEL_REQUEST                  98	/* 0x62 */
#define SSH2_MSG_CHANNEL_SUCCESS                  99	/* 0x63 */
#define SSH2_MSG_CHANNEL_FAILURE                  100	/* 0x64 */
#define SSH2_MSG_USERAUTH_GSSAPI_RESPONSE               60
#define SSH2_MSG_USERAUTH_GSSAPI_TOKEN                  61
#define SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE      63
#define SSH2_MSG_USERAUTH_GSSAPI_ERROR                  64
#define SSH2_MSG_USERAUTH_GSSAPI_ERRTOK                 65
#define SSH2_MSG_USERAUTH_GSSAPI_MIC                    66

/*
 * SSH-1 agent messages.
 */
#define SSH1_AGENTC_REQUEST_RSA_IDENTITIES    1
#define SSH1_AGENT_RSA_IDENTITIES_ANSWER      2
#define SSH1_AGENTC_RSA_CHALLENGE             3
#define SSH1_AGENT_RSA_RESPONSE               4
#define SSH1_AGENTC_ADD_RSA_IDENTITY          7
#define SSH1_AGENTC_REMOVE_RSA_IDENTITY       8
#define SSH1_AGENTC_REMOVE_ALL_RSA_IDENTITIES 9	/* openssh private? */

/*
 * Messages common to SSH-1 and OpenSSH's SSH-2.
 */
#define SSH_AGENT_FAILURE                    5
#define SSH_AGENT_SUCCESS                    6

/*
 * OpenSSH's SSH-2 agent messages.
 */
#define SSH2_AGENTC_REQUEST_IDENTITIES          11
#define SSH2_AGENT_IDENTITIES_ANSWER            12
#define SSH2_AGENTC_SIGN_REQUEST                13
#define SSH2_AGENT_SIGN_RESPONSE                14
#define SSH2_AGENTC_ADD_IDENTITY                17
#define SSH2_AGENTC_REMOVE_IDENTITY             18
#define SSH2_AGENTC_REMOVE_ALL_IDENTITIES       19

/*
 * Assorted other SSH-related enumerations.
 */
#define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1	/* 0x1 */
#define SSH2_DISCONNECT_PROTOCOL_ERROR            2	/* 0x2 */
#define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED       3	/* 0x3 */
#define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4	/* 0x4 */
#define SSH2_DISCONNECT_MAC_ERROR                 5	/* 0x5 */
#define SSH2_DISCONNECT_COMPRESSION_ERROR         6	/* 0x6 */
#define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE     7	/* 0x7 */
#define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8	/* 0x8 */
#define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE   9	/* 0x9 */
#define SSH2_DISCONNECT_CONNECTION_LOST           10	/* 0xa */
#define SSH2_DISCONNECT_BY_APPLICATION            11	/* 0xb */
#define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS      12	/* 0xc */
#define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER    13	/* 0xd */
#define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14	/* 0xe */
#define SSH2_DISCONNECT_ILLEGAL_USER_NAME         15	/* 0xf */

#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED     1	/* 0x1 */
#define SSH2_OPEN_CONNECT_FAILED                  2	/* 0x2 */
#define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE            3	/* 0x3 */
#define SSH2_OPEN_RESOURCE_SHORTAGE               4	/* 0x4 */

#define SSH2_EXTENDED_DATA_STDERR                 1	/* 0x1 */

/*
 * Need this to warn about support for the original SSH-2 keyfile
 * format.
 */
void old_keyfile_warning(void);