curl/lib/vssh/ssh.h

#ifndef HEADER_CURL_SSH_H
#define HEADER_CURL_SSH_H
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * SPDX-License-Identifier: curl
 *
 ***************************************************************************/

#include "curl_setup.h"

#if defined(USE_LIBSSH2)
#include <libssh2.h>
#include <libssh2_sftp.h>
#elif defined(USE_LIBSSH)
#include <libssh/libssh.h>
#include <libssh/sftp.h>
#elif defined(USE_WOLFSSH)
#include <wolfssh/ssh.h>
#include <wolfssh/wolfsftp.h>
#endif

/****************************************************************************
 * SSH unique setup
 ***************************************************************************/
typedef enum {
  SSH_NO_STATE = -1,  /* Used for "nextState" so say there is none */
  SSH_STOP = 0,       /* do nothing state, stops the state machine */

  SSH_INIT,           /* First state in SSH-CONNECT */
  SSH_S_STARTUP,      /* Session startup */
  SSH_HOSTKEY,        /* verify hostkey */
  SSH_AUTHLIST,
  SSH_AUTH_PKEY_INIT,
  SSH_AUTH_PKEY,
  SSH_AUTH_PASS_INIT,
  SSH_AUTH_PASS,
  SSH_AUTH_AGENT_INIT, /* initialize then wait for connection to agent */
  SSH_AUTH_AGENT_LIST, /* ask for list then wait for entire list to come */
  SSH_AUTH_AGENT,      /* attempt one key at a time */
  SSH_AUTH_HOST_INIT,
  SSH_AUTH_HOST,
  SSH_AUTH_KEY_INIT,
  SSH_AUTH_KEY,
  SSH_AUTH_GSSAPI,
  SSH_AUTH_DONE,
  SSH_SFTP_INIT,
  SSH_SFTP_REALPATH,   /* Last state in SSH-CONNECT */

  SSH_SFTP_QUOTE_INIT, /* First state in SFTP-DO */
  SSH_SFTP_POSTQUOTE_INIT, /* (Possibly) First state in SFTP-DONE */
  SSH_SFTP_QUOTE,
  SSH_SFTP_NEXT_QUOTE,
  SSH_SFTP_QUOTE_STAT,
  SSH_SFTP_QUOTE_SETSTAT,
  SSH_SFTP_QUOTE_SYMLINK,
  SSH_SFTP_QUOTE_MKDIR,
  SSH_SFTP_QUOTE_RENAME,
  SSH_SFTP_QUOTE_RMDIR,
  SSH_SFTP_QUOTE_UNLINK,
  SSH_SFTP_QUOTE_STATVFS,
  SSH_SFTP_GETINFO,
  SSH_SFTP_FILETIME,
  SSH_SFTP_TRANS_INIT,
  SSH_SFTP_UPLOAD_INIT,
  SSH_SFTP_CREATE_DIRS_INIT,
  SSH_SFTP_CREATE_DIRS,
  SSH_SFTP_CREATE_DIRS_MKDIR,
  SSH_SFTP_READDIR_INIT,
  SSH_SFTP_READDIR,
  SSH_SFTP_READDIR_LINK,
  SSH_SFTP_READDIR_BOTTOM,
  SSH_SFTP_READDIR_DONE,
  SSH_SFTP_DOWNLOAD_INIT,
  SSH_SFTP_DOWNLOAD_STAT, /* Last state in SFTP-DO */
  SSH_SFTP_CLOSE,    /* Last state in SFTP-DONE */
  SSH_SFTP_SHUTDOWN, /* First state in SFTP-DISCONNECT */
  SSH_SCP_TRANS_INIT, /* First state in SCP-DO */
  SSH_SCP_UPLOAD_INIT,
  SSH_SCP_DOWNLOAD_INIT,
  SSH_SCP_DOWNLOAD,
  SSH_SCP_DONE,
  SSH_SCP_SEND_EOF,
  SSH_SCP_WAIT_EOF,
  SSH_SCP_WAIT_CLOSE,
  SSH_SCP_CHANNEL_FREE,   /* Last state in SCP-DONE */
  SSH_SESSION_DISCONNECT, /* First state in SCP-DISCONNECT */
  SSH_SESSION_FREE,       /* Last state in SCP/SFTP-DISCONNECT */
  SSH_QUIT,
  SSH_LAST  /* never used */
} sshstate;

/* this struct is used in the HandleData struct which is part of the
   Curl_easy, which means this is used on a per-easy handle basis.
   Everything that is strictly related to a connection is banned from this
   struct. */
struct SSHPROTO {
  char *path;                  /* the path we operate on */
#ifdef USE_LIBSSH2
  struct dynbuf readdir_link;
  struct dynbuf readdir;
  char *readdir_filename;
  char *readdir_longentry;

  LIBSSH2_SFTP_ATTRIBUTES quote_attrs; /* used by the SFTP_QUOTE state */

  /* Here's a set of struct members used by the SFTP_READDIR state */
  LIBSSH2_SFTP_ATTRIBUTES readdir_attrs;
#endif
};

/* ssh_conn is used for struct connection-oriented data in the connectdata
   struct */
struct ssh_conn {
  const char *authlist;       /* List of auth. methods, managed by libssh2 */

  /* common */
  const char *passphrase;     /* pass-phrase to use */
  char *rsa_pub;              /* strdup'ed public key file */
  char *rsa;                  /* strdup'ed private key file */
  bool authed;                /* the connection has been authenticated fine */
  bool acceptfail;            /* used by the SFTP_QUOTE (continue if
                                 quote command fails) */
  sshstate state;             /* always use ssh.c:state() to change state! */
  sshstate nextstate;         /* the state to goto after stopping */
  CURLcode actualcode;        /* the actual error code */
  struct curl_slist *quote_item; /* for the quote option */
  char *quote_path1;          /* two generic pointers for the QUOTE stuff */
  char *quote_path2;

  char *homedir;              /* when doing SFTP we figure out home dir in the
                                 connect phase */
  char *readdir_line;
  /* end of READDIR stuff */

  int secondCreateDirs;         /* counter use by the code to see if the
                                   second attempt has been made to change
                                   to/create a directory */
  int orig_waitfor;             /* default READ/WRITE bits wait for */
  char *slash_pos;              /* used by the SFTP_CREATE_DIRS state */

#if defined(USE_LIBSSH)
  char *readdir_linkPath;
  size_t readdir_len, readdir_totalLen, readdir_currLen;
/* our variables */
  unsigned kbd_state; /* 0 or 1 */
  ssh_key privkey;
  ssh_key pubkey;
  int auth_methods;
  ssh_session ssh_session;
  ssh_scp scp_session;
  sftp_session sftp_session;
  sftp_file sftp_file;
  sftp_dir sftp_dir;

  unsigned sftp_recv_state; /* 0 or 1 */
  int sftp_file_index; /* for async read */
  sftp_attributes readdir_attrs; /* used by the SFTP readdir actions */
  sftp_attributes readdir_link_attrs; /* used by the SFTP readdir actions */
  sftp_attributes quote_attrs; /* used by the SFTP_QUOTE state */

  const char *readdir_filename; /* points within readdir_attrs */
  const char *readdir_longentry;
  char *readdir_tmp;
#elif defined(USE_LIBSSH2)
  LIBSSH2_SESSION *ssh_session; /* Secure Shell session */
  LIBSSH2_CHANNEL *ssh_channel; /* Secure Shell channel handle */
  LIBSSH2_SFTP *sftp_session;   /* SFTP handle */
  LIBSSH2_SFTP_HANDLE *sftp_handle;

#ifndef CURL_DISABLE_PROXY
  /* for HTTPS proxy storage */
  Curl_recv *tls_recv;
  Curl_send *tls_send;
#endif

#ifdef HAVE_LIBSSH2_AGENT_API
  LIBSSH2_AGENT *ssh_agent;     /* proxy to ssh-agent/pageant */
  struct libssh2_agent_publickey *sshagent_identity,
                                 *sshagent_prev_identity;
#endif

  /* note that HAVE_LIBSSH2_KNOWNHOST_API is a define set in the libssh2.h
     header */
#ifdef HAVE_LIBSSH2_KNOWNHOST_API
  LIBSSH2_KNOWNHOSTS *kh;
#endif
#elif defined(USE_WOLFSSH)
  WOLFSSH *ssh_session;
  WOLFSSH_CTX *ctx;
  word32 handleSz;
  byte handle[WOLFSSH_MAX_HANDLE];
  curl_off_t offset;
#endif /* USE_LIBSSH */
};

#if defined(USE_LIBSSH2)

/* Feature detection based on version numbers to better work with
   non-configure platforms */

#if !defined(LIBSSH2_VERSION_NUM) || (LIBSSH2_VERSION_NUM < 0x001000)
#  error "SCP/SFTP protocols require libssh2 0.16 or later"
#endif

#if LIBSSH2_VERSION_NUM >= 0x010000
#define HAVE_LIBSSH2_SFTP_SEEK64 1
#endif

#if LIBSSH2_VERSION_NUM >= 0x010100
#define HAVE_LIBSSH2_VERSION 1
#endif

#if LIBSSH2_VERSION_NUM >= 0x010205
#define HAVE_LIBSSH2_INIT 1
#define HAVE_LIBSSH2_EXIT 1
#endif

#if LIBSSH2_VERSION_NUM >= 0x010206
#define HAVE_LIBSSH2_KNOWNHOST_CHECKP 1
#define HAVE_LIBSSH2_SCP_SEND64 1
#endif

#if LIBSSH2_VERSION_NUM >= 0x010208
#define HAVE_LIBSSH2_SESSION_HANDSHAKE 1
#endif

#ifdef HAVE_LIBSSH2_VERSION
/* get it run-time if possible */
#define CURL_LIBSSH2_VERSION libssh2_version(0)
#else
/* use build-time if run-time not possible */
#define CURL_LIBSSH2_VERSION LIBSSH2_VERSION
#endif

#endif /* USE_LIBSSH2 */

#ifdef USE_SSH

extern const struct Curl_handler Curl_handler_scp;
extern const struct Curl_handler Curl_handler_sftp;

/* generic SSH backend functions */
CURLcode Curl_ssh_init(void);
void Curl_ssh_cleanup(void);
void Curl_ssh_version(char *buffer, size_t buflen);
void Curl_ssh_attach(struct Curl_easy *data,
                     struct connectdata *conn);
#else
/* for non-SSH builds */
#define Curl_ssh_cleanup()
#define Curl_ssh_attach(x,y)
#endif

#endif /* HEADER_CURL_SSH_H */