/* * sftp.h: definitions for SFTP and the sftp.c routines. */ #include "defs.h" #define SSH_FXP_INIT 1 /* 0x1 */ #define SSH_FXP_VERSION 2 /* 0x2 */ #define SSH_FXP_OPEN 3 /* 0x3 */ #define SSH_FXP_CLOSE 4 /* 0x4 */ #define SSH_FXP_READ 5 /* 0x5 */ #define SSH_FXP_WRITE 6 /* 0x6 */ #define SSH_FXP_LSTAT 7 /* 0x7 */ #define SSH_FXP_FSTAT 8 /* 0x8 */ #define SSH_FXP_SETSTAT 9 /* 0x9 */ #define SSH_FXP_FSETSTAT 10 /* 0xa */ #define SSH_FXP_OPENDIR 11 /* 0xb */ #define SSH_FXP_READDIR 12 /* 0xc */ #define SSH_FXP_REMOVE 13 /* 0xd */ #define SSH_FXP_MKDIR 14 /* 0xe */ #define SSH_FXP_RMDIR 15 /* 0xf */ #define SSH_FXP_REALPATH 16 /* 0x10 */ #define SSH_FXP_STAT 17 /* 0x11 */ #define SSH_FXP_RENAME 18 /* 0x12 */ #define SSH_FXP_STATUS 101 /* 0x65 */ #define SSH_FXP_HANDLE 102 /* 0x66 */ #define SSH_FXP_DATA 103 /* 0x67 */ #define SSH_FXP_NAME 104 /* 0x68 */ #define SSH_FXP_ATTRS 105 /* 0x69 */ #define SSH_FXP_EXTENDED 200 /* 0xc8 */ #define SSH_FXP_EXTENDED_REPLY 201 /* 0xc9 */ #define SSH_FX_OK 0 #define SSH_FX_EOF 1 #define SSH_FX_NO_SUCH_FILE 2 #define SSH_FX_PERMISSION_DENIED 3 #define SSH_FX_FAILURE 4 #define SSH_FX_BAD_MESSAGE 5 #define SSH_FX_NO_CONNECTION 6 #define SSH_FX_CONNECTION_LOST 7 #define SSH_FX_OP_UNSUPPORTED 8 #define SSH_FILEXFER_ATTR_SIZE 0x00000001 #define SSH_FILEXFER_ATTR_UIDGID 0x00000002 #define SSH_FILEXFER_ATTR_PERMISSIONS 0x00000004 #define SSH_FILEXFER_ATTR_ACMODTIME 0x00000008 #define SSH_FILEXFER_ATTR_EXTENDED 0x80000000 #define SSH_FXF_READ 0x00000001 #define SSH_FXF_WRITE 0x00000002 #define SSH_FXF_APPEND 0x00000004 #define SSH_FXF_CREAT 0x00000008 #define SSH_FXF_TRUNC 0x00000010 #define SSH_FXF_EXCL 0x00000020 #define SFTP_PROTO_VERSION 3 #define PERMS_DIRECTORY 040000 /* * External references. The sftp client module sftp.c expects to be * able to get at these functions. * * sftp_recvdata must never return less than len. It either blocks * until len is available and then returns true, or it returns false * for failure. * * sftp_senddata returns true on success, false on failure. * * sftp_sendbuffer returns the size of the backlog of data in the * transmit queue. */ bool sftp_senddata(const char *data, size_t len); size_t sftp_sendbuffer(void); bool sftp_recvdata(char *data, size_t len); /* * Free sftp_requests */ void sftp_cleanup_request(void); struct fxp_attrs { unsigned long flags; uint64_t size; unsigned long uid; unsigned long gid; unsigned long permissions; unsigned long atime; unsigned long mtime; }; extern const struct fxp_attrs no_attrs; /* * Copy between the possibly-unused permissions field in an fxp_attrs * and a possibly-negative integer containing the same permissions. */ #define PUT_PERMISSIONS(attrs, perms) \ ((perms) >= 0 ? \ ((attrs).flags |= SSH_FILEXFER_ATTR_PERMISSIONS, \ (attrs).permissions = (perms)) : \ ((attrs).flags &= ~SSH_FILEXFER_ATTR_PERMISSIONS)) #define GET_PERMISSIONS(attrs, defaultperms) \ ((attrs).flags & SSH_FILEXFER_ATTR_PERMISSIONS ? \ (attrs).permissions : defaultperms) struct fxp_handle { char *hstring; int hlen; }; struct fxp_name { char *filename, *longname; struct fxp_attrs attrs; }; struct fxp_names { int nnames; struct fxp_name *names; }; struct sftp_request; /* * Packet-manipulation functions. */ struct sftp_packet { char *data; size_t length, maxlen, savedpos; int type; BinarySink_IMPLEMENTATION; BinarySource_IMPLEMENTATION; }; /* When sending a packet, create it with sftp_pkt_init, then add * things to it by treating it as a BinarySink. When it's done, call * sftp_send_prepare, and then pkt->data and pkt->length describe its * wire format. */ struct sftp_packet *sftp_pkt_init(int pkt_type); void sftp_send_prepare(struct sftp_packet *pkt); /* When receiving a packet, create it with sftp_recv_prepare once you * decode its length from the first 4 bytes of wire data. Then write * that many bytes into pkt->data, and call sftp_recv_finish to set up * the type code and BinarySource. */ struct sftp_packet *sftp_recv_prepare(unsigned length); bool sftp_recv_finish(struct sftp_packet *pkt); /* Either kind of packet can be freed afterwards with sftp_pkt_free. */ void sftp_pkt_free(struct sftp_packet *pkt); void BinarySink_put_fxp_attrs(BinarySink *bs, struct fxp_attrs attrs); bool BinarySource_get_fxp_attrs(BinarySource *src, struct fxp_attrs *attrs); #define put_fxp_attrs(bs, attrs) \ BinarySink_put_fxp_attrs(BinarySink_UPCAST(bs), attrs) #define get_fxp_attrs(bs, attrs) \ BinarySource_get_fxp_attrs(BinarySource_UPCAST(bs), attrs) /* * Error handling. */ const char *fxp_error(void); int fxp_error_type(void); /* * Perform exchange of init/version packets. Return false on failure. */ bool fxp_init(void); /* * Canonify a pathname. Concatenate the two given path elements * with a separating slash, unless the second is NULL. */ struct sftp_request *fxp_realpath_send(const char *path); char *fxp_realpath_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Open a file. 'attrs' contains attributes to be applied to the file * if it's being created. */ struct sftp_request *fxp_open_send(const char *path, int type, const struct fxp_attrs *attrs); struct fxp_handle *fxp_open_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Open a directory. */ struct sftp_request *fxp_opendir_send(const char *path); struct fxp_handle *fxp_opendir_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Close a file/dir. Returns true on success, false on error. */ struct sftp_request *fxp_close_send(struct fxp_handle *handle); bool fxp_close_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Make a directory. */ struct sftp_request *fxp_mkdir_send(const char *path, const struct fxp_attrs *attrs); bool fxp_mkdir_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Remove a directory. */ struct sftp_request *fxp_rmdir_send(const char *path); bool fxp_rmdir_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Remove a file. */ struct sftp_request *fxp_remove_send(const char *fname); bool fxp_remove_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Rename a file. */ struct sftp_request *fxp_rename_send(const char *srcfname, const char *dstfname); bool fxp_rename_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Return file attributes. */ struct sftp_request *fxp_stat_send(const char *fname); bool fxp_stat_recv(struct sftp_packet *pktin, struct sftp_request *req, struct fxp_attrs *attrs); struct sftp_request *fxp_fstat_send(struct fxp_handle *handle); bool fxp_fstat_recv(struct sftp_packet *pktin, struct sftp_request *req, struct fxp_attrs *attrs); /* * Set file attributes. */ struct sftp_request *fxp_setstat_send(const char *fname, struct fxp_attrs attrs); bool fxp_setstat_recv(struct sftp_packet *pktin, struct sftp_request *req); struct sftp_request *fxp_fsetstat_send(struct fxp_handle *handle, struct fxp_attrs attrs); bool fxp_fsetstat_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Read from a file. */ struct sftp_request *fxp_read_send(struct fxp_handle *handle, uint64_t offset, int len); int fxp_read_recv(struct sftp_packet *pktin, struct sftp_request *req, char *buffer, int len); /* * Write to a file. */ struct sftp_request *fxp_write_send(struct fxp_handle *handle, void *buffer, uint64_t offset, int len); bool fxp_write_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Read from a directory. */ struct sftp_request *fxp_readdir_send(struct fxp_handle *handle); struct fxp_names *fxp_readdir_recv(struct sftp_packet *pktin, struct sftp_request *req); /* * Free up an fxp_names structure. */ void fxp_free_names(struct fxp_names *names); /* * Duplicate and free fxp_name structures. */ struct fxp_name *fxp_dup_name(struct fxp_name *name); void fxp_free_name(struct fxp_name *name); /* * Store user data in an sftp_request structure. */ void *fxp_get_userdata(struct sftp_request *req); void fxp_set_userdata(struct sftp_request *req, void *data); /* * These functions might well be temporary placeholders to be * replaced with more useful similar functions later. They form the * main dispatch loop for processing incoming SFTP responses. */ void sftp_register(struct sftp_request *req); struct sftp_request *sftp_find_request(struct sftp_packet *pktin); struct sftp_packet *sftp_recv(void); /* * A wrapper to go round fxp_read_* and fxp_write_*, which manages * the queueing of multiple read/write requests. */ struct fxp_xfer; struct fxp_xfer *xfer_download_init(struct fxp_handle *fh, uint64_t offset); void xfer_download_queue(struct fxp_xfer *xfer); int xfer_download_gotpkt(struct fxp_xfer *xfer, struct sftp_packet *pktin); bool xfer_download_data(struct fxp_xfer *xfer, void **buf, int *len); struct fxp_xfer *xfer_upload_init(struct fxp_handle *fh, uint64_t offset); bool xfer_upload_ready(struct fxp_xfer *xfer); void xfer_upload_data(struct fxp_xfer *xfer, char *buffer, int len); int xfer_upload_gotpkt(struct fxp_xfer *xfer, struct sftp_packet *pktin); bool xfer_done(struct fxp_xfer *xfer); void xfer_set_error(struct fxp_xfer *xfer); void xfer_cleanup(struct fxp_xfer *xfer); /* * Vtable for the platform-specific filesystem implementation that * answers requests in an SFTP server. */ typedef struct SftpReplyBuilder SftpReplyBuilder; struct SftpServer { const SftpServerVtable *vt; }; struct SftpServerVtable { SftpServer *(*new)(const SftpServerVtable *vt); void (*free)(SftpServer *srv); /* * Handle actual filesystem requests. * * Each of these functions replies by calling an appropriate * sftp_reply_foo() function on the given reply packet. */ /* Should call fxp_reply_error or fxp_reply_simple_name */ void (*realpath)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path); /* Should call fxp_reply_error or fxp_reply_handle */ void (*open)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path, unsigned flags, struct fxp_attrs attrs); /* Should call fxp_reply_error or fxp_reply_handle */ void (*opendir)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path); /* Should call fxp_reply_error or fxp_reply_ok */ void (*close)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle); /* Should call fxp_reply_error or fxp_reply_ok */ void (*mkdir)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path, struct fxp_attrs attrs); /* Should call fxp_reply_error or fxp_reply_ok */ void (*rmdir)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path); /* Should call fxp_reply_error or fxp_reply_ok */ void (*remove)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path); /* Should call fxp_reply_error or fxp_reply_ok */ void (*rename)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen srcpath, ptrlen dstpath); /* Should call fxp_reply_error or fxp_reply_attrs */ void (*stat)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path, bool follow_symlinks); /* Should call fxp_reply_error or fxp_reply_attrs */ void (*fstat)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle); /* Should call fxp_reply_error or fxp_reply_ok */ void (*setstat)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path, struct fxp_attrs attrs); /* Should call fxp_reply_error or fxp_reply_ok */ void (*fsetstat)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle, struct fxp_attrs attrs); /* Should call fxp_reply_error or fxp_reply_data */ void (*read)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle, uint64_t offset, unsigned length); /* Should call fxp_reply_error or fxp_reply_ok */ void (*write)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle, uint64_t offset, ptrlen data); /* Should call fxp_reply_error, or fxp_reply_name_count once and * then fxp_reply_full_name that many times */ void (*readdir)(SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle, int max_entries, bool omit_longname); }; static inline SftpServer *sftpsrv_new(const SftpServerVtable *vt) { return vt->new(vt); } static inline void sftpsrv_free(SftpServer *srv) { srv->vt->free(srv); } static inline void sftpsrv_realpath(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path) { srv->vt->realpath(srv, reply, path); } static inline void sftpsrv_open( SftpServer *srv, SftpReplyBuilder *reply, ptrlen path, unsigned flags, struct fxp_attrs attrs) { srv->vt->open(srv, reply, path, flags, attrs); } static inline void sftpsrv_opendir( SftpServer *srv, SftpReplyBuilder *reply, ptrlen path) { srv->vt->opendir(srv, reply, path); } static inline void sftpsrv_close( SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle) { srv->vt->close(srv, reply, handle); } static inline void sftpsrv_mkdir(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path, struct fxp_attrs attrs) { srv->vt->mkdir(srv, reply, path, attrs); } static inline void sftpsrv_rmdir( SftpServer *srv, SftpReplyBuilder *reply, ptrlen path) { srv->vt->rmdir(srv, reply, path); } static inline void sftpsrv_remove( SftpServer *srv, SftpReplyBuilder *reply, ptrlen path) { srv->vt->remove(srv, reply, path); } static inline void sftpsrv_rename(SftpServer *srv, SftpReplyBuilder *reply, ptrlen srcpath, ptrlen dstpath) { srv->vt->rename(srv, reply, srcpath, dstpath); } static inline void sftpsrv_stat( SftpServer *srv, SftpReplyBuilder *reply, ptrlen path, bool follow) { srv->vt->stat(srv, reply, path, follow); } static inline void sftpsrv_fstat( SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle) { srv->vt->fstat(srv, reply, handle); } static inline void sftpsrv_setstat(SftpServer *srv, SftpReplyBuilder *reply, ptrlen path, struct fxp_attrs attrs) { srv->vt->setstat(srv, reply, path, attrs); } static inline void sftpsrv_fsetstat(SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle, struct fxp_attrs attrs) { srv->vt->fsetstat(srv, reply, handle, attrs); } static inline void sftpsrv_read( SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle, uint64_t offset, unsigned length) { srv->vt->read(srv, reply, handle, offset, length); } static inline void sftpsrv_write(SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle, uint64_t offset, ptrlen data) { srv->vt->write(srv, reply, handle, offset, data); } static inline void sftpsrv_readdir( SftpServer *srv, SftpReplyBuilder *reply, ptrlen handle, int max_entries, bool omit_longname) { srv->vt->readdir(srv, reply, handle, max_entries, omit_longname); } typedef struct SftpReplyBuilderVtable SftpReplyBuilderVtable; struct SftpReplyBuilder { const SftpReplyBuilderVtable *vt; }; struct SftpReplyBuilderVtable { void (*reply_ok)(SftpReplyBuilder *reply); void (*reply_error)(SftpReplyBuilder *reply, unsigned code, const char *msg); void (*reply_simple_name)(SftpReplyBuilder *reply, ptrlen name); void (*reply_name_count)(SftpReplyBuilder *reply, unsigned count); void (*reply_full_name)(SftpReplyBuilder *reply, ptrlen name, ptrlen longname, struct fxp_attrs attrs); void (*reply_handle)(SftpReplyBuilder *reply, ptrlen handle); void (*reply_data)(SftpReplyBuilder *reply, ptrlen data); void (*reply_attrs)(SftpReplyBuilder *reply, struct fxp_attrs attrs); }; static inline void fxp_reply_ok(SftpReplyBuilder *reply) { reply->vt->reply_ok(reply); } static inline void fxp_reply_error(SftpReplyBuilder *reply, unsigned code, const char *msg) { reply->vt->reply_error(reply, code, msg); } static inline void fxp_reply_simple_name(SftpReplyBuilder *reply, ptrlen name) { reply->vt->reply_simple_name(reply, name); } static inline void fxp_reply_name_count( SftpReplyBuilder *reply, unsigned count) { reply->vt->reply_name_count(reply, count); } static inline void fxp_reply_full_name(SftpReplyBuilder *reply, ptrlen name, ptrlen longname, struct fxp_attrs attrs) { reply->vt->reply_full_name(reply, name, longname, attrs); } static inline void fxp_reply_handle(SftpReplyBuilder *reply, ptrlen handle) { reply->vt->reply_handle(reply, handle); } static inline void fxp_reply_data(SftpReplyBuilder *reply, ptrlen data) { reply->vt->reply_data(reply, data); } static inline void fxp_reply_attrs( SftpReplyBuilder *reply, struct fxp_attrs attrs) { reply->vt->reply_attrs(reply, attrs); } /* * The usual implementation of an SftpReplyBuilder, containing a * 'struct sftp_packet' which is assumed to be already initialised * before one of the above request methods is called. */ extern const struct SftpReplyBuilderVtable DefaultSftpReplyBuilder_vt; typedef struct DefaultSftpReplyBuilder DefaultSftpReplyBuilder; struct DefaultSftpReplyBuilder { SftpReplyBuilder rb; struct sftp_packet *pkt; }; /* * The top-level function that handles an SFTP request, given an * implementation of the above SftpServer abstraction to do the actual * filesystem work. It handles all the marshalling and unmarshalling * of packets, and the copying of request ids into the responses. */ struct sftp_packet *sftp_handle_request( SftpServer *srv, struct sftp_packet *request); /* ---------------------------------------------------------------------- * Not exactly SFTP-related, but here's a system that implements an * old-fashioned SCP server module, given an SftpServer vtable to use * as its underlying filesystem access. */ typedef struct ScpServer ScpServer; typedef struct ScpServerVtable ScpServerVtable; struct ScpServer { const struct ScpServerVtable *vt; }; struct ScpServerVtable { void (*free)(ScpServer *s); size_t (*send)(ScpServer *s, const void *data, size_t length); void (*throttle)(ScpServer *s, bool throttled); void (*eof)(ScpServer *s); }; static inline void scp_free(ScpServer *s) { s->vt->free(s); } static inline size_t scp_send(ScpServer *s, const void *data, size_t length) { return s->vt->send(s, data, length); } static inline void scp_throttle(ScpServer *s, bool throttled) { s->vt->throttle(s, throttled); } static inline void scp_eof(ScpServer *s) { s->vt->eof(s); } /* * Create an ScpServer by calling this function, giving it the command * you received from the SSH client to execute. If that command is * recognised as an scp command, it will construct an ScpServer object * and return it; otherwise, it will return NULL, and you should * execute the command in whatever way you normally would. * * The ScpServer will generate output for the client by writing it to * the provided SshChannel using sshfwd_write; you pass it input using * the send method in its own vtable. */ ScpServer *scp_recognise_exec( SshChannel *sc, const SftpServerVtable *sftpserver_vt, ptrlen command);