int sftp_server_main(int argc, char **argv, struct passwd *user_pw) { fd_set *rset, *wset; int i, in, out, max, ch, skipargs = 0, log_stderr = 0; ssize_t len, olen, set_size; SyslogFacility log_facility = SYSLOG_FACILITY_AUTH; char *cp, *homedir = NULL, buf[4*4096]; long mask; extern char *optarg; extern char *__progname; __progname = ssh_get_progname(argv[0]); log_init(__progname, log_level, log_facility, log_stderr); pw = pwcopy(user_pw); while (!skipargs && (ch = getopt(argc, argv, "d:f:l:P:p:Q:u:cehR")) != -1) { switch (ch) { case 'Q': if (strcasecmp(optarg, "requests") != 0) { fprintf(stderr, "Invalid query type\n"); exit(1); } for (i = 0; handlers[i].handler != NULL; i++) printf("%s\n", handlers[i].name); for (i = 0; extended_handlers[i].handler != NULL; i++) printf("%s\n", extended_handlers[i].name); exit(0); break; case 'R': readonly = 1; break; case 'c': /* * Ignore all arguments if we are invoked as a * shell using "sftp-server -c command" */ skipargs = 1; break; case 'e': log_stderr = 1; break; case 'l': log_level = log_level_number(optarg); if (log_level == SYSLOG_LEVEL_NOT_SET) error("Invalid log level \"%s\"", optarg); break; case 'f': log_facility = log_facility_number(optarg); if (log_facility == SYSLOG_FACILITY_NOT_SET) error("Invalid log facility \"%s\"", optarg); break; case 'd': cp = tilde_expand_filename(optarg, user_pw->pw_uid); homedir = percent_expand(cp, "d", user_pw->pw_dir, "u", user_pw->pw_name, (char *)NULL); free(cp); break; case 'p': if (request_whitelist != NULL) fatal("Permitted requests already set"); request_whitelist = xstrdup(optarg); break; case 'P': if (request_blacklist != NULL) fatal("Refused requests already set"); request_blacklist = xstrdup(optarg); break; case 'u': errno = 0; mask = strtol(optarg, &cp, 8); if (mask < 0 || mask > 0777 || *cp != '\0' || cp == optarg || (mask == 0 && errno != 0)) fatal("Invalid umask \"%s\"", optarg); (void)umask((mode_t)mask); break; case 'h': default: sftp_server_usage(); } } log_init(__progname, log_level, log_facility, log_stderr); #ifdef HAVE_PRCTL /* * On Linux, we should try to avoid making /proc/self/{mem,maps} * available to the user so that sftp access doesn't automatically * imply arbitrary code execution access that will break * restricted configurations. */ if (prctl(PR_SET_DUMPABLE, 0) != 0) fatal("unable to make the process undumpable"); #endif if ((cp = getenv("SSH_CONNECTION")) != NULL) { client_addr = xstrdup(cp); if ((cp = strchr(client_addr, ' ')) == NULL) { error("Malformed SSH_CONNECTION variable: \"%s\"", getenv("SSH_CONNECTION")); sftp_server_cleanup_exit(255); } *cp = '\0'; } else client_addr = xstrdup("UNKNOWN"); logit("session opened for local user %s from [%s]", pw->pw_name, client_addr); in = STDIN_FILENO; out = STDOUT_FILENO; #ifdef HAVE_CYGWIN setmode(in, O_BINARY); setmode(out, O_BINARY); #endif max = 0; if (in > max) max = in; if (out > max) max = out; buffer_init(&iqueue); buffer_init(&oqueue); set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask); rset = (fd_set *)xmalloc(set_size); wset = (fd_set *)xmalloc(set_size); if (homedir != NULL) { if (chdir(homedir) != 0) { error("chdir to \"%s\" failed: %s", homedir, strerror(errno)); } } for (;;) { memset(rset, 0, set_size); memset(wset, 0, set_size); /* * Ensure that we can read a full buffer and handle * the worst-case length packet it can generate, * otherwise apply backpressure by stopping reads. */ if (buffer_check_alloc(&iqueue, sizeof(buf)) && buffer_check_alloc(&oqueue, SFTP_MAX_MSG_LENGTH)) FD_SET(in, rset); olen = buffer_len(&oqueue); if (olen > 0) FD_SET(out, wset); if (select(max+1, rset, wset, NULL, NULL) < 0) { if (errno == EINTR) continue; error("select: %s", strerror(errno)); sftp_server_cleanup_exit(2); } /* copy stdin to iqueue */ if (FD_ISSET(in, rset)) { len = read(in, buf, sizeof buf); if (len == 0) { debug("read eof"); sftp_server_cleanup_exit(0); } else if (len < 0) { error("read: %s", strerror(errno)); sftp_server_cleanup_exit(1); } else { buffer_append(&iqueue, buf, len); } } /* send oqueue to stdout */ if (FD_ISSET(out, wset)) { len = write(out, buffer_ptr(&oqueue), olen); if (len < 0) { error("write: %s", strerror(errno)); sftp_server_cleanup_exit(1); } else { buffer_consume(&oqueue, len); } } /* * Process requests from client if we can fit the results * into the output buffer, otherwise stop processing input * and let the output queue drain. */ if (buffer_check_alloc(&oqueue, SFTP_MAX_MSG_LENGTH)) process(); } }
int sftp_server_main(int argc, char **argv, struct passwd *user_pw) { fd_set *rset, *wset; int in, out, max, ch, skipargs = 0, log_stderr = 0; ssize_t len, olen, set_size; SyslogFacility log_facility = SYSLOG_FACILITY_AUTH; char *cp, buf[4*4096]; const char *errmsg; mode_t mask; extern char *optarg; extern char *__progname; __progname = ssh_get_progname(argv[0]); log_init(__progname, log_level, log_facility, log_stderr); fake_permissions = 0; while (!skipargs && (ch = getopt(argc, argv, "f:l:u:cehRU")) != -1) { switch (ch) { case 'R': readonly = 1; break; case 'c': /* * Ignore all arguments if we are invoked as a * shell using "sftp-server -c command" */ skipargs = 1; break; case 'e': log_stderr = 1; break; case 'l': log_level = log_level_number(optarg); if (log_level == SYSLOG_LEVEL_NOT_SET) error("Invalid log level \"%s\"", optarg); break; case 'f': log_facility = log_facility_number(optarg); if (log_facility == SYSLOG_FACILITY_NOT_SET) error("Invalid log facility \"%s\"", optarg); break; case 'u': mask = (mode_t)strtonum(optarg, 0, 0777, &errmsg); if (errmsg != NULL) fatal("Invalid umask \"%s\": %s", optarg, errmsg); (void)umask(mask); break; case 'U': /* Fake permissions */ fake_permissions = 1; break; case 'h': default: sftp_server_usage(); } } log_init(__progname, log_level, log_facility, log_stderr); if ((cp = getenv("SSH_CONNECTION")) != NULL) { client_addr = xstrdup(cp); if ((cp = strchr(client_addr, ' ')) == NULL) { error("Malformed SSH_CONNECTION variable: \"%s\"", getenv("SSH_CONNECTION")); sftp_server_cleanup_exit(255); } *cp = '\0'; } else client_addr = xstrdup("UNKNOWN"); pw = pwcopy(user_pw); logit("session opened for local user %s from [%s]", pw->pw_name, client_addr); in = STDIN_FILENO; out = STDOUT_FILENO; #ifdef HAVE_CYGWIN setmode(in, O_BINARY); setmode(out, O_BINARY); #endif max = 0; if (in > max) max = in; if (out > max) max = out; buffer_init(&iqueue); buffer_init(&oqueue); set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask); rset = (fd_set *)xmalloc(set_size); wset = (fd_set *)xmalloc(set_size); for (;;) { memset(rset, 0, set_size); memset(wset, 0, set_size); /* * Ensure that we can read a full buffer and handle * the worst-case length packet it can generate, * otherwise apply backpressure by stopping reads. */ if (buffer_check_alloc(&iqueue, sizeof(buf)) && buffer_check_alloc(&oqueue, SFTP_MAX_MSG_LENGTH)) FD_SET(in, rset); olen = buffer_len(&oqueue); if (olen > 0) FD_SET(out, wset); if (select(max+1, rset, wset, NULL, NULL) < 0) { if (errno == EINTR) continue; error("select: %s", strerror(errno)); sftp_server_cleanup_exit(2); } /* copy stdin to iqueue */ if (FD_ISSET(in, rset)) { len = read(in, buf, sizeof buf); if (len == 0) { debug("read eof"); sftp_server_cleanup_exit(0); } else if (len < 0) { error("read: %s", strerror(errno)); sftp_server_cleanup_exit(1); } else { buffer_append(&iqueue, buf, len); } } /* send oqueue to stdout */ if (FD_ISSET(out, wset)) { len = write(out, buffer_ptr(&oqueue), olen); if (len < 0) { error("write: %s", strerror(errno)); sftp_server_cleanup_exit(1); } else { buffer_consume(&oqueue, len); } } /* * Process requests from client if we can fit the results * into the output buffer, otherwise stop processing input * and let the output queue drain. */ if (buffer_check_alloc(&oqueue, SFTP_MAX_MSG_LENGTH)) process(); } }