ftpd.c

功能强大的ftp服务器源代码

#define MLST_BEGIN "Begin" CRLF

void domlst(const char * const file)
{
    char line[MAXPATHLEN + 256U] = MLST_BEGIN;

    if (modernformat(file, line + (sizeof MLST_BEGIN - 1U),
                     sizeof line - (sizeof MLST_BEGIN - 1U)) >= 0) {
        addreply_noformat(0, line);
        addreply_noformat(250, "End.");
    } else {
        addreply_noformat(550, MSG_STAT_FAILURE2);
    }
}

void donoop(void)
{
#ifdef BORING_MODE
    addreply_noformat(200, "dc.w $4E71");
#else
    addreply_noformat(200, MSG_SLEEPING);
#endif
}

#endif

void dositetime(void)
{
    char tmp[64];
    const struct tm *tm;
    time_t now;
    
    if ((now = time(NULL)) == (time_t) -1 || (tm = localtime(&now)) == NULL) {
        addreply_noformat(550, "time()");
        return;
    }
    strftime(tmp, sizeof tmp, "%Y-%m-%d %H:%M:%S", tm);
    addreply_noformat(211, tmp);
}

static int doinitsupgroups(const char *user, const uid_t uid, const gid_t gid)
{
#ifndef NON_ROOT_FTP
# ifdef HAVE_SETGROUPS
    if (setgroups(1U, &gid) != 0) {
        return -1;
    }
# else
    (void) gid;
# endif
# ifdef HAVE_INITGROUPS            
    if (user == NULL) {
        const struct passwd * const lpwd = getpwuid(uid);
        
        if (lpwd != NULL && lpwd->pw_name != NULL) {
            user = lpwd->pw_name;
        } else {        
            return 0;
        }
    }
    initgroups(user, gid);
# else
    (void) user;
    (void) uid;
# endif
#else
    (void) user;
    (void) uid;
    (void) gid;    
#endif
    return 0;
}

void douser(const char *username)
{
    struct passwd *pw;

    if (loggedin) {
        if (username) {
            if (!guest) {
                addreply_noformat(530, MSG_ALREADY_LOGGED);
            } else if (broken_client_compat) {
                addreply_noformat(331, MSG_ANY_PASSWORD);
            } else {
                addreply_noformat(230, MSG_ANONYMOUS_LOGGED);
                dot_read_ok = dot_read_anon_ok;
                dot_write_ok = 0;
            }
        }
        return;
    }
    if (anon_only <= 0 && username != NULL && *username != 0 &&
        strcasecmp(username, "ftp") && strcasecmp(username, "anonymous")) {
        strncpy(account, username, sizeof(account) - 1);
        account[sizeof(account) - (size_t) 1U] = 0;
        addreply(331, MSG_USER_OK, account);
        loggedin = 0;
    } else if (anon_only < 0) {           /* anonymous, but -E */
        if (broken_client_compat != 0) {
            addreply(331, MSG_USER_OK, username);
            return;
        } else {
            die(530, LOG_DEBUG, MSG_NO_ANONYMOUS_LOGIN);
        }
    } else {
#ifdef WITH_VIRTUAL_HOSTS
        char name[MAXPATHLEN];
        char hbuf[NI_MAXHOST];
#endif
        if (chrooted != 0) {
            die(421, LOG_DEBUG, MSG_CANT_DO_TWICE);
        }
	
#ifdef PER_USER_LIMITS
        if (per_anon_max > 0U && ftpwho_read_count("ftp") >= per_anon_max) {
            addreply(421, MSG_PERUSER_MAX, (unsigned long) per_anon_max);
            doreply();
            _EXIT(1);
        }
#endif	
        
#ifdef NON_ROOT_FTP
        {
            static struct passwd pw_;
            char s[MAXPATHLEN + 1U];            
            
            if (getcwd(s, sizeof s - (size_t) 1U) == NULL) {
                cantsec:
                die(421, LOG_ERR, MSG_UNABLE_SECURE_ANON);
            }
            pw_.pw_uid = geteuid();
            pw_.pw_gid = getegid();
# if defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__CYGWIN__)
            if ((pw_.pw_dir = getenv("WIN32_ANON_DIR")) == NULL) {
                pw_.pw_dir = WIN32_ANON_DIR;
            }
# else
            pw_.pw_dir = strdup(s);    /* checked for == NULL later */
# endif
            pw = &pw_;
        }
#else
        if ((pw = getpwnam("ftp")) == NULL ||
            pw->pw_uid == 0 || pw->pw_gid == 0 ||
            doinitsupgroups("ftp", (uid_t) -1, pw->pw_gid) != 0 ||
            setgid(pw->pw_gid) || setegid(pw->pw_gid)) {
            cantsec:
            die(421, LOG_ERR, MSG_UNABLE_SECURE_ANON);
        }
#endif
#ifdef WITH_VIRTUAL_HOSTS
        if (getnameinfo((struct sockaddr *) &ctrlconn, STORAGE_LEN(ctrlconn),
                        hbuf, sizeof hbuf, NULL,
                        (size_t) 0U, NI_NUMERICHOST) != 0
            || SNCHECK(snprintf(name, sizeof name, VHOST_PATH "/%s", hbuf),
                       sizeof name)) {
            _EXIT(EXIT_FAILURE);
        }
        if (chdir(name) != 0)         /* non-virtual */
#endif
        {
            char *hd;
            size_t rd_len;
            
            if (pw->pw_dir == NULL || *pw->pw_dir != '/') {
                goto cantsec;
            }
            if ((hd = strstr(pw->pw_dir, "/./")) != NULL) {
                rd_len = (size_t) (hd - pw->pw_dir) + sizeof "/";
                if ((root_directory = malloc(rd_len)) == NULL) {
                    goto cantsec;
                }
                memcpy(root_directory, pw->pw_dir, rd_len);
                root_directory[rd_len - (size_t) 1U] = 0;
                hd += 2;
            } else {
                rd_len = strlen(pw->pw_dir) + sizeof "/";
                if ((root_directory = malloc(rd_len)) == NULL) {
                    goto cantsec;
                }
                snprintf(root_directory, rd_len, "%s/", pw->pw_dir);
                hd = (char *) "/";
            }
            if (chdir(root_directory) || chroot(root_directory) || chdir(hd)) {
                goto cantsec;
            }
            logfile(LOG_INFO, MSG_ANONYMOUS_LOGGED);
        }
#ifdef WITH_VIRTUAL_HOSTS
        else {                       /* virtual host */
            const size_t rd_len = strlen(hbuf) + sizeof ":/";
        
            if ((root_directory = malloc(rd_len)) == NULL ||
                chdir(name) || chroot(name) || chdir("/") ||
                SNCHECK(snprintf(root_directory, rd_len, "%s:/", hbuf),
                        rd_len)) {
                goto cantsec;
            }
            logfile(LOG_INFO, MSG_ANONYMOUS_LOGGED_VIRTUAL ": %s", hbuf);
        }
#endif
        chrooted = 1;
        authresult.uid = pw->pw_uid;
        authresult.gid = pw->pw_gid;
        if ((authresult.dir = strdup(pw->pw_dir)) == NULL) {
            die_mem();
        }

#ifdef THROTTLING
        if (throttling != 0) {
            addreply_noformat(0, MSG_BANDWIDTH_RESTRICTED);
            nice(NICE_VALUE);
        } else {
            throttling_delay = throttling_bandwidth_ul =
                throttling_bandwidth_dl = 0UL;
        }
#endif

#ifndef NON_ROOT_FTP
        if (authresult.uid > (uid_t) 0) {
# ifdef WITH_PRIVSEP
            if (setuid(authresult.uid) != 0 || seteuid(authresult.uid) != 0) {
                goto cantsec;
            }
# else
#  ifdef HAVE_SYS_FSUID_H
            setfsgid(authresult.gid);
            setfsuid(authresult.uid);
#  else
            if (seteuid(authresult.uid) != 0) {
                goto cantsec;
            }
#  endif
# endif
        }
#endif

#ifdef USE_CAPABILITIES
        drop_login_caps();
#endif

#ifndef MINIMAL
        dobanner(0);
#endif

        if (broken_client_compat) {
            addreply_noformat(331, MSG_ANONYMOUS_ANY_PASSWORD);
        } else {
            addreply_noformat(230, MSG_ANONYMOUS_LOGGED);
        }
        dot_write_ok = 0;
        dot_read_ok = dot_read_anon_ok;
        strncpy(account, "ftp", sizeof account - (size_t) 1U);
        account[(sizeof account) - 1U] = 0;
#ifdef FTPWHO
        if (shm_data_cur != NULL) {
            ftpwho_lock();
            strncpy(shm_data_cur->account, account,
                    sizeof shm_data_cur->account - (size_t) 1U);
            shm_data_cur->account[sizeof shm_data_cur->account - 1U] = 0;
            ftpwho_unlock();
            state_needs_update = 1;
        }
#endif
        loggedin = guest = 1;
#ifdef QUOTAS
        user_quota_size = user_quota_files = ULONG_LONG_MAX;
#endif
    }
    if (getcwd(wd, sizeof wd - (size_t) 1U) == NULL) {
        wd[0] = '/';
        wd[1] = 0;
    }
}

static AuthResult pw_check(const char *account, const char *password,
                           const struct sockaddr_storage * const sa,
                           const struct sockaddr_storage * const peer)
{
    Authentications *auth_scan = first_authentications;
    AuthResult result;

    result.auth_ok = -1;
    while (auth_scan != NULL) {
#ifdef THROTTLING
	result.throttling_bandwidth_ul = throttling_bandwidth_ul;
	result.throttling_bandwidth_dl = throttling_bandwidth_dl;
	result.throttling_ul_changed = result.throttling_dl_changed = 0;
#endif
#ifdef QUOTAS
	result.user_quota_size = user_quota_size;
	result.user_quota_files = user_quota_files;
	result.quota_size_changed = result.quota_files_changed = 0;
#endif
#ifdef RATIOS
	result.ratio_upload = ratio_upload;
	result.ratio_download = ratio_download;
	result.ratio_ul_changed = result.ratio_dl_changed = 0;
#endif
#ifdef PER_USER_LIMITS
	result.per_user_max = per_user_max;
#endif	
        auth_scan->auth->check(&result, account, password, sa, peer);
        if (result.auth_ok < 0) {
	    break;
	} else if (result.auth_ok > 0) {
#ifdef THROTTLING
            if ((result.throttling_ul_changed |
                 result.throttling_dl_changed) != 0) {
                if (result.throttling_ul_changed != 0 &&
                    result.throttling_bandwidth_ul > 0UL) {
                    throttling_bandwidth_ul = result.throttling_bandwidth_ul;
                    ul_chunk_size = throttling_bandwidth_ul;
                    if (ul_chunk_size > MAX_UL_CHUNK_SIZE) {
                        ul_chunk_size = MAX_UL_CHUNK_SIZE;
                    }
                }
                if (result.throttling_dl_changed != 0 &&
                    result.throttling_bandwidth_dl > 0UL) {
                    throttling_bandwidth_dl = result.throttling_bandwidth_dl;
                    dl_chunk_size = throttling_bandwidth_dl & ~(map_size - 1);
                    if (dl_chunk_size < map_size) {
                        dl_chunk_size = map_size;
                    }
                }
                throttling_delay = 1000000 /
                    (throttling_bandwidth_dl | throttling_bandwidth_ul);
                throttling = 2;
            }
#endif
#ifdef QUOTAS
            if (result.quota_size_changed != 0) {
                user_quota_size = result.user_quota_size;
            }
            if (result.quota_files_changed != 0) {
                user_quota_files = result.user_quota_files;
            }
#endif
#ifdef RATIOS
            if (result.ratio_ul_changed != 0) {
                ratio_upload = result.ratio_upload;
                ratio_for_non_anon = 1;
            }
            if (result.ratio_dl_changed != 0) {
                ratio_download = result.ratio_download;
            }
#endif
#ifdef PER_USER_LIMITS
            per_user_max = result.per_user_max;
#endif
            
#ifdef NON_ROOT_FTP
            result.uid = geteuid();
            result.gid = getegid();
#endif      
            
            return result;
        }
        auth_scan = auth_scan->next;
    }
    
    return result;
}

/*
 * Check if an user belongs to the trusted group, either in his
 * primary group, or his supplementary groups. Root is always trusted.
 */

static int check_trustedgroup(const uid_t uid, const gid_t gid)
{
    GETGROUPS_T *alloca_suppgroups;
    int n;
    int n2;
    int result = 0;

    if (uid == (uid_t) 0) {
        return 1;
    }
    if (userchroot == 2) {
        return 0;
    }
    if (gid == chroot_trustedgid) {
        return 1;
    }
#ifdef HAVE_GETGROUPS
    if ((n = getgroups(0, NULL)) <= 0) {
        return 0;
    }
    if ((alloca_suppgroups =
         ALLOCA(n * (sizeof *alloca_suppgroups))) == NULL) {
        die_mem();
    }
    n2 = getgroups(n, alloca_suppgroups);
    /* Jedi's paranoia */
    if (n2 < n) {
        n = n2;
    }
    result = 0;
    while (n != 0) {
        n--;
        if (alloca_suppgroups[n] == (GETGROUPS_T) chroot_trustedgid) {
            result = 1;
            break;
        }
    };
    ALLOCA_FREE(alloca_suppgroups);
#endif
    
    return result;
}

/*
 * Create a home directory on demand.
 */

static int create_home_and_chdir(const char * const home)
{
    char *pathcomp;
    char *z;    
    size_t len;
    const char delim = '/';        
    
    if (home == NULL || *home != '/') {
        return -1;
    }
    if (chdir(home) == 0) {
        return 0;
    }
    if (create_home == 0) {
        return -1;
    }
    len = strlen(home) + (size_t) 1U;
    if (len < (size_t) 2U || *home != delim) {
        return -1;
    }
    if ((pathcomp = ALLOCA(len)) == NULL) {
        return -1;
    }
    memcpy(pathcomp, home, len);       /* safe, no possible overflow */
    z = pathcomp;
    for (;;) {
        z++;        
        if (*z == 0) {
            break;
        }
        if (*z == delim) {
            *z = 0;            
            if (z[1] == 0) {
                break;
            }
            (void) mkdir(pathcomp, (mode_t) 0755);
            *z = delim;
        }
    }
    ALLOCA_FREE(pathcomp);
    (void) mkdir(home, (mode_t) 0700);
    if (chdir(home) != 0) {
	return -1;
    }
    if (chmod(home, (mode_t) 0755 & ~u_mask_d) < 0 ||
        chown(home, authresult.uid, authresult.gid) < 0) {
	return -1;
    }
    
    return chdir(home);
}

void dopass(char *password)
{
    static unsigned int tapping;    
    gid_t *groups = NULL;
    char *hd;
    int ngroups;
#if defined(NGROUPS_MAX) && NGROUPS_MAX > 0
    int ngroups_max = NGROUPS_MAX; /* Use the compile time value */
#else
    int ngroups_max = 1; /* use a sane default */
#endif
    
    if (loggedin != 0) {
        if (guest != 0) {
            addreply_noformat(230, MSG_NO_PASSWORD_NEEDED);
#ifdef LOG_ANON_EMAIL
            snprintf(account, sizeof account, "ftp: <%s> ", password);
#endif
        } else {
            addreply_noformat(530, MSG_CANT_DO_TWICE);
        }
        return;
    }
    if (*account == 0) {