X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fread_conf.c;fp=src%2Fread_conf.c;h=c41fff012cd4ff4f7ccfe2846982e41775019fc3;hb=04d33be4bd102de67bb6dba5c449e12fea0db4d2;hp=0000000000000000000000000000000000000000;hpb=b0a676988a8da3120e64ef0e1a4ea4c28b1511e1;p=tinc diff --git a/src/read_conf.c b/src/read_conf.c new file mode 100644 index 00000000..c41fff01 --- /dev/null +++ b/src/read_conf.c @@ -0,0 +1,411 @@ +/* + read_conf.c -- read the configuration files + Copyright (C) 1998 Robert van der Meulen + 1998-2002 Ivo Timmermans + 2000-2002 Guus Sliepen + 2000 Cris van Pelt + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + + $Id: read_conf.c,v 1.1 2002/04/28 12:46:26 zarq Exp $ +*/ + +#include "config.h" + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include /* for cp */ +#include + +#include "conf.h" +#include "netutl.h" /* for str2address */ +#include "logging.h" + +#include "system.h" + +/* + Read exactly one line and strip the trailing newline if any. If the + file was on EOF, return NULL. Otherwise, return all the data in a + dynamically allocated buffer. + + If line is non-NULL, it will be used as an initial buffer, to avoid + unnecessary mallocing each time this function is called. If buf is + given, and buf needs to be expanded, the var pointed to by buflen + will be increased. +*/ +char *readline(FILE *fp, char **buf, size_t *buflen) +{ + char *newline = NULL; + char *p; + char *line; /* The array that contains everything that has been read + so far */ + char *idx; /* Read into this pointer, which points to an offset + within line */ + size_t size, newsize; /* The size of the current array pointed to by + line */ + size_t maxlen; /* Maximum number of characters that may be read with + fgets. This is newsize - oldsize. */ + + if(feof(fp)) + return NULL; + + if((buf != NULL) && (buflen != NULL)) + { + size = *buflen; + line = *buf; + } + else + { + size = 100; + line = xmalloc(size); + } + + maxlen = size; + idx = line; + *idx = 0; + for(;;) + { + errno = 0; + p = fgets(idx, maxlen, fp); + if(p == NULL) /* EOF or error */ + { + if(feof(fp)) + break; + + /* otherwise: error; let the calling function print an error + message if applicable */ + free(line); + return NULL; + } + + newline = strchr(p, '\n'); + if(newline == NULL) + /* We haven't yet read everything to the end of the line */ + { + newsize = size << 1; + line = xrealloc(line, newsize); + idx = &line[size - 1]; + maxlen = newsize - size + 1; + size = newsize; + } + else + { + *newline = '\0'; /* kill newline */ + break; /* yay */ + } + } + + if((buf != NULL) && (buflen != NULL)) + { + *buflen = size; + *buf = line; + } + return line; +} + +/* + Parse a configuration file and put the results in the configuration tree + starting at *base. +*/ +int read_config_file(avl_tree_t *config_tree, const char *fname) +{ + int err = -2; /* Parse error */ + FILE *fp; + char *buffer, *line; + char *variable, *value; + int lineno = 0, ignore = 0; + config_t *cfg; + size_t bufsize; + +cp + if((fp = fopen (fname, "r")) == NULL) + { + syslog(LOG_ERR, _("Cannot open config file %s: %s"), fname, strerror(errno)); + return -3; + } + + bufsize = 100; + buffer = xmalloc(bufsize); + + for(;;) + { + if((line = readline(fp, &buffer, &bufsize)) == NULL) + { + err = -1; + break; + } + + if(feof(fp)) + { + err = 0; + break; + } + + lineno++; + + if((variable = strtok(line, "\t =")) == NULL) + continue; /* no tokens on this line */ + + if(variable[0] == '#') + continue; /* comment: ignore */ + + if(!strcmp(variable, "-----BEGIN")) + ignore = 1; + + if(!ignore) + { + if(((value = strtok(NULL, "\t\n\r =")) == NULL) || value[0] == '#') + { + syslog(LOG_ERR, _("No value for variable `%s' on line %d while reading config file %s"), + variable, lineno, fname); + break; + } + + cfg = new_config(); + cfg->variable = xstrdup(variable); + cfg->value = xstrdup(value); + cfg->file = xstrdup(fname); + cfg->line = lineno; + + config_add(config_tree, cfg); + } + + if(!strcmp(variable, "-----END")) + ignore = 0; + } + + free(buffer); + fclose (fp); +cp + return err; +} + +int read_server_config() +{ + char *fname; + int x; +cp + asprintf(&fname, "%s/tinc.conf", confbase); + x = read_config_file(config_tree, fname); + if(x == -1) /* System error: complain */ + { + syslog(LOG_ERR, _("Failed to read `%s': %s"), fname, strerror(errno)); + } + free(fname); +cp + return x; +} + +int isadir(const char* f) +{ + struct stat s; + + if(stat(f, &s) < 0) + return 0; + else + return S_ISDIR(s.st_mode); +} + +int is_safe_path(const char *file) +{ + char *p; + const char *f; + char x; + struct stat s; + char l[MAXBUFSIZE]; + + if(*file != '/') + { + syslog(LOG_ERR, _("`%s' is not an absolute path"), file); + return 0; + } + + p = strrchr(file, '/'); + + if(p == file) /* It's in the root */ + p++; + + x = *p; + *p = '\0'; + + f = file; +check1: + if(lstat(f, &s) < 0) + { + syslog(LOG_ERR, _("Couldn't stat `%s': %s"), f, strerror(errno)); + return 0; + } + + if(s.st_uid != geteuid()) + { + syslog(LOG_ERR, _("`%s' is owned by UID %d instead of %d"), + f, s.st_uid, geteuid()); + return 0; + } + + if(S_ISLNK(s.st_mode)) + { + syslog(LOG_WARNING, _("Warning: `%s' is a symlink"), + f); + + if(readlink(f, l, MAXBUFSIZE) < 0) + { + syslog(LOG_ERR, _("Unable to read symbolic link `%s': %s"), f, strerror(errno)); + return 0; + } + + f = l; + goto check1; + } + + *p = x; + f = file; + +check2: + if(lstat(f, &s) < 0 && errno != ENOENT) + { + syslog(LOG_ERR, _("Couldn't stat `%s': %s"), f, strerror(errno)); + return 0; + } + + if(errno == ENOENT) + return 1; + + if(s.st_uid != geteuid()) + { + syslog(LOG_ERR, _("`%s' is owned by UID %d instead of %d"), + f, s.st_uid, geteuid()); + return 0; + } + + if(S_ISLNK(s.st_mode)) + { + syslog(LOG_WARNING, _("Warning: `%s' is a symlink"), + f); + + if(readlink(f, l, MAXBUFSIZE) < 0) + { + syslog(LOG_ERR, _("Unable to read symbolic link `%s': %s"), f, strerror(errno)); + return 0; + } + + f = l; + goto check2; + } + + if(s.st_mode & 0007) + { + /* Accessible by others */ + syslog(LOG_ERR, _("`%s' has unsecure permissions"), + f); + return 0; + } + + return 1; +} + +FILE *ask_and_safe_open(const char* filename, const char* what, const char* mode) +{ + FILE *r; + char *directory; + char *fn; + + /* Check stdin and stdout */ + if(!isatty(0) || !isatty(1)) + { + /* Argh, they are running us from a script or something. Write + the files to the current directory and let them burn in hell + for ever. */ + fn = xstrdup(filename); + } + else + { + /* Ask for a file and/or directory name. */ + fprintf(stdout, _("Please enter a file to save %s to [%s]: "), + what, filename); + fflush(stdout); + + if((fn = readline(stdin, NULL, NULL)) == NULL) + { + fprintf(stderr, _("Error while reading stdin: %s\n"), strerror(errno)); + return NULL; + } + + if(strlen(fn) == 0) + /* User just pressed enter. */ + fn = xstrdup(filename); + } + + if((strchr(fn, '/') == NULL) || (fn[0] != '/')) + { + /* The directory is a relative path or a filename. */ + char *p; + + directory = get_current_dir_name(); + asprintf(&p, "%s/%s", directory, fn); + free(fn); + free(directory); + fn = p; + } + + umask(0077); /* Disallow everything for group and other */ + + /* Open it first to keep the inode busy */ + if((r = fopen(fn, mode)) == NULL) + { + fprintf(stderr, _("Error opening file `%s': %s\n"), + fn, strerror(errno)); + free(fn); + return NULL; + } + + /* Then check the file for nasty attacks */ + if(!is_safe_path(fn)) /* Do not permit any directories that are + readable or writeable by other users. */ + { + fprintf(stderr, _("The file `%s' (or any of the leading directories) has unsafe permissions.\n" + "I will not create or overwrite this file.\n"), + fn); + fclose(r); + free(fn); + return NULL; + } + + free(fn); + + return r; +} + +int read_connection_config(connection_t *c) +{ + char *fname; + int x; +cp + asprintf(&fname, "%s/hosts/%s", confbase, c->name); + x = read_config_file(c->config_tree, fname); + free(fname); +cp + return x; +}