along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- $Id: conf.c,v 1.9.4.23 2000/11/28 23:12:56 zarq Exp $
+ $Id: conf.c,v 1.9.4.28 2000/11/30 21:11:03 zarq Exp $
*/
#include "config.h"
+#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
#include <xalloc.h>
#include <utils.h> /* for cp */
#include "conf.h"
#include "netutl.h" /* for strtoip */
-#include "config.h"
#include "system.h"
config_t *config = NULL;
}
}
+/*
+ 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.
+*/
+char *readline(FILE *fp)
+{
+ 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;
+
+ size = 100;
+ maxlen = size;
+ line = xmalloc(size);
+ idx = line;
+ 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 */
+ }
+ }
+
+ return line;
+}
+
/*
Parse a configuration file and put the results in the configuration tree
starting at *base.
{
int err = -1;
FILE *fp;
- char line[MAXBUFSIZE]; /* There really should not be any line longer than this... */
+ char *line;
char *p, *q;
int i, lineno = 0;
config_t *cfg;
cp
if((fp = fopen (fname, "r")) == NULL)
- {
- return -1;
- }
+ return -1;
for(;;)
{
- if(fgets(line, MAXBUFSIZE, fp) == NULL)
- {
- err = 0;
- break;
- }
+ if((line = readline(fp)) == NULL)
+ {
+ err = -1;
+ break;
+ }
lineno++;
- if(!index(line, '\n'))
- {
- syslog(LOG_ERR, _("Line %d too long while reading config file %s"), lineno, fname);
- break;
- }
-
- if((p = strtok(line, "\t\n\r =")) == NULL)
+ if((p = strtok(line, "\t =")) == NULL)
continue; /* no tokens on this line */
if(p[0] == '#')
cfg->which = hazahaza[i].which;
if(!config)
config = cfg;
+ free(line);
}
+ free(line);
fclose (fp);
cp
return err;
cp
}
-#define is_safe_file(p) 1
+int isadir(const char* f)
+{
+ struct stat s;
+
+ if(stat(f, &s) < 0)
+ {
+ fprintf(stderr, _("Couldn't stat `%s': %m\n"),
+ f);
+ return -1;
+ }
+
+ return S_ISDIR(s.st_mode);
+}
+
+int is_safe_path(const char *file)
+{
+ char *p;
+ char *fn = xstrdup(file);
+ struct stat s;
+
+ p = strrchr(file, '/');
+ assert(p); /* p has to contain a / */
+ *p = '\0';
+ if(stat(file, &s) < 0)
+ {
+ fprintf(stderr, _("Couldn't stat `%s': %m\n"),
+ file);
+ return 0;
+ }
+ if(s.st_uid != geteuid())
+ {
+ fprintf(stderr, _("`%s' is owned by UID %d instead of %d.\n"),
+ file, s.st_uid, geteuid());
+ return 0;
+ }
+ if(S_ISLNK(s.st_mode))
+ {
+ fprintf(stderr, _("Warning: `%s' is a symlink\n"),
+ file);
+ /* fixme: read the symlink and start again */
+ }
+
+ *p = '/';
+ if(stat(file, &s) < 0 && errno != ENOENT)
+ {
+ fprintf(stderr, _("Couldn't stat `%s': %m\n"),
+ file);
+ return 0;
+ }
+ if(errno == ENOENT)
+ return 1;
+ if(s.st_uid != geteuid())
+ {
+ fprintf(stderr, _("`%s' is owned by UID %d instead of %d.\n"),
+ file, s.st_uid, geteuid());
+ return 0;
+ }
+ if(S_ISLNK(s.st_mode))
+ {
+ fprintf(stderr, _("Warning: `%s' is a symlink\n"),
+ file);
+ /* fixme: read the symlink and start again */
+ }
+ if(s.st_mode & 0007)
+ {
+ /* Accessible by others */
+ fprintf(stderr, _("`%s' has unsecure permissions.\n"),
+ file);
+ return 0;
+ }
+
+ return 1;
+}
-FILE *ask_and_safe_open(const char* filename)
+FILE *ask_and_safe_open(const char* filename, const char* what)
{
FILE *r;
char *directory;
char *fn;
int len;
- if(!isatty(0))
+ /* 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. */
- directory = "."; /* get_current_directory */
+ fn = xstrdup(filename);
}
else
{
- directory = ".";
+ /* Ask for a file and/or directory name. */
+ fprintf(stdout, _("Please enter a file to save %s to [%s]: "),
+ what, filename);
+ fflush(stdout); /* Don't wait for a newline */
+ if((fn = readline(stdin)) == NULL)
+ {
+ fprintf(stderr, _("Error while reading stdin: %m\n"));
+ return NULL;
+ }
+ if(strlen(fn) == 0)
+ /* User just pressed enter. */
+ fn = xstrdup(filename);
}
- len = strlen(filename) + strlen(directory) + 2; /* 1 for the / */
- fn = xmalloc(len);
- snprintf(fn, len, "%s/%s", directory, filename);
+ if((strchr(fn, '/') == NULL) || (fn[0] != '/'))
+ {
+ /* The directory is a relative path or a filename. */
+ char *p;
+
+ directory = get_current_dir_name();
+ len = strlen(fn) + strlen(directory) + 2; /* 1 for the / */
+ p = xmalloc(len);
+ snprintf(p, len, "%s/%s", directory, fn);
+ free(fn);
+ free(directory);
+ fn = p;
+ }
- if(!is_safe_file(fn))
+ if(isadir(fn) > 0) /* -1 is error */
{
- 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);
- return NULL;
+ char *p;
+
+ len = strlen(fn) + strlen(filename) + 2; /* 1 for the / */
+ p = xmalloc(len);
+ snprintf(p, len, "%s/%s", fn, filename);
+ free(fn);
+ fn = p;
}
+ umask(0077); /* Disallow everything for group and other */
+
+ /* Open it first to keep the inode busy */
if((r = fopen(fn, "w")) == NULL)
{
- fprintf(stderr, _("Error opening file `%s': %m"),
+ fprintf(stderr, _("Error opening file `%s': %m\n"),
fn);
+ 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);
projects / tinc / blobdiff