X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fconf.c;h=a3c5f693f8052f7b1712ff0c7bccedf62c8154cb;hp=37bfe9469639d3fd423ff57566ec97e2ccc96e99;hb=ab33c1aa6081f07333bf1de00e4036dd2b4628a6;hpb=3ff76eb10acc55b6f269c1075de6bbaa5bc83516 diff --git a/src/conf.c b/src/conf.c index 37bfe946..a3c5f693 100644 --- a/src/conf.c +++ b/src/conf.c @@ -19,11 +19,12 @@ 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 1.9.4.30 2000/12/01 12:36:36 zarq Exp $ */ #include "config.h" +#include #include #include #include @@ -31,6 +32,9 @@ #include #include #include +#include +#include +#include #include #include /* for cp */ @@ -38,7 +42,6 @@ #include "conf.h" #include "netutl.h" /* for strtoip */ -#include "config.h" #include "system.h" config_t *config = NULL; @@ -130,6 +133,83 @@ cp } } +/* + 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)) + *buf = size; + return line; +} + /* Parse a configuration file and put the results in the configuration tree starting at *base. @@ -138,33 +218,36 @@ int read_config_file(config_t **base, const char *fname) { 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; + size_t bufsize; + cp if((fp = fopen (fname, "r")) == NULL) - { - return -1; - } + return -1; + bufsize = 100; + line = xmalloc(bufsize); + for(;;) { - if(fgets(line, MAXBUFSIZE, fp) == NULL) - { - err = 0; - break; - } - - lineno++; + if((line = readline(fp, line, &bufsize)) == NULL) + { + err = -1; + break; + } - if(!index(line, '\n')) - { - syslog(LOG_ERR, _("Line %d too long while reading config file %s"), lineno, fname); - break; - } + if(feof(fp)) + { + err = 0; + break; + } + + lineno++; - if((p = strtok(line, "\t\n\r =")) == NULL) + if((p = strtok(line, "\t =")) == NULL) continue; /* no tokens on this line */ if(p[0] == '#') @@ -176,23 +259,23 @@ cp if(!hazahaza[i].name) { - syslog(LOG_ERR, _("Invalid variable name on line %d while reading config file %s"), - lineno, fname); + syslog(LOG_ERR, _("Invalid variable name `%s' on line %d while reading config file %s"), + p, lineno, fname); break; } if(((q = strtok(NULL, "\t\n\r =")) == NULL) || q[0] == '#') { - fprintf(stderr, _("No value for variable on line %d while reading config file %s"), - lineno, fname); + fprintf(stderr, _("No value for variable `%s' on line %d while reading config file %s"), + hazahaza[i].name, lineno, fname); break; } cfg = add_config_val(base, hazahaza[i].argtype, q); if(cfg == NULL) { - fprintf(stderr, _("Invalid value for variable on line %d while reading config file %s"), - lineno, fname); + fprintf(stderr, _("Invalid value for variable `%s' on line %d while reading config file %s"), + hazahaza[i].name, lineno, fname); break; } @@ -201,6 +284,7 @@ cp config = cfg; } + free(line); fclose (fp); cp return err; @@ -256,43 +340,156 @@ cp 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); +} -FILE *ask_and_safe_open(const char* filename) +int is_safe_path(const char *file) +{ + char *p; + 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, 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, NULL)) == 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);