From 8a52ef658cf7c6117cbbd19c2807c30bb798e436 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Mon, 1 Jul 2013 16:13:46 +0200 Subject: lib/canonical: use realpath() from libc .. after many many years it seems that we can follow libc code rather than duplicate realpath(3) implementation. Signed-off-by: Karel Zak --- lib/canonicalize.c | 180 +++++++++-------------------------------------------- 1 file changed, 29 insertions(+), 151 deletions(-) (limited to 'lib/canonicalize.c') diff --git a/lib/canonicalize.c b/lib/canonicalize.c index 548e29b75..cac60d7a4 100644 --- a/lib/canonicalize.c +++ b/lib/canonicalize.c @@ -1,24 +1,10 @@ /* * canonicalize.c -- canonicalize pathname by removing symlinks - * Copyright (C) 1993 Rick Sladkey * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU Library Public License as published by - * the Free Software Foundation; either version 2, 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 Library Public License for more details. + * This file may be distributed under the terms of the + * GNU Lesser General Public License. * - */ - -/* - * This routine is part of libc. We include it nevertheless, - * since the libc version has some security flaws. - * - * TODO: use canonicalize_file_name() when exist in glibc + * Copyright (C) 2009-2013 Karel Zak */ #include #include @@ -26,126 +12,18 @@ #include #include #include +#include +#include #include "canonicalize.h" -#ifndef MAXSYMLINKS -# define MAXSYMLINKS 256 -#endif - -static char * -myrealpath(const char *path, char *resolved_path, int maxreslth) { - int readlinks = 0; - char *npath; - char link_path[PATH_MAX+1]; - int n; - char *buf = NULL; - - npath = resolved_path; - - /* If it's a relative pathname use getcwd for starters. */ - if (*path != '/') { - if (!getcwd(npath, maxreslth-2)) - return NULL; - npath += strlen(npath); - if (npath[-1] != '/') - *npath++ = '/'; - } else { - *npath++ = '/'; - path++; - } - - /* Expand each slash-separated pathname component. */ - while (*path != '\0') { - /* Ignore stray "/" */ - if (*path == '/') { - path++; - continue; - } - if (*path == '.' && (path[1] == '\0' || path[1] == '/')) { - /* Ignore "." */ - path++; - continue; - } - if (*path == '.' && path[1] == '.' && - (path[2] == '\0' || path[2] == '/')) { - /* Backup for ".." */ - path += 2; - while (npath > resolved_path+1 && - (--npath)[-1] != '/') - ; - continue; - } - /* Safely copy the next pathname component. */ - while (*path != '\0' && *path != '/') { - if (npath-resolved_path > maxreslth-2) { - errno = ENAMETOOLONG; - goto err; - } - *npath++ = *path++; - } - - /* Protect against infinite loops. */ - if (readlinks++ > MAXSYMLINKS) { - errno = ELOOP; - goto err; - } - - /* See if last pathname component is a symlink. */ - *npath = '\0'; - n = readlink(resolved_path, link_path, PATH_MAX); - if (n < 0) { - /* EINVAL means the file exists but isn't a symlink. */ - if (errno != EINVAL) - goto err; - } else { - int m; - char *newbuf; - - /* Note: readlink doesn't add the null byte. */ - link_path[n] = '\0'; - if (*link_path == '/') - /* Start over for an absolute symlink. */ - npath = resolved_path; - else - /* Otherwise back up over this component. */ - while (*(--npath) != '/') - ; - - /* Insert symlink contents into path. */ - m = strlen(path); - newbuf = malloc(m + n + 1); - if (!newbuf) - goto err; - memcpy(newbuf, link_path, n); - memcpy(newbuf + n, path, m + 1); - free(buf); - path = buf = newbuf; - } - *npath++ = '/'; - } - /* Delete trailing slash but don't whomp a lone slash. */ - if (npath != resolved_path+1 && npath[-1] == '/') - npath--; - /* Make sure it's null terminated. */ - *npath = '\0'; - - free(buf); - return resolved_path; - - err: - free(buf); - return NULL; -} - /* * Converts private "dm-N" names to "/dev/mapper/" * * Since 2.6.29 (patch 784aae735d9b0bba3f8b9faef4c8b30df3bf0128) kernel sysfs * provides the real DM device names in /sys/block//dm/name */ -char * -canonicalize_dm_name(const char *ptname) +char *canonicalize_dm_name(const char *ptname) { FILE *f; size_t sz; @@ -170,34 +48,32 @@ canonicalize_dm_name(const char *ptname) return res; } -char * -canonicalize_path(const char *path) +char *canonicalize_path(const char *path) { - char canonical[PATH_MAX+2]; - char *p; + char *canonical, *p; if (!path || !*path) return NULL; - if (!myrealpath(path, canonical, PATH_MAX+1)) + canonical = realpath(path, NULL); + if (!canonical) return strdup(path); - p = strrchr(canonical, '/'); if (p && strncmp(p, "/dm-", 4) == 0 && isdigit(*(p + 4))) { - p = canonicalize_dm_name(p+1); - if (p) - return p; + char *dm = canonicalize_dm_name(p + 1); + if (dm) { + free(canonical); + return dm; + } } - return strdup(canonical); + return canonical; } -char * -canonicalize_path_restricted(const char *path) +char *canonicalize_path_restricted(const char *path) { - char canonical[PATH_MAX+2]; - char *p = NULL; + char *canonical, *p = NULL; int errsv; uid_t euid; gid_t egid; @@ -214,25 +90,27 @@ canonicalize_path_restricted(const char *path) errsv = errno = 0; - if (myrealpath(path, canonical, PATH_MAX+1)) { + canonical = realpath(path, NULL); + if (canonical) { p = strrchr(canonical, '/'); - if (p && strncmp(p, "/dm-", 4) == 0 && isdigit(*(p + 4))) - p = canonicalize_dm_name(p+1); - else - p = NULL; - if (!p) - p = strdup(canonical); + if (p && strncmp(p, "/dm-", 4) == 0 && isdigit(*(p + 4))) { + char *dm = canonicalize_dm_name(p + 1); + if (dm) { + free(canonical); + canonical = dm; + } + } } else errsv = errno; /* restore */ if (setegid(egid) < 0 || seteuid(euid) < 0) { - free(p); + free(canonical); return NULL; } errno = errsv; - return p; + return canonical; } -- cgit v1.2.3-55-g7522