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/*
SSSD
Check file permissions and open file
Authors:
Sumit Bose <sbose@redhat.com>
Copyright (C) 2009 Red Hat
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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "util/util.h"
errno_t check_file(const char *filename, const int uid, const int gid,
const int mode, enum check_file_type type,
struct stat *caller_stat_buf)
{
int ret;
struct stat local_stat_buf;
struct stat *stat_buf;
bool type_check;
if (caller_stat_buf == NULL) {
stat_buf = &local_stat_buf;
} else {
stat_buf = caller_stat_buf;
}
ret = lstat(filename, stat_buf);
if (ret == -1) {
DEBUG(1, ("lstat for [%s] failed: [%d][%s].\n", filename, errno,
strerror(errno)));
return errno;
}
switch (type) {
case CHECK_DONT_CHECK_FILE_TYPE:
type_check = true;
break;
case CHECK_REG:
type_check = S_ISREG(stat_buf->st_mode);
break;
case CHECK_DIR:
type_check = S_ISDIR(stat_buf->st_mode);
break;
case CHECK_CHR:
type_check = S_ISCHR(stat_buf->st_mode);
break;
case CHECK_BLK:
type_check = S_ISBLK(stat_buf->st_mode);
break;
case CHECK_FIFO:
type_check = S_ISFIFO(stat_buf->st_mode);
break;
case CHECK_LNK:
type_check = S_ISLNK(stat_buf->st_mode);
break;
case CHECK_SOCK:
type_check = S_ISSOCK(stat_buf->st_mode);
break;
default:
DEBUG(1, ("Unsupprted file type.\n"));
return EINVAL;
}
if (!type_check) {
DEBUG(1, ("File [%s] is not the right type.\n", filename));
return EINVAL;
}
if (mode >= 0 && (stat_buf->st_mode & ~S_IFMT) != mode) {
DEBUG(1, ("File [%s] has the wrong mode [%.7o], expected [%.7o].\n",
filename, (stat_buf->st_mode & ~S_IFMT), mode));
return EINVAL;
}
if (uid >= 0 && stat_buf->st_uid != uid) {
DEBUG(1, ("File [%s] must be owned by uid [%d].\n", filename, uid));
return EINVAL;
}
if (gid >= 0 && stat_buf->st_gid != gid) {
DEBUG(1, ("File [%s] must be owned by gid [%d].\n", filename, gid));
return EINVAL;
}
return EOK;
}
errno_t check_and_open_readonly(const char *filename, int *fd, const uid_t uid,
const gid_t gid, const mode_t mode,
enum check_file_type type)
{
int ret;
struct stat stat_buf;
struct stat fd_stat_buf;
*fd = -1;
ret = check_file(filename, uid, gid, mode, type, &stat_buf);
if (ret != EOK) {
DEBUG(1, ("check_file failed.\n"));
return ret;
}
*fd = open(filename, O_RDONLY);
if (*fd == -1) {
DEBUG(1, ("open [%s] failed: [%d][%s].\n", filename, errno,
strerror(errno)));
return errno;
}
ret = fstat(*fd, &fd_stat_buf);
if (ret == -1) {
DEBUG(1, ("fstat for [%s] failed: [%d][%s].\n", filename, errno,
strerror(errno)));
return errno;
}
if (stat_buf.st_dev != fd_stat_buf.st_dev ||
stat_buf.st_ino != fd_stat_buf.st_ino) {
DEBUG(1, ("File [%s] was modified between lstat and open.\n", filename));
close(*fd);
*fd = -1;
return EIO;
}
return EOK;
}
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