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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"
static errno_t perform_checks(struct stat *stat_buf,
uid_t uid, gid_t gid,
mode_t mode, mode_t mask);
errno_t check_file(const char *filename,
uid_t uid, uid_t gid, mode_t mode, mode_t mask,
struct stat *caller_stat_buf, bool follow_symlink)
{
int ret;
struct stat local_stat_buf;
struct stat *stat_buf;
if (caller_stat_buf == NULL) {
stat_buf = &local_stat_buf;
} else {
stat_buf = caller_stat_buf;
}
if (follow_symlink) {
ret = stat(filename, stat_buf);
} else {
ret = lstat(filename, stat_buf);
}
if (ret == -1) {
DEBUG(SSSDBG_TRACE_FUNC, "lstat for [%s] failed: [%d][%s].\n",
filename, errno, strerror(errno));
return errno;
}
return perform_checks(stat_buf, uid, gid, mode, mask);
}
errno_t check_fd(int fd, uid_t uid, gid_t gid,
mode_t mode, mode_t mask,
struct stat *caller_stat_buf)
{
int ret;
struct stat local_stat_buf;
struct stat *stat_buf;
if (caller_stat_buf == NULL) {
stat_buf = &local_stat_buf;
} else {
stat_buf = caller_stat_buf;
}
ret = fstat(fd, stat_buf);
if (ret == -1) {
DEBUG(SSSDBG_CRIT_FAILURE,
"fstat for [%d] failed: [%d][%s].\n", fd, errno,
strerror(errno));
return errno;
}
return perform_checks(stat_buf, uid, gid, mode, mask);
}
static errno_t perform_checks(struct stat *stat_buf,
uid_t uid, gid_t gid,
mode_t mode, mode_t mask)
{
mode_t st_mode;
if (mask) {
st_mode = stat_buf->st_mode & mask;
} else {
st_mode = stat_buf->st_mode & (S_IFMT|ALLPERMS);
}
if ((mode & S_IFMT) != (st_mode & S_IFMT)) {
DEBUG(SSSDBG_CRIT_FAILURE, "File is not the right type.\n");
return EINVAL;
}
if ((st_mode & ALLPERMS) != (mode & ALLPERMS)) {
DEBUG(SSSDBG_CRIT_FAILURE,
"File has the wrong (bit masked) mode [%.7o], "
"expected [%.7o].\n",
(st_mode & ALLPERMS), (mode & ALLPERMS));
return EINVAL;
}
if (uid != (uid_t)(-1) && stat_buf->st_uid != uid) {
DEBUG(SSSDBG_CRIT_FAILURE, "File must be owned by uid [%d].\n", uid);
return EINVAL;
}
if (gid != (gid_t)(-1) && stat_buf->st_gid != gid) {
DEBUG(SSSDBG_CRIT_FAILURE, "File must be owned by gid [%d].\n", gid);
return EINVAL;
}
return EOK;
}
errno_t check_and_open_readonly(const char *filename, int *fd,
uid_t uid, gid_t gid,
mode_t mode, mode_t mask)
{
int ret;
struct stat stat_buf;
*fd = open(filename, O_RDONLY);
if (*fd == -1) {
DEBUG(SSSDBG_CRIT_FAILURE,
"open [%s] failed: [%d][%s].\n", filename, errno,
strerror(errno));
return errno;
}
ret = check_fd(*fd, uid, gid, mode, mask, &stat_buf);
if (ret != EOK) {
close(*fd);
*fd = -1;
DEBUG(SSSDBG_CRIT_FAILURE, "check_fd failed.\n");
return ret;
}
return EOK;
}
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