7cb53855dc
We open the target path with O_DIRECTORY|O_NOFOLLOW, and if that doesn't work, we call unlink() on the path. In neither case we will follow the symlink, so we can relax our check to also not follow symlinks. Fixes #5864.
236 lines
8.4 KiB
C
236 lines
8.4 KiB
C
/***
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This file is part of systemd.
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Copyright 2015 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <fcntl.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <sys/stat.h>
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#include <sys/statfs.h>
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#include <unistd.h>
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#include "btrfs-util.h"
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#include "cgroup-util.h"
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#include "dirent-util.h"
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#include "fd-util.h"
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#include "log.h"
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#include "macro.h"
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#include "mount-util.h"
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#include "path-util.h"
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#include "rm-rf.h"
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#include "stat-util.h"
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#include "string-util.h"
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static bool is_physical_fs(const struct statfs *sfs) {
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return !is_temporary_fs(sfs) && !is_cgroup_fs(sfs);
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}
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int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
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_cleanup_closedir_ DIR *d = NULL;
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struct dirent *de;
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int ret = 0, r;
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struct statfs sfs;
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assert(fd >= 0);
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/* This returns the first error we run into, but nevertheless
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* tries to go on. This closes the passed fd. */
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if (!(flags & REMOVE_PHYSICAL)) {
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r = fstatfs(fd, &sfs);
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if (r < 0) {
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safe_close(fd);
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return -errno;
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}
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if (is_physical_fs(&sfs)) {
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/* We refuse to clean physical file systems
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* with this call, unless explicitly
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* requested. This is extra paranoia just to
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* be sure we never ever remove non-state
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* data */
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log_error("Attempted to remove disk file system, and we can't allow that.");
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safe_close(fd);
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return -EPERM;
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}
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}
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d = fdopendir(fd);
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if (!d) {
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safe_close(fd);
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return errno == ENOENT ? 0 : -errno;
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}
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FOREACH_DIRENT_ALL(de, d, return -errno) {
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bool is_dir;
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struct stat st;
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if (dot_or_dot_dot(de->d_name))
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continue;
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if (de->d_type == DT_UNKNOWN ||
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(de->d_type == DT_DIR && (root_dev || (flags & REMOVE_SUBVOLUME)))) {
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if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
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if (ret == 0 && errno != ENOENT)
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ret = -errno;
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continue;
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}
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is_dir = S_ISDIR(st.st_mode);
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} else
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is_dir = de->d_type == DT_DIR;
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if (is_dir) {
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int subdir_fd;
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/* if root_dev is set, remove subdirectories only if device is same */
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if (root_dev && st.st_dev != root_dev->st_dev)
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continue;
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subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
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if (subdir_fd < 0) {
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if (ret == 0 && errno != ENOENT)
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ret = -errno;
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continue;
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}
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/* Stop at mount points */
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r = fd_is_mount_point(fd, de->d_name, 0);
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if (r < 0) {
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if (ret == 0 && r != -ENOENT)
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ret = r;
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safe_close(subdir_fd);
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continue;
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}
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if (r) {
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safe_close(subdir_fd);
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continue;
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}
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if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {
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/* This could be a subvolume, try to remove it */
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r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
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if (r < 0) {
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if (r != -ENOTTY && r != -EINVAL) {
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if (ret == 0)
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ret = r;
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safe_close(subdir_fd);
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continue;
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}
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/* ENOTTY, then it wasn't a
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* btrfs subvolume, continue
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* below. */
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} else {
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/* It was a subvolume, continue. */
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safe_close(subdir_fd);
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continue;
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}
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}
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/* We pass REMOVE_PHYSICAL here, to avoid
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* doing the fstatfs() to check the file
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* system type again for each directory */
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r = rm_rf_children(subdir_fd, flags | REMOVE_PHYSICAL, root_dev);
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if (r < 0 && ret == 0)
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ret = r;
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if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
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if (ret == 0 && errno != ENOENT)
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ret = -errno;
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}
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} else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {
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if (unlinkat(fd, de->d_name, 0) < 0) {
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if (ret == 0 && errno != ENOENT)
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ret = -errno;
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}
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}
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}
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return ret;
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}
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int rm_rf(const char *path, RemoveFlags flags) {
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int fd, r;
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struct statfs s;
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assert(path);
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/* We refuse to clean the root file system with this
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* call. This is extra paranoia to never cause a really
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* seriously broken system. */
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if (path_equal_or_files_same(path, "/", AT_SYMLINK_NOFOLLOW)) {
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log_error("Attempted to remove entire root file system, and we can't allow that.");
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return -EPERM;
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}
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if ((flags & (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) == (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) {
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/* Try to remove as subvolume first */
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r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
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if (r >= 0)
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return r;
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if (r != -ENOTTY && r != -EINVAL && r != -ENOTDIR)
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return r;
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/* Not btrfs or not a subvolume */
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}
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fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
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if (fd < 0) {
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if (errno != ENOTDIR && errno != ELOOP)
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return -errno;
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if (!(flags & REMOVE_PHYSICAL)) {
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if (statfs(path, &s) < 0)
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return -errno;
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if (is_physical_fs(&s)) {
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log_error("Attempted to remove disk file system, and we can't allow that.");
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return -EPERM;
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}
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}
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if ((flags & REMOVE_ROOT) && !(flags & REMOVE_ONLY_DIRECTORIES))
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if (unlink(path) < 0 && errno != ENOENT)
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return -errno;
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return 0;
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}
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r = rm_rf_children(fd, flags, NULL);
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if (flags & REMOVE_ROOT) {
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if (rmdir(path) < 0) {
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if (r == 0 && errno != ENOENT)
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r = -errno;
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}
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}
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return r;
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}
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