From 2cb7e0aaedad73b076ea18c6900b0e86c5760d79 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 15:00:47 +0200 Subject: Adding upstream version 247.3. Signed-off-by: Daniel Baumann --- src/basic/rm-rf.c | 265 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 265 insertions(+) create mode 100644 src/basic/rm-rf.c (limited to 'src/basic/rm-rf.c') diff --git a/src/basic/rm-rf.c b/src/basic/rm-rf.c new file mode 100644 index 0000000..b0d682f --- /dev/null +++ b/src/basic/rm-rf.c @@ -0,0 +1,265 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include +#include +#include +#include +#include + +#include "alloc-util.h" +#include "btrfs-util.h" +#include "cgroup-util.h" +#include "dirent-util.h" +#include "fd-util.h" +#include "log.h" +#include "macro.h" +#include "mountpoint-util.h" +#include "path-util.h" +#include "rm-rf.h" +#include "stat-util.h" +#include "string-util.h" + +static bool is_physical_fs(const struct statfs *sfs) { + return !is_temporary_fs(sfs) && !is_cgroup_fs(sfs); +} + +static int unlinkat_harder( + int dfd, + const char *filename, + int unlink_flags, + RemoveFlags remove_flags) { + + struct stat st; + int r; + + /* Like unlinkat(), but tries harder: if we get EACCESS we'll try to set the r/w/x bits on the + * directory. This is useful if we run unprivileged and have some files where the w bit is + * missing. */ + + if (unlinkat(dfd, filename, unlink_flags) >= 0) + return 0; + if (errno != EACCES || !FLAGS_SET(remove_flags, REMOVE_CHMOD)) + return -errno; + + if (fstat(dfd, &st) < 0) + return -errno; + if (!S_ISDIR(st.st_mode)) + return -ENOTDIR; + if (FLAGS_SET(st.st_mode, 0700)) /* Already set? */ + return -EACCES; /* original error */ + if (st.st_uid != geteuid()) /* this only works if the UID matches ours */ + return -EACCES; + + if (fchmod(dfd, (st.st_mode | 0700) & 07777) < 0) + return -errno; + + if (unlinkat(dfd, filename, unlink_flags) < 0) { + r = -errno; + /* Try to restore the original access mode if this didn't work */ + (void) fchmod(dfd, st.st_mode & 07777); + return r; + } + + return 0; +} + +int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) { + _cleanup_closedir_ DIR *d = NULL; + struct dirent *de; + int ret = 0, r; + struct statfs sfs; + + assert(fd >= 0); + + /* This returns the first error we run into, but nevertheless tries to go on. This closes the passed + * fd, in all cases, including on failure.. */ + + if (!(flags & REMOVE_PHYSICAL)) { + + r = fstatfs(fd, &sfs); + if (r < 0) { + safe_close(fd); + return -errno; + } + + if (is_physical_fs(&sfs)) { + /* We refuse to clean physical file systems with this call, + * unless explicitly requested. This is extra paranoia just + * to be sure we never ever remove non-state data. */ + _cleanup_free_ char *path = NULL; + + (void) fd_get_path(fd, &path); + log_error("Attempted to remove disk file system under \"%s\", and we can't allow that.", + strna(path)); + + safe_close(fd); + return -EPERM; + } + } + + d = fdopendir(fd); + if (!d) { + safe_close(fd); + return errno == ENOENT ? 0 : -errno; + } + + FOREACH_DIRENT_ALL(de, d, return -errno) { + bool is_dir; + struct stat st; + + if (dot_or_dot_dot(de->d_name)) + continue; + + if (de->d_type == DT_UNKNOWN || + (de->d_type == DT_DIR && (root_dev || (flags & REMOVE_SUBVOLUME)))) { + if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) { + if (ret == 0 && errno != ENOENT) + ret = -errno; + continue; + } + + is_dir = S_ISDIR(st.st_mode); + } else + is_dir = de->d_type == DT_DIR; + + if (is_dir) { + _cleanup_close_ int subdir_fd = -1; + + /* if root_dev is set, remove subdirectories only if device is same */ + if (root_dev && st.st_dev != root_dev->st_dev) + continue; + + subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); + if (subdir_fd < 0) { + if (ret == 0 && errno != ENOENT) + ret = -errno; + continue; + } + + /* Stop at mount points */ + r = fd_is_mount_point(fd, de->d_name, 0); + if (r < 0) { + if (ret == 0 && r != -ENOENT) + ret = r; + + continue; + } + if (r > 0) + continue; + + if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) { + + /* This could be a subvolume, try to remove it */ + + r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA); + if (r < 0) { + if (!IN_SET(r, -ENOTTY, -EINVAL)) { + if (ret == 0) + ret = r; + + continue; + } + + /* ENOTTY, then it wasn't a btrfs subvolume, continue below. */ + } else + /* It was a subvolume, continue. */ + continue; + } + + /* We pass REMOVE_PHYSICAL here, to avoid doing the fstatfs() to check the file + * system type again for each directory */ + r = rm_rf_children(TAKE_FD(subdir_fd), flags | REMOVE_PHYSICAL, root_dev); + if (r < 0 && ret == 0) + ret = r; + + r = unlinkat_harder(fd, de->d_name, AT_REMOVEDIR, flags); + if (r < 0 && r != -ENOENT && ret == 0) + ret = r; + + } else if (!(flags & REMOVE_ONLY_DIRECTORIES)) { + + r = unlinkat_harder(fd, de->d_name, 0, flags); + if (r < 0 && r != -ENOENT && ret == 0) + ret = r; + } + } + return ret; +} + +int rm_rf(const char *path, RemoveFlags flags) { + int fd, r; + struct statfs s; + + assert(path); + + /* For now, don't support dropping subvols when also only dropping directories, since we can't do + * this race-freely. */ + if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES|REMOVE_SUBVOLUME)) + return -EINVAL; + + /* We refuse to clean the root file system with this call. This is extra paranoia to never cause a + * really seriously broken system. */ + if (path_equal_or_files_same(path, "/", AT_SYMLINK_NOFOLLOW)) + return log_error_errno(SYNTHETIC_ERRNO(EPERM), + "Attempted to remove entire root file system (\"%s\"), and we can't allow that.", + path); + + if (FLAGS_SET(flags, REMOVE_SUBVOLUME | REMOVE_ROOT | REMOVE_PHYSICAL)) { + /* Try to remove as subvolume first */ + r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA); + if (r >= 0) + return r; + + if (FLAGS_SET(flags, REMOVE_MISSING_OK) && r == -ENOENT) + return 0; + + if (!IN_SET(r, -ENOTTY, -EINVAL, -ENOTDIR)) + return r; + + /* Not btrfs or not a subvolume */ + } + + fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); + if (fd < 0) { + if (FLAGS_SET(flags, REMOVE_MISSING_OK) && errno == ENOENT) + return 0; + + if (!IN_SET(errno, ENOTDIR, ELOOP)) + return -errno; + + if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES)) + return 0; + + if (FLAGS_SET(flags, REMOVE_ROOT)) { + + if (!FLAGS_SET(flags, REMOVE_PHYSICAL)) { + if (statfs(path, &s) < 0) + return -errno; + + if (is_physical_fs(&s)) + return log_error_errno(SYNTHETIC_ERRNO(EPERM), + "Attempted to remove files from a disk file system under \"%s\", refusing.", + path); + } + + if (unlink(path) < 0) { + if (FLAGS_SET(flags, REMOVE_MISSING_OK) && errno == ENOENT) + return 0; + + return -errno; + } + } + + return 0; + } + + r = rm_rf_children(fd, flags, NULL); + + if (FLAGS_SET(flags, REMOVE_ROOT) && + rmdir(path) < 0 && + r >= 0 && + (!FLAGS_SET(flags, REMOVE_MISSING_OK) || errno != ENOENT)) + r = -errno; + + return r; +} -- cgit v1.2.3