56a13a495c
Read-only /var/tmp is more likely, because it's backed by a real device. /tmp is (by default) backed by tmpfs, but it doesn't have to be. In both cases the same consideration applies. If we boot with read-only /var/tmp, any unit with PrivateTmp=yes would fail because we cannot create the subdir under /var/tmp to mount the private directory. But many services actually don't require /var/tmp (either because they only use it occasionally, or because they only use /tmp, or even because they don't use the temporary directories at all, and PrivateTmp=yes is used to isolate them from the rest of the system). To handle both cases let's create a read-only directory under /run/systemd and mount it as the private /tmp or /var/tmp. (Read-only to not fool the service into dumping too much data in /run.) $ sudo systemd-run -t -p PrivateTmp=yes bash Running as unit: run-u14.service Press ^] three times within 1s to disconnect TTY. [root@workstation /]# ls -l /tmp/ total 0 [root@workstation /]# ls -l /var/tmp/ total 0 [root@workstation /]# touch /tmp/f [root@workstation /]# touch /var/tmp/f touch: cannot touch '/var/tmp/f': Read-only file system This commit has more changes than I like to put in one commit, but it's touching all the same paths so it's hard to split. exec_runtime_make() was using the wrong cleanup function, so the directory would be left behind on error.
138 lines
4 KiB
C
138 lines
4 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#pragma once
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/***
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Copyright © 2016 Djalal Harouni
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***/
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typedef struct NamespaceInfo NamespaceInfo;
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typedef struct BindMount BindMount;
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typedef struct TemporaryFileSystem TemporaryFileSystem;
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#include <stdbool.h>
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#include "dissect-image.h"
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#include "fs-util.h"
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#include "macro.h"
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#include "string-util.h"
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typedef enum ProtectHome {
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PROTECT_HOME_NO,
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PROTECT_HOME_YES,
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PROTECT_HOME_READ_ONLY,
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PROTECT_HOME_TMPFS,
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_PROTECT_HOME_MAX,
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_PROTECT_HOME_INVALID = -1
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} ProtectHome;
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typedef enum NamespaceType {
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NAMESPACE_MOUNT,
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NAMESPACE_CGROUP,
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NAMESPACE_UTS,
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NAMESPACE_IPC,
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NAMESPACE_USER,
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NAMESPACE_PID,
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NAMESPACE_NET,
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_NAMESPACE_TYPE_MAX,
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_NAMESPACE_TYPE_INVALID = -1,
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} NamespaceType;
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typedef enum ProtectSystem {
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PROTECT_SYSTEM_NO,
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PROTECT_SYSTEM_YES,
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PROTECT_SYSTEM_FULL,
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PROTECT_SYSTEM_STRICT,
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_PROTECT_SYSTEM_MAX,
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_PROTECT_SYSTEM_INVALID = -1
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} ProtectSystem;
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struct NamespaceInfo {
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bool ignore_protect_paths:1;
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bool private_dev:1;
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bool private_mounts:1;
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bool protect_control_groups:1;
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bool protect_kernel_tunables:1;
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bool protect_kernel_modules:1;
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bool protect_kernel_logs:1;
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bool mount_apivfs:1;
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bool protect_hostname:1;
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};
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struct BindMount {
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char *source;
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char *destination;
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bool read_only:1;
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bool nosuid:1;
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bool recursive:1;
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bool ignore_enoent:1;
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};
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struct TemporaryFileSystem {
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char *path;
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char *options;
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};
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int setup_namespace(
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const char *root_directory,
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const char *root_image,
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const NamespaceInfo *ns_info,
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char **read_write_paths,
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char **read_only_paths,
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char **inaccessible_paths,
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char **empty_directories,
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const BindMount *bind_mounts,
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size_t n_bind_mounts,
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const TemporaryFileSystem *temporary_filesystems,
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size_t n_temporary_filesystems,
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const char *tmp_dir,
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const char *var_tmp_dir,
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const char *log_namespace,
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ProtectHome protect_home,
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ProtectSystem protect_system,
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unsigned long mount_flags,
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const void *root_hash,
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size_t root_hash_size,
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const char *root_hash_path,
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const void *root_hash_sig,
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size_t root_hash_sig_size,
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const char *root_hash_sig_path,
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const char *root_verity,
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DissectImageFlags dissected_image_flags,
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char **error_path);
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#define RUN_SYSTEMD_EMPTY "/run/systemd/empty"
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static inline void namespace_cleanup_tmpdir(char *p) {
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PROTECT_ERRNO;
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if (!streq_ptr(p, RUN_SYSTEMD_EMPTY))
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(void) rmdir(p);
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free(p);
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}
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DEFINE_TRIVIAL_CLEANUP_FUNC(char*, namespace_cleanup_tmpdir);
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int setup_tmp_dirs(
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const char *id,
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char **tmp_dir,
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char **var_tmp_dir);
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int setup_netns(const int netns_storage_socket[static 2]);
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int open_netns_path(const int netns_storage_socket[static 2], const char *path);
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const char* protect_home_to_string(ProtectHome p) _const_;
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ProtectHome protect_home_from_string(const char *s) _pure_;
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const char* protect_system_to_string(ProtectSystem p) _const_;
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ProtectSystem protect_system_from_string(const char *s) _pure_;
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void bind_mount_free_many(BindMount *b, size_t n);
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int bind_mount_add(BindMount **b, size_t *n, const BindMount *item);
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void temporary_filesystem_free_many(TemporaryFileSystem *t, size_t n);
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int temporary_filesystem_add(TemporaryFileSystem **t, size_t *n,
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const char *path, const char *options);
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const char* namespace_type_to_string(NamespaceType t) _const_;
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NamespaceType namespace_type_from_string(const char *s) _pure_;
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bool ns_type_supported(NamespaceType type);
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