src/core/execute.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 typedef struct ExecStatus ExecStatus;
   5 typedef struct ExecCommand ExecCommand;
   6 typedef struct ExecContext ExecContext;
   7 typedef struct ExecRuntime ExecRuntime;
   8 typedef struct ExecParameters ExecParameters;
   9 typedef struct Manager Manager;
  10
  11 #include <sched.h>
  12 #include <stdbool.h>
  13 #include <stdio.h>
  14 #include <sys/capability.h>
  15
  16 #include "cgroup-util.h"
  17 #include "fdset.h"
  18 #include "list.h"
  19 #include "missing_resource.h"
  20 #include "namespace.h"
  21 #include "nsflags.h"
  22 #include "time-util.h"
  23
  24 #define EXEC_STDIN_DATA_MAX (64U*1024U*1024U)
  25
  26 typedef enum ExecUtmpMode {
  27         EXEC_UTMP_INIT,
  28         EXEC_UTMP_LOGIN,
  29         EXEC_UTMP_USER,
  30         _EXEC_UTMP_MODE_MAX,
  31         _EXEC_UTMP_MODE_INVALID = -1
  32 } ExecUtmpMode;
  33
  34 typedef enum ExecInput {
  35         EXEC_INPUT_NULL,
  36         EXEC_INPUT_TTY,
  37         EXEC_INPUT_TTY_FORCE,
  38         EXEC_INPUT_TTY_FAIL,
  39         EXEC_INPUT_SOCKET,
  40         EXEC_INPUT_NAMED_FD,
  41         EXEC_INPUT_DATA,
  42         EXEC_INPUT_FILE,
  43         _EXEC_INPUT_MAX,
  44         _EXEC_INPUT_INVALID = -1
  45 } ExecInput;
  46
  47 typedef enum ExecOutput {
  48         EXEC_OUTPUT_INHERIT,
  49         EXEC_OUTPUT_NULL,
  50         EXEC_OUTPUT_TTY,
  51         EXEC_OUTPUT_SYSLOG,
  52         EXEC_OUTPUT_SYSLOG_AND_CONSOLE,
  53         EXEC_OUTPUT_KMSG,
  54         EXEC_OUTPUT_KMSG_AND_CONSOLE,
  55         EXEC_OUTPUT_JOURNAL,
  56         EXEC_OUTPUT_JOURNAL_AND_CONSOLE,
  57         EXEC_OUTPUT_SOCKET,
  58         EXEC_OUTPUT_NAMED_FD,
  59         EXEC_OUTPUT_FILE,
  60         EXEC_OUTPUT_FILE_APPEND,
  61         _EXEC_OUTPUT_MAX,
  62         _EXEC_OUTPUT_INVALID = -1
  63 } ExecOutput;
  64
  65 typedef enum ExecPreserveMode {
  66         EXEC_PRESERVE_NO,
  67         EXEC_PRESERVE_YES,
  68         EXEC_PRESERVE_RESTART,
  69         _EXEC_PRESERVE_MODE_MAX,
  70         _EXEC_PRESERVE_MODE_INVALID = -1
  71 } ExecPreserveMode;
  72
  73 typedef enum ExecKeyringMode {
  74         EXEC_KEYRING_INHERIT,
  75         EXEC_KEYRING_PRIVATE,
  76         EXEC_KEYRING_SHARED,
  77         _EXEC_KEYRING_MODE_MAX,
  78         _EXEC_KEYRING_MODE_INVALID = -1,
  79 } ExecKeyringMode;
  80
  81 /* Contains start and exit information about an executed command.  */
  82 struct ExecStatus {
  83         dual_timestamp start_timestamp;
  84         dual_timestamp exit_timestamp;
  85         pid_t pid;
  86         int code;     /* as in siginfo_t::si_code */
  87         int status;   /* as in sigingo_t::si_status */
  88 };
  89
  90 typedef enum ExecCommandFlags {
  91         EXEC_COMMAND_IGNORE_FAILURE   = 1 << 0,
  92         EXEC_COMMAND_FULLY_PRIVILEGED = 1 << 1,
  93         EXEC_COMMAND_NO_SETUID        = 1 << 2,
  94         EXEC_COMMAND_AMBIENT_MAGIC    = 1 << 3,
  95         EXEC_COMMAND_NO_ENV_EXPAND    = 1 << 4,
  96 } ExecCommandFlags;
  97
  98 /* Stores information about commands we execute. Covers both configuration settings as well as runtime data. */
  99 struct ExecCommand {
 100         char *path;
 101         char **argv;
 102         ExecStatus exec_status;
 103         ExecCommandFlags flags;
 104         LIST_FIELDS(ExecCommand, command); /* useful for chaining commands */
 105 };
 106
 107 /* Encapsulates certain aspects of the runtime environment that is to be shared between multiple otherwise separate
 108  * invocations of commands. Specifically, this allows sharing of /tmp and /var/tmp data as well as network namespaces
 109  * between invocations of commands. This is a reference counted object, with one reference taken by each currently
 110  * active command invocation that wants to share this runtime. */
 111 struct ExecRuntime {
 112         unsigned n_ref;
 113
 114         Manager *manager;
 115
 116         char *id; /* Unit id of the owner */
 117
 118         char *tmp_dir;
 119         char *var_tmp_dir;
 120
 121         /* An AF_UNIX socket pair, that contains a datagram containing a file descriptor referring to the network
 122          * namespace. */
 123         int netns_storage_socket[2];
 124 };
 125
 126 typedef enum ExecDirectoryType {
 127         EXEC_DIRECTORY_RUNTIME = 0,
 128         EXEC_DIRECTORY_STATE,
 129         EXEC_DIRECTORY_CACHE,
 130         EXEC_DIRECTORY_LOGS,
 131         EXEC_DIRECTORY_CONFIGURATION,
 132         _EXEC_DIRECTORY_TYPE_MAX,
 133         _EXEC_DIRECTORY_TYPE_INVALID = -1,
 134 } ExecDirectoryType;
 135
 136 typedef struct ExecDirectory {
 137         char **paths;
 138         mode_t mode;
 139 } ExecDirectory;
 140
 141 /* Encodes configuration parameters applied to invoked commands. Does not carry runtime data, but only configuration
 142  * changes sourced from unit files and suchlike. ExecContext objects are usually embedded into Unit objects, and do not
 143  * change after being loaded. */
 144 struct ExecContext {
 145         char **environment;
 146         char **environment_files;
 147         char **pass_environment;
 148         char **unset_environment;
 149
 150         struct rlimit *rlimit[_RLIMIT_MAX];
 151         char *working_directory, *root_directory, *root_image;
 152         bool working_directory_missing_ok:1;
 153         bool working_directory_home:1;
 154
 155         bool oom_score_adjust_set:1;
 156         bool nice_set:1;
 157         bool ioprio_set:1;
 158         bool cpu_sched_set:1;
 159
 160         /* This is not exposed to the user but available internally. We need it to make sure that whenever we
 161          * spawn /usr/bin/mount it is run in the same process group as us so that the autofs logic detects
 162          * that it belongs to us and we don't enter a trigger loop. */
 163         bool same_pgrp;
 164
 165         bool cpu_sched_reset_on_fork;
 166         bool non_blocking;
 167
 168         mode_t umask;
 169         int oom_score_adjust;
 170         int nice;
 171         int ioprio;
 172         int cpu_sched_policy;
 173         int cpu_sched_priority;
 174
 175         unsigned cpuset_ncpus;
 176         cpu_set_t *cpuset;
 177
 178         ExecInput std_input;
 179         ExecOutput std_output;
 180         ExecOutput std_error;
 181         bool stdio_as_fds;
 182         char *stdio_fdname[3];
 183         char *stdio_file[3];
 184
 185         void *stdin_data;
 186         size_t stdin_data_size;
 187
 188         nsec_t timer_slack_nsec;
 189
 190         char *tty_path;
 191
 192         bool tty_reset;
 193         bool tty_vhangup;
 194         bool tty_vt_disallocate;
 195
 196         bool ignore_sigpipe;
 197
 198         ExecKeyringMode keyring_mode;
 199
 200         /* Since resolving these names might involve socket
 201          * connections and we don't want to deadlock ourselves these
 202          * names are resolved on execution only and in the child
 203          * process. */
 204         char *user;
 205         char *group;
 206         char **supplementary_groups;
 207
 208         char *pam_name;
 209
 210         char *utmp_id;
 211         ExecUtmpMode utmp_mode;
 212
 213         bool no_new_privileges;
 214
 215         bool selinux_context_ignore;
 216         bool apparmor_profile_ignore;
 217         bool smack_process_label_ignore;
 218
 219         char *selinux_context;
 220         char *apparmor_profile;
 221         char *smack_process_label;
 222
 223         char **read_write_paths, **read_only_paths, **inaccessible_paths;
 224         unsigned long mount_flags;
 225         BindMount *bind_mounts;
 226         size_t n_bind_mounts;
 227         TemporaryFileSystem *temporary_filesystems;
 228         size_t n_temporary_filesystems;
 229
 230         uint64_t capability_bounding_set;
 231         uint64_t capability_ambient_set;
 232         int secure_bits;
 233
 234         int syslog_priority;
 235         bool syslog_level_prefix;
 236         char *syslog_identifier;
 237
 238         struct iovec* log_extra_fields;
 239         size_t n_log_extra_fields;
 240
 241         usec_t log_rate_limit_interval_usec;
 242         unsigned log_rate_limit_burst;
 243
 244         int log_level_max;
 245
 246         bool private_tmp;
 247         bool private_network;
 248         bool private_devices;
 249         bool private_users;
 250         bool private_mounts;
 251         bool protect_kernel_tunables;
 252         bool protect_kernel_modules;
 253         bool protect_control_groups;
 254         ProtectSystem protect_system;
 255         ProtectHome protect_home;
 256         bool protect_hostname;
 257         bool mount_apivfs;
 258
 259         bool dynamic_user;
 260         bool remove_ipc;
 261
 262         bool memory_deny_write_execute;
 263         bool restrict_realtime;
 264         bool restrict_suid_sgid;
 265
 266         bool lock_personality;
 267         unsigned long personality;
 268
 269         unsigned long restrict_namespaces; /* The CLONE_NEWxyz flags permitted to the unit's processes */
 270
 271         Hashmap *syscall_filter;
 272         Set *syscall_archs;
 273         int syscall_errno;
 274         bool syscall_whitelist:1;
 275
 276         bool address_families_whitelist:1;
 277         Set *address_families;
 278
 279         char *network_namespace_path;
 280
 281         ExecDirectory directories[_EXEC_DIRECTORY_TYPE_MAX];
 282         ExecPreserveMode runtime_directory_preserve_mode;
 283 };
 284
 285 static inline bool exec_context_restrict_namespaces_set(const ExecContext *c) {
 286         assert(c);
 287
 288         return (c->restrict_namespaces & NAMESPACE_FLAGS_ALL) != NAMESPACE_FLAGS_ALL;
 289 }
 290
 291 typedef enum ExecFlags {
 292         EXEC_APPLY_SANDBOXING  = 1 << 0,
 293         EXEC_APPLY_CHROOT      = 1 << 1,
 294         EXEC_APPLY_TTY_STDIN   = 1 << 2,
 295         EXEC_PASS_LOG_UNIT     = 1 << 3, /* Whether to pass the unit name to the service's journal stream connection */
 296         EXEC_CHOWN_DIRECTORIES = 1 << 4, /* chown() the runtime/state/cache/log directories to the user we run as, under all conditions */
 297         EXEC_NSS_BYPASS_BUS    = 1 << 5, /* Set the SYSTEMD_NSS_BYPASS_BUS environment variable, to disable nss-systemd for dbus */
 298         EXEC_CGROUP_DELEGATE   = 1 << 6,
 299         EXEC_IS_CONTROL        = 1 << 7,
 300         EXEC_CONTROL_CGROUP    = 1 << 8, /* Place the process not in the indicated cgroup but in a subcgroup '/.control', but only EXEC_CGROUP_DELEGATE and EXEC_IS_CONTROL is set, too */
 301
 302         /* The following are not used by execute.c, but by consumers internally */
 303         EXEC_PASS_FDS          = 1 << 9,
 304         EXEC_SETENV_RESULT     = 1 << 10,
 305         EXEC_SET_WATCHDOG      = 1 << 11,
 306 } ExecFlags;
 307
 308 /* Parameters for a specific invocation of a command. This structure is put together right before a command is
 309  * executed. */
 310 struct ExecParameters {
 311         char **environment;
 312
 313         int *fds;
 314         char **fd_names;
 315         size_t n_socket_fds;
 316         size_t n_storage_fds;
 317
 318         ExecFlags flags;
 319         bool selinux_context_net:1;
 320
 321         CGroupMask cgroup_supported;
 322         const char *cgroup_path;
 323
 324         char **prefix;
 325
 326         const char *confirm_spawn;
 327
 328         usec_t watchdog_usec;
 329
 330         int *idle_pipe;
 331
 332         int stdin_fd;
 333         int stdout_fd;
 334         int stderr_fd;
 335
 336         /* An fd that is closed by the execve(), and thus will result in EOF when the execve() is done */
 337         int exec_fd;
 338 };
 339
 340 #include "unit.h"
 341 #include "dynamic-user.h"
 342
 343 int exec_spawn(Unit *unit,
 344                ExecCommand *command,
 345                const ExecContext *context,
 346                const ExecParameters *exec_params,
 347                ExecRuntime *runtime,
 348                DynamicCreds *dynamic_creds,
 349                pid_t *ret);
 350
 351 void exec_command_done_array(ExecCommand *c, size_t n);
 352 ExecCommand* exec_command_free_list(ExecCommand *c);
 353 void exec_command_free_array(ExecCommand **c, size_t n);
 354 void exec_command_reset_status_array(ExecCommand *c, size_t n);
 355 void exec_command_reset_status_list_array(ExecCommand **c, size_t n);
 356 void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix);
 357 void exec_command_append_list(ExecCommand **l, ExecCommand *e);
 358 int exec_command_set(ExecCommand *c, const char *path, ...) _sentinel_;
 359 int exec_command_append(ExecCommand *c, const char *path, ...) _sentinel_;
 360
 361 void exec_context_init(ExecContext *c);
 362 void exec_context_done(ExecContext *c);
 363 void exec_context_dump(const ExecContext *c, FILE* f, const char *prefix);
 364
 365 int exec_context_destroy_runtime_directory(const ExecContext *c, const char *runtime_root);
 366
 367 const char* exec_context_fdname(const ExecContext *c, int fd_index);
 368
 369 bool exec_context_may_touch_console(const ExecContext *c);
 370 bool exec_context_maintains_privileges(const ExecContext *c);
 371
 372 int exec_context_get_effective_ioprio(const ExecContext *c);
 373
 374 void exec_context_free_log_extra_fields(ExecContext *c);
 375
 376 void exec_context_revert_tty(ExecContext *c);
 377
 378 void exec_status_start(ExecStatus *s, pid_t pid);
 379 void exec_status_exit(ExecStatus *s, const ExecContext *context, pid_t pid, int code, int status);
 380 void exec_status_dump(const ExecStatus *s, FILE *f, const char *prefix);
 381 void exec_status_reset(ExecStatus *s);
 382
 383 int exec_runtime_acquire(Manager *m, const ExecContext *c, const char *name, bool create, ExecRuntime **ret);
 384 ExecRuntime *exec_runtime_unref(ExecRuntime *r, bool destroy);
 385
 386 int exec_runtime_serialize(const Manager *m, FILE *f, FDSet *fds);
 387 int exec_runtime_deserialize_compat(Unit *u, const char *key, const char *value, FDSet *fds);
 388 void exec_runtime_deserialize_one(Manager *m, const char *value, FDSet *fds);
 389 void exec_runtime_vacuum(Manager *m);
 390
 391 void exec_params_clear(ExecParameters *p);
 392
 393 const char* exec_output_to_string(ExecOutput i) _const_;
 394 ExecOutput exec_output_from_string(const char *s) _pure_;
 395
 396 const char* exec_input_to_string(ExecInput i) _const_;
 397 ExecInput exec_input_from_string(const char *s) _pure_;
 398
 399 const char* exec_utmp_mode_to_string(ExecUtmpMode i) _const_;
 400 ExecUtmpMode exec_utmp_mode_from_string(const char *s) _pure_;
 401
 402 const char* exec_preserve_mode_to_string(ExecPreserveMode i) _const_;
 403 ExecPreserveMode exec_preserve_mode_from_string(const char *s) _pure_;
 404
 405 const char* exec_keyring_mode_to_string(ExecKeyringMode i) _const_;
 406 ExecKeyringMode exec_keyring_mode_from_string(const char *s) _pure_;
 407
 408 const char* exec_directory_type_to_string(ExecDirectoryType i) _const_;
 409 ExecDirectoryType exec_directory_type_from_string(const char *s) _pure_;