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