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 "cpu-set-util.h"
  18 #include "exec-util.h"
  19 #include "fdset.h"
  20 #include "list.h"
  21 #include "missing_resource.h"
  22 #include "namespace.h"
  23 #include "nsflags.h"
  24 #include "time-util.h"
  25
  26 #define EXEC_STDIN_DATA_MAX (64U*1024U*1024U)
  27
  28 typedef enum ExecUtmpMode {
  29         EXEC_UTMP_INIT,
  30         EXEC_UTMP_LOGIN,
  31         EXEC_UTMP_USER,
  32         _EXEC_UTMP_MODE_MAX,
  33         _EXEC_UTMP_MODE_INVALID = -1
  34 } ExecUtmpMode;
  35
  36 typedef enum ExecInput {
  37         EXEC_INPUT_NULL,
  38         EXEC_INPUT_TTY,
  39         EXEC_INPUT_TTY_FORCE,
  40         EXEC_INPUT_TTY_FAIL,
  41         EXEC_INPUT_SOCKET,
  42         EXEC_INPUT_NAMED_FD,
  43         EXEC_INPUT_DATA,
  44         EXEC_INPUT_FILE,
  45         _EXEC_INPUT_MAX,
  46         _EXEC_INPUT_INVALID = -1
  47 } ExecInput;
  48
  49 typedef enum ExecOutput {
  50         EXEC_OUTPUT_INHERIT,
  51         EXEC_OUTPUT_NULL,
  52         EXEC_OUTPUT_TTY,
  53         EXEC_OUTPUT_SYSLOG,
  54         EXEC_OUTPUT_SYSLOG_AND_CONSOLE,
  55         EXEC_OUTPUT_KMSG,
  56         EXEC_OUTPUT_KMSG_AND_CONSOLE,
  57         EXEC_OUTPUT_JOURNAL,
  58         EXEC_OUTPUT_JOURNAL_AND_CONSOLE,
  59         EXEC_OUTPUT_SOCKET,
  60         EXEC_OUTPUT_NAMED_FD,
  61         EXEC_OUTPUT_FILE,
  62         EXEC_OUTPUT_FILE_APPEND,
  63         _EXEC_OUTPUT_MAX,
  64         _EXEC_OUTPUT_INVALID = -1
  65 } ExecOutput;
  66
  67 typedef enum ExecPreserveMode {
  68         EXEC_PRESERVE_NO,
  69         EXEC_PRESERVE_YES,
  70         EXEC_PRESERVE_RESTART,
  71         _EXEC_PRESERVE_MODE_MAX,
  72         _EXEC_PRESERVE_MODE_INVALID = -1
  73 } ExecPreserveMode;
  74
  75 typedef enum ExecKeyringMode {
  76         EXEC_KEYRING_INHERIT,
  77         EXEC_KEYRING_PRIVATE,
  78         EXEC_KEYRING_SHARED,
  79         _EXEC_KEYRING_MODE_MAX,
  80         _EXEC_KEYRING_MODE_INVALID = -1,
  81 } ExecKeyringMode;
  82
  83 /* Contains start and exit information about an executed command.  */
  84 struct ExecStatus {
  85         dual_timestamp start_timestamp;
  86         dual_timestamp exit_timestamp;
  87         pid_t pid;
  88         int code;     /* as in siginfo_t::si_code */
  89         int status;   /* as in sigingo_t::si_status */
  90 };
  91
  92 /* Stores information about commands we execute. Covers both configuration settings as well as runtime data. */
  93 struct ExecCommand {
  94         char *path;
  95         char **argv;
  96         ExecStatus exec_status;
  97         ExecCommandFlags flags;
  98         LIST_FIELDS(ExecCommand, command); /* useful for chaining commands */
  99 };
 100
 101 /* Encapsulates certain aspects of the runtime environment that is to be shared between multiple otherwise separate
 102  * invocations of commands. Specifically, this allows sharing of /tmp and /var/tmp data as well as network namespaces
 103  * between invocations of commands. This is a reference counted object, with one reference taken by each currently
 104  * active command invocation that wants to share this runtime. */
 105 struct ExecRuntime {
 106         unsigned n_ref;
 107
 108         Manager *manager;
 109
 110         char *id; /* Unit id of the owner */
 111
 112         char *tmp_dir;
 113         char *var_tmp_dir;
 114
 115         /* An AF_UNIX socket pair, that contains a datagram containing a file descriptor referring to the network
 116          * namespace. */
 117         int netns_storage_socket[2];
 118 };
 119
 120 typedef enum ExecDirectoryType {
 121         EXEC_DIRECTORY_RUNTIME = 0,
 122         EXEC_DIRECTORY_STATE,
 123         EXEC_DIRECTORY_CACHE,
 124         EXEC_DIRECTORY_LOGS,
 125         EXEC_DIRECTORY_CONFIGURATION,
 126         _EXEC_DIRECTORY_TYPE_MAX,
 127         _EXEC_DIRECTORY_TYPE_INVALID = -1,
 128 } ExecDirectoryType;
 129
 130 typedef struct ExecDirectory {
 131         char **paths;
 132         mode_t mode;
 133 } ExecDirectory;
 134
 135 typedef enum ExecCleanMask {
 136         /* In case you wonder why the bitmask below doesn't use "directory" in its name: we want to keep this
 137          * generic so that .timer timestamp files can nicely be covered by this too, and similar. */
 138         EXEC_CLEAN_RUNTIME       = 1U << EXEC_DIRECTORY_RUNTIME,
 139         EXEC_CLEAN_STATE         = 1U << EXEC_DIRECTORY_STATE,
 140         EXEC_CLEAN_CACHE         = 1U << EXEC_DIRECTORY_CACHE,
 141         EXEC_CLEAN_LOGS          = 1U << EXEC_DIRECTORY_LOGS,
 142         EXEC_CLEAN_CONFIGURATION = 1U << EXEC_DIRECTORY_CONFIGURATION,
 143         EXEC_CLEAN_NONE          = 0,
 144         EXEC_CLEAN_ALL           = (1U << _EXEC_DIRECTORY_TYPE_MAX) - 1,
 145         _EXEC_CLEAN_MASK_INVALID = -1,
 146 } ExecCleanMask;
 147
 148 /* Encodes configuration parameters applied to invoked commands. Does not carry runtime data, but only configuration
 149  * changes sourced from unit files and suchlike. ExecContext objects are usually embedded into Unit objects, and do not
 150  * change after being loaded. */
 151 struct ExecContext {
 152         char **environment;
 153         char **environment_files;
 154         char **pass_environment;
 155         char **unset_environment;
 156
 157         struct rlimit *rlimit[_RLIMIT_MAX];
 158         char *working_directory, *root_directory, *root_image;
 159         bool working_directory_missing_ok:1;
 160         bool working_directory_home:1;
 161
 162         bool oom_score_adjust_set:1;
 163         bool nice_set:1;
 164         bool ioprio_set:1;
 165         bool cpu_sched_set:1;
 166
 167         /* This is not exposed to the user but available internally. We need it to make sure that whenever we
 168          * spawn /usr/bin/mount it is run in the same process group as us so that the autofs logic detects
 169          * that it belongs to us and we don't enter a trigger loop. */
 170         bool same_pgrp;
 171
 172         bool cpu_sched_reset_on_fork;
 173         bool non_blocking;
 174
 175         mode_t umask;
 176         int oom_score_adjust;
 177         int nice;
 178         int ioprio;
 179         int cpu_sched_policy;
 180         int cpu_sched_priority;
 181
 182         CPUSet cpu_set;
 183         NUMAPolicy numa_policy;
 184
 185         ExecInput std_input;
 186         ExecOutput std_output;
 187         ExecOutput std_error;
 188         bool stdio_as_fds;
 189         char *stdio_fdname[3];
 190         char *stdio_file[3];
 191
 192         void *stdin_data;
 193         size_t stdin_data_size;
 194
 195         nsec_t timer_slack_nsec;
 196
 197         char *tty_path;
 198
 199         bool tty_reset;
 200         bool tty_vhangup;
 201         bool tty_vt_disallocate;
 202
 203         bool ignore_sigpipe;
 204
 205         ExecKeyringMode keyring_mode;
 206
 207         /* Since resolving these names might involve socket
 208          * connections and we don't want to deadlock ourselves these
 209          * names are resolved on execution only and in the child
 210          * process. */
 211         char *user;
 212         char *group;
 213         char **supplementary_groups;
 214
 215         char *pam_name;
 216
 217         char *utmp_id;
 218         ExecUtmpMode utmp_mode;
 219
 220         bool no_new_privileges;
 221
 222         bool selinux_context_ignore;
 223         bool apparmor_profile_ignore;
 224         bool smack_process_label_ignore;
 225
 226         char *selinux_context;
 227         char *apparmor_profile;
 228         char *smack_process_label;
 229
 230         char **read_write_paths, **read_only_paths, **inaccessible_paths;
 231         unsigned long mount_flags;
 232         BindMount *bind_mounts;
 233         size_t n_bind_mounts;
 234         TemporaryFileSystem *temporary_filesystems;
 235         size_t n_temporary_filesystems;
 236
 237         uint64_t capability_bounding_set;
 238         uint64_t capability_ambient_set;
 239         int secure_bits;
 240
 241         int syslog_priority;
 242         bool syslog_level_prefix;
 243         char *syslog_identifier;
 244
 245         struct iovec* log_extra_fields;
 246         size_t n_log_extra_fields;
 247
 248         usec_t log_ratelimit_interval_usec;
 249         unsigned log_ratelimit_burst;
 250
 251         int log_level_max;
 252
 253         bool private_tmp;
 254         bool private_network;
 255         bool private_devices;
 256         bool private_users;
 257         bool private_mounts;
 258         bool protect_kernel_tunables;
 259         bool protect_kernel_modules;
 260         bool protect_kernel_logs;
 261         bool protect_control_groups;
 262         ProtectSystem protect_system;
 263         ProtectHome protect_home;
 264         bool protect_hostname;
 265         bool mount_apivfs;
 266
 267         bool dynamic_user;
 268         bool remove_ipc;
 269
 270         bool memory_deny_write_execute;
 271         bool restrict_realtime;
 272         bool restrict_suid_sgid;
 273
 274         bool lock_personality;
 275         unsigned long personality;
 276
 277         unsigned long restrict_namespaces; /* The CLONE_NEWxyz flags permitted to the unit's processes */
 278
 279         Hashmap *syscall_filter;
 280         Set *syscall_archs;
 281         int syscall_errno;
 282         bool syscall_whitelist:1;
 283
 284         bool address_families_whitelist:1;
 285         Set *address_families;
 286
 287         char *network_namespace_path;
 288
 289         ExecDirectory directories[_EXEC_DIRECTORY_TYPE_MAX];
 290         ExecPreserveMode runtime_directory_preserve_mode;
 291         usec_t timeout_clean_usec;
 292 };
 293
 294 static inline bool exec_context_restrict_namespaces_set(const ExecContext *c) {
 295         assert(c);
 296
 297         return (c->restrict_namespaces & NAMESPACE_FLAGS_ALL) != NAMESPACE_FLAGS_ALL;
 298 }
 299
 300 typedef enum ExecFlags {
 301         EXEC_APPLY_SANDBOXING  = 1 << 0,
 302         EXEC_APPLY_CHROOT      = 1 << 1,
 303         EXEC_APPLY_TTY_STDIN   = 1 << 2,
 304         EXEC_PASS_LOG_UNIT     = 1 << 3, /* Whether to pass the unit name to the service's journal stream connection */
 305         EXEC_CHOWN_DIRECTORIES = 1 << 4, /* chown() the runtime/state/cache/log directories to the user we run as, under all conditions */
 306         EXEC_NSS_BYPASS_BUS    = 1 << 5, /* Set the SYSTEMD_NSS_BYPASS_BUS environment variable, to disable nss-systemd for dbus */
 307         EXEC_CGROUP_DELEGATE   = 1 << 6,
 308         EXEC_IS_CONTROL        = 1 << 7,
 309         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 */
 310
 311         /* The following are not used by execute.c, but by consumers internally */
 312         EXEC_PASS_FDS          = 1 << 9,
 313         EXEC_SETENV_RESULT     = 1 << 10,
 314         EXEC_SET_WATCHDOG      = 1 << 11,
 315 } ExecFlags;
 316
 317 /* Parameters for a specific invocation of a command. This structure is put together right before a command is
 318  * executed. */
 319 struct ExecParameters {
 320         char **environment;
 321
 322         int *fds;
 323         char **fd_names;
 324         size_t n_socket_fds;
 325         size_t n_storage_fds;
 326
 327         ExecFlags flags;
 328         bool selinux_context_net:1;
 329
 330         CGroupMask cgroup_supported;
 331         const char *cgroup_path;
 332
 333         char **prefix;
 334
 335         const char *confirm_spawn;
 336
 337         usec_t watchdog_usec;
 338
 339         int *idle_pipe;
 340
 341         int stdin_fd;
 342         int stdout_fd;
 343         int stderr_fd;
 344
 345         /* An fd that is closed by the execve(), and thus will result in EOF when the execve() is done */
 346         int exec_fd;
 347 };
 348
 349 #include "unit.h"
 350 #include "dynamic-user.h"
 351
 352 int exec_spawn(Unit *unit,
 353                ExecCommand *command,
 354                const ExecContext *context,
 355                const ExecParameters *exec_params,
 356                ExecRuntime *runtime,
 357                DynamicCreds *dynamic_creds,
 358                pid_t *ret);
 359
 360 void exec_command_done_array(ExecCommand *c, size_t n);
 361 ExecCommand* exec_command_free_list(ExecCommand *c);
 362 void exec_command_free_array(ExecCommand **c, size_t n);
 363 void exec_command_reset_status_array(ExecCommand *c, size_t n);
 364 void exec_command_reset_status_list_array(ExecCommand **c, size_t n);
 365 void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix);
 366 void exec_command_append_list(ExecCommand **l, ExecCommand *e);
 367 int exec_command_set(ExecCommand *c, const char *path, ...) _sentinel_;
 368 int exec_command_append(ExecCommand *c, const char *path, ...) _sentinel_;
 369
 370 void exec_context_init(ExecContext *c);
 371 void exec_context_done(ExecContext *c);
 372 void exec_context_dump(const ExecContext *c, FILE* f, const char *prefix);
 373
 374 int exec_context_destroy_runtime_directory(const ExecContext *c, const char *runtime_root);
 375
 376 const char* exec_context_fdname(const ExecContext *c, int fd_index);
 377
 378 bool exec_context_may_touch_console(const ExecContext *c);
 379 bool exec_context_maintains_privileges(const ExecContext *c);
 380
 381 int exec_context_get_effective_ioprio(const ExecContext *c);
 382
 383 void exec_context_free_log_extra_fields(ExecContext *c);
 384
 385 void exec_context_revert_tty(ExecContext *c);
 386
 387 int exec_context_get_clean_directories(ExecContext *c, char **prefix, ExecCleanMask mask, char ***ret);
 388 int exec_context_get_clean_mask(ExecContext *c, ExecCleanMask *ret);
 389
 390 void exec_status_start(ExecStatus *s, pid_t pid);
 391 void exec_status_exit(ExecStatus *s, const ExecContext *context, pid_t pid, int code, int status);
 392 void exec_status_dump(const ExecStatus *s, FILE *f, const char *prefix);
 393 void exec_status_reset(ExecStatus *s);
 394
 395 int exec_runtime_acquire(Manager *m, const ExecContext *c, const char *name, bool create, ExecRuntime **ret);
 396 ExecRuntime *exec_runtime_unref(ExecRuntime *r, bool destroy);
 397
 398 int exec_runtime_serialize(const Manager *m, FILE *f, FDSet *fds);
 399 int exec_runtime_deserialize_compat(Unit *u, const char *key, const char *value, FDSet *fds);
 400 void exec_runtime_deserialize_one(Manager *m, const char *value, FDSet *fds);
 401 void exec_runtime_vacuum(Manager *m);
 402
 403 void exec_params_clear(ExecParameters *p);
 404
 405 const char* exec_output_to_string(ExecOutput i) _const_;
 406 ExecOutput exec_output_from_string(const char *s) _pure_;
 407
 408 const char* exec_input_to_string(ExecInput i) _const_;
 409 ExecInput exec_input_from_string(const char *s) _pure_;
 410
 411 const char* exec_utmp_mode_to_string(ExecUtmpMode i) _const_;
 412 ExecUtmpMode exec_utmp_mode_from_string(const char *s) _pure_;
 413
 414 const char* exec_preserve_mode_to_string(ExecPreserveMode i) _const_;
 415 ExecPreserveMode exec_preserve_mode_from_string(const char *s) _pure_;
 416
 417 const char* exec_keyring_mode_to_string(ExecKeyringMode i) _const_;
 418 ExecKeyringMode exec_keyring_mode_from_string(const char *s) _pure_;
 419
 420 const char* exec_directory_type_to_string(ExecDirectoryType i) _const_;
 421 ExecDirectoryType exec_directory_type_from_string(const char *s) _pure_;
 422
 423 const char* exec_resource_type_to_string(ExecDirectoryType i) _const_;
 424 ExecDirectoryType exec_resource_type_from_string(const char *s) _pure_;