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