src/import/import-common.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <sched.h>
   4 #include <sys/prctl.h>
   5 #include <sys/stat.h>
   6 #include <unistd.h>
   7
   8 #include "alloc-util.h"
   9 #include "btrfs-util.h"
  10 #include "capability-util.h"
  11 #include "chattr-util.h"
  12 #include "dirent-util.h"
  13 #include "fd-util.h"
  14 #include "fileio.h"
  15 #include "fs-util.h"
  16 #include "hostname-util.h"
  17 #include "import-common.h"
  18 #include "os-util.h"
  19 #include "process-util.h"
  20 #include "selinux-util.h"
  21 #include "signal-util.h"
  22 #include "stat-util.h"
  23 #include "tmpfile-util.h"
  24
  25 int import_fork_tar_x(const char *path, pid_t *ret) {
  26         _cleanup_close_pair_ int pipefd[2] = PIPE_EBADF;
  27         bool use_selinux;
  28         pid_t pid;
  29         int r;
  30
  31         assert(path);
  32         assert(ret);
  33
  34         if (pipe2(pipefd, O_CLOEXEC) < 0)
  35                 return log_error_errno(errno, "Failed to create pipe for tar: %m");
  36
  37         use_selinux = mac_selinux_use();
  38
  39         r = safe_fork_full("(tar)",
  40                            (int[]) { pipefd[0], -EBADF, STDERR_FILENO },
  41                            NULL, 0,
  42                            FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG|FORK_REARRANGE_STDIO|FORK_LOG, &pid);
  43         if (r < 0)
  44                 return r;
  45         if (r == 0) {
  46                 const char *cmdline[] = {
  47                        "tar",
  48                        "--ignore-zeros",
  49                        "--numeric-owner",
  50                        "-C", path,
  51                        "-pxf",
  52                        "-",
  53                        "--xattrs",
  54                        "--xattrs-include=*",
  55                        use_selinux ? "--selinux" : "--no-selinux",
  56                        NULL
  57                 };
  58
  59                 uint64_t retain =
  60                         (1ULL << CAP_CHOWN) |
  61                         (1ULL << CAP_FOWNER) |
  62                         (1ULL << CAP_FSETID) |
  63                         (1ULL << CAP_MKNOD) |
  64                         (1ULL << CAP_SETFCAP) |
  65                         (1ULL << CAP_DAC_OVERRIDE);
  66
  67                 /* Child */
  68
  69                 if (unshare(CLONE_NEWNET) < 0)
  70                         log_warning_errno(errno, "Failed to lock tar into network namespace, ignoring: %m");
  71
  72                 r = capability_bounding_set_drop(retain, true);
  73                 if (r < 0)
  74                         log_warning_errno(r, "Failed to drop capabilities, ignoring: %m");
  75
  76                 /* Try "gtar" before "tar". We only test things upstream with GNU tar. Some distros appear to
  77                  * install a different implementation as "tar" (in particular some that do not support the
  78                  * same command line switches), but then provide "gtar" as alias for the real thing, hence
  79                  * let's prefer that. (Yes, it's a bad idea they do that, given they don't provide equivalent
  80                  * command line support, but we are not here to argue, let's just expose the same
  81                  * behaviour/implementation everywhere.) */
  82                 execvp("gtar", (char* const*) cmdline);
  83                 execvp("tar", (char* const*) cmdline);
  84
  85                 log_error_errno(errno, "Failed to execute tar: %m");
  86                 _exit(EXIT_FAILURE);
  87         }
  88
  89         *ret = pid;
  90
  91         return TAKE_FD(pipefd[1]);
  92 }
  93
  94 int import_fork_tar_c(const char *path, pid_t *ret) {
  95         _cleanup_close_pair_ int pipefd[2] = PIPE_EBADF;
  96         bool use_selinux;
  97         pid_t pid;
  98         int r;
  99
 100         assert(path);
 101         assert(ret);
 102
 103         if (pipe2(pipefd, O_CLOEXEC) < 0)
 104                 return log_error_errno(errno, "Failed to create pipe for tar: %m");
 105
 106         use_selinux = mac_selinux_use();
 107
 108         r = safe_fork_full("(tar)",
 109                            (int[]) { -EBADF, pipefd[1], STDERR_FILENO },
 110                            NULL, 0,
 111                            FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG|FORK_REARRANGE_STDIO|FORK_LOG, &pid);
 112         if (r < 0)
 113                 return r;
 114         if (r == 0) {
 115                 const char *cmdline[] = {
 116                         "tar",
 117                         "-C", path,
 118                         "-c",
 119                         "--xattrs",
 120                         "--xattrs-include=*",
 121                        use_selinux ? "--selinux" : "--no-selinux",
 122                         ".",
 123                         NULL
 124                 };
 125
 126                 uint64_t retain = (1ULL << CAP_DAC_OVERRIDE);
 127
 128                 /* Child */
 129
 130                 if (unshare(CLONE_NEWNET) < 0)
 131                         log_error_errno(errno, "Failed to lock tar into network namespace, ignoring: %m");
 132
 133                 r = capability_bounding_set_drop(retain, true);
 134                 if (r < 0)
 135                         log_error_errno(r, "Failed to drop capabilities, ignoring: %m");
 136
 137                 execvp("gtar", (char* const*) cmdline);
 138                 execvp("tar", (char* const*) cmdline);
 139
 140                 log_error_errno(errno, "Failed to execute tar: %m");
 141                 _exit(EXIT_FAILURE);
 142         }
 143
 144         *ret = pid;
 145
 146         return TAKE_FD(pipefd[0]);
 147 }
 148
 149 int import_mangle_os_tree(const char *path) {
 150         _cleanup_free_ char *child = NULL, *t = NULL, *joined = NULL;
 151         _cleanup_closedir_ DIR *d = NULL, *cd = NULL;
 152         struct dirent *dent;
 153         struct stat st;
 154         int r;
 155
 156         assert(path);
 157
 158         /* Some tarballs contain a single top-level directory that contains the actual OS directory tree. Try to
 159          * recognize this, and move the tree one level up. */
 160
 161         r = path_is_os_tree(path);
 162         if (r < 0)
 163                 return log_error_errno(r, "Failed to determine whether '%s' is an OS tree: %m", path);
 164         if (r > 0) {
 165                 log_debug("Directory tree '%s' is a valid OS tree.", path);
 166                 return 0;
 167         }
 168
 169         log_debug("Directory tree '%s' is not recognizable as OS tree, checking whether to rearrange it.", path);
 170
 171         d = opendir(path);
 172         if (!d)
 173                 return log_error_errno(r, "Failed to open directory '%s': %m", path);
 174
 175         errno = 0;
 176         dent = readdir_no_dot(d);
 177         if (!dent) {
 178                 if (errno != 0)
 179                         return log_error_errno(errno, "Failed to iterate through directory '%s': %m", path);
 180
 181                 log_debug("Directory '%s' is empty, leaving it as it is.", path);
 182                 return 0;
 183         }
 184
 185         child = strdup(dent->d_name);
 186         if (!child)
 187                 return log_oom();
 188
 189         errno = 0;
 190         dent = readdir_no_dot(d);
 191         if (dent) {
 192                 if (errno != 0)
 193                         return log_error_errno(errno, "Failed to iterate through directory '%s': %m", path);
 194
 195                 log_debug("Directory '%s' does not look like an OS tree, and has multiple children, leaving as it is.", path);
 196                 return 0;
 197         }
 198
 199         if (fstatat(dirfd(d), child, &st, AT_SYMLINK_NOFOLLOW) < 0)
 200                 return log_debug_errno(errno, "Failed to stat file '%s/%s': %m", path, child);
 201         r = stat_verify_directory(&st);
 202         if (r < 0) {
 203                 log_debug_errno(r, "Child '%s' of directory '%s' is not a directory, leaving things as they are.", child, path);
 204                 return 0;
 205         }
 206
 207         joined = path_join(path, child);
 208         if (!joined)
 209                 return log_oom();
 210         r = path_is_os_tree(joined);
 211         if (r == -ENOTDIR) {
 212                 log_debug("Directory '%s' does not look like an OS tree, and contains a single regular file only, leaving as it is.", path);
 213                 return 0;
 214         }
 215         if (r < 0)
 216                 return log_error_errno(r, "Failed to determine whether '%s' is an OS tree: %m", joined);
 217         if (r == 0) {
 218                 log_debug("Neither '%s' nor '%s' is a valid OS tree, leaving them as they are.", path, joined);
 219                 return 0;
 220         }
 221
 222         /* Nice, we have checked now:
 223          *
 224          * 1. The top-level directory does not qualify as OS tree
 225          * 1. The top-level directory only contains one item
 226          * 2. That item is a directory
 227          * 3. And that directory qualifies as OS tree
 228          *
 229          * Let's now rearrange things, moving everything in the inner directory one level up */
 230
 231         cd = xopendirat(dirfd(d), child, O_NOFOLLOW);
 232         if (!cd)
 233                 return log_error_errno(errno, "Can't open directory '%s': %m", joined);
 234
 235         log_info("Rearranging '%s', moving OS tree one directory up.", joined);
 236
 237         /* Let's rename the child to an unguessable name so that we can be sure all files contained in it can be
 238          * safely moved up and won't collide with the name. */
 239         r = tempfn_random(child, NULL, &t);
 240         if (r < 0)
 241                 return log_oom();
 242         r = rename_noreplace(dirfd(d), child, dirfd(d), t);
 243         if (r < 0)
 244                 return log_error_errno(r, "Unable to rename '%s' to '%s/%s': %m", joined, path, t);
 245
 246         FOREACH_DIRENT_ALL(de, cd, return log_error_errno(errno, "Failed to iterate through directory '%s': %m", joined)) {
 247                 if (dot_or_dot_dot(de->d_name))
 248                         continue;
 249
 250                 r = rename_noreplace(dirfd(cd), de->d_name, dirfd(d), de->d_name);
 251                 if (r < 0)
 252                         return log_error_errno(r, "Unable to move '%s/%s/%s' to '%s/%s': %m", path, t, de->d_name, path, de->d_name);
 253         }
 254
 255         if (unlinkat(dirfd(d), t, AT_REMOVEDIR) < 0)
 256                 return log_error_errno(errno, "Failed to remove temporary directory '%s/%s': %m", path, t);
 257
 258         r = futimens(dirfd(d), (struct timespec[2]) { st.st_atim, st.st_mtim });
 259         if (r < 0)
 260                 log_debug_errno(r, "Failed to adjust top-level timestamps '%s', ignoring: %m", path);
 261
 262         r = fchmod_and_chown(dirfd(d), st.st_mode, st.st_uid, st.st_gid);
 263         if (r < 0)
 264                 return log_error_errno(r, "Failed to adjust top-level directory mode/ownership '%s': %m", path);
 265
 266         log_info("Successfully rearranged OS tree.");
 267
 268         return 0;
 269 }
 270
 271 bool import_validate_local(const char *name, ImportFlags flags) {
 272
 273         /* By default we insist on a valid hostname for naming images. But optionally we relax that, in which
 274          * case it can be any path name */
 275
 276         if (FLAGS_SET(flags, IMPORT_DIRECT))
 277                 return path_is_valid(name);
 278
 279         return hostname_is_valid(name, 0);
 280 }
 281
 282 static int interrupt_signal_handler(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
 283         log_notice("Transfer aborted.");
 284         sd_event_exit(sd_event_source_get_event(s), EINTR);
 285         return 0;
 286 }
 287
 288 int import_allocate_event_with_signals(sd_event **ret) {
 289         _cleanup_(sd_event_unrefp) sd_event *event = NULL;
 290         int r;
 291
 292         assert(ret);
 293
 294         r = sd_event_default(&event);
 295         if (r < 0)
 296                 return log_error_errno(r, "Failed to allocate event loop: %m");
 297
 298         assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGTERM, SIGINT, -1) >= 0);
 299         (void) sd_event_add_signal(event, NULL, SIGTERM, interrupt_signal_handler,  NULL);
 300         (void) sd_event_add_signal(event, NULL, SIGINT, interrupt_signal_handler, NULL);
 301
 302         *ret = TAKE_PTR(event);
 303         return 0;
 304 }