Line data Source code
1 : /* SPDX-License-Identifier: LGPL-2.1+ */
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 "dirent-util.h"
12 : #include "fd-util.h"
13 : #include "fileio.h"
14 : #include "fs-util.h"
15 : #include "import-common.h"
16 : #include "os-util.h"
17 : #include "process-util.h"
18 : #include "selinux-util.h"
19 : #include "signal-util.h"
20 : #include "tmpfile-util.h"
21 : #include "util.h"
22 :
23 0 : int import_make_read_only_fd(int fd) {
24 : int r;
25 :
26 0 : assert(fd >= 0);
27 :
28 : /* First, let's make this a read-only subvolume if it refers
29 : * to a subvolume */
30 0 : r = btrfs_subvol_set_read_only_fd(fd, true);
31 0 : if (IN_SET(r, -ENOTTY, -ENOTDIR, -EINVAL)) {
32 : struct stat st;
33 :
34 : /* This doesn't refer to a subvolume, or the file
35 : * system isn't even btrfs. In that, case fall back to
36 : * chmod()ing */
37 :
38 0 : r = fstat(fd, &st);
39 0 : if (r < 0)
40 0 : return log_error_errno(errno, "Failed to stat temporary image: %m");
41 :
42 : /* Drop "w" flag */
43 0 : if (fchmod(fd, st.st_mode & 07555) < 0)
44 0 : return log_error_errno(errno, "Failed to chmod() final image: %m");
45 :
46 0 : return 0;
47 :
48 0 : } else if (r < 0)
49 0 : return log_error_errno(r, "Failed to make subvolume read-only: %m");
50 :
51 0 : return 0;
52 : }
53 :
54 0 : int import_make_read_only(const char *path) {
55 0 : _cleanup_close_ int fd = 1;
56 :
57 0 : fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
58 0 : if (fd < 0)
59 0 : return log_error_errno(errno, "Failed to open %s: %m", path);
60 :
61 0 : return import_make_read_only_fd(fd);
62 : }
63 :
64 0 : int import_fork_tar_x(const char *path, pid_t *ret) {
65 0 : _cleanup_close_pair_ int pipefd[2] = { -1, -1 };
66 : bool use_selinux;
67 : pid_t pid;
68 : int r;
69 :
70 0 : assert(path);
71 0 : assert(ret);
72 :
73 0 : if (pipe2(pipefd, O_CLOEXEC) < 0)
74 0 : return log_error_errno(errno, "Failed to create pipe for tar: %m");
75 :
76 0 : use_selinux = mac_selinux_use();
77 :
78 0 : r = safe_fork("(tar)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
79 0 : if (r < 0)
80 0 : return r;
81 0 : if (r == 0) {
82 0 : uint64_t retain =
83 : (1ULL << CAP_CHOWN) |
84 : (1ULL << CAP_FOWNER) |
85 : (1ULL << CAP_FSETID) |
86 : (1ULL << CAP_MKNOD) |
87 : (1ULL << CAP_SETFCAP) |
88 : (1ULL << CAP_DAC_OVERRIDE);
89 :
90 : /* Child */
91 :
92 0 : pipefd[1] = safe_close(pipefd[1]);
93 :
94 0 : r = rearrange_stdio(pipefd[0], -1, STDERR_FILENO);
95 0 : if (r < 0) {
96 0 : log_error_errno(r, "Failed to rearrange stdin/stdout: %m");
97 0 : _exit(EXIT_FAILURE);
98 : }
99 :
100 0 : if (unshare(CLONE_NEWNET) < 0)
101 0 : log_error_errno(errno, "Failed to lock tar into network namespace, ignoring: %m");
102 :
103 0 : r = capability_bounding_set_drop(retain, true);
104 0 : if (r < 0)
105 0 : log_error_errno(r, "Failed to drop capabilities, ignoring: %m");
106 :
107 0 : execlp("tar", "tar", "--numeric-owner", "-C", path, "-px", "--xattrs", "--xattrs-include=*",
108 : use_selinux ? "--selinux" : "--no-selinux", NULL);
109 0 : log_error_errno(errno, "Failed to execute tar: %m");
110 0 : _exit(EXIT_FAILURE);
111 : }
112 :
113 0 : *ret = pid;
114 :
115 0 : return TAKE_FD(pipefd[1]);
116 : }
117 :
118 0 : int import_fork_tar_c(const char *path, pid_t *ret) {
119 0 : _cleanup_close_pair_ int pipefd[2] = { -1, -1 };
120 : bool use_selinux;
121 : pid_t pid;
122 : int r;
123 :
124 0 : assert(path);
125 0 : assert(ret);
126 :
127 0 : if (pipe2(pipefd, O_CLOEXEC) < 0)
128 0 : return log_error_errno(errno, "Failed to create pipe for tar: %m");
129 :
130 0 : use_selinux = mac_selinux_use();
131 :
132 0 : r = safe_fork("(tar)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
133 0 : if (r < 0)
134 0 : return r;
135 0 : if (r == 0) {
136 0 : uint64_t retain = (1ULL << CAP_DAC_OVERRIDE);
137 :
138 : /* Child */
139 :
140 0 : pipefd[0] = safe_close(pipefd[0]);
141 :
142 0 : r = rearrange_stdio(-1, pipefd[1], STDERR_FILENO);
143 0 : if (r < 0) {
144 0 : log_error_errno(r, "Failed to rearrange stdin/stdout: %m");
145 0 : _exit(EXIT_FAILURE);
146 : }
147 :
148 0 : if (unshare(CLONE_NEWNET) < 0)
149 0 : log_error_errno(errno, "Failed to lock tar into network namespace, ignoring: %m");
150 :
151 0 : r = capability_bounding_set_drop(retain, true);
152 0 : if (r < 0)
153 0 : log_error_errno(r, "Failed to drop capabilities, ignoring: %m");
154 :
155 0 : execlp("tar", "tar", "-C", path, "-c", "--xattrs", "--xattrs-include=*",
156 : use_selinux ? "--selinux" : "--no-selinux", ".", NULL);
157 0 : log_error_errno(errno, "Failed to execute tar: %m");
158 0 : _exit(EXIT_FAILURE);
159 : }
160 :
161 0 : *ret = pid;
162 :
163 0 : return TAKE_FD(pipefd[0]);
164 : }
165 :
166 0 : int import_mangle_os_tree(const char *path) {
167 0 : _cleanup_closedir_ DIR *d = NULL, *cd = NULL;
168 0 : _cleanup_free_ char *child = NULL, *t = NULL;
169 : const char *joined;
170 : struct dirent *de;
171 : int r;
172 :
173 0 : assert(path);
174 :
175 : /* Some tarballs contain a single top-level directory that contains the actual OS directory tree. Try to
176 : * recognize this, and move the tree one level up. */
177 :
178 0 : r = path_is_os_tree(path);
179 0 : if (r < 0)
180 0 : return log_error_errno(r, "Failed to determine whether '%s' is an OS tree: %m", path);
181 0 : if (r > 0) {
182 0 : log_debug("Directory tree '%s' is a valid OS tree.", path);
183 0 : return 0;
184 : }
185 :
186 0 : log_debug("Directory tree '%s' is not recognizable as OS tree, checking whether to rearrange it.", path);
187 :
188 0 : d = opendir(path);
189 0 : if (!d)
190 0 : return log_error_errno(r, "Failed to open directory '%s': %m", path);
191 :
192 0 : errno = 0;
193 0 : de = readdir_no_dot(d);
194 0 : if (!de) {
195 0 : if (errno != 0)
196 0 : return log_error_errno(errno, "Failed to iterate through directory '%s': %m", path);
197 :
198 0 : log_debug("Directory '%s' is empty, leaving it as it is.", path);
199 0 : return 0;
200 : }
201 :
202 0 : child = strdup(de->d_name);
203 0 : if (!child)
204 0 : return log_oom();
205 :
206 0 : errno = 0;
207 0 : de = readdir_no_dot(d);
208 0 : if (de) {
209 0 : if (errno != 0)
210 0 : return log_error_errno(errno, "Failed to iterate through directory '%s': %m", path);
211 :
212 0 : log_debug("Directory '%s' does not look like a directory tree, and has multiple children, leaving as it is.", path);
213 0 : return 0;
214 : }
215 :
216 0 : joined = prefix_roota(path, child);
217 0 : r = path_is_os_tree(joined);
218 0 : if (r == -ENOTDIR) {
219 0 : log_debug("Directory '%s' does not look like a directory tree, and contains a single regular file only, leaving as it is.", path);
220 0 : return 0;
221 : }
222 0 : if (r < 0)
223 0 : return log_error_errno(r, "Failed to determine whether '%s' is an OS tree: %m", joined);
224 0 : if (r == 0) {
225 0 : log_debug("Neither '%s' nor '%s' is a valid OS tree, leaving them as they are.", path, joined);
226 0 : return 0;
227 : }
228 :
229 : /* Nice, we have checked now:
230 : *
231 : * 1. The top-level directory does not qualify as OS tree
232 : * 1. The top-level directory only contains one item
233 : * 2. That item is a directory
234 : * 3. And that directory qualifies as OS tree
235 : *
236 : * Let's now rearrange things, moving everything in the inner directory one level up */
237 :
238 0 : cd = xopendirat(dirfd(d), child, O_NOFOLLOW);
239 0 : if (!cd)
240 0 : return log_error_errno(errno, "Can't open directory '%s': %m", joined);
241 :
242 0 : log_info("Rearranging '%s', moving OS tree one directory up.", joined);
243 :
244 : /* Let's rename the child to an unguessable name so that we can be sure all files contained in it can be
245 : * safely moved up and won't collide with the name. */
246 0 : r = tempfn_random(child, NULL, &t);
247 0 : if (r < 0)
248 0 : return log_oom();
249 0 : r = rename_noreplace(dirfd(d), child, dirfd(d), t);
250 0 : if (r < 0)
251 0 : return log_error_errno(r, "Unable to rename '%s' to '%s/%s': %m", joined, path, t);
252 :
253 0 : FOREACH_DIRENT_ALL(de, cd, return log_error_errno(errno, "Failed to iterate through directory '%s': %m", joined)) {
254 0 : if (dot_or_dot_dot(de->d_name))
255 0 : continue;
256 :
257 0 : r = rename_noreplace(dirfd(cd), de->d_name, dirfd(d), de->d_name);
258 0 : if (r < 0)
259 0 : return log_error_errno(r, "Unable to move '%s/%s/%s' to '%s/%s': %m", path, t, de->d_name, path, de->d_name);
260 : }
261 :
262 0 : if (unlinkat(dirfd(d), t, AT_REMOVEDIR) < 0)
263 0 : return log_error_errno(errno, "Failed to remove temporary directory '%s/%s': %m", path, t);
264 :
265 0 : log_info("Successfully rearranged OS tree.");
266 :
267 0 : return 0;
268 : }
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