@@ -1,280 +0,0 @@
1−/**************************************************************************
2−
3−Copyright (c) 2004-16 Simon Peter
4−Portions Copyright (c) 2010 RazZziel
5−
6−All Rights Reserved.
7−
8−Permission is hereby granted, free of charge, to any person obtaining a copy
9−of this software and associated documentation files (the "Software"), to deal
10−in the Software without restriction, including without limitation the rights
11−to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12−copies of the Software, and to permit persons to whom the Software is
13−furnished to do so, subject to the following conditions:
14−
15−The above copyright notice and this permission notice shall be included in
16−all copies or substantial portions of the Software.
17−
18−THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19−IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20−FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21−AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22−LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23−OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24−THE SOFTWARE.
25−
26−**************************************************************************/
27−
28−#define _GNU_SOURCE
29−#include <stdio.h>
30−#include <stdlib.h>
31−#include <unistd.h>
32−#include <libgen.h>
33−#include <dirent.h>
34−#include <string.h>
35−#include <sys/stat.h>
36−#include <sched.h>
37−#include <fcntl.h>
38−#include <sys/mount.h>
39−#include <errno.h>
40−
41−#define die(...) \
42− do { \
43− fprintf(stderr, "Error: " __VA_ARGS__); \
44− exit(1); \
45− } while (0);
46−
47−#define PATH_MAX 4096
48−
49−#define LINE_SIZE 255
50−
51−#define err_exit(format, ...) { fprintf(stderr, format ": %s\n", ##__VA_ARGS__, strerror(errno)); exit(EXIT_FAILURE); }
52−
53−int filter (const struct dirent *dir) {
54− char *p = (char*) &dir->d_name;
55− p = strrchr(p, '.');
56− return p && !strcmp(p, ".desktop");
57−}
58−
59−static void update_map(char *mapping, char *map_file) {
60− int fd;
61−
62− fd = open(map_file, O_WRONLY);
63− if (fd < 0) {
64− err_exit("map open");
65− }
66−
67− int map_len = strlen(mapping);
68− if (write(fd, mapping, map_len) != map_len) {
69− err_exit("map write");
70− }
71−
72− close(fd);
73−}
74−
75−static void add_path(const char* name, const char* rootdir) {
76− char path_buf[PATH_MAX];
77− snprintf(path_buf, sizeof(path_buf), "/%s", name);
78−
79− struct stat statbuf;
80− if (stat(path_buf, &statbuf) < 0) {
81− fprintf(stderr, "Cannot stat %s: %s\n", path_buf, strerror(errno));
82− return;
83− }
84−
85− char path_buf2[PATH_MAX];
86− snprintf(path_buf2, sizeof(path_buf2), "%s/%s", rootdir, name);
87−
88− mkdir(path_buf2, statbuf.st_mode & ~S_IFMT);
89− if (mount(path_buf, path_buf2, "none", MS_BIND | MS_REC, NULL) < 0) {
90− fprintf(stderr, "Cannot bind mount %s to %s: %s\n", path_buf, path_buf2, strerror(errno));
91− }
92−}
93−
94−#define SAVE_ENV_VAR(x) char *x = getenv(#x)
95−#define LOAD_ENV_VAR(x) do { if (x != NULL) setenv(#x, x, 1); } while(0)
96−
97−int main(int argc, char *argv[]) {
98− char *appdir = dirname(realpath("/proc/self/exe", NULL));
99− if (!appdir)
100− die("Could not access /proc/self/exe\n");
101−
102− char *tmpdir = getenv("TMPDIR");
103− if (!tmpdir) {
104− tmpdir = "/tmp";
105− }
106−
107− char template[PATH_MAX];
108− int needed = snprintf(template, PATH_MAX, "%s/nixXXXXXX", tmpdir);
109− if (needed < 0) {
110− err_exit("TMPDIR too long: '%s'", tmpdir);
111− }
112−
113− char *rootdir = mkdtemp(template);
114− if (!rootdir) {
115− err_exit("mkdtemp(%s)", template);
116− }
117−
118− int ret;
119−
120− struct dirent **namelist;
121−
122− ret = scandir(appdir, &namelist, filter, NULL);
123−
124− if (ret == 0) {
125− die("No .desktop files found\n");
126− } else if(ret == -1) {
127− die("Could not scan directory %s\n", appdir);
128− }
129−
130− /* Extract executable from .desktop file */
131−
132− FILE *f;
133− char *desktop_file = malloc(LINE_SIZE);
134− snprintf(desktop_file, LINE_SIZE-1, "%s/%s", appdir, namelist[0]->d_name);
135− f = fopen(desktop_file, "r");
136−
137− char *line = malloc(LINE_SIZE);
138− size_t n = LINE_SIZE;
139− int found = 0;
140−
141− while (getline(&line, &n, f) != -1)
142− {
143− if (!strncmp(line,"Exec=",5))
144− {
145− char *p = line+5;
146− while (*++p && *p != ' ' && *p != '%' && *p != '\n');
147− *p = 0;
148− found = 1;
149− break;
150− }
151− }
152−
153− fclose(f);
154−
155− if (!found)
156− die("Executable not found, make sure there is a line starting with 'Exec='\n");
157−
158− /* Execution */
159− char *executable = basename(line+5);
160−
161− char full_exec[PATH_MAX];
162− snprintf(full_exec, sizeof(full_exec), "/usr/bin/%s", executable);
163−
164− // get uid, gid before going to new namespace
165− uid_t uid = getuid();
166− gid_t gid = getgid();
167−
168− // "unshare" into new namespace
169− if (unshare(CLONE_NEWNS | CLONE_NEWUSER) < 0) {
170− err_exit("unshare()");
171− }
172−
173− // add necessary system stuff to rootdir namespace
174− add_path("dev", rootdir);
175− add_path("proc", rootdir);
176− add_path("sys", rootdir);
177− add_path("run", rootdir);
178− add_path("etc", rootdir);
179− add_path("home", rootdir);
180−
181− // setup skeleton
182− char path_buf[PATH_MAX];
183− snprintf(path_buf, sizeof(path_buf), "%s/tmp", rootdir);
184− mkdir(path_buf, ~0);
185− snprintf(path_buf, sizeof(path_buf), "%s/var", rootdir);
186− mkdir(path_buf, ~0);
187−
188− // make sure nixdir exists
189− struct stat statbuf2;
190− if (stat(appdir, &statbuf2) < 0) {
191− err_exit("stat(%s)", appdir);
192− }
193−
194− char nixdir[PATH_MAX];
195− snprintf(nixdir, sizeof(nixdir), "%s/nix", appdir);
196− snprintf(path_buf, sizeof(path_buf), "%s/nix", rootdir);
197− mkdir(path_buf, statbuf2.st_mode & ~S_IFMT);
198− if (mount(nixdir, path_buf, "none", MS_BIND | MS_REC, NULL) < 0) {
199− err_exit("mount(%s, %s)", nixdir, path_buf);
200− }
201−
202− char usrdir[PATH_MAX];
203− snprintf(usrdir, sizeof(usrdir), "%s/usr", appdir);
204− snprintf(path_buf, sizeof(path_buf), "%s/usr", rootdir);
205− mkdir(path_buf, statbuf2.st_mode & ~S_IFMT);
206− if (mount(usrdir, path_buf, "none", MS_BIND | MS_REC, NULL) < 0) {
207− err_exit("mount(%s, %s)", usrdir, path_buf);
208− }
209−
210− snprintf(path_buf, sizeof(path_buf), "%s/bin", rootdir);
211− if (symlink("/usr/bin", path_buf) < 0) {
212− err_exit("symlink(/usr/bin, %s)", path_buf);
213− }
214−
215− // fixes issue #1 where writing to /proc/self/gid_map fails
216− // see user_namespaces(7) for more documentation
217− int fd_setgroups = open("/proc/self/setgroups", O_WRONLY);
218− if (fd_setgroups > 0) {
219− write(fd_setgroups, "deny", 4);
220− }
221−
222− // map the original uid/gid in the new ns
223− char map_buf[1024];
224− snprintf(map_buf, sizeof(map_buf), "%d %d 1", uid, uid);
225− update_map(map_buf, "/proc/self/uid_map");
226− snprintf(map_buf, sizeof(map_buf), "%d %d 1", gid, gid);
227− update_map(map_buf, "/proc/self/gid_map");
228−
229− // chroot to rootdir
230− if (chroot(rootdir) < 0) {
231− err_exit("chroot(%s)", rootdir);
232− }
233−
234− char *pwddir = getenv("PWD");
235− chdir(pwddir);
236−
237− SAVE_ENV_VAR(PWD);
238− SAVE_ENV_VAR(DBUS_SESSION_BUS_ADDRESS);
239− SAVE_ENV_VAR(USER);
240− SAVE_ENV_VAR(HOSTNAME);
241− SAVE_ENV_VAR(LANG);
242− SAVE_ENV_VAR(LC_ALL);
243− SAVE_ENV_VAR(TERM);
244− SAVE_ENV_VAR(DISPLAY);
245− SAVE_ENV_VAR(XDG_RUNTIME_DIR);
246− SAVE_ENV_VAR(XAUTHORITY);
247− SAVE_ENV_VAR(XDG_SESSION_ID);
248− SAVE_ENV_VAR(XDG_SEAT);
249− SAVE_ENV_VAR(HOME);
250−
251− clearenv();
252−
253− LOAD_ENV_VAR(PWD);
254− LOAD_ENV_VAR(DBUS_SESSION_BUS_ADDRESS);
255− LOAD_ENV_VAR(USER);
256− LOAD_ENV_VAR(HOSTNAME);
257− LOAD_ENV_VAR(LANG);
258− LOAD_ENV_VAR(LC_ALL);
259− LOAD_ENV_VAR(TERM);
260− LOAD_ENV_VAR(DISPLAY);
261− LOAD_ENV_VAR(XDG_RUNTIME_DIR);
262− LOAD_ENV_VAR(XAUTHORITY);
263− LOAD_ENV_VAR(XDG_SESSION_ID);
264− LOAD_ENV_VAR(XDG_SEAT);
265− LOAD_ENV_VAR(HOME);
266−
267− setenv("PATH", ENV_PATH, 1);
268− setenv("TMPDIR", "/tmp", 1);
269−
270− /* Run */
271− // FIXME: What about arguments in the Exec= line of the desktop file?
272− ret = execvp(full_exec, argv);
273−
274− if (ret == -1)
275− die("Error executing '%s'; return code: %d\n", full_exec, ret);
276−
277− free(line);
278− free(desktop_file);
279− return 0;
280−}