15175033720

Committed 21 May 2025 10:22PM UTC coverage: 72.079% (+0.03%) from 72.047%

Build # 15175033720

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push

github

Committed by

web-flow

Commit Message

Several minor follow-ups for #33995 (#37558)

Coverage Stats

3 of 3 new or added lines in 1 file covered. (100.0%)

34302 existing lines in 652 files now uncovered.

299232 of 415142 relevant lines covered (72.08%)

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77.27

/src/nspawn/nspawn-setuid.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <fcntl.h>
#include <unistd.h>

#include "alloc-util.h"
#include "errno.h"
#include "extract-word.h"
#include "fd-util.h"
#include "fileio.h"
#include "log.h"
#include "mkdir.h"
#include "nspawn-setuid.h"
#include "process-util.h"
#include "string-util.h"
#include "strv.h"
#include "user-util.h"

static int spawn_getent(const char *database, const char *key, pid_t *rpid) {
        int pipe_fds[2], r;
        pid_t pid;

        assert(database);
        assert(key);
        assert(rpid);

        if (pipe2(pipe_fds, O_CLOEXEC) < 0)
                return log_error_errno(errno, "Failed to allocate pipe: %m");

        r = safe_fork_full("(getent)",
                           (int[]) { -EBADF, pipe_fds[1], -EBADF }, NULL, 0,
                           FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG_SIGTERM|FORK_REARRANGE_STDIO|FORK_LOG|FORK_RLIMIT_NOFILE_SAFE,
                           &pid);
        if (r < 0) {
                safe_close_pair(pipe_fds);
                return r;
        }
        if (r == 0) {
                execle("/usr/bin/getent", "getent", database, key, NULL, &(char*[1]){});
                execle("/bin/getent", "getent", database, key, NULL, &(char*[1]){});
                _exit(EXIT_FAILURE);
        }

        pipe_fds[1] = safe_close(pipe_fds[1]);

        *rpid = pid;

        return pipe_fds[0];
}

int change_uid_gid_raw(
                uid_t uid,
                gid_t gid,
                const gid_t *supplementary_gids,
                size_t n_supplementary_gids,
                bool chown_stdio) {

        int r;

        if (!uid_is_valid(uid))
                uid = 0;
        if (!gid_is_valid(gid))
                gid = 0;

        if (chown_stdio) {
                (void) fchown(STDIN_FILENO, uid, gid);
                (void) fchown(STDOUT_FILENO, uid, gid);
                (void) fchown(STDERR_FILENO, uid, gid);
        }

        r = fully_set_uid_gid(uid, gid, supplementary_gids, n_supplementary_gids);
        if (r < 0)
                return log_error_errno(r, "Changing privileges failed: %m");

        return 0;
}

int change_uid_gid(const char *user, bool chown_stdio, char **ret_home) {
        char *x, *u, *g, *h;
        _cleanup_free_ gid_t *gids = NULL;
        _cleanup_free_ char *home = NULL, *line = NULL;
        _cleanup_fclose_ FILE *f = NULL;
        _cleanup_close_ int fd = -EBADF;
        unsigned n_gids = 0;
        uid_t uid;
        gid_t gid;
        pid_t pid;
        int r;

        assert(ret_home);

        if (!user || STR_IN_SET(user, "root", "0")) {
                /* Reset everything fully to 0, just in case */

                r = reset_uid_gid();
                if (r < 0)
                        return log_error_errno(r, "Failed to become root: %m");

                *ret_home = NULL;
                return 0;
        }

        /* First, get user credentials */
        fd = spawn_getent("passwd", user, &pid);
        if (fd < 0)
                return fd;

        f = take_fdopen(&fd, "r");
        if (!f)
                return log_oom();

        r = read_line(f, LONG_LINE_MAX, &line);
        if (r == 0)
                return log_error_errno(SYNTHETIC_ERRNO(ESRCH),
                                       "Failed to resolve user %s.", user);
        if (r < 0)
                return log_error_errno(r, "Failed to read from getent: %m");

        (void) wait_for_terminate_and_check("getent passwd", pid, WAIT_LOG);

        x = strchr(line, ':');
        if (!x)
                return log_error_errno(SYNTHETIC_ERRNO(EIO),
                                       "/etc/passwd entry has invalid user field.");

        u = strchr(x+1, ':');
        if (!u)
                return log_error_errno(SYNTHETIC_ERRNO(EIO),
                                       "/etc/passwd entry has invalid password field.");

        u++;
        g = strchr(u, ':');
        if (!g)
                return log_error_errno(SYNTHETIC_ERRNO(EIO),
                                       "/etc/passwd entry has invalid UID field.");

        *g = 0;
        g++;
        x = strchr(g, ':');
        if (!x)
                return log_error_errno(SYNTHETIC_ERRNO(EIO),
                                       "/etc/passwd entry has invalid GID field.");

        *x = 0;
        h = strchr(x+1, ':');
        if (!h)
                return log_error_errno(SYNTHETIC_ERRNO(EIO),
                                       "/etc/passwd entry has invalid GECOS field.");

        h++;
        x = strchr(h, ':');
        if (!x)
                return log_error_errno(SYNTHETIC_ERRNO(EIO),
                                       "/etc/passwd entry has invalid home directory field.");

        *x = 0;

        r = parse_uid(u, &uid);
        if (r < 0)
                return log_error_errno(SYNTHETIC_ERRNO(EIO),
                                       "Failed to parse UID of user.");

        r = parse_gid(g, &gid);
        if (r < 0)
                return log_error_errno(SYNTHETIC_ERRNO(EIO),
                                       "Failed to parse GID of user.");

        home = strdup(h);
        if (!home)
                return log_oom();

        f = safe_fclose(f);
        line = mfree(line);

        /* Second, get group memberships */
        fd = spawn_getent("initgroups", user, &pid);
        if (fd < 0)
                return fd;

        f = take_fdopen(&fd, "r");
        if (!f)
                return log_oom();

        r = read_line(f, LONG_LINE_MAX, &line);
        if (r == 0)
                return log_error_errno(SYNTHETIC_ERRNO(ESRCH),
                                       "Failed to resolve user %s.", user);
        if (r < 0)
                return log_error_errno(r, "Failed to read from getent: %m");

        (void) wait_for_terminate_and_check("getent initgroups", pid, WAIT_LOG);

        /* Skip over the username and subsequent separator whitespace */
        x = line;
        x += strcspn(x, WHITESPACE);
        x += strspn(x, WHITESPACE);

        for (const char *p = x;;) {
               _cleanup_free_ char *word = NULL;

                r = extract_first_word(&p, &word, NULL, 0);
                if (r < 0)
                        return log_error_errno(r, "Failed to parse group data from getent: %m");
                if (r == 0)
                        break;

                if (!GREEDY_REALLOC(gids, n_gids+1))
                        return log_oom();

                r = parse_gid(word, &gids[n_gids++]);
                if (r < 0)
                        return log_error_errno(r, "Failed to parse group data from getent: %m");
        }

        r = mkdir_parents(home, 0775);
        if (r < 0)
                return log_error_errno(r, "Failed to make home root directory: %m");

        r = mkdir_safe(home, 0755, uid, gid, 0);
        if (r < 0 && !IN_SET(r, -EEXIST, -ENOTDIR))
                return log_error_errno(r, "Failed to make home directory: %m");

        r = change_uid_gid_raw(uid, gid, gids, n_gids, chown_stdio);
        if (r < 0)
                return r;

        if (ret_home)
                *ret_home = TAKE_PTR(home);

        return 0;
}

1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3	#include <fcntl.h>
4	#include <unistd.h>
5
6	#include "alloc-util.h"
7	#include "errno.h"
8	#include "extract-word.h"
9	#include "fd-util.h"
10	#include "fileio.h"
11	#include "log.h"
12	#include "mkdir.h"
13	#include "nspawn-setuid.h"
14	#include "process-util.h"
15	#include "string-util.h"
16	#include "strv.h"
17	#include "user-util.h"
18
19	static int spawn_getent(const char database, const char key, pid_t *rpid) {	6✔
20	int pipe_fds[2], r;	6✔
21	pid_t pid;	6✔
22
23	assert(database);	6✔
24	assert(key);	6✔
25	assert(rpid);	6✔
26
27	if (pipe2(pipe_fds, O_CLOEXEC) < 0)	6✔
UNCOV 28	return log_error_errno(errno, "Failed to allocate pipe: %m");	×
29
30	r = safe_fork_full("(getent)",	18✔
31	(int[]) { -EBADF, pipe_fds[1], -EBADF }, NULL, 0,	6✔
32	FORK_RESET_SIGNALS\|FORK_CLOSE_ALL_FDS\|FORK_DEATHSIG_SIGTERM\|FORK_REARRANGE_STDIO\|FORK_LOG\|FORK_RLIMIT_NOFILE_SAFE,
33	&pid);
34	if (r < 0) {	12✔
UNCOV 35	safe_close_pair(pipe_fds);	×
UNCOV 36	return r;	×
37	}
38	if (r == 0) {	12✔
39	execle("/usr/bin/getent", "getent", database, key, NULL, &(char*[1]){});	6✔
40	execle("/bin/getent", "getent", database, key, NULL, &(char*[1]){});	6✔
41	_exit(EXIT_FAILURE);	6✔
42	}
43
44	pipe_fds[1] = safe_close(pipe_fds[1]);	6✔
45
46	*rpid = pid;	6✔
47
48	return pipe_fds[0];	6✔
49	}
50
51	int change_uid_gid_raw(	3✔
52	uid_t uid,
53	gid_t gid,
54	const gid_t *supplementary_gids,
55	size_t n_supplementary_gids,
56	bool chown_stdio) {
57
58	int r;	3✔
59
60	if (!uid_is_valid(uid))	3✔
UNCOV 61	uid = 0;	×
62	if (!gid_is_valid(gid))	3✔
UNCOV 63	gid = 0;	×
64
65	if (chown_stdio) {	3✔
66	(void) fchown(STDIN_FILENO, uid, gid);	3✔
67	(void) fchown(STDOUT_FILENO, uid, gid);	3✔
68	(void) fchown(STDERR_FILENO, uid, gid);	3✔
69	}
70
71	r = fully_set_uid_gid(uid, gid, supplementary_gids, n_supplementary_gids);	3✔
72	if (r < 0)	3✔
UNCOV 73	return log_error_errno(r, "Changing privileges failed: %m");	×
74
75	return 0;
76	}
77
78	int change_uid_gid(const char user, bool chown_stdio, char *ret_home) {	107✔
79	char x, u, g, h;	107✔
80	_cleanup_free_ gid_t *gids = NULL;	214✔
81	_cleanup_free_ char home = NULL, line = NULL;	107✔
82	_cleanup_fclose_ FILE *f = NULL;	107✔
83	_cleanup_close_ int fd = -EBADF;	107✔
84	unsigned n_gids = 0;	107✔
85	uid_t uid;	107✔
86	gid_t gid;	107✔
87	pid_t pid;	107✔
88	int r;	107✔
89
90	assert(ret_home);	107✔
91
92	if (!user \|\| STR_IN_SET(user, "root", "0")) {	107✔
93	/* Reset everything fully to 0, just in case */
94
95	r = reset_uid_gid();	104✔
96	if (r < 0)	104✔
97	return log_error_errno(r, "Failed to become root: %m");	104✔
98
99	*ret_home = NULL;	104✔
100	return 0;	104✔
101	}
102
103	/* First, get user credentials */
104	fd = spawn_getent("passwd", user, &pid);	3✔
105	if (fd < 0)	3✔
106	return fd;
107
108	f = take_fdopen(&fd, "r");	3✔
109	if (!f)	3✔
UNCOV 110	return log_oom();	×
111
112	r = read_line(f, LONG_LINE_MAX, &line);	3✔
113	if (r == 0)	3✔
UNCOV 114	return log_error_errno(SYNTHETIC_ERRNO(ESRCH),	×
115	"Failed to resolve user %s.", user);
116	if (r < 0)	3✔
117	return log_error_errno(r, "Failed to read from getent: %m");	×
118
119	(void) wait_for_terminate_and_check("getent passwd", pid, WAIT_LOG);	3✔
120
121	x = strchr(line, ':');	3✔
122	if (!x)	3✔
UNCOV 123	return log_error_errno(SYNTHETIC_ERRNO(EIO),	×
124	"/etc/passwd entry has invalid user field.");
125
126	u = strchr(x+1, ':');	3✔
127	if (!u)	3✔
UNCOV 128	return log_error_errno(SYNTHETIC_ERRNO(EIO),	×
129	"/etc/passwd entry has invalid password field.");
130
131	u++;	3✔
132	g = strchr(u, ':');	3✔
133	if (!g)	3✔
UNCOV 134	return log_error_errno(SYNTHETIC_ERRNO(EIO),	×
135	"/etc/passwd entry has invalid UID field.");
136
137	*g = 0;	3✔
138	g++;	3✔
139	x = strchr(g, ':');	3✔
140	if (!x)	3✔
UNCOV 141	return log_error_errno(SYNTHETIC_ERRNO(EIO),	×
142	"/etc/passwd entry has invalid GID field.");
143
144	*x = 0;	3✔
145	h = strchr(x+1, ':');	3✔
146	if (!h)	3✔
UNCOV 147	return log_error_errno(SYNTHETIC_ERRNO(EIO),	×
148	"/etc/passwd entry has invalid GECOS field.");
149
150	h++;	3✔
151	x = strchr(h, ':');	3✔
152	if (!x)	3✔
UNCOV 153	return log_error_errno(SYNTHETIC_ERRNO(EIO),	×
154	"/etc/passwd entry has invalid home directory field.");
155
156	*x = 0;	3✔
157
158	r = parse_uid(u, &uid);	3✔
159	if (r < 0)	3✔
UNCOV 160	return log_error_errno(SYNTHETIC_ERRNO(EIO),	×
161	"Failed to parse UID of user.");
162
163	r = parse_gid(g, &gid);	3✔
164	if (r < 0)	3✔
UNCOV 165	return log_error_errno(SYNTHETIC_ERRNO(EIO),	×
166	"Failed to parse GID of user.");
167
168	home = strdup(h);	3✔
169	if (!home)	3✔
UNCOV 170	return log_oom();	×
171
172	f = safe_fclose(f);	3✔
173	line = mfree(line);	3✔
174
175	/* Second, get group memberships */
176	fd = spawn_getent("initgroups", user, &pid);	3✔
177	if (fd < 0)	3✔
178	return fd;
179
180	f = take_fdopen(&fd, "r");	3✔
181	if (!f)	3✔
UNCOV 182	return log_oom();	×
183
184	r = read_line(f, LONG_LINE_MAX, &line);	3✔
185	if (r == 0)	3✔
UNCOV 186	return log_error_errno(SYNTHETIC_ERRNO(ESRCH),	×
187	"Failed to resolve user %s.", user);
188	if (r < 0)	3✔
189	return log_error_errno(r, "Failed to read from getent: %m");	×
190
191	(void) wait_for_terminate_and_check("getent initgroups", pid, WAIT_LOG);	3✔
192
193	/* Skip over the username and subsequent separator whitespace */
194	x = line;	3✔
195	x += strcspn(x, WHITESPACE);	3✔
196	x += strspn(x, WHITESPACE);	3✔
197
198	for (const char *p = x;;) {	3✔
UNCOV 199	_cleanup_free_ char *word = NULL;	×
200
201	r = extract_first_word(&p, &word, NULL, 0);	3✔
202	if (r < 0)	3✔
UNCOV 203	return log_error_errno(r, "Failed to parse group data from getent: %m");	×
204	if (r == 0)	3✔
205	break;
206
UNCOV 207	if (!GREEDY_REALLOC(gids, n_gids+1))	×
UNCOV 208	return log_oom();	×
209
210	r = parse_gid(word, &gids[n_gids++]);	×
211	if (r < 0)	×
UNCOV 212	return log_error_errno(r, "Failed to parse group data from getent: %m");	×
213	}
214
215	r = mkdir_parents(home, 0775);	3✔
216	if (r < 0)	3✔
UNCOV 217	return log_error_errno(r, "Failed to make home root directory: %m");	×
218
219	r = mkdir_safe(home, 0755, uid, gid, 0);	3✔
220	if (r < 0 && !IN_SET(r, -EEXIST, -ENOTDIR))	3✔
UNCOV 221	return log_error_errno(r, "Failed to make home directory: %m");	×
222
223	r = change_uid_gid_raw(uid, gid, gids, n_gids, chown_stdio);	3✔
224	if (r < 0)	3✔
225	return r;
226
227	if (ret_home)	3✔
228	*ret_home = TAKE_PTR(home);	3✔
229
230	return 0;
231	}

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