/* SPDX-License-Identifier: LGPL-2.1+ */
-/***
- This file is part of systemd.
-
- Copyright 2010 Lennart Poettering
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
-***/
#include <alloca.h>
#include <errno.h>
return uid_to_name(getuid());
}
-int get_user_creds(
+static bool is_nologin_shell(const char *shell) {
+
+ return PATH_IN_SET(shell,
+ /* 'nologin' is the friendliest way to disable logins for a user account. It prints a nice
+ * message and exits. Different distributions place the binary at different places though,
+ * hence let's list them all. */
+ "/bin/nologin",
+ "/sbin/nologin",
+ "/usr/bin/nologin",
+ "/usr/sbin/nologin",
+ /* 'true' and 'false' work too for the same purpose, but are less friendly as they don't do
+ * any message printing. Different distributions place the binary at various places but at
+ * least not in the 'sbin' directory. */
+ "/bin/false",
+ "/usr/bin/false",
+ "/bin/true",
+ "/usr/bin/true");
+}
+
+static int synthesize_user_creds(
const char **username,
uid_t *uid, gid_t *gid,
const char **home,
- const char **shell) {
-
- struct passwd *p;
- uid_t u;
-
- assert(username);
- assert(*username);
+ const char **shell,
+ UserCredsFlags flags) {
/* We enforce some special rules for uid=0 and uid=65534: in order to avoid NSS lookups for root we hardcode
* their user record data. */
*gid = GID_NOBODY;
if (home)
- *home = "/";
+ *home = FLAGS_SET(flags, USER_CREDS_CLEAN) ? NULL : "/";
if (shell)
- *shell = "/sbin/nologin";
+ *shell = FLAGS_SET(flags, USER_CREDS_CLEAN) ? NULL : "/sbin/nologin";
return 0;
}
+ return -ENOMEDIUM;
+}
+
+int get_user_creds(
+ const char **username,
+ uid_t *uid, gid_t *gid,
+ const char **home,
+ const char **shell,
+ UserCredsFlags flags) {
+
+ uid_t u = UID_INVALID;
+ struct passwd *p;
+ int r;
+
+ assert(username);
+ assert(*username);
+
+ if (!FLAGS_SET(flags, USER_CREDS_PREFER_NSS) ||
+ (!home && !shell)) {
+
+ /* So here's the deal: normally, we'll try to synthesize all records we can synthesize, and override
+ * the user database with that. However, if the user specifies USER_CREDS_PREFER_NSS then the
+ * user database will override the synthetic records instead — except if the user is only interested in
+ * the UID and/or GID (but not the home directory, or the shell), in which case we'll always override
+ * the user database (i.e. the USER_CREDS_PREFER_NSS flag has no effect in this case). Why?
+ * Simply because there are valid usecase where the user might change the home directory or the shell
+ * of the relevant users, but changing the UID/GID mappings for them is something we explicitly don't
+ * support. */
+
+ r = synthesize_user_creds(username, uid, gid, home, shell, flags);
+ if (r >= 0)
+ return 0;
+ if (r != -ENOMEDIUM) /* not a username we can synthesize */
+ return r;
+ }
+
if (parse_uid(*username, &u) >= 0) {
errno = 0;
p = getpwuid(u);
- /* If there are multiple users with the same id, make
- * sure to leave $USER to the configured value instead
- * of the first occurrence in the database. However if
- * the uid was configured by a numeric uid, then let's
- * pick the real username from /etc/passwd. */
+ /* If there are multiple users with the same id, make sure to leave $USER to the configured value
+ * instead of the first occurrence in the database. However if the uid was configured by a numeric uid,
+ * then let's pick the real username from /etc/passwd. */
if (p)
*username = p->pw_name;
+ else if (FLAGS_SET(flags, USER_CREDS_ALLOW_MISSING) && !gid && !home && !shell) {
+
+ /* If the specified user is a numeric UID and it isn't in the user database, and the caller
+ * passed USER_CREDS_ALLOW_MISSING and was only interested in the UID, then juts return that
+ * and don't complain. */
+
+ if (uid)
+ *uid = u;
+
+ return 0;
+ }
} else {
errno = 0;
p = getpwnam(*username);
}
+ if (!p) {
+ r = errno > 0 ? -errno : -ESRCH;
- if (!p)
- return errno > 0 ? -errno : -ESRCH;
+ /* If the user requested that we only synthesize as fallback, do so now */
+ if (FLAGS_SET(flags, USER_CREDS_PREFER_NSS)) {
+ if (synthesize_user_creds(username, uid, gid, home, shell, flags) >= 0)
+ return 0;
+ }
+
+ return r;
+ }
if (uid) {
if (!uid_is_valid(p->pw_uid))
*gid = p->pw_gid;
}
- if (home)
- *home = p->pw_dir;
-
- if (shell)
- *shell = p->pw_shell;
-
- return 0;
-}
-
-int get_user_creds_clean(
- const char **username,
- uid_t *uid, gid_t *gid,
- const char **home,
- const char **shell) {
-
- int r;
-
- /* Like get_user_creds(), but resets home/shell to NULL if they don't contain anything relevant. */
-
- r = get_user_creds(username, uid, gid, home, shell);
- if (r < 0)
- return r;
-
- if (shell &&
- (isempty(*shell) || PATH_IN_SET(*shell,
- "/bin/nologin",
- "/sbin/nologin",
- "/usr/bin/nologin",
- "/usr/sbin/nologin")))
- *shell = NULL;
+ if (home) {
+ if (FLAGS_SET(flags, USER_CREDS_CLEAN) && empty_or_root(p->pw_dir))
+ *home = NULL;
+ else
+ *home = p->pw_dir;
+ }
- if (home &&
- (isempty(*home) || path_equal(*home, "/")))
- *home = NULL;
+ if (shell) {
+ if (FLAGS_SET(flags, USER_CREDS_CLEAN) && (isempty(p->pw_shell) || is_nologin_shell(p->pw_shell)))
+ *shell = NULL;
+ else
+ *shell = p->pw_shell;
+ }
return 0;
}
-int get_group_creds(const char **groupname, gid_t *gid) {
+int get_group_creds(const char **groupname, gid_t *gid, UserCredsFlags flags) {
struct group *g;
gid_t id;
assert(groupname);
- /* We enforce some special rules for gid=0: in order to avoid
- * NSS lookups for root we hardcode its data. */
+ /* We enforce some special rules for gid=0: in order to avoid NSS lookups for root we hardcode its data. */
if (STR_IN_SET(*groupname, "root", "0")) {
*groupname = "root";
if (g)
*groupname = g->gr_name;
+ else if (FLAGS_SET(flags, USER_CREDS_ALLOW_MISSING)) {
+ if (gid)
+ *gid = id;
+
+ return 0;
+ }
} else {
errno = 0;
g = getgrnam(*groupname);
int r;
gid_t gid;
- r = get_group_creds(&name, &gid);
+ r = get_group_creds(&name, &gid, 0);
if (r < 0)
return r;
* awfully racy, and thus we just won't do them. */
if (root)
- path = prefix_roota(root, "/etc/.pwd.lock");
+ path = prefix_roota(root, ETC_PASSWD_LOCK_PATH);
else
- path = "/etc/.pwd.lock";
+ path = ETC_PASSWD_LOCK_PATH;
fd = open(path, O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, 0600);
if (fd < 0)
- return -errno;
+ return log_debug_errno(errno, "Cannot open %s: %m", path);
r = fcntl(fd, F_SETLKW, &flock);
if (r < 0) {
safe_close(fd);
- return -errno;
+ return log_debug_errno(errno, "Locking %s failed: %m", path);
}
return fd;
}
bool valid_home(const char *p) {
+ /* Note that this function is also called by valid_shell(), any
+ * changes must account for that. */
if (isempty(p))
return false;
}
bool synthesize_nobody(void) {
-
-#ifdef NOLEGACY
- return true;
-#else
/* Returns true when we shall synthesize the "nobody" user (which we do by default). This can be turned off by
* touching /etc/systemd/dont-synthesize-nobody in order to provide upgrade compatibility with legacy systems
* that used the "nobody" user name and group name for other UIDs/GIDs than 65534.
cache = access("/etc/systemd/dont-synthesize-nobody", F_OK) < 0;
return cache;
+}
+
+int putpwent_sane(const struct passwd *pw, FILE *stream) {
+ assert(pw);
+ assert(stream);
+
+ errno = 0;
+ if (putpwent(pw, stream) != 0)
+ return errno > 0 ? -errno : -EIO;
+
+ return 0;
+}
+
+int putspent_sane(const struct spwd *sp, FILE *stream) {
+ assert(sp);
+ assert(stream);
+
+ errno = 0;
+ if (putspent(sp, stream) != 0)
+ return errno > 0 ? -errno : -EIO;
+
+ return 0;
+}
+
+int putgrent_sane(const struct group *gr, FILE *stream) {
+ assert(gr);
+ assert(stream);
+
+ errno = 0;
+ if (putgrent(gr, stream) != 0)
+ return errno > 0 ? -errno : -EIO;
+
+ return 0;
+}
+
+#if ENABLE_GSHADOW
+int putsgent_sane(const struct sgrp *sg, FILE *stream) {
+ assert(sg);
+ assert(stream);
+
+ errno = 0;
+ if (putsgent(sg, stream) != 0)
+ return errno > 0 ? -errno : -EIO;
+
+ return 0;
+}
#endif
+
+int fgetpwent_sane(FILE *stream, struct passwd **pw) {
+ struct passwd *p;
+
+ assert(pw);
+ assert(stream);
+
+ errno = 0;
+ p = fgetpwent(stream);
+ if (!p && errno != ENOENT)
+ return errno > 0 ? -errno : -EIO;
+
+ *pw = p;
+ return !!p;
+}
+
+int fgetspent_sane(FILE *stream, struct spwd **sp) {
+ struct spwd *s;
+
+ assert(sp);
+ assert(stream);
+
+ errno = 0;
+ s = fgetspent(stream);
+ if (!s && errno != ENOENT)
+ return errno > 0 ? -errno : -EIO;
+
+ *sp = s;
+ return !!s;
+}
+
+int fgetgrent_sane(FILE *stream, struct group **gr) {
+ struct group *g;
+
+ assert(gr);
+ assert(stream);
+
+ errno = 0;
+ g = fgetgrent(stream);
+ if (!g && errno != ENOENT)
+ return errno > 0 ? -errno : -EIO;
+
+ *gr = g;
+ return !!g;
}
+
+#if ENABLE_GSHADOW
+int fgetsgent_sane(FILE *stream, struct sgrp **sg) {
+ struct sgrp *s;
+
+ assert(sg);
+ assert(stream);
+
+ errno = 0;
+ s = fgetsgent(stream);
+ if (!s && errno != ENOENT)
+ return errno > 0 ? -errno : -EIO;
+
+ *sg = s;
+ return !!s;
+}
+#endif
projects / thirdparty / systemd.git / blobdiff