1 files changed, 150 insertions, 0 deletions
diff --git a/src/basic/user-util.h b/src/basic/user-util.h
new file mode 100644
index 0000000..a08683b
--- /dev/null
+++ b/src/basic/user-util.h
@@ -0,0 +1,150 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+#include <grp.h>
+#if ENABLE_GSHADOW
+#  include <gshadow.h>
+#endif
+#include <pwd.h>
+#include <shadow.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+/* Users managed by systemd-homed. See https://systemd.io/UIDS-GIDS for details how this range fits into the rest of the world */
+#define HOME_UID_MIN ((uid_t) 60001)
+#define HOME_UID_MAX ((uid_t) 60513)
+
+/* Users mapped from host into a container */
+#define MAP_UID_MIN ((uid_t) 60514)
+#define MAP_UID_MAX ((uid_t) 60577)
+
+bool uid_is_valid(uid_t uid);
+
+static inline bool gid_is_valid(gid_t gid) {
+        return uid_is_valid((uid_t) gid);
+}
+
+int parse_uid(const char *s, uid_t* ret_uid);
+int parse_uid_range(const char *s, uid_t *ret_lower, uid_t *ret_upper);
+
+static inline int parse_gid(const char *s, gid_t *ret_gid) {
+        return parse_uid(s, (uid_t*) ret_gid);
+}
+
+char* getlogname_malloc(void);
+char* getusername_malloc(void);
+
+typedef enum UserCredsFlags {
+        USER_CREDS_PREFER_NSS    = 1 << 0,  /* if set, only synthesize user records if database lacks them. Normally we bypass the userdb entirely for the records we can synthesize */
+        USER_CREDS_ALLOW_MISSING = 1 << 1,  /* if a numeric UID string is resolved, be OK if there's no record for it */
+        USER_CREDS_CLEAN         = 1 << 2,  /* try to clean up shell and home fields with invalid data */
+} UserCredsFlags;
+
+int get_user_creds(const char **username, uid_t *uid, gid_t *gid, const char **home, const char **shell, UserCredsFlags flags);
+int get_group_creds(const char **groupname, gid_t *gid, UserCredsFlags flags);
+
+char* uid_to_name(uid_t uid);
+char* gid_to_name(gid_t gid);
+
+int in_gid(gid_t gid);
+int in_group(const char *name);
+
+int merge_gid_lists(const gid_t *list1, size_t size1, const gid_t *list2, size_t size2, gid_t **result);
+int getgroups_alloc(gid_t** gids);
+
+int get_home_dir(char **ret);
+int get_shell(char **ret);
+
+int reset_uid_gid(void);
+
+int take_etc_passwd_lock(const char *root);
+
+#define UID_INVALID ((uid_t) -1)
+#define GID_INVALID ((gid_t) -1)
+
+#define UID_NOBODY ((uid_t) 65534U)
+#define GID_NOBODY ((gid_t) 65534U)
+
+/* If REMOUNT_IDMAPPING_HOST_ROOT is set for remount_idmap() we'll include a mapping here that maps the host
+ * root user accessing the idmapped mount to the this user ID on the backing fs. This is the last valid UID in
+ * the *signed* 32bit range. You might wonder why precisely use this specific UID for this purpose? Well, we
+ * definitely cannot use the first 0…65536 UIDs for that, since in most cases that's precisely the file range
+ * we intend to map to some high UID range, and since UID mappings have to be bijective we thus cannot use
+ * them at all. Furthermore the UID range beyond INT32_MAX (i.e. the range above the signed 32bit range) is
+ * icky, since many APIs cannot use it (example: setfsuid() returns the old UID as signed integer). Following
+ * our usual logic of assigning a 16bit UID range to each container, so that the upper 16bit of a 32bit UID
+ * value indicate kind of a "container ID" and the lower 16bit map directly to the intended user you can read
+ * this specific UID as the "nobody" user of the container with ID 0x7FFF, which is kinda nice. */
+#define UID_MAPPED_ROOT ((uid_t) (INT32_MAX-1))
+#define GID_MAPPED_ROOT ((gid_t) (INT32_MAX-1))
+
+#define ETC_PASSWD_LOCK_PATH "/etc/.pwd.lock"
+
+/* The following macros add 1 when converting things, since UID 0 is a valid UID, while the pointer
+ * NULL is special */
+#define PTR_TO_UID(p) ((uid_t) (((uintptr_t) (p))-1))
+#define UID_TO_PTR(u) ((void*) (((uintptr_t) (u))+1))
+
+#define PTR_TO_GID(p) ((gid_t) (((uintptr_t) (p))-1))
+#define GID_TO_PTR(u) ((void*) (((uintptr_t) (u))+1))
+
+static inline bool userns_supported(void) {
+        return access("/proc/self/uid_map", F_OK) >= 0;
+}
+
+typedef enum ValidUserFlags {
+        VALID_USER_RELAX         = 1 << 0,
+        VALID_USER_WARN          = 1 << 1,
+        VALID_USER_ALLOW_NUMERIC = 1 << 2,
+} ValidUserFlags;
+
+bool valid_user_group_name(const char *u, ValidUserFlags flags);
+bool valid_gecos(const char *d);
+char *mangle_gecos(const char *d);
+bool valid_home(const char *p);
+
+static inline bool valid_shell(const char *p) {
+        /* We have the same requirements, so just piggy-back on the home check.
+         *
+         * Let's ignore /etc/shells because this is only applicable to real and
+         * not system users. It is also incompatible with the idea of empty /etc.
+         */
+        return valid_home(p);
+}
+
+int maybe_setgroups(size_t size, const gid_t *list);
+
+bool synthesize_nobody(void);
+
+int fgetpwent_sane(FILE *stream, struct passwd **pw);
+int fgetspent_sane(FILE *stream, struct spwd **sp);
+int fgetgrent_sane(FILE *stream, struct group **gr);
+int putpwent_sane(const struct passwd *pw, FILE *stream);
+int putspent_sane(const struct spwd *sp, FILE *stream);
+int putgrent_sane(const struct group *gr, FILE *stream);
+#if ENABLE_GSHADOW
+int fgetsgent_sane(FILE *stream, struct sgrp **sg);
+int putsgent_sane(const struct sgrp *sg, FILE *stream);
+#endif
+
+bool is_nologin_shell(const char *shell);
+const char* default_root_shell(const char *root);
+
+int is_this_me(const char *username);
+
+const char *get_home_root(void);
+
+static inline bool hashed_password_is_locked_or_invalid(const char *password) {
+        return password && password[0] != '$';
+}
+
+/* A locked *and* invalid password for "struct spwd"'s .sp_pwdp and "struct passwd"'s .pw_passwd field */
+#define PASSWORD_LOCKED_AND_INVALID "!*"
+
+/* A password indicating "look in shadow file, please!" for "struct passwd"'s .pw_passwd */
+#define PASSWORD_SEE_SHADOW "x"
+
+/* A password indicating "hey, no password required for login" */
+#define PASSWORD_NONE ""