Imported Upstream version 4.1.5.1upstream/4.1.5.1

1 files changed, 209 insertions, 0 deletions

diff --git a/libmisc/find_new_uid.c b/libmisc/find_new_uid.c
new file mode 100644
index 00000000..aac1909c
--- /dev/null
+++ b/libmisc/find_new_uid.c
@@ -0,0 +1,209 @@
+/*
+ * Copyright (c) 1991 - 1994, Julianne Frances Haugh
+ * Copyright (c) 2008 - 2011, Nicolas François
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the copyright holders or contributors may not be used to
+ *    endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <config.h>
+
+#include <assert.h>
+#include <stdio.h>
+#include <errno.h>
+
+#include "prototypes.h"
+#include "pwio.h"
+#include "getdef.h"
+
+/*
+ * find_new_uid - Find a new unused UID.
+ *
+ * If successful, find_new_uid provides an unused user ID in the
+ * [UID_MIN:UID_MAX] range.
+ * This ID should be higher than all the used UID, but if not possible,
+ * the lowest unused ID in the range will be returned.
+ * 
+ * Return 0 on success, -1 if no unused UIDs are available.
+ */
+int find_new_uid (bool sys_user,
+                  uid_t *uid,
+                  /*@null@*/uid_t const *preferred_uid)
+{
+	const struct passwd *pwd;
+	uid_t uid_min, uid_max, user_id;
+	bool *used_uids;
+
+	assert (uid != NULL);
+
+	if (!sys_user) {
+		uid_min = (uid_t) getdef_ulong ("UID_MIN", 1000UL);
+		uid_max = (uid_t) getdef_ulong ("UID_MAX", 60000UL);
+		if (uid_max < uid_min) {
+			(void) fprintf (stderr,
+			                _("%s: Invalid configuration: UID_MIN (%lu), UID_MAX (%lu)\n"),
+			                Prog, (unsigned long) uid_min, (unsigned long) uid_max);
+			return -1;
+		}
+	} else {
+		uid_min = (uid_t) getdef_ulong ("SYS_UID_MIN", 101UL);
+		uid_max = (uid_t) getdef_ulong ("UID_MIN", 1000UL) - 1;
+		uid_max = (uid_t) getdef_ulong ("SYS_UID_MAX", (unsigned long) uid_max);
+		if (uid_max < uid_min) {
+			(void) fprintf (stderr,
+			                _("%s: Invalid configuration: SYS_UID_MIN (%lu), UID_MIN (%lu), SYS_UID_MAX (%lu)\n"),
+			                Prog, (unsigned long) uid_min, getdef_ulong ("UID_MIN", 1000UL), (unsigned long) uid_max);
+			return -1;
+		}
+	}
+	used_uids = malloc (sizeof (bool) * (uid_max +1));
+	if (NULL == used_uids) {
+		fprintf (stderr,
+		         _("%s: failed to allocate memory: %s\n"),
+		         Prog, strerror (errno));
+		return -1;
+	}
+	memset (used_uids, false, sizeof (bool) * (uid_max + 1));
+
+	if (   (NULL != preferred_uid)
+	    && (*preferred_uid >= uid_min)
+	    && (*preferred_uid <= uid_max)
+	    /* Check if the user exists according to NSS */
+	    && (getpwuid (*preferred_uid) == NULL)
+	    /* Check also the local database in case of uncommitted
+	     * changes */
+	    && (pw_locate_uid (*preferred_uid) == NULL)) {
+		*uid = *preferred_uid;
+		free (used_uids);
+		return 0;
+	}
+
+
+	/*
+	 * Search the entire password file,
+	 * looking for the largest unused value.
+	 *
+	 * We check the list of users according to NSS (setpwent/getpwent),
+	 * but we also check the local database (pw_rewind/pw_next) in case
+	 * some users were created but the changes were not committed yet.
+	 */
+	if (sys_user) {
+		uid_t id;
+		/* setpwent / getpwent / endpwent can be very slow with
+		 * LDAP configurations (and many accounts).
+		 * Since there is a limited amount of IDs to be tested
+		 * for system accounts, we just check the existence
+		 * of IDs with getpwuid.
+		 */
+		user_id = uid_max;
+		for (id = uid_max; id >= uid_min; id--) {
+			if (getpwuid (id) != NULL) {
+				user_id = id - 1;
+				used_uids[id] = true;
+			}
+		}
+
+		(void) pw_rewind ();
+		while ((pwd = pw_next ()) != NULL) {
+			if ((pwd->pw_uid <= user_id) && (pwd->pw_uid >= uid_min)) {
+				user_id = pwd->pw_uid - 1;
+			}
+			/* create index of used UIDs */
+			if (pwd->pw_uid <= uid_max) {
+				used_uids[pwd->pw_uid] = true;
+			}
+		}
+	} else {
+		user_id = uid_min;
+		setpwent ();
+		while ((pwd = getpwent ()) != NULL) {
+			if ((pwd->pw_uid >= user_id) && (pwd->pw_uid <= uid_max)) {
+				user_id = pwd->pw_uid + 1;
+			}
+			/* create index of used UIDs */
+			if (pwd->pw_uid <= uid_max) {
+				used_uids[pwd->pw_uid] = true;
+			}
+		}
+		endpwent ();
+
+		(void) pw_rewind ();
+		while ((pwd = pw_next ()) != NULL) {
+			if ((pwd->pw_uid >= user_id) && (pwd->pw_uid <= uid_max)) {
+				user_id = pwd->pw_uid + 1;
+			}
+			/* create index of used UIDs */
+			if (pwd->pw_uid <= uid_max) {
+				used_uids[pwd->pw_uid] = true;
+			}
+		}
+	}
+
+	/*
+	 * If a user (resp. system user) with UID equal to UID_MAX (resp.
+	 * UID_MIN) exists, the above algorithm will give us UID_MAX+1
+	 * (resp. UID_MIN-1) even if not unique. Search for the first free
+	 * UID starting with UID_MIN (resp. UID_MAX).
+	 */
+	if (sys_user) {
+		if (user_id < uid_min) {
+			for (user_id = uid_max; user_id >= uid_min; user_id--) {
+				if (false == used_uids[user_id]) {
+					break;
+				}
+			}
+			if (user_id < uid_min ) {
+				fprintf (stderr,
+				         _("%s: Can't get unique system UID (no more available UIDs)\n"),
+				         Prog);
+				SYSLOG ((LOG_WARN,
+				         "no more available UID on the system"));
+				free (used_uids);
+				return -1;
+			}
+		}
+	} else {
+		if (user_id > uid_max) {
+			for (user_id = uid_min; user_id <= uid_max; user_id++) {
+				if (false == used_uids[user_id]) {
+					break;
+				}
+			}
+			if (user_id > uid_max) {
+				fprintf (stderr,
+				         _("%s: Can't get unique UID (no more available UIDs)\n"),
+				         Prog);
+				SYSLOG ((LOG_WARN, "no more available UID on the system"));
+				free (used_uids);
+				return -1;
+			}
+		}
+	}
+
+	free (used_uids);
+	*uid = user_id;
+	return 0;
+}
+