1 files changed, 338 insertions, 0 deletions
diff --git a/usr.bin/newgrp/grutil.c b/usr.bin/newgrp/grutil.c
new file mode 100644
index 0000000..ee81590
--- /dev/null
+++ b/usr.bin/newgrp/grutil.c
@@ -0,0 +1,338 @@
+/*	$NetBSD: grutil.c,v 1.4 2014/06/23 06:57:31 shm Exp $	*/
+
+/*-
+ * Copyright (c) 2007 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Brian Ginsbach.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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 <sys/cdefs.h>
+__RCSID("$NetBSD: grutil.c,v 1.4 2014/06/23 06:57:31 shm Exp $");
+
+#include <sys/param.h>
+#include <err.h>
+#include <errno.h>
+#include <grp.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <util.h>
+
+#ifdef LOGIN_CAP
+#include <login_cap.h>
+#endif
+
+#include "grutil.h"
+
+typedef enum {
+	ADDGRP_NOERROR		= 0,	/* must be zero */
+	ADDGRP_EMALLOC		= 1,
+	ADDGRP_EGETGROUPS	= 2,
+	ADDGRP_ESETGROUPS	= 3
+} addgrp_ret_t;
+
+static void
+free_groups(void *groups)
+{
+	int oerrno;
+
+	oerrno = errno;
+	free(groups);
+	errno = oerrno;
+}
+
+static addgrp_ret_t
+alloc_groups(int *ngroups, gid_t **groups, int *ngroupsmax)
+{
+	*ngroupsmax = (int)sysconf(_SC_NGROUPS_MAX);
+	if (*ngroupsmax < 0)
+		*ngroupsmax = NGROUPS_MAX;
+
+	*groups = malloc(*ngroupsmax * sizeof(**groups));
+	if (*groups == NULL)
+		return ADDGRP_EMALLOC;
+
+	*ngroups = getgroups(*ngroupsmax, *groups);
+	if (*ngroups == -1) {
+		free_groups(*groups);
+		return ADDGRP_ESETGROUPS;
+	}
+	return ADDGRP_NOERROR;
+}
+
+static addgrp_ret_t
+addgid(gid_t *groups, int ngroups, int ngroupsmax, gid_t gid, int makespace)
+{
+	int i;
+
+	/* search for gid in supplemental group list */
+	for (i = 0; i < ngroups && groups[i] != gid; i++)
+		continue;
+
+	/* add the gid to the supplemental group list */
+	if (i == ngroups) {
+		if (ngroups < ngroupsmax)
+			groups[ngroups++] = gid;
+		else {	/*
+			 * setgroups(2) will fail with errno = EINVAL
+			 * if ngroups > nmaxgroups.  If makespace is
+			 * set, replace the last group with the new
+			 * one.  Otherwise, fail the way setgroups(2)
+			 * would if we passed the larger groups array.
+			 */
+			if (makespace) {
+				/*
+				 * Find a slot that doesn't contain
+				 * the primary group.
+				 */
+				struct passwd *pwd;
+				gid_t pgid;
+				pwd = getpwuid(getuid());
+				if (pwd == NULL)
+					goto error;
+				pgid = pwd->pw_gid;
+				for (i = ngroupsmax - 1; i >= 0; i--)
+					if (groups[i] != pgid)
+						break;
+				if (i < 0)
+					goto error;
+				groups[i] = gid;
+			}
+			else {
+		error:
+				errno = EINVAL;
+				return ADDGRP_ESETGROUPS;
+			}
+		}
+		if (setgroups(ngroups, groups) < 0)
+			return ADDGRP_ESETGROUPS;
+	}
+	return ADDGRP_NOERROR;
+}
+
+static addgrp_ret_t
+addgrp(gid_t newgid, int makespace)
+{
+	int ngroups, ngroupsmax;
+	addgrp_ret_t rval;
+	gid_t *groups;
+	gid_t oldgid;
+
+	oldgid = getgid();
+	if (oldgid == newgid) /* nothing to do */
+		return ADDGRP_NOERROR;
+
+	rval = alloc_groups(&ngroups, &groups, &ngroupsmax);
+	if (rval != ADDGRP_NOERROR)
+		return rval;
+
+	/*
+	 * BSD based systems normally have the egid in the supplemental
+	 * group list.
+	 */
+#if (defined(BSD) && BSD >= 199306)
+	/*
+	 * According to POSIX/XPG6:
+	 * On system where the egid is normally in the supplemental group list
+	 * (or whenever the old egid actually is in the supplemental group
+	 * list):
+	 *	o If the new egid is in the supplemental group list,
+	 *	  just change the egid.
+	 *	o If the new egid is not in the supplemental group list,
+	 *	  add the new egid to the list if there is room.
+	 */
+
+	rval = addgid(groups, ngroups, ngroupsmax, newgid, makespace);
+#else
+	/*
+	 * According to POSIX/XPG6:
+	 * On systems where the egid is not normally in the supplemental group
+	 * list (or whenever the old egid is not in the supplemental group
+	 * list):
+	 *	o If the new egid is in the supplemental group list, delete
+	 *	  it from the list.
+	 *	o If the old egid is not in the supplemental group list,
+	 *	  add the old egid to the list if there is room.
+	 */
+	{
+		int i;
+
+		/* search for new egid in supplemental group list */
+		for (i = 0; i < ngroups && groups[i] != newgid; i++)
+			continue;
+
+		/* remove new egid from supplemental group list */
+		if (i != ngroups)
+			for (--ngroups; i < ngroups; i++)
+				groups[i] = groups[i + 1];
+
+		rval = addgid(groups, ngroups, ngroupsmax, oldgid, makespace);
+	}
+#endif
+	free_groups(groups);
+	return rval;
+}
+
+/*
+ * If newgrp fails, it returns (gid_t)-1 and the errno variable is
+ * set to:
+ *	[EINVAL]	Unknown group.
+ *	[EPERM]		Bad password.
+ */
+static gid_t
+newgrp(const char *gname, struct passwd *pwd, uid_t ruid, const char *prompt)
+{
+	struct group *grp;
+	char **ap;
+	char *p;
+	gid_t *groups;
+	int ngroups, ngroupsmax;
+
+	if (gname == NULL)
+		return pwd->pw_gid;
+
+	grp = getgrnam(gname);
+
+#ifdef GRUTIL_ACCEPT_GROUP_NUMBERS
+	if (grp == NULL) {
+		gid_t gid;
+		if (*gname != '-') {
+		    gid = (gid_t)strtol(gname, &p, 10);
+		    if (*p == '\0')
+			    grp = getgrgid(gid);
+		}
+	}
+#endif
+	if (grp == NULL) {
+		errno = EINVAL;
+		return (gid_t)-1;
+	}
+
+	if (ruid == 0 || pwd->pw_gid == grp->gr_gid)
+		return grp->gr_gid;
+
+	if (alloc_groups(&ngroups, &groups, &ngroupsmax) == ADDGRP_NOERROR) {
+		int i;
+		for (i = 0; i < ngroups; i++)
+			if (groups[i] == grp->gr_gid) {
+				free_groups(groups);
+				return grp->gr_gid;
+			}
+		free_groups(groups);
+	}
+
+	/*
+	 * Check the group membership list in case the groups[] array
+	 * was maxed out or the user has been added to it since login.
+	 */
+	for (ap = grp->gr_mem; *ap != NULL; ap++)
+		if (strcmp(*ap, pwd->pw_name) == 0)
+			return grp->gr_gid;
+
+	if (*grp->gr_passwd != '\0') {
+		p = getpass(prompt);
+		if (strcmp(grp->gr_passwd, crypt(p, grp->gr_passwd)) == 0) {
+			(void)memset(p, '\0', _PASSWORD_LEN);
+			return grp->gr_gid;
+		}
+		(void)memset(p, '\0', _PASSWORD_LEN);
+	}
+
+	errno = EPERM;
+	return (gid_t)-1;
+}
+
+#ifdef GRUTIL_SETGROUPS_MAKESPACE
+# define ADDGRP_MAKESPACE	1
+#else
+# define ADDGRP_MAKESPACE	0
+#endif
+
+#ifdef GRUTIL_ALLOW_GROUP_ERRORS
+# define maybe_exit(e)
+#else
+# define maybe_exit(e)	exit(e);
+#endif
+
+void
+addgroup(
+#ifdef LOGIN_CAP
+    login_cap_t *lc,
+#endif
+    const char *gname, struct passwd *pwd, uid_t ruid, const char *prompt)
+{
+	pwd->pw_gid = newgrp(gname, pwd, ruid, prompt);
+	if (pwd->pw_gid == (gid_t)-1) {
+		switch (errno) {
+		case EINVAL:
+			warnx("Unknown group `%s'", gname);
+			maybe_exit(EXIT_FAILURE);
+			break;
+		case EPERM:	/* password failure */
+			warnx("Sorry");
+			maybe_exit(EXIT_FAILURE);
+			break;
+		default: /* XXX - should never happen */
+			err(EXIT_FAILURE, "unknown error");
+			break;
+		}
+		pwd->pw_gid = getgid();
+	}
+
+	switch (addgrp(pwd->pw_gid, ADDGRP_MAKESPACE)) {
+	case ADDGRP_NOERROR:
+		break;
+	case ADDGRP_EMALLOC:
+		err(EXIT_FAILURE, "malloc");
+		break;
+	case ADDGRP_EGETGROUPS:
+		err(EXIT_FAILURE, "getgroups");
+		break;
+	case ADDGRP_ESETGROUPS:
+		switch(errno) {
+		case EINVAL:
+			warnx("setgroups: ngroups > ngroupsmax");
+			maybe_exit(EXIT_FAILURE);
+			break;
+		case EPERM:
+		case EFAULT:
+		default:
+			warn("setgroups");
+			maybe_exit(EXIT_FAILURE);
+			break;
+		}
+		break;
+	}
+
+#ifdef LOGIN_CAP
+	if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGID) == -1)
+		err(EXIT_FAILURE, "setting user context");
+#else
+	if (setgid(pwd->pw_gid) == -1)
+		err(EXIT_FAILURE, "setgid");
+#endif
+}