On Sat, 13 Oct 2018 21:16:10 -0600, "Todd C. Miller" wrote:
> I think it is safest to use user_from_uid, uid_from_user, group_from_gid
> and gid_from_group in all places where the return value of getpw*
> and getgr* is unused.
Updated diff that adds wrapper functions for improved readability.
It's arguable that user(8) should check the local master.passwd and
group files directly but that's a discussion for another time.
- todd
Index: usr.sbin/user/user.c
===================================================================
RCS file: /cvs/src/usr.sbin/user/user.c,v
retrieving revision 1.122
diff -u -p -u -r1.122 user.c
--- usr.sbin/user/user.c 26 Sep 2018 14:54:58 -0000 1.122
+++ usr.sbin/user/user.c 15 Oct 2018 03:54:42 -0000
@@ -319,6 +319,22 @@ copydotfiles(char *skeldir, char *dir)
return n;
}
+/* returns 1 if the specified gid exists in the group file, else 0 */
+static int
+gid_exists(gid_t gid)
+{
+ return group_from_gid(gid, 1) != NULL;
+}
+
+/* return 1 if the specified group exists in the group file, else 0 */
+static int
+group_exists(const char *group)
+{
+ gid_t gid;
+
+ return gid_from_group(group, &gid) != -1;
+}
+
/* create a group entry with gid `gid' */
static int
creategid(char *group, gid_t gid, const char *name)
@@ -332,7 +348,7 @@ creategid(char *group, gid_t gid, const
int wroteit = 0;
size_t len;
- if (getgrnam(group) != NULL) {
+ if (group_exists(group)) {
warnx("group `%s' already exists", group);
return 0;
}
@@ -673,7 +689,7 @@ static int
getnextgid(uid_t *gidp, uid_t lo, uid_t hi)
{
for (*gidp = lo ; *gidp < hi ; *gidp += 1) {
- if (getgrgid((gid_t)*gidp) == NULL) {
+ if (!gid_exists((gid_t)*gidp)) {
return 1;
}
}
@@ -857,14 +873,30 @@ read_defaults(user_t *up)
up->u_defrc = up->u_rc;
}
+/* return 1 if the specified uid exists in the passwd file, else 0 */
+static int
+uid_exists(uid_t uid)
+{
+ return user_from_uid(uid, 1) != NULL;
+}
+
+/* return 1 if the specified user exists in the passwd file, else 0 */
+static int
+user_exists(const char *user)
+{
+ uid_t uid;
+
+ return uid_from_user(user, &uid) != -1;
+}
+
/* return the next valid unused uid */
static int
getnextuid(int sync_uid_gid, uid_t *uid, uid_t low_uid, uid_t high_uid)
{
for (*uid = low_uid ; *uid <= high_uid ; (*uid)++) {
- if (getpwuid((uid_t)(*uid)) == NULL && *uid != NOBODY_UID) {
+ if (!uid_exists((uid_t)*uid) && *uid != NOBODY_UID) {
if (sync_uid_gid) {
- if (getgrgid((gid_t)(*uid)) == NULL) {
+ if (!gid_exists((gid_t)*uid)) {
return 1;
}
} else {
@@ -1048,14 +1080,14 @@ adduser(char *login_name, user_t *up)
}
}
/* check uid isn't already allocated */
- if (!(up->u_flags & F_DUPUID) && getpwuid((uid_t)(up->u_uid)) != NULL) {
+ if (!(up->u_flags & F_DUPUID) && uid_exists((uid_t)up->u_uid)) {
close(ptmpfd);
pw_abort();
errx(EXIT_FAILURE, "uid %u is already in use", up->u_uid);
}
/* if -g=uid was specified, check gid is unused */
if (sync_uid_gid) {
- if (getgrgid((gid_t)(up->u_uid)) != NULL) {
+ if (gid_exists((gid_t)up->u_uid)) {
close(ptmpfd);
pw_abort();
errx(EXIT_FAILURE, "gid %u is already in use",
up->u_uid);
@@ -1070,7 +1102,7 @@ adduser(char *login_name, user_t *up)
gid = grp->gr_gid;
}
/* check name isn't already in use */
- if (!(up->u_flags & F_DUPUID) && getpwnam(login_name) != NULL) {
+ if (!(up->u_flags & F_DUPUID) && user_exists(login_name)) {
close(ptmpfd);
pw_abort();
errx(EXIT_FAILURE, "already a `%s' user", login_name);
@@ -1186,8 +1218,7 @@ adduser(char *login_name, user_t *up)
(void) asystem("%s -R u+w %s", CHMOD, home);
}
}
- if (strcmp(up->u_primgrp, "=uid") == 0 &&
- getgrnam(login_name) == NULL &&
+ if (strcmp(up->u_primgrp, "=uid") == 0 && !group_exists(login_name) &&
!creategid(login_name, gid, "")) {
close(ptmpfd);
pw_abort();
@@ -1369,7 +1400,6 @@ moduser(char *login_name, char *newlogin
int ptmpfd;
int rval;
int i;
- uid_t uid;
if (!valid_login(newlogin)) {
errx(EXIT_FAILURE, "`%s' is not a valid login name",
login_name);
@@ -1429,7 +1459,7 @@ moduser(char *login_name, char *newlogin
if (up->u_flags & F_USERNAME) {
/* if changing name, check new name isn't already in
use */
if (strcmp(login_name, newlogin) != 0 &&
- uid_from_user(newlogin, &uid) != -1) {
+ user_exists(newlogin)) {
close(ptmpfd);
pw_abort();
errx(EXIT_FAILURE, "already a `%s' user",
newlogin);
@@ -1515,7 +1545,8 @@ moduser(char *login_name, char *newlogin
}
if (up->u_flags & F_UID) {
/* check uid isn't already allocated */
- if (!(up->u_flags & F_DUPUID) &&
getpwuid((uid_t)(up->u_uid)) != NULL) {
+ if (!(up->u_flags & F_DUPUID) &&
+ uid_exists((uid_t)up->u_uid)) {
close(ptmpfd);
pw_abort();
errx(EXIT_FAILURE, "uid %u is already in use",
up->u_uid);
@@ -1525,7 +1556,7 @@ moduser(char *login_name, char *newlogin
if (up->u_flags & F_GROUP) {
/* if -g=uid was specified, check gid is unused */
if (strcmp(up->u_primgrp, "=uid") == 0) {
- if (getgrgid((gid_t)(pwp->pw_uid)) != NULL) {
+ if (gid_exists((gid_t)pwp->pw_uid)) {
close(ptmpfd);
pw_abort();
errx(EXIT_FAILURE, "gid %u is already "
@@ -1639,7 +1670,7 @@ moduser(char *login_name, char *newlogin
}
if (up->u_flags & F_SETSECGROUP) {
for (i = 0 ; i < up->u_groupc ; i++) {
- if (getgrnam(up->u_groupv[i]) == NULL) {
+ if (!group_exists(up->u_groupv[i])) {
close(ptmpfd);
pw_abort();
errx(EXIT_FAILURE,
@@ -2117,7 +2148,7 @@ groupadd(int argc, char **argv)
if (gid < 0 && !getnextgid(&gid, LowGid, HighGid)) {
errx(EXIT_FAILURE, "can't add group: can't get next gid");
}
- if (!dupgid && getgrgid((gid_t) gid) != NULL) {
+ if (!dupgid && gid_exists((gid_t)gid)) {
errx(EXIT_FAILURE, "can't add group: gid %d is a duplicate",
gid);
}
openlog("groupadd", LOG_PID, LOG_USER);
@@ -2150,7 +2181,7 @@ groupdel(int argc, char **argv)
}
checkeuid();
openlog("groupdel", LOG_PID, LOG_USER);
- if (getgrnam(*argv) == NULL) {
+ if (!group_exists(*argv)) {
warnx("No such group: `%s'", *argv);
return EXIT_FAILURE;
}
