addgroup: "disallow addgroup -g num user group"; make -g 0 work

(Tito <farmatito@tiscali.it>)

1 files changed, 34 insertions, 26 deletions

diff --git a/loginutils/addgroup.c b/loginutils/addgroup.c
index b29b66527..cf7cca907 100644
--- a/loginutils/addgroup.c
+++ b/loginutils/addgroup.c
@@ -14,34 +14,32 @@
 
 static void xgroup_study(struct group *g)
 {
-        enum { max = 65000 };
-        /* Use a particular gid. */
-        int desired = (g->gr_gid > 0);
-
         /* Make sure gr_name is unused */
         if (getgrnam(g->gr_name)) {
                 goto error;
         }
 
-        /* Check if the desired gid is free or
-           find the first free one */
-        do {
-                if (g->gr_gid == max) { /* out of bounds: exit */
-                        bb_error_msg_and_die("no gids left");
-                }
+        /* Check if the desired gid is free
+         * or find the first free one */
+        while (1) {
                 if (!getgrgid(g->gr_gid)) {
-                        return; /* ok */
+                        return; /* found free group: return */
                 }
-                if (desired) { /* the desired gid is already in use: exit */
+                if (option_mask32) {
+                        /* -g N, cannot pick gid other than N: error */
                         g->gr_name = itoa(g->gr_gid);
                         goto error;
                 }
                 g->gr_gid++;
-        } while (1);
+                if (g->gr_gid <= 0) {
+                        /* overflowed: error */
+                        bb_error_msg_and_die("no gids left");
+                }
+        }
 
-error:
+ error:
         /* exit */
-        bb_error_msg_and_die("%s: already in use", g->gr_name);
+        bb_error_msg_and_die("group %s already exists", g->gr_name);
 }
 
 /* append a new user to the passwd file */
@@ -53,7 +51,7 @@ static void new_group(char *group, gid_t gid)
         /* make sure gid and group haven't already been allocated */
         gr.gr_gid = gid;
         gr.gr_name = group;
-        xgroup_study( &gr);
+        xgroup_study(&gr);
 
         /* add entry to group */
         file = xfopen(bb_path_group_file, "a");
@@ -88,7 +86,7 @@ static void add_user_to_group(char **args,
         while ((line = xmalloc_getline(group_file))) {
                 /* Find the group */
                 if (!strncmp(line, args[1], len)
-                && line[len] == ':'
+                 && line[len] == ':'
                 ) {
                         /* Add the new user */
                         line = xasprintf("%s%s%s", line,
@@ -121,7 +119,7 @@ static void add_user_to_group(char **args,
  * addgroup will take a login_name as its first parameter.
  *
  * gid can be customized via command-line parameters.
- * If  called with two non-option arguments, addgroup
+ * If called with two non-option arguments, addgroup
  * will add an existing user to an existing group.
  */
 int addgroup_main(int argc, char **argv);
@@ -130,24 +128,34 @@ int addgroup_main(int argc, char **argv)
         char *group;
         gid_t gid = 0;
 
-        /* check for min, max and missing args and exit on error */
-        opt_complementary = "-1:?2:?";
+        /* need to be root */
+        if (geteuid()) {
+                bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
+        }
+
+        /* Syntax:
+         *  addgroup group
+         *  addgroup -g num group
+         *  addgroup user group
+         * Check for min, max and missing args */
+        opt_complementary = "-1:?2";
         if (getopt32(argc, argv, "g:", &group)) {
-                gid = xatoul_range(group, 0, (gid_t)ULONG_MAX);
+                gid = xatoul_range(group, 0, ((unsigned long)(gid_t)ULONG_MAX) >> 1);
         }
         /* move past the commandline options */
         argv += optind;
         argc -= optind;
 
-        /* need to be root */
-        if (geteuid()) {
-                bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
-        }
-
 #if ENABLE_FEATURE_ADDUSER_TO_GROUP
         if (argc == 2) {
                 struct group *gr;
 
+                if (option_mask32) {
+                        /* -g was there, but "addgroup -g num user group"
+                         * is a no-no */
+                        bb_show_usage();
+                }
+
                 /* check if group and user exist */
                 xuname2uid(argv[0]); /* unknown user: exit */
                 xgroup2gid(argv[1]); /* unknown group: exit */