vol_id: use primary group of 'nobody' instead of 'nogroup'

This fixes a Fedora issue not having the group 'nogroup'.

diff --git a/extras/volume_id/vol_id.c b/extras/volume_id/vol_id.c
index 7bdfda17e7ab5b967ac923935cbee08c7351e140..0a1b756fa3174c62d557234844220faed798ac7b 100644 (file)
--- a/extras/volume_id/vol_id.c
+++ b/extras/volume_id/vol_id.c
@@ -27,6 +27,8 @@
 #include <unistd.h>
 #include <string.h>
 #include <ctype.h>
+#include <errno.h>
+#include <pwd.h>
 #include <grp.h>
 #include <sys/ioctl.h>
 
@@ -131,8 +133,7 @@ int main(int argc, char *argv[])
        int skip_raid = 0;
        int probe_all = 0;
        const char *node = NULL;
-       uid_t nobody_uid;
-       gid_t nobody_gid;
+       struct passwd *pw;
        int retval;
        int rc = 0;
 
@@ -180,13 +181,14 @@ int main(int argc, char *argv[])
                size = 0;
        dbg("BLKGETSIZE64=%llu", size);
 
-       /* drop all privileges */
-       nobody_uid = lookup_user("nobody");
-       nobody_gid = lookup_group("nogroup");
-       if (nobody_uid > 0 && nobody_gid > 0) {
+       /* try to drop all privileges before reading disk content */
+       pw = getpwnam ("nobody");
+       if (pw != NULL && pw->pw_uid > 0 && pw->pw_gid > 0) {
+               dbg("dropping privileges to %u:%u", (unsigned int)pw->pw_uid, (unsigned int)pw->pw_gid);
                if (setgroups(0, NULL) != 0 ||
-                   setgid(nobody_gid) != 0 ||
-                   setuid(nobody_uid) != 0) {
+                   setgid(pw->pw_gid) != 0 ||
+                   setuid(pw->pw_uid) != 0) {
+                       fprintf(stderr, "error dropping privileges: %s\n", strerror(errno));
                        rc = 3;
                        goto exit;
                }