unshare: Fix "you (user xxxx) don't exist" error when uid differs from primary gid

This problem affected the --map-auto and --map-groups=auto command-line switches.
The root cause is that /etc/subgid is indexed by user or uid, not by group or gid;
therefore, we should be using the effective uid to find entries in this file, just
as we do for /etc/subuid.

Signed-off-by: Sol Boucher <sboucher@cmu.edu>

diff --git a/sys-utils/unshare.c b/sys-utils/unshare.c
index 88306f0f46f9e5a24378ad985a73402c473a67f5..a379e8aedec7a4bdc16b046f685b6d3133a5930d 100644 (file)
--- a/sys-utils/unshare.c
+++ b/sys-utils/unshare.c
@@ -864,14 +864,14 @@ int main(int argc, char *argv[])
                case OPT_MAPGROUPS:
                        unshare_flags |= CLONE_NEWUSER;
                        if (!strcmp(optarg, "auto"))
-                               groupmap = read_subid_range(_PATH_SUBGID, real_egid);
+                               groupmap = read_subid_range(_PATH_SUBGID, real_euid);
                        else
                                groupmap = get_map_range(optarg);
                        break;
                case OPT_MAPAUTO:
                        unshare_flags |= CLONE_NEWUSER;
                        usermap = read_subid_range(_PATH_SUBUID, real_euid);
-                       groupmap = read_subid_range(_PATH_SUBGID, real_egid);
+                       groupmap = read_subid_range(_PATH_SUBGID, real_euid);
                        break;
                case OPT_SETGROUPS:
                        setgrpcmd = setgroups_str2id(optarg);