Hmm ... It's impossible ;-) This RPM doesn't exist on any FTP server

Provides :
config(gdm)
gdm
gdm(x86-64)
gdm-plugin-fingerprint
gdm-plugin-smartcard
gdm-user-switch-applet
libgdm.so.1()(64bit)
service(graphical-login)

Requires :

libgdk-3.so.0()(64bit)
libc.so.6()(64bit)
libpam.so.0(LIBPAM_1.0)(64bit)
systemd => 186
gnome-settings-daemon => 2.21.92
libsystemd-daemon.so.0(LIBSYSTEMD_DAEMON_31)(64bit)
libaudit.so.1()(64bit)
libXdmcp.so.6()(64bit)
rtld(GNU_HASH)
libgtk-3.so.0()(64bit)
libgio-2.0.so.0()(64bit)
libpam.so.0()(64bit)
libsystemd-login.so.0(LIBSYSTEMD_LOGIN_38)(64bit)
libaccountsservice.so.0()(64bit)
libsystemd-login.so.0(LIBSYSTEMD_LOGIN_43)(64bit)
libsystemd-login.so.0(LIBSYSTEMD_LOGIN_31)(64bit)
libXau.so.6()(64bit)
pulseaudio-gdm-hooks
gnome-keyring-pam
gnome-icon-theme-symbolic
rpmlib(PayloadIsXz) <= 5.2-1
libXau => 1.0.4-4
libcanberra.so.0()(64bit)
libcanberra-gtk3.so.0()(64bit)
gnome-session
libgobject-2.0.so.0()(64bit)
gnome-shell
accountsservice
pam => 0:0.99.8.1-11
libc.so.6(GLIBC_2.14)(64bit)
libc.so.6(GLIBC_2.2.5)(64bit)
libc.so.6(GLIBC_2.3.4)(64bit)
libsystemd-daemon.so.0()(64bit)
libX11.so.6()(64bit)
audit-libs => 1.0.6
/usr/sbin/useradd
/bin/sh
config(gdm) = 1:3.8.4-27.el7
rpmlib(PayloadFilesHavePrefix) <= 4.0-1
libpthread.so.0(GLIBC_2.2.5)(64bit)
libpthread.so.0()(64bit)
rpmlib(FileDigests) <= 4.6.0-1
rpmlib(CompressedFileNames) <= 3.0.4-1
libsystemd-login.so.0(LIBSYSTEMD_LOGIN_186)(64bit)
xorg-x11-xinit
system-logos
xorg-x11-server-utils
libsystemd-journal.so.0(LIBSYSTEMD_JOURNAL_38)(64bit)
libc.so.6(GLIBC_2.4)(64bit)
libsystemd-journal.so.0()(64bit)
libselinux.so.1()(64bit)
libgdk_pixbuf-2.0.so.0()(64bit)
libglib-2.0.so.0()(64bit)
systemd
setxkbmap
libsystemd-login.so.0()(64bit)
dconf
libc.so.6(GLIBC_2.3)(64bit)
/sbin/nologin
libXrandr.so.2()(64bit)
libgdm.so.1()(64bit)
iso-codes

Content of RPM :
/etc/dbus-1/system.d/gdm.conf
/etc/dconf/db/gdm.d
/etc/dconf/db/gdm.d/00-upstream-settings
/etc/dconf/db/gdm.d/locks
/etc/dconf/db/gdm.d/locks/00-upstream-settings-locks
/etc/dconf/profile/gdm
/etc/gdm
/etc/gdm/Init
/etc/gdm/Init/Default
/etc/gdm/PostLogin
/etc/gdm/PostLogin/Default.sample
/etc/gdm/PostSession
/etc/gdm/PostSession/Default
/etc/gdm/PreSession
/etc/gdm/PreSession/Default
/etc/gdm/Xsession
/etc/gdm/custom.conf
/etc/pam.d/gdm-autologin
/etc/pam.d/gdm-fingerprint
/etc/pam.d/gdm-launch-environment
/etc/pam.d/gdm-password
/etc/pam.d/gdm-pin
/etc/pam.d/gdm-smartcard
/run/gdm
/usr/bin/gdm-screenshot
/usr/bin/gdmflexiserver
/usr/lib/systemd/system/gdm.service
/usr/lib64/libgdm.so
/usr/lib64/libgdm.so.1
/usr/lib64/libgdm.so.1.0.0
There is 143 files more in these RPM.