diff -Nru shadow-4.8.1/debian/changelog shadow-4.8.1/debian/changelog
--- shadow-4.8.1/debian/changelog	2021-11-15 23:13:44.000000000 +0100
+++ shadow-4.8.1/debian/changelog	2022-01-28 10:03:42.000000000 +0100
@@ -1,3 +1,10 @@
+shadow (1:4.8.1-2ubuntu2~ppa1) jammy; urgency=medium
+
+  * Add automatic detection of "extrausers" for usermod -G
+    (LP: 1959375)
+
+ -- Michael Vogt <michael.vogt@ubuntu.com>  Fri, 28 Jan 2022 10:03:42 +0100
+
 shadow (1:4.8.1-2ubuntu1) jammy; urgency=low
 
   * Merge from Debian unstable (LP: #1951161). Remaining changes:
diff -Nru shadow-4.8.1/debian/patches/1010_extrausers.patch shadow-4.8.1/debian/patches/1010_extrausers.patch
--- shadow-4.8.1/debian/patches/1010_extrausers.patch	2020-02-07 16:32:06.000000000 +0100
+++ shadow-4.8.1/debian/patches/1010_extrausers.patch	2022-01-28 10:03:42.000000000 +0100
@@ -9,11 +9,11 @@
  src/usermod.c  | 48 +++++++++++++++++++++++++++++++++++++++++++
  4 files changed, 122 insertions(+), 1 deletion(-)
 
-diff --git a/lib/commonio.c b/lib/commonio.c
-index 9f6ceca..008691f 100644
---- a/lib/commonio.c
-+++ b/lib/commonio.c
-@@ -419,6 +419,7 @@ int commonio_lock (struct commonio_db *db)
+Index: shadow-4.8.1/lib/commonio.c
+===================================================================
+--- shadow-4.8.1.orig/lib/commonio.c
++++ shadow-4.8.1/lib/commonio.c
+@@ -419,6 +419,7 @@ int commonio_lock (struct commonio_db *d
  	int i;
  
  #ifdef HAVE_LCKPWDF
@@ -21,7 +21,7 @@
  	/*
  	 * Only if the system libc has a real lckpwdf() - the one from
  	 * lockpw.c calls us and would cause infinite recursion!
-@@ -448,6 +449,7 @@ int commonio_lock (struct commonio_db *db)
+@@ -448,6 +449,7 @@ int commonio_lock (struct commonio_db *d
  		ulckpwdf ();
  		return 0;		/* failure */
  	}
@@ -29,11 +29,11 @@
  #endif				/* !HAVE_LCKPWDF */
  
  	/*
-diff --git a/lib/defines.h b/lib/defines.h
-index 2fb1b56..ffa8b6a 100644
---- a/lib/defines.h
-+++ b/lib/defines.h
-@@ -316,6 +316,14 @@ char *strchr (), *strrchr (), *strtok ();
+Index: shadow-4.8.1/lib/defines.h
+===================================================================
+--- shadow-4.8.1.orig/lib/defines.h
++++ shadow-4.8.1/lib/defines.h
+@@ -316,6 +316,14 @@ char *strchr (), *strrchr (), *strtok ()
  #endif
  #endif
  
@@ -48,10 +48,10 @@
  #ifndef NULL
  #define NULL ((void *) 0)
  #endif
-diff --git a/src/passwd.c b/src/passwd.c
-index 13619b1..bfe0aea 100644
---- a/src/passwd.c
-+++ b/src/passwd.c
+Index: shadow-4.8.1/src/passwd.c
+===================================================================
+--- shadow-4.8.1.orig/src/passwd.c
++++ shadow-4.8.1/src/passwd.c
 @@ -559,8 +559,15 @@ static void update_noshadow (void)
  {
  	const struct passwd *pw;
@@ -170,10 +170,10 @@
  		return;
  	}
  	nsp = __spw_dup (sp);
-diff --git a/src/usermod.c b/src/usermod.c
-index 05b9871..fb833e1 100644
---- a/src/usermod.c
-+++ b/src/usermod.c
+Index: shadow-4.8.1/src/usermod.c
+===================================================================
+--- shadow-4.8.1.orig/src/usermod.c
++++ shadow-4.8.1/src/usermod.c
 @@ -1566,7 +1566,16 @@ static void close_files (void)
   */
  static void open_files (void)
@@ -239,7 +239,50 @@
  		fprintf (stderr,
  		         _("%s: cannot open %s\n"),
  		         Prog, spw_dbname ());
-@@ -1675,11 +1712,22 @@ static void usr_update (void)
+@@ -1599,6 +1636,12 @@ static void open_files (void)
+ 		 * group entries.
+ 		 */
+ 		if (gr_lock () == 0) {
++                        if (try_extrausers) {
++                               gr_setdbname (EXTRAUSERS_GROUP_FILE);
++                               sgr_setdbname (EXTRAUSERS_SHADOWGROUP_FILE);
++                               open_files ();
++                               return;
++                        }
+ 			fprintf (stderr,
+ 			         _("%s: cannot lock %s; try again later.\n"),
+ 			         Prog, gr_dbname ());
+@@ -1606,6 +1649,14 @@ static void open_files (void)
+ 		}
+ 		gr_locked = true;
+ 		if (gr_open (O_CREAT | O_RDWR) == 0) {
++                        if (try_extrausers) {
++                               gr_unlock ();
++                               gr_locked = false;
++                               gr_setdbname (EXTRAUSERS_GROUP_FILE);
++                               sgr_setdbname (EXTRAUSERS_SHADOWGROUP_FILE);
++                               open_files ();
++                               return;
++                        }
+ 			fprintf (stderr,
+ 			         _("%s: cannot open %s\n"),
+ 			         Prog, gr_dbname ());
+@@ -1613,6 +1664,14 @@ static void open_files (void)
+ 		}
+ #ifdef SHADOWGRP
+ 		if (is_shadow_grp && (sgr_lock () == 0)) {
++                        if (try_extrausers) {
++                               gr_unlock ();
++                               gr_locked = false;
++                               gr_setdbname (EXTRAUSERS_GROUP_FILE);
++                               sgr_setdbname (EXTRAUSERS_SHADOWGROUP_FILE);
++                               open_files ();
++                               return;
++                        }
+ 			fprintf (stderr,
+ 			         _("%s: cannot lock %s; try again later.\n"),
+ 			         Prog, sgr_dbname ());
+@@ -1675,11 +1734,22 @@ static void usr_update (void)
  	struct spwd spent;
  	const struct spwd *spwd = NULL;