shadow-utils/shadow-4.1.5.1-ingroup.patch

Index: shadow-4.5/src/newgrp.c
===================================================================
--- shadow-4.5.orig/src/newgrp.c
+++ shadow-4.5/src/newgrp.c
@@ -83,15 +83,29 @@ static void usage (void)
 	}
 }
 
+static bool ingroup(const char *name, struct group *gr)
+{
+	char **look;
+	bool notfound = true;
+
+	look = gr->gr_mem;
+	while (*look && notfound)
+		notfound = strcmp (*look++, name);
+
+	return !notfound;
+}
+
 /*
- * find_matching_group - search all groups of a given group id for
+ * find_matching_group - search all groups of a gr's group id for
  *                       membership of a given username
+ *                       but check gr itself first
  */
-static /*@null@*/struct group *find_matching_group (const char *name, gid_t gid)
+static /*@null@*/struct group *find_matching_group (const char *name, struct group *gr)
 {
-	struct group *gr;
-	char **look;
-	bool notfound = true;
+	gid_t gid = gr->gr_gid;
+
+	if (ingroup(name, gr))
+		return gr;
 
 	setgrent ();
 	while ((gr = getgrent ()) != NULL) {
@@ -103,14 +117,8 @@ static /*@null@*/struct group *find_matc
 		 * A group with matching GID was found.
 		 * Test for membership of 'name'.
 		 */
-		look = gr->gr_mem;
-		while ((NULL != *look) && notfound) {
-			notfound = (strcmp (*look, name) != 0);
-			look++;
-		}
-		if (!notfound) {
+		if (ingroup(name, gr))
 			break;
-		}
 	}
 	endgrent ();
 	return gr;
@@ -630,7 +638,7 @@ int main (int argc, char **argv)
 	 * groups of the same GID like the requested group for
 	 * membership of the current user.
 	 */
-	grp = find_matching_group (name, grp->gr_gid);
+	grp = find_matching_group (name, grp);
 	if (NULL == grp) {
 		/*
 		 * No matching group found. As we already know that