diff --git a/ident.c b/ident.c
index ea6034581c..ead09ff7f6 100644
--- a/ident.c
+++ b/ident.c
@@ -203,6 +203,15 @@ static int crud(unsigned char c)
 		c == '\'';
 }
 
+static int has_non_crud(const char *str)
+{
+	for (; *str; str++) {
+		if (!crud(*str))
+			return 1;
+	}
+	return 0;
+}
+
 /*
  * Copy over a string to the destination, but avoid special
  * characters ('\n', '<' and '>') and remove crud at the end
@@ -389,6 +398,8 @@ const char *fmt_ident(const char *name, const char *email,
 			pw = xgetpwuid_self(NULL);
 			name = pw->pw_name;
 		}
+		if (strict && !has_non_crud(name))
+			die(_("name consists only of disallowed characters: %s"), name);
 	}
 
 	strbuf_reset(&ident);
diff --git a/t/t7518-ident-corner-cases.sh b/t/t7518-ident-corner-cases.sh
index 6c057afc11..667f110f59 100755
--- a/t/t7518-ident-corner-cases.sh
+++ b/t/t7518-ident-corner-cases.sh
@@ -17,4 +17,9 @@ test_expect_success 'empty name and missing email' '
 	)
 '
 
+test_expect_success 'commit rejects all-crud name' '
+	test_must_fail env GIT_AUTHOR_NAME=" .;<>" \
+		git commit --allow-empty -m foo
+'
+
 test_done