From 64aa2622a3baea1f62732f136230543c9d669cd1 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 13 Nov 2019 23:28:05 +0100
Subject: [PATCH] libcrypt-util: add superficial validator for UNIX hashed
 password strings

---
 src/shared/libcrypt-util.c | 11 +++++++++++
 src/shared/libcrypt-util.h |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/src/shared/libcrypt-util.c b/src/shared/libcrypt-util.c
index b1a8168030..f41685ae45 100644
--- a/src/shared/libcrypt-util.c
+++ b/src/shared/libcrypt-util.c
@@ -73,3 +73,14 @@ int make_salt(char **ret) {
         return 0;
 #endif
 }
+
+bool hashed_password_valid(const char *s) {
+
+        /* Returns true if the specified string is a 'valid' hashed UNIX password, i.e. if starts with '$' or
+         * with '!$' (the latter being a valid, yet locked password). */
+
+        if (isempty(s))
+                return false;
+
+        return STARTSWITH_SET(s, "$", "!$");
+}
diff --git a/src/shared/libcrypt-util.h b/src/shared/libcrypt-util.h
index 3da1ab5ad9..93f0e13ffb 100644
--- a/src/shared/libcrypt-util.h
+++ b/src/shared/libcrypt-util.h
@@ -18,3 +18,5 @@
 #include <stdlib.h>
 
 int make_salt(char **ret);
+
+bool hashed_password_valid(const char *s);