1 files changed, 70 insertions, 0 deletions
diff --git a/lib/password.c b/lib/password.c
new file mode 100644
index 0000000..7457878
--- /dev/null
+++ b/lib/password.c
@@ -0,0 +1,70 @@
+#include "lslib.h"
+
+#include <errno.h>
+#include <pwd.h>
+#include <shadow.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define SHADOW_BUFSIZE 256
+
+static const char* get_passwd(const struct passwd* pw) {
+	const char *pass;
+
+	if (!pw)
+		return "aa"; /* "aa" will never match */
+
+	pass = pw->pw_passwd;
+
+	if ((pass[0] == 'x' || pass[0] == '*') && !pass[1]) {
+		struct spwd* result;
+
+        errno = 0;
+		result = getspnam(pw->pw_name);
+        
+        if (errno == EACCES) {
+            errno = 0;
+            error("binary not properly installed");
+        }
+
+		pass = (result == NULL) ? "aa" : result->sp_pwdp;
+	}
+
+	return pass;
+}
+
+int check_password(const struct passwd *pw, char* plaintext) {
+	char* encrypted;
+    char* salt;
+    char* p;
+	const char *pw_pass;
+	int r;
+
+	pw_pass = get_passwd(pw);
+	if (!pw_pass[0]) {
+		return PASSWORD_EMPTY;
+	}
+
+    salt = strdup(pw_pass);
+    if (salt == NULL) die();
+    p = strchr(salt + 1, '$');
+    if (p == NULL) die();
+    p = strchr(p + 1, '$');
+    if (p == NULL) die();
+    p[1] = 0;
+
+    encrypted = crypt(plaintext, salt);
+	r = (strcmp(encrypted, pw_pass) == 0);
+
+    nuke_str(plaintext); 
+    free(salt);
+
+	return r;
+}
+
+int prompt_password(const struct passwd *pw, char* prompt) {
+    char* plaintext = getpass(prompt);
+	return check_password(pw, plaintext);
+}