1 files changed, 77 insertions, 0 deletions
diff --git a/windows/utils/get_username.c b/windows/utils/get_username.c
new file mode 100644
index 00000000..bc5780e4
--- /dev/null
+++ b/windows/utils/get_username.c
@@ -0,0 +1,77 @@
+/*
+ * Implementation of get_username() for Windows.
+ */
+
+#include "putty.h"
+
+#ifndef SECURITY_WIN32
+#define SECURITY_WIN32
+#endif
+#include <security.h>
+
+char *get_username(void)
+{
+    DWORD namelen;
+    char *user;
+    bool got_username = false;
+    DECL_WINDOWS_FUNCTION(static, BOOLEAN, GetUserNameExA,
+                          (EXTENDED_NAME_FORMAT, LPSTR, PULONG));
+
+    {
+        static bool tried_usernameex = false;
+        if (!tried_usernameex) {
+            /* Not available on Win9x, so load dynamically */
+            HMODULE secur32 = load_system32_dll("secur32.dll");
+            /* If MIT Kerberos is installed, the following call to
+               GET_WINDOWS_FUNCTION makes Windows implicitly load
+               sspicli.dll WITHOUT proper path sanitizing, so better
+               load it properly before */
+            HMODULE sspicli = load_system32_dll("sspicli.dll");
+            (void)sspicli; /* squash compiler warning about unused variable */
+            GET_WINDOWS_FUNCTION(secur32, GetUserNameExA);
+            tried_usernameex = true;
+        }
+    }
+
+    if (p_GetUserNameExA) {
+        /*
+         * If available, use the principal -- this avoids the problem
+         * that the local username is case-insensitive but Kerberos
+         * usernames are case-sensitive.
+         */
+
+        /* Get the length */
+        namelen = 0;
+        (void) p_GetUserNameExA(NameUserPrincipal, NULL, &namelen);
+
+        user = snewn(namelen, char);
+        got_username = p_GetUserNameExA(NameUserPrincipal, user, &namelen);
+        if (got_username) {
+            char *p = strchr(user, '@');
+            if (p) *p = 0;
+        } else {
+            sfree(user);
+        }
+    }
+
+    if (!got_username) {
+        /* Fall back to local user name */
+        namelen = 0;
+        if (!GetUserName(NULL, &namelen)) {
+            /*
+             * Apparently this doesn't work at least on Windows XP SP2.
+             * Thus assume a maximum of 256. It will fail again if it
+             * doesn't fit.
+             */
+            namelen = 256;
+        }
+
+        user = snewn(namelen, char);
+        got_username = GetUserName(user, &namelen);
+        if (!got_username) {
+            sfree(user);
+        }
+    }
+
+    return got_username ? user : NULL;
+}