[Qemu-devel] [PATCH] qemu-ga: implement win32 guest-set-user-password

[Marc-André Lureau]

Use NetUserSetInfo() to set the user password.

This function is notoriously known to be problematic for users with EFS
encrypted files. But the alternative, NetUserChangePassword() requires
the old password. Nevertheless, The EFS file should be recovered by
changing back to the old password.

Signed-off-by: Marc-André Lureau <address@hidden>
---
 configure            |  2 +-
 qga/commands-win32.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 76 insertions(+), 3 deletions(-)

diff --git a/configure b/configure
index 3063739..400de0d 100755
--- a/configure
+++ b/configure
@@ -732,7 +732,7 @@ if test "$mingw32" = "yes" ; then
   sysconfdir="\${prefix}"
   local_statedir=
   confsuffix=""
-  libs_qga="-lws2_32 -lwinmm -lpowrprof $libs_qga"
+  libs_qga="-lws2_32 -lwinmm -lpowrprof -lnetapi32 $libs_qga"
 fi
 
 werror=""
diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index fbddc8b..d31530c 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -16,6 +16,8 @@
 #include <powrprof.h>
 #include <stdio.h>
 #include <string.h>
+#include <lm.h>
+
 #include "qga/guest-agent-core.h"
 #include "qga/vss-win32.h"
 #include "qga-qmp-commands.h"
@@ -676,12 +678,84 @@ int64_t qmp_guest_set_vcpus(GuestLogicalProcessorList 
*vcpus, Error **errp)
     return -1;
 }
 
+static gchar *
+get_net_error_message(gint error)
+{
+    HMODULE module = NULL;
+    gchar *retval = NULL;
+    wchar_t *msg = NULL;
+    int flags, nchars;
+
+    flags = FORMAT_MESSAGE_ALLOCATE_BUFFER
+        |FORMAT_MESSAGE_IGNORE_INSERTS
+        |FORMAT_MESSAGE_FROM_SYSTEM;
+
+    if (error >= NERR_BASE && error <= MAX_NERR) {
+        module = LoadLibraryExW(L"netmsg.dll", NULL, LOAD_LIBRARY_AS_DATAFILE);
+
+        if (module != NULL) {
+            flags |= FORMAT_MESSAGE_FROM_HMODULE;
+        }
+    }
+
+    FormatMessageW(flags, module, error, 0, (LPWSTR)&msg, 0, NULL);
+
+    if (msg != NULL) {
+        nchars = wcslen(msg);
+
+        if (nchars > 2 && msg[nchars-1] == '\n' && msg[nchars-2] == '\r') {
+            msg[nchars-2] = '\0';
+        }
+
+        retval = g_utf16_to_utf8(msg, -1, NULL, NULL, NULL);
+
+        LocalFree(msg);
+    }
+
+    if (module != NULL) {
+        FreeLibrary(module);
+    }
+
+    return retval;
+}
+
 void qmp_guest_set_user_password(const char *username,
                                  const char *password,
                                  bool crypted,
                                  Error **errp)
 {
-    error_setg(errp, QERR_UNSUPPORTED);
+    NET_API_STATUS nas;
+    char *rawpasswddata = NULL;
+    size_t rawpasswdlen;
+    wchar_t *user, *wpass;
+    USER_INFO_1003 pi1003 = { 0, };
+
+    if (crypted) {
+        error_setg(errp, QERR_UNSUPPORTED);
+        return;
+    }
+
+    rawpasswddata = (char *)g_base64_decode(password, &rawpasswdlen);
+    rawpasswddata = g_renew(char, rawpasswddata, rawpasswdlen + 1);
+    rawpasswddata[rawpasswdlen] = '\0';
+
+    user = g_utf8_to_utf16(username, -1, NULL, NULL, NULL);
+    wpass = g_utf8_to_utf16(rawpasswddata, -1, NULL, NULL, NULL);
+
+    pi1003.usri1003_password = wpass;
+    nas = NetUserSetInfo(NULL, user,
+                         1003, (LPBYTE)&pi1003,
+                         NULL);
+
+    if (nas != NERR_Success) {
+        gchar *msg = get_net_error_message(nas);
+        error_setg(errp, "failed to set password: %s", msg);
+        g_free(msg);
+    }
+
+    g_free(user);
+    g_free(wpass);
+    g_free(rawpasswddata);
 }
 
 GuestMemoryBlockList *qmp_guest_get_memory_blocks(Error **errp)
@@ -709,7 +783,6 @@ GList *ga_command_blacklist_init(GList *blacklist)
     const char *list_unsupported[] = {
         "guest-suspend-hybrid", "guest-network-get-interfaces",
         "guest-get-vcpus", "guest-set-vcpus",
-        "guest-set-user-password",
         "guest-get-memory-blocks", "guest-set-memory-blocks",
         "guest-get-memory-block-size",
         "guest-fsfreeze-freeze-list", "guest-get-fsinfo",
-- 
2.4.3