/* Copyright (c) University of Cambridge 1995 - 2018 */
/* Copyright (c) The Exim Maintainers 2020 */
/* See the file NOTICE for conditions of use and distribution. */
+/* SPDX-License-Identifier: GPL-2.0-or-later */
/* This file, which provides support for Microsoft's Secure Password
Authentication, was contributed by Marc Prud'hommeaux. Tom Kistner added SPA
SPAAuthResponse response;
SPAAuthResponse *responseptr = &response;
uschar msgbuf[2048];
-uschar *clearpass;
+uschar *clearpass, *s;
+unsigned off;
/* send a 334, MS Exchange style, and grab the client's request,
unless we already have it via an initial response. */
{
int i;
- char * p = (CS responseptr) + IVAL(&responseptr->uUser.offset,0);
+ char * p;
int len = SVAL(&responseptr->uUser.len,0)/2;
+ if ( (off = IVAL(&responseptr->uUser.offset,0)) >= sizeof(SPAAuthResponse)
+ || len >= sizeof(responseptr->buffer)/2
+ || (p = (CS responseptr) + off) + len*2 >= CS (responseptr+1)
+ )
+ {
+ DEBUG(D_auth)
+ debug_printf("auth_spa_server(): bad uUser spec in response\n");
+ return FAIL;
+ }
+
if (len + 1 >= sizeof(msgbuf)) return FAIL;
for (i = 0; i < len; ++i)
{
/* compare NT hash (LM may not be available) */
-if (memcmp(ntRespData, (US responseptr)+IVAL(&responseptr->ntResponse.offset,0),
- 24) == 0)
+off = IVAL(&responseptr->ntResponse.offset,0);
+if (off >= sizeof(SPAAuthResponse) - 24)
+ {
+ DEBUG(D_auth)
+ debug_printf("auth_spa_server(): bad ntRespData spec in response\n");
+ return FAIL;
+ }
+s = (US responseptr) + off;
+
+if (memcmp(ntRespData, s, 24) == 0)
return auth_check_serv_cond(ablock); /* success. we have a winner. */
/* Expand server_condition as an authorization check (PH) */