From 1ec07af70925ece698b733d55dedd1d9878b70f2 Mon Sep 17 00:00:00 2001
From: Tadeusz Struk <tadeusz.struk@intel.com>
Date: Fri, 24 Jan 2020 19:05:34 -0800
Subject: [PATCH] esys: zero out ctx->salt after on startAuthSession_finish

The ctx->salt is used to calculate session key during
startAuthSession call if the caller pass a valid tpmKey
parameter. There salt is calculated in the _Async call
and the the session key is calculated in the _Finish call.
The problem is that if in the same context an unsalted
session is created after a salted session the ctx->salt
will still hold the old value and it will incorrectly
be used for session key calculation in the the subsequent
_Finish call. To fix this the salt needs to be set to
cleaned after no longer needed.

Fixes: #1574

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
---
 src/tss2-esys/api/Esys_StartAuthSession.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/tss2-esys/api/Esys_StartAuthSession.c b/src/tss2-esys/api/Esys_StartAuthSession.c
index 1717928a717d..6367419d7c9a 100644
--- a/src/tss2-esys/api/Esys_StartAuthSession.c
+++ b/src/tss2-esys/api/Esys_StartAuthSession.c
@@ -497,6 +497,7 @@ Esys_StartAuthSession_Finish(
     goto_if_error(r, "Marshal session name", error_cleanup);
 
     sessionHandleNode->rsrc.name.size = offset;
+    memset(&esysContext->salt, '\0', sizeof(esysContext->salt));
     esysContext->state = _ESYS_STATE_INIT;
 
     return TSS2_RC_SUCCESS;
-- 
2.27.0