From: Jason Andryuk <jandryuk@gmail.com>
Date: Thu, 6 May 2021 13:59:20 +0000 (-0400)
Subject: vtpmmgr: Remove bogus cast from TPM2_GetRandom
X-Git-Tag: archive/raspbian/4.16.0+51-g0941d6cb-1+rpi1~2^2~42^2~541
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=7f4276fad8f0bfba5bb3fd012bf2df51c05fcf02;p=xen.git

vtpmmgr: Remove bogus cast from TPM2_GetRandom

The UINT32 <-> UINT16 casting in TPM2_GetRandom is incorrect.  Use a
local UINT16 as needed for the TPM hardware command and assign the
result.

Suggested-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: Daniel P. Smith <dpsmith@apertussolutions.com>
---

diff --git a/stubdom/vtpmmgr/tpm2.c b/stubdom/vtpmmgr/tpm2.c
index 655e6d164c..ebd06eac74 100644
--- a/stubdom/vtpmmgr/tpm2.c
+++ b/stubdom/vtpmmgr/tpm2.c
@@ -427,15 +427,22 @@ abort_egress:
 
 TPM_RC TPM2_GetRandom(UINT32 * bytesRequested, BYTE * randomBytes)
 {
+    UINT16 bytesReq;
     TPM_BEGIN(TPM_ST_NO_SESSIONS, TPM_CC_GetRandom);
 
-    ptr = pack_UINT16(ptr, (UINT16)*bytesRequested);
+    if (*bytesRequested > UINT16_MAX)
+        bytesReq = UINT16_MAX;
+    else
+        bytesReq = *bytesRequested;
+
+    ptr = pack_UINT16(ptr, bytesReq);
 
     TPM_TRANSMIT();
     TPM_UNPACK_VERIFY();
 
-    ptr = unpack_UINT16(ptr, (UINT16 *)bytesRequested);
-    ptr = unpack_TPM_BUFFER(ptr, randomBytes, *bytesRequested);
+    ptr = unpack_UINT16(ptr, &bytesReq);
+    *bytesRequested = bytesReq;
+    ptr = unpack_TPM_BUFFER(ptr, randomBytes, bytesReq);
 
 abort_egress:
     return status;