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tpm2_import: Do not use fixed AES wrapping key

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Fix for CVE-2021-3565

resolves: rhbz#1965982

Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
This commit is contained in:
Jerry Snitselaar 2021-06-28 08:28:16 -07:00
parent 4f7195a767
commit b9bc887c84
2 changed files with 52 additions and 1 deletions
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46
0001-tpm2_import-fix-fixed-AES-key-CVE-2021-3565.patch Normal file
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@ -0,0 +1,46 @@
From c069e4f179d5e6653a84fb236816c375dca82515 Mon Sep 17 00:00:00 2001
From: William Roberts <william.c.roberts@intel.com>
Date: Fri, 21 May 2021 12:22:31 -0500
Subject: [PATCH] tpm2_import: fix fixed AES key CVE-2021-3565
tpm2_import used a fixed AES key for the inner wrapper, which means that
a MITM attack would be able to unwrap the imported key. Even the
use of an encrypted session will not prevent this. The TPM only
encrypts the first parameter which is the fixed symmetric key.
To fix this, ensure the key size is 16 bytes or bigger and use
OpenSSL to generate a secure random AES key.
Fixes: #2738
Signed-off-by: William Roberts <william.c.roberts@intel.com>
---
tools/tpm2_import.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/tools/tpm2_import.c b/tools/tpm2_import.c
index cfb6f207ba9c..f44326c87e7e 100644
--- a/tools/tpm2_import.c
+++ b/tools/tpm2_import.c
@@ -118,7 +118,17 @@ static tool_rc key_import(ESYS_CONTEXT *ectx, TPM2B_PUBLIC *parent_pub,
TPM2B_DATA enc_sensitive_key = {
.size = parent_pub->publicArea.parameters.rsaDetail.symmetric.keyBits.sym / 8
};
- memset(enc_sensitive_key.buffer, 0xFF, enc_sensitive_key.size);
+
+ if(enc_sensitive_key.size < 16) {
+ LOG_ERR("Calculated wrapping keysize is less than 16 bytes, got: %u", enc_sensitive_key.size);
+ return tool_rc_general_error;
+ }
+
+ int ossl_rc = RAND_bytes(enc_sensitive_key.buffer, enc_sensitive_key.size);
+ if (ossl_rc != 1) {
+ LOG_ERR("RAND_bytes failed: %s", ERR_error_string(ERR_get_error(), NULL));
+ return tool_rc_general_error;
+ }
/*
* Calculate the object name.
--
2.31.0

7
tpm2-tools.spec
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@ -2,12 +2,13 @@
Name: tpm2-tools
Version: 5.0
Release: 6%{?candidate:.%{candidate}}%{?dist}
Release: 7%{?candidate:.%{candidate}}%{?dist}
Summary: A bunch of TPM testing toolS build upon tpm2-tss
License: BSD
URL: https://github.com/tpm2-software/tpm2-tools
Source0: https://github.com/tpm2-software/tpm2-tools/releases/download/%{version}%{?candidate:-%{candidate}}/%{name}-%{version}%{?candidate:-%{candidate}}.tar.gz
Patch0: 0001-tpm2_import-fix-fixed-AES-key-CVE-2021-3565.patch
BuildRequires: make
BuildRequires: gcc-c++
@ -57,6 +58,10 @@ tpm2-tools is a batch of tools for tpm2.0. It is based on tpm2-tss.
%{_mandir}/man1/tss2_*.1.gz
%changelog
* Mon Jun 28 2021 Jerry Snitselaar <jsnitsel@redhat.com> - 5.0-7
- Fix for CVE-2021-3565
Resolves: rhbz#1965982
* Wed Jun 16 2021 Mohan Boddu <mboddu@redhat.com> - 5.0-6
- Rebuilt for RHEL 9 BETA for openssl 3.0
Related: rhbz#1971065