From 28d8e756676c5efc6979a0606d82d0223558fbff Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Wed, 17 Mar 2021 16:29:00 +0400 Subject: [PATCH] tpm2: CryptSym: fix AES output IV MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The TPM is supposed to provide the output IV in the ivInOut parameter in CryptSymmetricEncrypt. In the case of using the openssl routines, the output IV is missed, and the resulting output from the TPM is in the input IV. OpenSSL unfortunately does not export EVP_CIPHER_CTX_iv() until tags/OpenSSL_1_1_0, so we have to fall back to the reference code for previous OpenSSL versions. Signed-off-by: William Roberts Signed-off-by: Stefan Berger Signed-off-by: Marc-André Lureau --- configure.ac | 1 + src/tpm2/crypto/openssl/CryptSym.c | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/configure.ac b/configure.ac index 2895bc9..f113f17 100644 --- a/configure.ac +++ b/configure.ac @@ -165,6 +165,7 @@ AS_IF([test "x$enable_use_openssl_functions" != "xno"], [ AC_CHECK_LIB([crypto], [EVP_aes_128_cbc],, not_found=1) AC_CHECK_LIB([crypto], [EVP_des_ede3_cbc],, not_found=1) AC_CHECK_LIB([crypto], [DES_random_key],, not_found=1) + AC_CHECK_LIB([crypto], [EVP_CIPHER_CTX_iv],, not_found=1) if test "x$not_found" = "x0"; then use_openssl_functions_symmetric=1 use_openssl_functions_for="symmetric (AES, TDES) " diff --git a/src/tpm2/crypto/openssl/CryptSym.c b/src/tpm2/crypto/openssl/CryptSym.c index 7aa90da..856def6 100644 --- a/src/tpm2/crypto/openssl/CryptSym.c +++ b/src/tpm2/crypto/openssl/CryptSym.c @@ -531,6 +531,7 @@ CryptSymmetricEncrypt( BYTE keyToUse[MAX_SYM_KEY_BYTES]; UINT16 keyToUseLen = (UINT16)sizeof(keyToUse); TPM_RC retVal = TPM_RC_SUCCESS; + int ivLen; pAssert(dOut != NULL && key != NULL && dIn != NULL); if(dSize == 0) @@ -595,6 +596,14 @@ CryptSymmetricEncrypt( if (EVP_EncryptFinal_ex(ctx, pOut + outlen1, &outlen2) != 1) ERROR_RETURN(TPM_RC_FAILURE); + if (ivInOut) { + ivLen = EVP_CIPHER_CTX_iv_length(ctx); + if (ivLen < 0 || (size_t)ivLen > sizeof(ivInOut->t.buffer)) + ERROR_RETURN(TPM_RC_FAILURE); + + ivInOut->t.size = ivLen; + memcpy(ivInOut->t.buffer, EVP_CIPHER_CTX_iv(ctx), ivInOut->t.size); + } Exit: if (retVal == TPM_RC_SUCCESS && pOut != dOut) memcpy(dOut, pOut, outlen1 + outlen2); @@ -636,6 +645,7 @@ CryptSymmetricDecrypt( BYTE keyToUse[MAX_SYM_KEY_BYTES]; UINT16 keyToUseLen = (UINT16)sizeof(keyToUse); TPM_RC retVal = TPM_RC_SUCCESS; + int ivLen; // These are used but the compiler can't tell because they are initialized // in case statements and it can't tell if they are always initialized @@ -707,6 +717,15 @@ CryptSymmetricDecrypt( pAssert((int)buffersize >= outlen1 + outlen2); + if (ivInOut) { + ivLen = EVP_CIPHER_CTX_iv_length(ctx); + if (ivLen < 0 || (size_t)ivLen > sizeof(ivInOut->t.buffer)) + ERROR_RETURN(TPM_RC_FAILURE); + + ivInOut->t.size = ivLen; + memcpy(ivInOut->t.buffer, EVP_CIPHER_CTX_iv(ctx), ivInOut->t.size); + } + Exit: if (retVal == TPM_RC_SUCCESS) { pAssert(dSize >= outlen1 + outlen2); -- 2.29.0