From 8a1716c3bb18bac169f68d24cdd095cf617eb908 Mon Sep 17 00:00:00 2001 From: root Date: Tue, 6 Apr 2021 16:22:04 +0800 Subject: [PATCH] tpm2: CryptSym: fix AES output IV 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 --- configure.ac | 1 + src/tpm2/crypto/openssl/CryptSym.c | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/configure.ac b/configure.ac index 1bb45d1..0c57ef3 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); -- 2.27.0