Re: [libvirt] [PATCH v5 2/6] util: Introduce encryption APIs

On 05/20/2016 08:56 AM, Peter Krempa wrote: > On Thu, May 19, 2016 at 16:29:01 -0400, John Ferlan wrote: >> Introduce virCryptoHaveCipher and virCryptoEncryptData to handle >> performing encryption. >> >> virCryptoHaveCipher: >> Boolean function to determine whether the requested cipher algorithm >> is available. It's expected this API will be called prior to >> virCryptoEncryptdata. It will return true/false. >> >> virCryptoEncryptData: >> Based on the requested cipher type, call the specific encryption >> API to encrypt the data. >> >> Currently the only algorithm support is the AES 256 CBC encryption. >> >> Adjust tests for the API's >> >> Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; >> --- >> configure.ac | 1 + >> src/libvirt_private.syms | 2 + >> src/util/vircrypto.c | 192 ++++++++++++++++++++++++++++++++++++++++++++++- >> src/util/vircrypto.h | 20 ++++- >> tests/vircryptotest.c | 100 +++++++++++++++++++++++- >> 5 files changed, 312 insertions(+), 3 deletions(-)

>> + /* Fill in the padding of the buffer with the size of the padding >> + * which is required for decryption. */ >> + for (i = datalen; i < ciphertextlen; i++) >> + ciphertext[i] = ciphertextlen - datalen; >> + >> + /* Initialize the gnutls cipher */ >> + enc_key.size = enckeylen; >> + enc_key.data = enckey; >> + if (iv) { >> + iv_buf.size = ivlen; >> + iv_buf.data = iv; >> + } >> + if ((rc = gnutls_cipher_init(&handle, gnutls_enc_alg, >> + &enc_key, &iv_buf)) < 0) { >> + virReportError(VIR_ERR_INTERNAL_ERROR, >> + _("failed to initialize cipher: '%s'"), >> + gnutls_strerror(rc)); >> + goto error; >> + } >> + >> + /* Encrypt the data and free the memory for cipher operations */ >> + rc = gnutls_cipher_encrypt(handle, ciphertext, ciphertextlen); >> + gnutls_cipher_deinit(handle); memset(&enc_key, 0, sizeof(gnutls_datum_t)); memset(&iv_key, 0, sizeof(gnutls_datum_t));

>> + if (rc < 0) { >> + virReportError(VIR_ERR_INTERNAL_ERROR, >> + _("failed to encrypt the data: '%s'"), >> + gnutls_strerror(rc)); >> + goto error; >> + } >> + >> + *ciphertextret = ciphertext; >> + *ciphertextlenret = ciphertextlen; >> + return 0; >> + >> + error: >> + VIR_DISPOSE_N(ciphertext, ciphertextlen); >> + return -1; > > In both cases you should clear the stack'd copy of the encryption key. > >> +} >> +#endif >> +