On Fri, 2019-09-06 at 14:11 +0100, Daniel P. Berrangé wrote:
> On Mon, Aug 26, 2019 at 04:50:59PM +0300, Maxim Levitsky wrote:
> > This is just to make qcrypto_block_luks_open more
> > reasonable in size.
> >
> > Signed-off-by: Maxim Levitsky <mlevi...@redhat.com>
> > ---
> > crypto/block-luks.c | 254 +++++++++++++++++++++++++-------------------
> > 1 file changed, 146 insertions(+), 108 deletions(-)
> >
> > diff --git a/crypto/block-luks.c b/crypto/block-luks.c
> > index b4dc6fc899..cc9a52c9af 100644
> > --- a/crypto/block-luks.c
> > +++ b/crypto/block-luks.c
> > @@ -508,6 +508,148 @@ fail:
> > return ret;
> > }
> >
> > +/*
> > + * Does basic sanity checks on the LUKS header
> > + */
> > +static int
> > +qcrypto_block_luks_check_header(const QCryptoBlockLUKS *luks, Error **errp)
> > +{
> > + int ret;
> > +
> > + if (memcmp(luks->header.magic, qcrypto_block_luks_magic,
> > + QCRYPTO_BLOCK_LUKS_MAGIC_LEN) != 0) {
> > + error_setg(errp, "Volume is not in LUKS format");
> > + ret = -EINVAL;
> > + goto fail;
> > + }
>
> Just 'return -1' here immediately - don't return an errno, as we're
> using Error objects for reporting.
>
> > +
> > + if (luks->header.version != QCRYPTO_BLOCK_LUKS_VERSION) {
> > + error_setg(errp, "LUKS version %" PRIu32 " is not supported",
> > + luks->header.version);
> > + ret = -ENOTSUP;
> > + goto fail;
> > + }
> > +
> > + return 0;
> > +fail:
> > + return ret;
> > +}
> > +
> > +/*
> > + * Parses the crypto parameters that are stored in the LUKS header
> > + */
> > +
> > +static int
> > +qcrypto_block_luks_parse_header(QCryptoBlockLUKS *luks, Error **errp)
> > +{
> > + g_autofree char *cipher_mode = g_strdup(luks->header.cipher_mode);
> > + char *ivgen_name, *ivhash_name;
> > + int ret = -1;
> > + Error *local_err = NULL;
> > +
> > + /*
> > + * The cipher_mode header contains a string that we have
> > + * to further parse, of the format
> > + *
> > + * <cipher-mode>-<iv-generator>[:<iv-hash>]
> > + *
> > + * eg cbc-essiv:sha256, cbc-plain64
> > + */
> > + ivgen_name = strchr(cipher_mode, '-');
> > + if (!ivgen_name) {
> > + ret = -EINVAL;
>
> Again, don't use errnos - just return -1 in this method.
>
> > + error_setg(errp, "Unexpected cipher mode string format %s",
> > + luks->header.cipher_mode);
> > + goto out;
> > + }
> > + *ivgen_name = '\0';
> > + ivgen_name++;
> > +
> > + ivhash_name = strchr(ivgen_name, ':');
> > + if (!ivhash_name) {
> > + luks->ivgen_hash_alg = 0;
> > + } else {
> > + *ivhash_name = '\0';
> > + ivhash_name++;
> > +
> > + luks->ivgen_hash_alg =
> > qcrypto_block_luks_hash_name_lookup(ivhash_name,
> > +
> > &local_err);
> > + if (local_err) {
> > + ret = -ENOTSUP;
> > + error_propagate(errp, local_err);
> > + goto out;
> > + }
> > + }
> > +
> > + luks->cipher_mode = qcrypto_block_luks_cipher_mode_lookup(cipher_mode,
> > + &local_err);
> > + if (local_err) {
> > + ret = -ENOTSUP;
> > + error_propagate(errp, local_err);
> > + goto out;
> > + }
> > +
> > + luks->cipher_alg =
> > + qcrypto_block_luks_cipher_name_lookup(luks->header.cipher_name,
> > + luks->cipher_mode,
> > +
> > luks->header.master_key_len,
> > + &local_err);
> > + if (local_err) {
> > + ret = -ENOTSUP;
> > + error_propagate(errp, local_err);
> > + goto out;
> > + }
> > +
> > + luks->hash_alg =
> > + qcrypto_block_luks_hash_name_lookup(luks->header.hash_spec,
> > + &local_err);
> > + if (local_err) {
> > + ret = -ENOTSUP;
> > + error_propagate(errp, local_err);
> > + goto out;
> > + }
> > +
> > + luks->ivgen_alg = qcrypto_block_luks_ivgen_name_lookup(ivgen_name,
> > + &local_err);
> > + if (local_err) {
> > + ret = -ENOTSUP;
> > + error_propagate(errp, local_err);
> > + goto out;
> > + }
> > +
> > + if (luks->ivgen_alg == QCRYPTO_IVGEN_ALG_ESSIV) {
> > + if (!ivhash_name) {
> > + ret = -EINVAL;
> > + error_setg(errp, "Missing IV generator hash specification");
> > + goto out;
> > + }
> > + luks->ivgen_cipher_alg =
> > + qcrypto_block_luks_essiv_cipher(luks->cipher_alg,
> > + luks->ivgen_hash_alg,
> > + &local_err);
> > + if (local_err) {
> > + ret = -ENOTSUP;
> > + error_propagate(errp, local_err);
> > + goto out;
> > + }
> > + } else {
> > +
> > + /*
> > + * Note we parsed the ivhash_name earlier in the cipher_mode
> > + * spec string even with plain/plain64 ivgens, but we
> > + * will ignore it, since it is irrelevant for these ivgens.
> > + * This is for compat with dm-crypt which will silently
> > + * ignore hash names with these ivgens rather than report
> > + * an error about the invalid usage
> > + */
> > + luks->ivgen_cipher_alg = luks->cipher_alg;
> > + }
> > + ret = 0;
> > +out:
> > + return ret;
> > +
> > +}
> > +
> > /*
> > * Given a key slot, and user password, this will attempt to unlock
> > * the master encryption key from the key slot.
> > @@ -720,12 +862,9 @@ qcrypto_block_luks_open(QCryptoBlock *block,
> > Error **errp)
> > {
> > QCryptoBlockLUKS *luks = NULL;
> > - Error *local_err = NULL;
> > int ret = 0;
> > g_autofree uint8_t *masterkey = NULL;
> > - char *ivgen_name, *ivhash_name;
> > g_autofree char *password = NULL;
> > - g_autofree char *cipher_mode = NULL;
> >
> > if (!(flags & QCRYPTO_BLOCK_OPEN_NO_IO)) {
> > if (!options->u.luks.key_secret) {
> > @@ -748,117 +887,16 @@ qcrypto_block_luks_open(QCryptoBlock *block,
> > goto fail;
> > }
> >
> > -
> > - if (memcmp(luks->header.magic, qcrypto_block_luks_magic,
> > - QCRYPTO_BLOCK_LUKS_MAGIC_LEN) != 0) {
> > - error_setg(errp, "Volume is not in LUKS format");
> > - ret = -EINVAL;
>
> I can't remember why I set ret to an errno in my original code.
> it is entirely pointless, as the caller of this method merely
> checks "ret < 0" and doesn't do anything else with the return
> value. IOW, we should just purge the errnors from this existing
> code entirely.
Nothing against that, I'll do that in a separate patch now.
Best regards,
Maxim Levitsky
