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Mon, 26 Aug 2019 13:52:24 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.67]) by smtp.corp.redhat.com (Postfix) with ESMTP id B1B8B5D704; Mon, 26 Aug 2019 13:52:21 +0000 (UTC) From: Maxim Levitsky To: qemu-devel@nongnu.org Date: Mon, 26 Aug 2019 16:51:01 +0300 Message-Id: <20190826135103.22410-12-mlevitsk@redhat.com> In-Reply-To: <20190826135103.22410-1-mlevitsk@redhat.com> References: <20190826135103.22410-1-mlevitsk@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Mon, 26 Aug 2019 13:52:24 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2 11/13] qcrypto-luks: refactoring: simplify the math used for keyslot locations X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , qemu-block@nongnu.org, Markus Armbruster , Max Reitz , Stefan Hajnoczi , Maxim Levitsky Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Signed-off-by: Maxim Levitsky --- crypto/block-luks.c | 64 +++++++++++++++++++++++++++++---------------- 1 file changed, 41 insertions(+), 23 deletions(-) diff --git a/crypto/block-luks.c b/crypto/block-luks.c index d713125925..6a43d97ce5 100644 --- a/crypto/block-luks.c +++ b/crypto/block-luks.c @@ -409,6 +409,32 @@ qcrypto_block_luks_essiv_cipher(QCryptoCipherAlgorithm cipher, } } +/* + * Returns number of sectors needed to store the key material + * given number of anti forensic stripes + */ +static int +qcrypto_block_luks_splitkeylen_sectors(const QCryptoBlockLUKS *luks, + unsigned int stripes) +{ + /* + * This calculation doesn't match that shown in the spec, + * but instead follows the cryptsetup implementation. + */ + + size_t header_sectors = QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / + QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; + + size_t splitkeylen = luks->header.master_key_len * stripes; + + /* First align the key material size to block size*/ + size_t splitkeylen_sectors = + DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE); + + /* Then also align the key material size to the size of the header */ + return ROUND_UP(splitkeylen_sectors, header_sectors); +} + /* * Stores the main LUKS header, taking care of endianess */ @@ -1151,7 +1177,8 @@ qcrypto_block_luks_create(QCryptoBlock *block, QCryptoBlockCreateOptionsLUKS luks_opts; Error *local_err = NULL; g_autofree uint8_t *masterkey = NULL; - size_t splitkeylen = 0; + size_t header_sectors; + size_t split_key_sectors; size_t i; g_autofree char *password; const char *cipher_alg; @@ -1370,37 +1397,28 @@ qcrypto_block_luks_create(QCryptoBlock *block, goto error; } + /* start with the sector that follows the header*/ + header_sectors = QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / + QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; + + split_key_sectors = + qcrypto_block_luks_splitkeylen_sectors(luks, + QCRYPTO_BLOCK_LUKS_STRIPES); - /* Although LUKS has multiple key slots, we're just going - * to use the first key slot */ - splitkeylen = luks->header.master_key_len * QCRYPTO_BLOCK_LUKS_STRIPES; for (i = 0; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS; i++) { - luks->header.key_slots[i].active = QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED; - luks->header.key_slots[i].stripes = QCRYPTO_BLOCK_LUKS_STRIPES; + QCryptoBlockLUKSKeySlot *slot = &luks->header.key_slots[i]; + slot->active = QCRYPTO_BLOCK_LUKS_KEY_SLOT_DISABLED; - /* This calculation doesn't match that shown in the spec, - * but instead follows the cryptsetup implementation. - */ - luks->header.key_slots[i].key_offset_sector = - (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / - QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) + - (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE), - (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / - QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) * i); + slot->key_offset_sector = header_sectors + i * split_key_sectors; + slot->stripes = QCRYPTO_BLOCK_LUKS_STRIPES; } - /* The total size of the LUKS headers is the partition header + key * slot headers, rounded up to the nearest sector, combined with * the size of each master key material region, also rounded up * to the nearest sector */ - luks->header.payload_offset_sector = - (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / - QCRYPTO_BLOCK_LUKS_SECTOR_SIZE) + - (ROUND_UP(DIV_ROUND_UP(splitkeylen, QCRYPTO_BLOCK_LUKS_SECTOR_SIZE), - (QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET / - QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) * - QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS); + luks->header.payload_offset_sector = header_sectors + + QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS * split_key_sectors; block->sector_size = QCRYPTO_BLOCK_LUKS_SECTOR_SIZE; block->payload_offset = luks->header.payload_offset_sector * -- 2.17.2