From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.90_1) id 1klzbi-00025C-Ei for mharc-grub-devel@gnu.org; Sun, 06 Dec 2020 14:22:06 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:49046) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1klzbg-000254-UA for grub-devel@gnu.org; Sun, 06 Dec 2020 14:22:05 -0500 Received: from out3-smtp.messagingengine.com ([66.111.4.27]:35069) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1klzbe-00020X-DV for grub-devel@gnu.org; Sun, 06 Dec 2020 14:22:04 -0500 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.nyi.internal (Postfix) with ESMTP id 27CCA5C0059; Sun, 6 Dec 2020 14:22:01 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute1.internal (MEProxy); Sun, 06 Dec 2020 14:22:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pks.im; h=date :from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=fm2; bh=dBPXFQdXoqKM0S44YwytCCDx3J4 T6PTvNxxjlLIfmQc=; b=ZkXb/hrQ9/rGumKDWwF5K9wZcEWIa9/jPFDU3/dux37 PFhnA0yv9XEmXb52lz9y6G0Q5YQOYl946QI1QFr7Y12ond3Zn2g7gk3IP7/ltpLN 6iefwbRguQYCr40QRD6eAjXYXKbWJHswMCfsx2IML3jNrrhZqCOgN6zCFbzREHRc n/bwVfQmksAXRKyvlKksWYfelbCjemvSdrrCqWGPzkVJxLxdTugQHL32YK+O/1UT xdHHgs+NqknAf+U+Um0482cu8zMWkKVTPlQl/3mLzr0BBQ44a9qUUL+NAkNJgMUt 31OAdaaSMcKkwY294nRgNqSHrJSAD7+0L2bhEOc13/A== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=dBPXFQ dXoqKM0S44YwytCCDx3J4T6PTvNxxjlLIfmQc=; b=RDXVobyqRJdcMGK/XK1TtH 9OfBGo0uLOBK+iA9S/flGktJlMZGscNIIFfgA0oQl0x2Uh0B5TM0AgstNfq2XY+g 0rI8FpPGO5K7VxzfMXqYXXdQ7KJUOI5ezwhOsJjSvL4ij5BM11YMrrzo8fq6vEvh 5ns6ONopW4z6y6c+3atBftY9A2Pj26vFb5yOGpQTyjSpdQLSsadfxCEinvp4hHop KqnpCHps+RcLxcS9jmrXNquxM+VeqmO6aUrR+BNtsIT2uwa3XaN8pBZQJffKE0Q9 ygssSzXOiTY+RjMNjFf54WomH2HT379+3yHWlf2Mq/Rby3jNvv+AJwIDTbTCBEsA == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedujedrudejvddguddvhecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd enucfjughrpeffhffvuffkfhggtggujgesghdtreertddtvdenucfhrhhomheprfgrthhr ihgtkhcuufhtvghinhhhrghrughtuceophhssehpkhhsrdhimheqnecuggftrfgrthhtvg hrnhepheeghfdtfeeuffehkefgffduleffjedthfdvjeektdfhhedvlefgtefgvdettdfh necukfhppeejjedrudekfedrudejrdduuddtnecuvehluhhsthgvrhfuihiivgeptdenuc frrghrrghmpehmrghilhhfrhhomhepphhssehpkhhsrdhimh X-ME-Proxy: Received: from vm-mail (x4db7116e.dyn.telefonica.de [77.183.17.110]) by mail.messagingengine.com (Postfix) with ESMTPA id 7962E1080059; Sun, 6 Dec 2020 14:21:59 -0500 (EST) Received: from localhost (ncase [10.192.0.11]) by vm-mail (OpenSMTPD) with ESMTPSA id 7deff119 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Sun, 6 Dec 2020 19:21:57 +0000 (UTC) Date: Sun, 6 Dec 2020 20:21:55 +0100 From: Patrick Steinhardt To: Glenn Washburn Cc: grub-devel@gnu.org, Daniel Kiper , Daniel Kiper Subject: Re: [PATCH v7 11/17] cryptodisk: Properly handle non-512 byte sized sectors Message-ID: References: <1fe9c38ed3a31716c81581eac6d6d7ce12a2c7d7.1607098915.git.development@efficientek.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ZvW20eCuJEzv1Rom" Content-Disposition: inline In-Reply-To: <1fe9c38ed3a31716c81581eac6d6d7ce12a2c7d7.1607098915.git.development@efficientek.com> Received-SPF: pass client-ip=66.111.4.27; envelope-from=ps@pks.im; helo=out3-smtp.messagingengine.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 06 Dec 2020 19:22:05 -0000 --ZvW20eCuJEzv1Rom Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Dec 04, 2020 at 10:43:40AM -0600, Glenn Washburn wrote: > By default, dm-crypt internally uses an IV that corresponds to 512-byte > sectors, even when a larger sector size is specified. What this means is > that when using a larger sector size, the IV is incremented every sector. > However, the amount the IV is incremented is the number of 512 byte blocks > in a sector (ie 8 for 4K sectors). Confusingly the IV does not corespond = to > the number of, for example, 4K sectors. So each 512 byte cipher block in a > sector will be encrypted with the same IV and the IV will be incremented > afterwards by the number of 512 byte cipher blocks in the sector. >=20 > There are some encryption utilities which do it the intuitive way and have > the IV equal to the sector number regardless of sector size (ie. the fifth > sector would have an IV of 4 for each cipher block). And this is supported > by dm-crypt with the iv_large_sectors option and also cryptsetup as of 2.= 3.3 > with the --iv-large-sectors, though not with LUKS headers (only with --ty= pe > plain). However, support for this has not been included as grub does not > support plain devices right now. >=20 > One gotcha here is that the encrypted split keys are encrypted with a har= d- > coded 512-byte sector size. So even if your data is encrypted with 4K sec= tor > sizes, the split key encrypted area must be decrypted with a block size of > 512 (ie the IV increments every 512 bytes). This made these changes less > aestetically pleasing than desired. >=20 > Reviewed-by: Daniel Kiper > Signed-off-by: Glenn Washburn Reviewed-by: Patrick Steinhardt > --- > grub-core/disk/cryptodisk.c | 55 +++++++++++++++++++++++-------------- > grub-core/disk/luks.c | 5 ++-- > grub-core/disk/luks2.c | 7 ++++- > include/grub/cryptodisk.h | 8 +++++- > 4 files changed, 50 insertions(+), 25 deletions(-) >=20 > diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c > index 5aa0c4720..b62835acc 100644 > --- a/grub-core/disk/cryptodisk.c > +++ b/grub-core/disk/cryptodisk.c > @@ -224,7 +224,8 @@ lrw_xor (const struct lrw_sector *sec, > static gcry_err_code_t > grub_cryptodisk_endecrypt (struct grub_cryptodisk *dev, > grub_uint8_t * data, grub_size_t len, > - grub_disk_addr_t sector, int do_encrypt) > + grub_disk_addr_t sector, grub_size_t log_sector_size, > + int do_encrypt) > { > grub_size_t i; > gcry_err_code_t err; > @@ -237,7 +238,7 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *de= v, > return (do_encrypt ? grub_crypto_ecb_encrypt (dev->cipher, data, dat= a, len) > : grub_crypto_ecb_decrypt (dev->cipher, data, data, len)); > =20 > - for (i =3D 0; i < len; i +=3D (1U << dev->log_sector_size)) > + for (i =3D 0; i < len; i +=3D (1U << log_sector_size)) > { > grub_size_t sz =3D ((dev->cipher->cipher->blocksize > + sizeof (grub_uint32_t) - 1) > @@ -270,7 +271,7 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *de= v, > if (!ctx) > return GPG_ERR_OUT_OF_MEMORY; > =20 > - tmp =3D grub_cpu_to_le64 (sector << dev->log_sector_size); > + tmp =3D grub_cpu_to_le64 (sector << log_sector_size); > dev->iv_hash->init (ctx); > dev->iv_hash->write (ctx, dev->iv_prefix, dev->iv_prefix_len); > dev->iv_hash->write (ctx, &tmp, sizeof (tmp)); > @@ -281,15 +282,27 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *= dev, > } > break; > case GRUB_CRYPTODISK_MODE_IV_PLAIN64: > - iv[1] =3D grub_cpu_to_le32 (sector >> GRUB_TYPE_BITS (iv[0])); > - /* FALLTHROUGH */ > case GRUB_CRYPTODISK_MODE_IV_PLAIN: > - iv[0] =3D grub_cpu_to_le32 (sector & GRUB_TYPE_U_MAX (iv[0])); > + /* > + * The IV is a 32 or 64 bit value of the dm-crypt native sector > + * number. If using 32 bit IV mode, zero out the most significant > + * 32 bits. > + */ > + { > + grub_uint64_t iv64; > + > + iv64 =3D grub_cpu_to_le64 (sector << (log_sector_size > + - GRUB_CRYPTODISK_IV_LOG_SIZE)); > + grub_set_unaligned64 (iv, iv64); > + if (dev->mode_iv =3D=3D GRUB_CRYPTODISK_MODE_IV_PLAIN) > + iv[1] =3D 0; > + } > break; > case GRUB_CRYPTODISK_MODE_IV_BYTECOUNT64: > + /* The IV is the 64 bit byte offset of the sector. */ > iv[1] =3D grub_cpu_to_le32 (sector >> (GRUB_TYPE_BITS (iv[1]) > - - dev->log_sector_size)); > - iv[0] =3D grub_cpu_to_le32 ((sector << dev->log_sector_size) > + - log_sector_size)); > + iv[0] =3D grub_cpu_to_le32 ((sector << log_sector_size) > & GRUB_TYPE_U_MAX (iv[0])); > break; > case GRUB_CRYPTODISK_MODE_IV_BENBI: > @@ -312,10 +325,10 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *= dev, > case GRUB_CRYPTODISK_MODE_CBC: > if (do_encrypt) > err =3D grub_crypto_cbc_encrypt (dev->cipher, data + i, data + i, > - (1U << dev->log_sector_size), iv); > + (1U << log_sector_size), iv); > else > err =3D grub_crypto_cbc_decrypt (dev->cipher, data + i, data + i, > - (1U << dev->log_sector_size), iv); > + (1U << log_sector_size), iv); > if (err) > return err; > break; > @@ -323,10 +336,10 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *= dev, > case GRUB_CRYPTODISK_MODE_PCBC: > if (do_encrypt) > err =3D grub_crypto_pcbc_encrypt (dev->cipher, data + i, data + i, > - (1U << dev->log_sector_size), iv); > + (1U << log_sector_size), iv); > else > err =3D grub_crypto_pcbc_decrypt (dev->cipher, data + i, data + i, > - (1U << dev->log_sector_size), iv); > + (1U << log_sector_size), iv); > if (err) > return err; > break; > @@ -338,7 +351,7 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *de= v, > if (err) > return err; > =20 > - for (j =3D 0; j < (1U << dev->log_sector_size); > + for (j =3D 0; j < (1U << log_sector_size); > j +=3D dev->cipher->cipher->blocksize) > { > grub_crypto_xor (data + i + j, data + i + j, iv, > @@ -369,11 +382,11 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *= dev, > if (do_encrypt) > err =3D grub_crypto_ecb_encrypt (dev->cipher, data + i,=20 > data + i, > - (1U << dev->log_sector_size)); > + (1U << log_sector_size)); > else > err =3D grub_crypto_ecb_decrypt (dev->cipher, data + i,=20 > data + i, > - (1U << dev->log_sector_size)); > + (1U << log_sector_size)); > if (err) > return err; > lrw_xor (&sec, dev, data + i); > @@ -382,10 +395,10 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *= dev, > case GRUB_CRYPTODISK_MODE_ECB: > if (do_encrypt) > err =3D grub_crypto_ecb_encrypt (dev->cipher, data + i, data + i, > - (1U << dev->log_sector_size)); > + (1U << log_sector_size)); > else > err =3D grub_crypto_ecb_decrypt (dev->cipher, data + i, data + i, > - (1U << dev->log_sector_size)); > + (1U << log_sector_size)); > if (err) > return err; > break; > @@ -400,9 +413,9 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *de= v, > gcry_err_code_t > grub_cryptodisk_decrypt (struct grub_cryptodisk *dev, > grub_uint8_t * data, grub_size_t len, > - grub_disk_addr_t sector) > + grub_disk_addr_t sector, grub_size_t log_sector_size) > { > - return grub_cryptodisk_endecrypt (dev, data, len, sector, 0); > + return grub_cryptodisk_endecrypt (dev, data, len, sector, log_sector_s= ize, 0); > } > =20 > grub_err_t > @@ -767,7 +780,7 @@ grub_cryptodisk_read (grub_disk_t disk, grub_disk_add= r_t sector, > } > gcry_err =3D grub_cryptodisk_endecrypt (dev, (grub_uint8_t *) buf, > size << disk->log_sector_size, > - sector, 0); > + sector, dev->log_sector_size, 0); > return grub_crypto_gcry_error (gcry_err); > } > =20 > @@ -808,7 +821,7 @@ grub_cryptodisk_write (grub_disk_t disk, grub_disk_ad= dr_t sector, > =20 > gcry_err =3D grub_cryptodisk_endecrypt (dev, (grub_uint8_t *) tmp, > size << disk->log_sector_size, > - sector, 1); > + sector, disk->log_sector_size, 1); > if (gcry_err) > { > grub_free (tmp); > diff --git a/grub-core/disk/luks.c b/grub-core/disk/luks.c > index 5fc79d880..13103ea6a 100644 > --- a/grub-core/disk/luks.c > +++ b/grub-core/disk/luks.c > @@ -124,7 +124,7 @@ configure_ciphers (grub_disk_t disk, const char *chec= k_uuid, > return NULL; > newdev->offset_sectors =3D grub_be_to_cpu32 (header.payloadOffset); > newdev->source_disk =3D NULL; > - newdev->log_sector_size =3D 9; > + newdev->log_sector_size =3D GRUB_LUKS1_LOG_SECTOR_SIZE; > newdev->total_sectors =3D grub_disk_native_sectors (disk) - newdev->of= fset_sectors; > grub_memcpy (newdev->uuid, uuid, sizeof (uuid)); > newdev->modname =3D "luks"; > @@ -247,7 +247,8 @@ luks_recover_key (grub_disk_t source, > return err; > } > =20 > - gcry_err =3D grub_cryptodisk_decrypt (dev, split_key, length, 0); > + gcry_err =3D grub_cryptodisk_decrypt (dev, split_key, length, 0, > + GRUB_LUKS1_LOG_SECTOR_SIZE); > if (gcry_err) > { > grub_free (split_key); > diff --git a/grub-core/disk/luks2.c b/grub-core/disk/luks2.c > index bdf40768b..de2e70796 100644 > --- a/grub-core/disk/luks2.c > +++ b/grub-core/disk/luks2.c > @@ -504,7 +504,12 @@ luks2_decrypt_key (grub_uint8_t *out_key, > goto err; > } > =20 > - gcry_ret =3D grub_cryptodisk_decrypt (crypt, split_key, k->area.size, = 0); > + /* > + * The key slots area is always encrypted in 512-byte sectors, > + * regardless of encrypted data sector size. > + */ > + gcry_ret =3D grub_cryptodisk_decrypt (crypt, split_key, k->area.size, = 0, > + GRUB_LUKS1_LOG_SECTOR_SIZE); > if (gcry_ret) > { > ret =3D grub_crypto_gcry_error (gcry_ret); > diff --git a/include/grub/cryptodisk.h b/include/grub/cryptodisk.h > index c9bf7597a..938912cf3 100644 > --- a/include/grub/cryptodisk.h > +++ b/include/grub/cryptodisk.h > @@ -48,6 +48,12 @@ typedef enum > =20 > #define GRUB_CRYPTODISK_MAX_UUID_LENGTH 71 > =20 > +/* LUKS1 specification defines the block size to always be 512 bytes. */ > +#define GRUB_LUKS1_LOG_SECTOR_SIZE 9 > + > +/* By default dm-crypt increments the IV every 512 bytes. */ > +#define GRUB_CRYPTODISK_IV_LOG_SIZE 9 > + > #define GRUB_CRYPTODISK_GF_LOG_SIZE 7 > #define GRUB_CRYPTODISK_GF_SIZE (1U << GRUB_CRYPTODISK_GF_LOG_SIZE) > #define GRUB_CRYPTODISK_GF_LOG_BYTES (GRUB_CRYPTODISK_GF_LOG_SIZE - 3) > @@ -144,7 +150,7 @@ grub_cryptodisk_setkey (grub_cryptodisk_t dev, > gcry_err_code_t > grub_cryptodisk_decrypt (struct grub_cryptodisk *dev, > grub_uint8_t * data, grub_size_t len, > - grub_disk_addr_t sector); > + grub_disk_addr_t sector, grub_size_t log_sector_size); > grub_err_t > grub_cryptodisk_insert (grub_cryptodisk_t newdev, const char *name, > grub_disk_t source); > --=20 > 2.27.0 >=20 --ZvW20eCuJEzv1Rom Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEF9hrgiFbCdvenl/rVbJhu7ckPpQFAl/NL1MACgkQVbJhu7ck PpSYQxAArmwgTz9TtuYKO/O95CsfD7QotAK4HmWUYD22G+Z+o6hY4gbX1N3lFcZ6 Fag90jxmDrCbUNrt5Ft6a7K6CIoniYMcpBftIpuDW9uk+DK+m3w1Qxc0ZBwf/2zv z9LtR5GLFPHW/bLiggpsFCYz36Sbpc8IVtxcbNCxfwVJpzMj9r7N7j7QZQYYgZNL AphVpdndV7wiO1wzMxo+yGrMpn2C4vyUn7+FHpM2oNPWP826ZpCLbz3RuX1PUYWD L9KYg1asGDO6y5mMx47i9uAJaA9t8XrVePEw2mLBTMcRLWIbEK+qM68pGOnLdqaA zbTW/P43Hn8WZCNvz3qmmnXlU6iMM3AW2vMvfsBdNQghco7YGKocPa2TIN1061R7 C1dnIWpHyOZo3FOw/jpWA4fUfX6qTuGqYu2XdoHIfSbgpxGV2zW2Bd1mmJscDHCe BgwVYq8PT0YQEQKwsfSb80mPRBuZIfzXP5LWjTvog2zDxBUjW0xO6glG+o2KHTbq kA+s40nE5jRMYub9JZ9q4VrPAefSwthvDLNv8wZDL+j332ySdjvZMaTFeccHwCut DKXHNH7Pyitl/XS6+dDXDE2MNBmVU8BUYMX6/X6KNekUxKsFK5ALcbglcgpwoi7s chBJ5vICcJegvmLDO5auPbiWH+Qu2FnCCjFEUTks1drXpMfBi7Y= =c4zn -----END PGP SIGNATURE----- --ZvW20eCuJEzv1Rom--