From: behanw@converseincode.com Subject: [PATCH RFC 1/6] crypto, dm: LLVMLinux: Remove VLAIS usage from dm-crypt Date: Tue, 2 Sep 2014 15:32:28 -0700 Message-ID: <1409697153-7006-2-git-send-email-behanw@converseincode.com> References: <1409697153-7006-1-git-send-email-behanw@converseincode.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: akpm@linux-foundation.org, james.l.morris@oracle.com, john.johansen@canonical.com, linux-btrfs@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, linux-security-module@vger.kernel.org, neilb@suse.de, serge@hallyn.com, torvalds@linux-foundation.org, =?UTF-8?q?Jan-Simon=20M=C3=B6ller?= , Behan Webster , pageexec@freemail.hu To: agk@redhat.com, clm@fb.com, davem@davemloft.net, dm-devel@redhat.com, fabf@skynet.be, herbert@gondor.apana.org.au, jbacik@fb.com, snitzer@redhat.com Return-path: In-Reply-To: <1409697153-7006-1-git-send-email-behanw@converseincode.com> Sender: linux-btrfs-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org =46rom: Jan-Simon M=C3=B6ller The use of variable length arrays in structs (VLAIS) in the Linux Kerne= l code precludes the use of compilers which don't implement VLAIS (for instanc= e the Clang compiler). This patch instead allocates the appropriate amount of= memory using an char array. struct shash_desc contains a flexible array member member ctx declared = with CRYPTO_MINALIGN_ATTR, so sizeof(struct shash_desc) aligns the beginning of the array declared after struct shash_desc with long long. No trailing padding is required because it is not a struct type that ca= n be used in an array. The CRYPTO_MINALIGN_ATTR is required so that desc is aligned with long = long as would be the case for a struct containing a member with CRYPTO_MINALIGN_ATTR. Signed-off-by: Jan-Simon M=C3=B6ller Signed-off-by: Behan Webster Cc: pageexec@freemail.hu --- drivers/md/dm-crypt.c | 38 ++++++++++++++++++-------------------- 1 file changed, 18 insertions(+), 20 deletions(-) diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index cd15e08..4d940d3 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -526,29 +526,28 @@ static int crypt_iv_lmk_one(struct crypt_config *= cc, u8 *iv, u8 *data) { struct iv_lmk_private *lmk =3D &cc->iv_gen_private.lmk; - struct { - struct shash_desc desc; - char ctx[crypto_shash_descsize(lmk->hash_tfm)]; - } sdesc; + char sdesc[sizeof(struct shash_desc) + + crypto_shash_descsize(lmk->hash_tfm)] CRYPTO_MINALIGN_ATTR; + struct shash_desc *desc =3D (struct shash_desc *)sdesc; struct md5_state md5state; __le32 buf[4]; int i, r; =20 - sdesc.desc.tfm =3D lmk->hash_tfm; - sdesc.desc.flags =3D CRYPTO_TFM_REQ_MAY_SLEEP; + desc->tfm =3D lmk->hash_tfm; + desc->flags =3D CRYPTO_TFM_REQ_MAY_SLEEP; =20 - r =3D crypto_shash_init(&sdesc.desc); + r =3D crypto_shash_init(desc); if (r) return r; =20 if (lmk->seed) { - r =3D crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE); + r =3D crypto_shash_update(desc, lmk->seed, LMK_SEED_SIZE); if (r) return r; } =20 /* Sector is always 512B, block size 16, add data of blocks 1-31 */ - r =3D crypto_shash_update(&sdesc.desc, data + 16, 16 * 31); + r =3D crypto_shash_update(desc, data + 16, 16 * 31); if (r) return r; =20 @@ -557,12 +556,12 @@ static int crypt_iv_lmk_one(struct crypt_config *= cc, u8 *iv, buf[1] =3D cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) |= 0x80000000); buf[2] =3D cpu_to_le32(4024); buf[3] =3D 0; - r =3D crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf)); + r =3D crypto_shash_update(desc, (u8 *)buf, sizeof(buf)); if (r) return r; =20 /* No MD5 padding here */ - r =3D crypto_shash_export(&sdesc.desc, &md5state); + r =3D crypto_shash_export(desc, &md5state); if (r) return r; =20 @@ -679,10 +678,9 @@ static int crypt_iv_tcw_whitening(struct crypt_con= fig *cc, struct iv_tcw_private *tcw =3D &cc->iv_gen_private.tcw; u64 sector =3D cpu_to_le64((u64)dmreq->iv_sector); u8 buf[TCW_WHITENING_SIZE]; - struct { - struct shash_desc desc; - char ctx[crypto_shash_descsize(tcw->crc32_tfm)]; - } sdesc; + char sdesc[sizeof(struct shash_desc) + + crypto_shash_descsize(tcw->crc32_tfm)] CRYPTO_MINALIGN_ATTR; + struct shash_desc *desc =3D (struct shash_desc *)sdesc; int i, r; =20 /* xor whitening with sector number */ @@ -691,16 +689,16 @@ static int crypt_iv_tcw_whitening(struct crypt_co= nfig *cc, crypto_xor(&buf[8], (u8 *)§or, 8); =20 /* calculate crc32 for every 32bit part and xor it */ - sdesc.desc.tfm =3D tcw->crc32_tfm; - sdesc.desc.flags =3D CRYPTO_TFM_REQ_MAY_SLEEP; + desc->tfm =3D tcw->crc32_tfm; + desc->flags =3D CRYPTO_TFM_REQ_MAY_SLEEP; for (i =3D 0; i < 4; i++) { - r =3D crypto_shash_init(&sdesc.desc); + r =3D crypto_shash_init(desc); if (r) goto out; - r =3D crypto_shash_update(&sdesc.desc, &buf[i * 4], 4); + r =3D crypto_shash_update(desc, &buf[i * 4], 4); if (r) goto out; - r =3D crypto_shash_final(&sdesc.desc, &buf[i * 4]); + r =3D crypto_shash_final(desc, &buf[i * 4]); if (r) goto out; } --=20 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html