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[96.50.97.138]) by mx.google.com with ESMTPSA id c2sm6945161pds.32.2014.09.02.15.33.07 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 02 Sep 2014 15:33:08 -0700 (PDT) From: behanw@converseincode.com 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 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 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> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1409697153-7006-1-git-send-email-behanw@converseincode.com> References: <1409697153-7006-1-git-send-email-behanw@converseincode.com> MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-8.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Jan-Simon Möller The use of variable length arrays in structs (VLAIS) in the Linux Kernel code precludes the use of compilers which don't implement VLAIS (for instance 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 can 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 Möller 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 = &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 = (struct shash_desc *)sdesc; struct md5_state md5state; __le32 buf[4]; int i, r; - sdesc.desc.tfm = lmk->hash_tfm; - sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; + desc->tfm = lmk->hash_tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; - r = crypto_shash_init(&sdesc.desc); + r = crypto_shash_init(desc); if (r) return r; if (lmk->seed) { - r = crypto_shash_update(&sdesc.desc, lmk->seed, LMK_SEED_SIZE); + r = crypto_shash_update(desc, lmk->seed, LMK_SEED_SIZE); if (r) return r; } /* Sector is always 512B, block size 16, add data of blocks 1-31 */ - r = crypto_shash_update(&sdesc.desc, data + 16, 16 * 31); + r = crypto_shash_update(desc, data + 16, 16 * 31); if (r) return r; @@ -557,12 +556,12 @@ static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv, buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000); buf[2] = cpu_to_le32(4024); buf[3] = 0; - r = crypto_shash_update(&sdesc.desc, (u8 *)buf, sizeof(buf)); + r = crypto_shash_update(desc, (u8 *)buf, sizeof(buf)); if (r) return r; /* No MD5 padding here */ - r = crypto_shash_export(&sdesc.desc, &md5state); + r = crypto_shash_export(desc, &md5state); if (r) return r; @@ -679,10 +678,9 @@ static int crypt_iv_tcw_whitening(struct crypt_config *cc, struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; u64 sector = 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 = (struct shash_desc *)sdesc; int i, r; /* xor whitening with sector number */ @@ -691,16 +689,16 @@ static int crypt_iv_tcw_whitening(struct crypt_config *cc, crypto_xor(&buf[8], (u8 *)§or, 8); /* calculate crc32 for every 32bit part and xor it */ - sdesc.desc.tfm = tcw->crc32_tfm; - sdesc.desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; + desc->tfm = tcw->crc32_tfm; + desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; for (i = 0; i < 4; i++) { - r = crypto_shash_init(&sdesc.desc); + r = crypto_shash_init(desc); if (r) goto out; - r = crypto_shash_update(&sdesc.desc, &buf[i * 4], 4); + r = crypto_shash_update(desc, &buf[i * 4], 4); if (r) goto out; - r = crypto_shash_final(&sdesc.desc, &buf[i * 4]); + r = crypto_shash_final(desc, &buf[i * 4]); if (r) goto out; }