From: Jussi Kivilinna Subject: [PATCH 1/4] crypto: gcm - make GMAC work when dst and src are different Date: Sun, 07 Apr 2013 16:43:41 +0300 Message-ID: <20130407134340.8718.96643.stgit@localhost6.localdomain6> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Herbert Xu , "David S. Miller" To: linux-crypto@vger.kernel.org Return-path: Received: from sd-mail-sa-01.sanoma.fi ([158.127.18.161]:53067 "EHLO sd-mail-sa-01.sanoma.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933606Ab3DGNno (ORCPT ); Sun, 7 Apr 2013 09:43:44 -0400 Sender: linux-crypto-owner@vger.kernel.org List-ID: The GMAC code assumes that dst==src, which causes problems when trying to add rfc4543(gcm(aes)) test vectors. So fix this code to work when source and destination buffer are different. Signed-off-by: Jussi Kivilinna --- crypto/Kconfig | 1 + crypto/gcm.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++---------- 2 files changed, 81 insertions(+), 17 deletions(-) diff --git a/crypto/Kconfig b/crypto/Kconfig index a654b13..6cc27f1 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -198,6 +198,7 @@ config CRYPTO_GCM select CRYPTO_CTR select CRYPTO_AEAD select CRYPTO_GHASH + select CRYPTO_NULL help Support for Galois/Counter Mode (GCM) and Galois Message Authentication Code (GMAC). Required for IPSec. diff --git a/crypto/gcm.c b/crypto/gcm.c index 137ad1e..4ff2139 100644 --- a/crypto/gcm.c +++ b/crypto/gcm.c @@ -37,8 +37,14 @@ struct crypto_rfc4106_ctx { u8 nonce[4]; }; +struct crypto_rfc4543_instance_ctx { + struct crypto_aead_spawn aead; + struct crypto_skcipher_spawn null; +}; + struct crypto_rfc4543_ctx { struct crypto_aead *child; + struct crypto_blkcipher *null; u8 nonce[4]; }; @@ -1094,20 +1100,20 @@ static int crypto_rfc4543_setauthsize(struct crypto_aead *parent, } static struct aead_request *crypto_rfc4543_crypt(struct aead_request *req, - int enc) + bool enc) { struct crypto_aead *aead = crypto_aead_reqtfm(req); struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(aead); struct crypto_rfc4543_req_ctx *rctx = crypto_rfc4543_reqctx(req); struct aead_request *subreq = &rctx->subreq; - struct scatterlist *dst = req->dst; + struct scatterlist *src = req->src; struct scatterlist *cipher = rctx->cipher; struct scatterlist *payload = rctx->payload; struct scatterlist *assoc = rctx->assoc; unsigned int authsize = crypto_aead_authsize(aead); unsigned int assoclen = req->assoclen; - struct page *dstp; - u8 *vdst; + struct page *srcp; + u8 *vsrc; u8 *iv = PTR_ALIGN((u8 *)(rctx + 1) + crypto_aead_reqsize(ctx->child), crypto_aead_alignmask(ctx->child) + 1); @@ -1118,19 +1124,19 @@ static struct aead_request *crypto_rfc4543_crypt(struct aead_request *req, if (enc) memset(rctx->auth_tag, 0, authsize); else - scatterwalk_map_and_copy(rctx->auth_tag, dst, + scatterwalk_map_and_copy(rctx->auth_tag, src, req->cryptlen - authsize, authsize, 0); sg_init_one(cipher, rctx->auth_tag, authsize); /* construct the aad */ - dstp = sg_page(dst); - vdst = PageHighMem(dstp) ? NULL : page_address(dstp) + dst->offset; + srcp = sg_page(src); + vsrc = PageHighMem(srcp) ? NULL : page_address(srcp) + src->offset; sg_init_table(payload, 2); sg_set_buf(payload, req->iv, 8); - scatterwalk_crypto_chain(payload, dst, vdst == req->iv + 8, 2); + scatterwalk_crypto_chain(payload, src, vsrc == req->iv + 8, 2); assoclen += 8 + req->cryptlen - (enc ? 0 : authsize); sg_init_table(assoc, 2); @@ -1147,6 +1153,19 @@ static struct aead_request *crypto_rfc4543_crypt(struct aead_request *req, return subreq; } +static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc) +{ + struct crypto_aead *aead = crypto_aead_reqtfm(req); + struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(aead); + unsigned int authsize = crypto_aead_authsize(aead); + unsigned int nbytes = req->cryptlen - (enc ? 0 : authsize); + struct blkcipher_desc desc = { + .tfm = ctx->null, + }; + + return crypto_blkcipher_encrypt(&desc, req->dst, req->src, nbytes); +} + static int crypto_rfc4543_encrypt(struct aead_request *req) { struct crypto_aead *aead = crypto_aead_reqtfm(req); @@ -1154,7 +1173,13 @@ static int crypto_rfc4543_encrypt(struct aead_request *req) struct aead_request *subreq; int err; - subreq = crypto_rfc4543_crypt(req, 1); + if (req->src != req->dst) { + err = crypto_rfc4543_copy_src_to_dst(req, true); + if (err) + return err; + } + + subreq = crypto_rfc4543_crypt(req, true); err = crypto_aead_encrypt(subreq); if (err) return err; @@ -1167,7 +1192,15 @@ static int crypto_rfc4543_encrypt(struct aead_request *req) static int crypto_rfc4543_decrypt(struct aead_request *req) { - req = crypto_rfc4543_crypt(req, 0); + int err; + + if (req->src != req->dst) { + err = crypto_rfc4543_copy_src_to_dst(req, false); + if (err) + return err; + } + + req = crypto_rfc4543_crypt(req, false); return crypto_aead_decrypt(req); } @@ -1175,16 +1208,25 @@ static int crypto_rfc4543_decrypt(struct aead_request *req) static int crypto_rfc4543_init_tfm(struct crypto_tfm *tfm) { struct crypto_instance *inst = (void *)tfm->__crt_alg; - struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst); + struct crypto_rfc4543_instance_ctx *ictx = crypto_instance_ctx(inst); + struct crypto_aead_spawn *spawn = &ictx->aead; struct crypto_rfc4543_ctx *ctx = crypto_tfm_ctx(tfm); struct crypto_aead *aead; + struct crypto_blkcipher *null; unsigned long align; + int err = 0; aead = crypto_spawn_aead(spawn); if (IS_ERR(aead)) return PTR_ERR(aead); + null = crypto_spawn_blkcipher(&ictx->null.base); + err = PTR_ERR(null); + if (IS_ERR(null)) + goto err_free_aead; + ctx->child = aead; + ctx->null = null; align = crypto_aead_alignmask(aead); align &= ~(crypto_tfm_ctx_alignment() - 1); @@ -1194,6 +1236,10 @@ static int crypto_rfc4543_init_tfm(struct crypto_tfm *tfm) align + 16; return 0; + +err_free_aead: + crypto_free_aead(aead); + return err; } static void crypto_rfc4543_exit_tfm(struct crypto_tfm *tfm) @@ -1201,6 +1247,7 @@ static void crypto_rfc4543_exit_tfm(struct crypto_tfm *tfm) struct crypto_rfc4543_ctx *ctx = crypto_tfm_ctx(tfm); crypto_free_aead(ctx->child); + crypto_free_blkcipher(ctx->null); } static struct crypto_instance *crypto_rfc4543_alloc(struct rtattr **tb) @@ -1209,6 +1256,7 @@ static struct crypto_instance *crypto_rfc4543_alloc(struct rtattr **tb) struct crypto_instance *inst; struct crypto_aead_spawn *spawn; struct crypto_alg *alg; + struct crypto_rfc4543_instance_ctx *ctx; const char *ccm_name; int err; @@ -1223,11 +1271,12 @@ static struct crypto_instance *crypto_rfc4543_alloc(struct rtattr **tb) if (IS_ERR(ccm_name)) return ERR_CAST(ccm_name); - inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL); + inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); if (!inst) return ERR_PTR(-ENOMEM); - spawn = crypto_instance_ctx(inst); + ctx = crypto_instance_ctx(inst); + spawn = &ctx->aead; crypto_set_aead_spawn(spawn, inst); err = crypto_grab_aead(spawn, ccm_name, 0, crypto_requires_sync(algt->type, algt->mask)); @@ -1236,15 +1285,23 @@ static struct crypto_instance *crypto_rfc4543_alloc(struct rtattr **tb) alg = crypto_aead_spawn_alg(spawn); + crypto_set_skcipher_spawn(&ctx->null, inst); + err = crypto_grab_skcipher(&ctx->null, "ecb(cipher_null)", 0, + CRYPTO_ALG_ASYNC); + if (err) + goto out_drop_alg; + + crypto_skcipher_spawn_alg(&ctx->null); + err = -EINVAL; /* We only support 16-byte blocks. */ if (alg->cra_aead.ivsize != 16) - goto out_drop_alg; + goto out_drop_ecbnull; /* Not a stream cipher? */ if (alg->cra_blocksize != 1) - goto out_drop_alg; + goto out_drop_ecbnull; err = -ENAMETOOLONG; if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, @@ -1252,7 +1309,7 @@ static struct crypto_instance *crypto_rfc4543_alloc(struct rtattr **tb) snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, "rfc4543(%s)", alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME) - goto out_drop_alg; + goto out_drop_ecbnull; inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD; inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC; @@ -1279,6 +1336,8 @@ static struct crypto_instance *crypto_rfc4543_alloc(struct rtattr **tb) out: return inst; +out_drop_ecbnull: + crypto_drop_skcipher(&ctx->null); out_drop_alg: crypto_drop_aead(spawn); out_free_inst: @@ -1289,7 +1348,11 @@ out_free_inst: static void crypto_rfc4543_free(struct crypto_instance *inst) { - crypto_drop_spawn(crypto_instance_ctx(inst)); + struct crypto_rfc4543_instance_ctx *ctx = crypto_instance_ctx(inst); + + crypto_drop_aead(&ctx->aead); + crypto_drop_skcipher(&ctx->null); + kfree(inst); }