Revision - ba91c49 - sch_cake: Fix out of bounds when parsing TCP options and header

Revision ba91c49dedbde758ba0b72f57ac90b06ddf8e548 authored by Maxim Mikityanskiy on 10 June 2021, 16:40:31 UTC, committed by David S. Miller on 10 June 2021, 21:26:18 UTC

sch_cake: Fix out of bounds when parsing TCP options and header

The TCP option parser in cake qdisc (cake_get_tcpopt and
cake_tcph_may_drop) could read one byte out of bounds. When the length
is 1, the execution flow gets into the loop, reads one byte of the
opcode, and if the opcode is neither TCPOPT_EOL nor TCPOPT_NOP, it reads
one more byte, which exceeds the length of 1.

This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack
out of bounds when parsing TCP options.").

v2 changes:

Added doff validation in cake_get_tcphdr to avoid parsing garbage as TCP
header. Although it wasn't strictly an out-of-bounds access (memory was
allocated), garbage values could be read where CAKE expected the TCP
header if doff was smaller than 5.

Cc: Young Xiao <92siuyang@gmail.com>
Fixes: 8b7138814f29 ("sch_cake: Add optional ACK filter")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 parent 07718be

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gcm.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * GCM: Galois/Counter Mode.
 *
 * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
 */

#include <crypto/gf128mul.h>
#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/internal/hash.h>
#include <crypto/null.h>
#include <crypto/scatterwalk.h>
#include <crypto/gcm.h>
#include <crypto/hash.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>

struct gcm_instance_ctx {
	struct crypto_skcipher_spawn ctr;
	struct crypto_ahash_spawn ghash;
};

struct crypto_gcm_ctx {
	struct crypto_skcipher *ctr;
	struct crypto_ahash *ghash;
};

struct crypto_rfc4106_ctx {
	struct crypto_aead *child;
	u8 nonce[4];
};

struct crypto_rfc4106_req_ctx {
	struct scatterlist src[3];
	struct scatterlist dst[3];
	struct aead_request subreq;
};

struct crypto_rfc4543_instance_ctx {
	struct crypto_aead_spawn aead;
};

struct crypto_rfc4543_ctx {
	struct crypto_aead *child;
	struct crypto_sync_skcipher *null;
	u8 nonce[4];
};

struct crypto_rfc4543_req_ctx {
	struct aead_request subreq;
};

struct crypto_gcm_ghash_ctx {
	unsigned int cryptlen;
	struct scatterlist *src;
	int (*complete)(struct aead_request *req, u32 flags);
};

struct crypto_gcm_req_priv_ctx {
	u8 iv[16];
	u8 auth_tag[16];
	u8 iauth_tag[16];
	struct scatterlist src[3];
	struct scatterlist dst[3];
	struct scatterlist sg;
	struct crypto_gcm_ghash_ctx ghash_ctx;
	union {
		struct ahash_request ahreq;
		struct skcipher_request skreq;
	} u;
};

static struct {
	u8 buf[16];
	struct scatterlist sg;
} *gcm_zeroes;

static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc);

static inline struct crypto_gcm_req_priv_ctx *crypto_gcm_reqctx(
	struct aead_request *req)
{
	unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));

	return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
}

static int crypto_gcm_setkey(struct crypto_aead *aead, const u8 *key,
			     unsigned int keylen)
{
	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
	struct crypto_ahash *ghash = ctx->ghash;
	struct crypto_skcipher *ctr = ctx->ctr;
	struct {
		be128 hash;
		u8 iv[16];

		struct crypto_wait wait;

		struct scatterlist sg[1];
		struct skcipher_request req;
	} *data;
	int err;

	crypto_skcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
	crypto_skcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
				       CRYPTO_TFM_REQ_MASK);
	err = crypto_skcipher_setkey(ctr, key, keylen);
	if (err)
		return err;

	data = kzalloc(sizeof(*data) + crypto_skcipher_reqsize(ctr),
		       GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	crypto_init_wait(&data->wait);
	sg_init_one(data->sg, &data->hash, sizeof(data->hash));
	skcipher_request_set_tfm(&data->req, ctr);
	skcipher_request_set_callback(&data->req, CRYPTO_TFM_REQ_MAY_SLEEP |
						  CRYPTO_TFM_REQ_MAY_BACKLOG,
				      crypto_req_done,
				      &data->wait);
	skcipher_request_set_crypt(&data->req, data->sg, data->sg,
				   sizeof(data->hash), data->iv);

	err = crypto_wait_req(crypto_skcipher_encrypt(&data->req),
							&data->wait);

	if (err)
		goto out;

	crypto_ahash_clear_flags(ghash, CRYPTO_TFM_REQ_MASK);
	crypto_ahash_set_flags(ghash, crypto_aead_get_flags(aead) &
			       CRYPTO_TFM_REQ_MASK);
	err = crypto_ahash_setkey(ghash, (u8 *)&data->hash, sizeof(be128));
out:
	kfree_sensitive(data);
	return err;
}

static int crypto_gcm_setauthsize(struct crypto_aead *tfm,
				  unsigned int authsize)
{
	return crypto_gcm_check_authsize(authsize);
}

static void crypto_gcm_init_common(struct aead_request *req)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	__be32 counter = cpu_to_be32(1);
	struct scatterlist *sg;

	memset(pctx->auth_tag, 0, sizeof(pctx->auth_tag));
	memcpy(pctx->iv, req->iv, GCM_AES_IV_SIZE);
	memcpy(pctx->iv + GCM_AES_IV_SIZE, &counter, 4);

	sg_init_table(pctx->src, 3);
	sg_set_buf(pctx->src, pctx->auth_tag, sizeof(pctx->auth_tag));
	sg = scatterwalk_ffwd(pctx->src + 1, req->src, req->assoclen);
	if (sg != pctx->src + 1)
		sg_chain(pctx->src, 2, sg);

	if (req->src != req->dst) {
		sg_init_table(pctx->dst, 3);
		sg_set_buf(pctx->dst, pctx->auth_tag, sizeof(pctx->auth_tag));
		sg = scatterwalk_ffwd(pctx->dst + 1, req->dst, req->assoclen);
		if (sg != pctx->dst + 1)
			sg_chain(pctx->dst, 2, sg);
	}
}

static void crypto_gcm_init_crypt(struct aead_request *req,
				  unsigned int cryptlen)
{
	struct crypto_aead *aead = crypto_aead_reqtfm(req);
	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct skcipher_request *skreq = &pctx->u.skreq;
	struct scatterlist *dst;

	dst = req->src == req->dst ? pctx->src : pctx->dst;

	skcipher_request_set_tfm(skreq, ctx->ctr);
	skcipher_request_set_crypt(skreq, pctx->src, dst,
				     cryptlen + sizeof(pctx->auth_tag),
				     pctx->iv);
}

static inline unsigned int gcm_remain(unsigned int len)
{
	len &= 0xfU;
	return len ? 16 - len : 0;
}

static void gcm_hash_len_done(struct crypto_async_request *areq, int err);

static int gcm_hash_update(struct aead_request *req,
			   crypto_completion_t compl,
			   struct scatterlist *src,
			   unsigned int len, u32 flags)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct ahash_request *ahreq = &pctx->u.ahreq;

	ahash_request_set_callback(ahreq, flags, compl, req);
	ahash_request_set_crypt(ahreq, src, NULL, len);

	return crypto_ahash_update(ahreq);
}

static int gcm_hash_remain(struct aead_request *req,
			   unsigned int remain,
			   crypto_completion_t compl, u32 flags)
{
	return gcm_hash_update(req, compl, &gcm_zeroes->sg, remain, flags);
}

static int gcm_hash_len(struct aead_request *req, u32 flags)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct ahash_request *ahreq = &pctx->u.ahreq;
	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
	be128 lengths;

	lengths.a = cpu_to_be64(req->assoclen * 8);
	lengths.b = cpu_to_be64(gctx->cryptlen * 8);
	memcpy(pctx->iauth_tag, &lengths, 16);
	sg_init_one(&pctx->sg, pctx->iauth_tag, 16);
	ahash_request_set_callback(ahreq, flags, gcm_hash_len_done, req);
	ahash_request_set_crypt(ahreq, &pctx->sg,
				pctx->iauth_tag, sizeof(lengths));

	return crypto_ahash_finup(ahreq);
}

static int gcm_hash_len_continue(struct aead_request *req, u32 flags)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;

	return gctx->complete(req, flags);
}

static void gcm_hash_len_done(struct crypto_async_request *areq, int err)
{
	struct aead_request *req = areq->data;

	if (err)
		goto out;

	err = gcm_hash_len_continue(req, 0);
	if (err == -EINPROGRESS)
		return;

out:
	aead_request_complete(req, err);
}

static int gcm_hash_crypt_remain_continue(struct aead_request *req, u32 flags)
{
	return gcm_hash_len(req, flags) ?:
	       gcm_hash_len_continue(req, flags);
}

static void gcm_hash_crypt_remain_done(struct crypto_async_request *areq,
				       int err)
{
	struct aead_request *req = areq->data;

	if (err)
		goto out;

	err = gcm_hash_crypt_remain_continue(req, 0);
	if (err == -EINPROGRESS)
		return;

out:
	aead_request_complete(req, err);
}

static int gcm_hash_crypt_continue(struct aead_request *req, u32 flags)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
	unsigned int remain;

	remain = gcm_remain(gctx->cryptlen);
	if (remain)
		return gcm_hash_remain(req, remain,
				       gcm_hash_crypt_remain_done, flags) ?:
		       gcm_hash_crypt_remain_continue(req, flags);

	return gcm_hash_crypt_remain_continue(req, flags);
}

static void gcm_hash_crypt_done(struct crypto_async_request *areq, int err)
{
	struct aead_request *req = areq->data;

	if (err)
		goto out;

	err = gcm_hash_crypt_continue(req, 0);
	if (err == -EINPROGRESS)
		return;

out:
	aead_request_complete(req, err);
}

static int gcm_hash_assoc_remain_continue(struct aead_request *req, u32 flags)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;

	if (gctx->cryptlen)
		return gcm_hash_update(req, gcm_hash_crypt_done,
				       gctx->src, gctx->cryptlen, flags) ?:
		       gcm_hash_crypt_continue(req, flags);

	return gcm_hash_crypt_remain_continue(req, flags);
}

static void gcm_hash_assoc_remain_done(struct crypto_async_request *areq,
				       int err)
{
	struct aead_request *req = areq->data;

	if (err)
		goto out;

	err = gcm_hash_assoc_remain_continue(req, 0);
	if (err == -EINPROGRESS)
		return;

out:
	aead_request_complete(req, err);
}

static int gcm_hash_assoc_continue(struct aead_request *req, u32 flags)
{
	unsigned int remain;

	remain = gcm_remain(req->assoclen);
	if (remain)
		return gcm_hash_remain(req, remain,
				       gcm_hash_assoc_remain_done, flags) ?:
		       gcm_hash_assoc_remain_continue(req, flags);

	return gcm_hash_assoc_remain_continue(req, flags);
}

static void gcm_hash_assoc_done(struct crypto_async_request *areq, int err)
{
	struct aead_request *req = areq->data;

	if (err)
		goto out;

	err = gcm_hash_assoc_continue(req, 0);
	if (err == -EINPROGRESS)
		return;

out:
	aead_request_complete(req, err);
}

static int gcm_hash_init_continue(struct aead_request *req, u32 flags)
{
	if (req->assoclen)
		return gcm_hash_update(req, gcm_hash_assoc_done,
				       req->src, req->assoclen, flags) ?:
		       gcm_hash_assoc_continue(req, flags);

	return gcm_hash_assoc_remain_continue(req, flags);
}

static void gcm_hash_init_done(struct crypto_async_request *areq, int err)
{
	struct aead_request *req = areq->data;

	if (err)
		goto out;

	err = gcm_hash_init_continue(req, 0);
	if (err == -EINPROGRESS)
		return;

out:
	aead_request_complete(req, err);
}

static int gcm_hash(struct aead_request *req, u32 flags)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct ahash_request *ahreq = &pctx->u.ahreq;
	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));

	ahash_request_set_tfm(ahreq, ctx->ghash);

	ahash_request_set_callback(ahreq, flags, gcm_hash_init_done, req);
	return crypto_ahash_init(ahreq) ?:
	       gcm_hash_init_continue(req, flags);
}

static int gcm_enc_copy_hash(struct aead_request *req, u32 flags)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct crypto_aead *aead = crypto_aead_reqtfm(req);
	u8 *auth_tag = pctx->auth_tag;

	crypto_xor(auth_tag, pctx->iauth_tag, 16);
	scatterwalk_map_and_copy(auth_tag, req->dst,
				 req->assoclen + req->cryptlen,
				 crypto_aead_authsize(aead), 1);
	return 0;
}

static int gcm_encrypt_continue(struct aead_request *req, u32 flags)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;

	gctx->src = sg_next(req->src == req->dst ? pctx->src : pctx->dst);
	gctx->cryptlen = req->cryptlen;
	gctx->complete = gcm_enc_copy_hash;

	return gcm_hash(req, flags);
}

static void gcm_encrypt_done(struct crypto_async_request *areq, int err)
{
	struct aead_request *req = areq->data;

	if (err)
		goto out;

	err = gcm_encrypt_continue(req, 0);
	if (err == -EINPROGRESS)
		return;

out:
	aead_request_complete(req, err);
}

static int crypto_gcm_encrypt(struct aead_request *req)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct skcipher_request *skreq = &pctx->u.skreq;
	u32 flags = aead_request_flags(req);

	crypto_gcm_init_common(req);
	crypto_gcm_init_crypt(req, req->cryptlen);
	skcipher_request_set_callback(skreq, flags, gcm_encrypt_done, req);

	return crypto_skcipher_encrypt(skreq) ?:
	       gcm_encrypt_continue(req, flags);
}

static int crypto_gcm_verify(struct aead_request *req)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct crypto_aead *aead = crypto_aead_reqtfm(req);
	u8 *auth_tag = pctx->auth_tag;
	u8 *iauth_tag = pctx->iauth_tag;
	unsigned int authsize = crypto_aead_authsize(aead);
	unsigned int cryptlen = req->cryptlen - authsize;

	crypto_xor(auth_tag, iauth_tag, 16);
	scatterwalk_map_and_copy(iauth_tag, req->src,
				 req->assoclen + cryptlen, authsize, 0);
	return crypto_memneq(iauth_tag, auth_tag, authsize) ? -EBADMSG : 0;
}

static void gcm_decrypt_done(struct crypto_async_request *areq, int err)
{
	struct aead_request *req = areq->data;

	if (!err)
		err = crypto_gcm_verify(req);

	aead_request_complete(req, err);
}

static int gcm_dec_hash_continue(struct aead_request *req, u32 flags)
{
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct skcipher_request *skreq = &pctx->u.skreq;
	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;

	crypto_gcm_init_crypt(req, gctx->cryptlen);
	skcipher_request_set_callback(skreq, flags, gcm_decrypt_done, req);
	return crypto_skcipher_decrypt(skreq) ?: crypto_gcm_verify(req);
}

static int crypto_gcm_decrypt(struct aead_request *req)
{
	struct crypto_aead *aead = crypto_aead_reqtfm(req);
	struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
	struct crypto_gcm_ghash_ctx *gctx = &pctx->ghash_ctx;
	unsigned int authsize = crypto_aead_authsize(aead);
	unsigned int cryptlen = req->cryptlen;
	u32 flags = aead_request_flags(req);

	cryptlen -= authsize;

	crypto_gcm_init_common(req);

	gctx->src = sg_next(pctx->src);
	gctx->cryptlen = cryptlen;
	gctx->complete = gcm_dec_hash_continue;

	return gcm_hash(req, flags);
}

static int crypto_gcm_init_tfm(struct crypto_aead *tfm)
{
	struct aead_instance *inst = aead_alg_instance(tfm);
	struct gcm_instance_ctx *ictx = aead_instance_ctx(inst);
	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(tfm);
	struct crypto_skcipher *ctr;
	struct crypto_ahash *ghash;
	unsigned long align;
	int err;

	ghash = crypto_spawn_ahash(&ictx->ghash);
	if (IS_ERR(ghash))
		return PTR_ERR(ghash);

	ctr = crypto_spawn_skcipher(&ictx->ctr);
	err = PTR_ERR(ctr);
	if (IS_ERR(ctr))
		goto err_free_hash;

	ctx->ctr = ctr;
	ctx->ghash = ghash;

	align = crypto_aead_alignmask(tfm);
	align &= ~(crypto_tfm_ctx_alignment() - 1);
	crypto_aead_set_reqsize(tfm,
		align + offsetof(struct crypto_gcm_req_priv_ctx, u) +
		max(sizeof(struct skcipher_request) +
		    crypto_skcipher_reqsize(ctr),
		    sizeof(struct ahash_request) +
		    crypto_ahash_reqsize(ghash)));

	return 0;

err_free_hash:
	crypto_free_ahash(ghash);
	return err;
}

static void crypto_gcm_exit_tfm(struct crypto_aead *tfm)
{
	struct crypto_gcm_ctx *ctx = crypto_aead_ctx(tfm);

	crypto_free_ahash(ctx->ghash);
	crypto_free_skcipher(ctx->ctr);
}

static void crypto_gcm_free(struct aead_instance *inst)
{
	struct gcm_instance_ctx *ctx = aead_instance_ctx(inst);

	crypto_drop_skcipher(&ctx->ctr);
	crypto_drop_ahash(&ctx->ghash);
	kfree(inst);
}

static int crypto_gcm_create_common(struct crypto_template *tmpl,
				    struct rtattr **tb,
				    const char *ctr_name,
				    const char *ghash_name)
{
	u32 mask;
	struct aead_instance *inst;
	struct gcm_instance_ctx *ctx;
	struct skcipher_alg *ctr;
	struct hash_alg_common *ghash;
	int err;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
	if (err)
		return err;

	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
	if (!inst)
		return -ENOMEM;
	ctx = aead_instance_ctx(inst);

	err = crypto_grab_ahash(&ctx->ghash, aead_crypto_instance(inst),
				ghash_name, 0, mask);
	if (err)
		goto err_free_inst;
	ghash = crypto_spawn_ahash_alg(&ctx->ghash);

	err = -EINVAL;
	if (strcmp(ghash->base.cra_name, "ghash") != 0 ||
	    ghash->digestsize != 16)
		goto err_free_inst;

	err = crypto_grab_skcipher(&ctx->ctr, aead_crypto_instance(inst),
				   ctr_name, 0, mask);
	if (err)
		goto err_free_inst;
	ctr = crypto_spawn_skcipher_alg(&ctx->ctr);

	/* The skcipher algorithm must be CTR mode, using 16-byte blocks. */
	err = -EINVAL;
	if (strncmp(ctr->base.cra_name, "ctr(", 4) != 0 ||
	    crypto_skcipher_alg_ivsize(ctr) != 16 ||
	    ctr->base.cra_blocksize != 1)
		goto err_free_inst;

	err = -ENAMETOOLONG;
	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
		     "gcm(%s", ctr->base.cra_name + 4) >= CRYPTO_MAX_ALG_NAME)
		goto err_free_inst;

	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
		     "gcm_base(%s,%s)", ctr->base.cra_driver_name,
		     ghash->base.cra_driver_name) >=
	    CRYPTO_MAX_ALG_NAME)
		goto err_free_inst;

	inst->alg.base.cra_priority = (ghash->base.cra_priority +
				       ctr->base.cra_priority) / 2;
	inst->alg.base.cra_blocksize = 1;
	inst->alg.base.cra_alignmask = ghash->base.cra_alignmask |
				       ctr->base.cra_alignmask;
	inst->alg.base.cra_ctxsize = sizeof(struct crypto_gcm_ctx);
	inst->alg.ivsize = GCM_AES_IV_SIZE;
	inst->alg.chunksize = crypto_skcipher_alg_chunksize(ctr);
	inst->alg.maxauthsize = 16;
	inst->alg.init = crypto_gcm_init_tfm;
	inst->alg.exit = crypto_gcm_exit_tfm;
	inst->alg.setkey = crypto_gcm_setkey;
	inst->alg.setauthsize = crypto_gcm_setauthsize;
	inst->alg.encrypt = crypto_gcm_encrypt;
	inst->alg.decrypt = crypto_gcm_decrypt;

	inst->free = crypto_gcm_free;

	err = aead_register_instance(tmpl, inst);
	if (err) {
err_free_inst:
		crypto_gcm_free(inst);
	}
	return err;
}

static int crypto_gcm_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	const char *cipher_name;
	char ctr_name[CRYPTO_MAX_ALG_NAME];

	cipher_name = crypto_attr_alg_name(tb[1]);
	if (IS_ERR(cipher_name))
		return PTR_ERR(cipher_name);

	if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)", cipher_name) >=
	    CRYPTO_MAX_ALG_NAME)
		return -ENAMETOOLONG;

	return crypto_gcm_create_common(tmpl, tb, ctr_name, "ghash");
}

static int crypto_gcm_base_create(struct crypto_template *tmpl,
				  struct rtattr **tb)
{
	const char *ctr_name;
	const char *ghash_name;

	ctr_name = crypto_attr_alg_name(tb[1]);
	if (IS_ERR(ctr_name))
		return PTR_ERR(ctr_name);

	ghash_name = crypto_attr_alg_name(tb[2]);
	if (IS_ERR(ghash_name))
		return PTR_ERR(ghash_name);

	return crypto_gcm_create_common(tmpl, tb, ctr_name, ghash_name);
}

static int crypto_rfc4106_setkey(struct crypto_aead *parent, const u8 *key,
				 unsigned int keylen)
{
	struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(parent);
	struct crypto_aead *child = ctx->child;

	if (keylen < 4)
		return -EINVAL;

	keylen -= 4;
	memcpy(ctx->nonce, key + keylen, 4);

	crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
				     CRYPTO_TFM_REQ_MASK);
	return crypto_aead_setkey(child, key, keylen);
}

static int crypto_rfc4106_setauthsize(struct crypto_aead *parent,
				      unsigned int authsize)
{
	struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(parent);
	int err;

	err = crypto_rfc4106_check_authsize(authsize);
	if (err)
		return err;

	return crypto_aead_setauthsize(ctx->child, authsize);
}

static struct aead_request *crypto_rfc4106_crypt(struct aead_request *req)
{
	struct crypto_rfc4106_req_ctx *rctx = aead_request_ctx(req);
	struct crypto_aead *aead = crypto_aead_reqtfm(req);
	struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(aead);
	struct aead_request *subreq = &rctx->subreq;
	struct crypto_aead *child = ctx->child;
	struct scatterlist *sg;
	u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
			   crypto_aead_alignmask(child) + 1);

	scatterwalk_map_and_copy(iv + GCM_AES_IV_SIZE, req->src, 0, req->assoclen - 8, 0);

	memcpy(iv, ctx->nonce, 4);
	memcpy(iv + 4, req->iv, 8);

	sg_init_table(rctx->src, 3);
	sg_set_buf(rctx->src, iv + GCM_AES_IV_SIZE, req->assoclen - 8);
	sg = scatterwalk_ffwd(rctx->src + 1, req->src, req->assoclen);
	if (sg != rctx->src + 1)
		sg_chain(rctx->src, 2, sg);

	if (req->src != req->dst) {
		sg_init_table(rctx->dst, 3);
		sg_set_buf(rctx->dst, iv + GCM_AES_IV_SIZE, req->assoclen - 8);
		sg = scatterwalk_ffwd(rctx->dst + 1, req->dst, req->assoclen);
		if (sg != rctx->dst + 1)
			sg_chain(rctx->dst, 2, sg);
	}

	aead_request_set_tfm(subreq, child);
	aead_request_set_callback(subreq, req->base.flags, req->base.complete,
				  req->base.data);
	aead_request_set_crypt(subreq, rctx->src,
			       req->src == req->dst ? rctx->src : rctx->dst,
			       req->cryptlen, iv);
	aead_request_set_ad(subreq, req->assoclen - 8);

	return subreq;
}

static int crypto_rfc4106_encrypt(struct aead_request *req)
{
	int err;

	err = crypto_ipsec_check_assoclen(req->assoclen);
	if (err)
		return err;

	req = crypto_rfc4106_crypt(req);

	return crypto_aead_encrypt(req);
}

static int crypto_rfc4106_decrypt(struct aead_request *req)
{
	int err;

	err = crypto_ipsec_check_assoclen(req->assoclen);
	if (err)
		return err;

	req = crypto_rfc4106_crypt(req);

	return crypto_aead_decrypt(req);
}

static int crypto_rfc4106_init_tfm(struct crypto_aead *tfm)
{
	struct aead_instance *inst = aead_alg_instance(tfm);
	struct crypto_aead_spawn *spawn = aead_instance_ctx(inst);
	struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(tfm);
	struct crypto_aead *aead;
	unsigned long align;

	aead = crypto_spawn_aead(spawn);
	if (IS_ERR(aead))
		return PTR_ERR(aead);

	ctx->child = aead;

	align = crypto_aead_alignmask(aead);
	align &= ~(crypto_tfm_ctx_alignment() - 1);
	crypto_aead_set_reqsize(
		tfm,
		sizeof(struct crypto_rfc4106_req_ctx) +
		ALIGN(crypto_aead_reqsize(aead), crypto_tfm_ctx_alignment()) +
		align + 24);

	return 0;
}

static void crypto_rfc4106_exit_tfm(struct crypto_aead *tfm)
{
	struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(tfm);

	crypto_free_aead(ctx->child);
}

static void crypto_rfc4106_free(struct aead_instance *inst)
{
	crypto_drop_aead(aead_instance_ctx(inst));
	kfree(inst);
}

static int crypto_rfc4106_create(struct crypto_template *tmpl,
				 struct rtattr **tb)
{
	u32 mask;
	struct aead_instance *inst;
	struct crypto_aead_spawn *spawn;
	struct aead_alg *alg;
	int err;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
	if (err)
		return err;

	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
	if (!inst)
		return -ENOMEM;

	spawn = aead_instance_ctx(inst);
	err = crypto_grab_aead(spawn, aead_crypto_instance(inst),
			       crypto_attr_alg_name(tb[1]), 0, mask);
	if (err)
		goto err_free_inst;

	alg = crypto_spawn_aead_alg(spawn);

	err = -EINVAL;

	/* Underlying IV size must be 12. */
	if (crypto_aead_alg_ivsize(alg) != GCM_AES_IV_SIZE)
		goto err_free_inst;

	/* Not a stream cipher? */
	if (alg->base.cra_blocksize != 1)
		goto err_free_inst;

	err = -ENAMETOOLONG;
	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
		     "rfc4106(%s)", alg->base.cra_name) >=
	    CRYPTO_MAX_ALG_NAME ||
	    snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
		     "rfc4106(%s)", alg->base.cra_driver_name) >=
	    CRYPTO_MAX_ALG_NAME)
		goto err_free_inst;

	inst->alg.base.cra_priority = alg->base.cra_priority;
	inst->alg.base.cra_blocksize = 1;
	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;

	inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc4106_ctx);

	inst->alg.ivsize = GCM_RFC4106_IV_SIZE;
	inst->alg.chunksize = crypto_aead_alg_chunksize(alg);
	inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(alg);

	inst->alg.init = crypto_rfc4106_init_tfm;
	inst->alg.exit = crypto_rfc4106_exit_tfm;

	inst->alg.setkey = crypto_rfc4106_setkey;
	inst->alg.setauthsize = crypto_rfc4106_setauthsize;
	inst->alg.encrypt = crypto_rfc4106_encrypt;
	inst->alg.decrypt = crypto_rfc4106_decrypt;

	inst->free = crypto_rfc4106_free;

	err = aead_register_instance(tmpl, inst);
	if (err) {
err_free_inst:
		crypto_rfc4106_free(inst);
	}
	return err;
}

static int crypto_rfc4543_setkey(struct crypto_aead *parent, const u8 *key,
				 unsigned int keylen)
{
	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(parent);
	struct crypto_aead *child = ctx->child;

	if (keylen < 4)
		return -EINVAL;

	keylen -= 4;
	memcpy(ctx->nonce, key + keylen, 4);

	crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
	crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
				     CRYPTO_TFM_REQ_MASK);
	return crypto_aead_setkey(child, key, keylen);
}

static int crypto_rfc4543_setauthsize(struct crypto_aead *parent,
				      unsigned int authsize)
{
	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(parent);

	if (authsize != 16)
		return -EINVAL;

	return crypto_aead_setauthsize(ctx->child, authsize);
}

static int crypto_rfc4543_crypt(struct aead_request *req, 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 = aead_request_ctx(req);
	struct aead_request *subreq = &rctx->subreq;
	unsigned int authsize = crypto_aead_authsize(aead);
	u8 *iv = PTR_ALIGN((u8 *)(rctx + 1) + crypto_aead_reqsize(ctx->child),
			   crypto_aead_alignmask(ctx->child) + 1);
	int err;

	if (req->src != req->dst) {
		err = crypto_rfc4543_copy_src_to_dst(req, enc);
		if (err)
			return err;
	}

	memcpy(iv, ctx->nonce, 4);
	memcpy(iv + 4, req->iv, 8);

	aead_request_set_tfm(subreq, ctx->child);
	aead_request_set_callback(subreq, req->base.flags,
				  req->base.complete, req->base.data);
	aead_request_set_crypt(subreq, req->src, req->dst,
			       enc ? 0 : authsize, iv);
	aead_request_set_ad(subreq, req->assoclen + req->cryptlen -
				    subreq->cryptlen);

	return enc ? crypto_aead_encrypt(subreq) : crypto_aead_decrypt(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->assoclen + req->cryptlen -
			      (enc ? 0 : authsize);
	SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->null);

	skcipher_request_set_sync_tfm(nreq, ctx->null);
	skcipher_request_set_callback(nreq, req->base.flags, NULL, NULL);
	skcipher_request_set_crypt(nreq, req->src, req->dst, nbytes, NULL);

	return crypto_skcipher_encrypt(nreq);
}

static int crypto_rfc4543_encrypt(struct aead_request *req)
{
	return crypto_ipsec_check_assoclen(req->assoclen) ?:
	       crypto_rfc4543_crypt(req, true);
}

static int crypto_rfc4543_decrypt(struct aead_request *req)
{
	return crypto_ipsec_check_assoclen(req->assoclen) ?:
	       crypto_rfc4543_crypt(req, false);
}

static int crypto_rfc4543_init_tfm(struct crypto_aead *tfm)
{
	struct aead_instance *inst = aead_alg_instance(tfm);
	struct crypto_rfc4543_instance_ctx *ictx = aead_instance_ctx(inst);
	struct crypto_aead_spawn *spawn = &ictx->aead;
	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(tfm);
	struct crypto_aead *aead;
	struct crypto_sync_skcipher *null;
	unsigned long align;
	int err = 0;

	aead = crypto_spawn_aead(spawn);
	if (IS_ERR(aead))
		return PTR_ERR(aead);

	null = crypto_get_default_null_skcipher();
	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);
	crypto_aead_set_reqsize(
		tfm,
		sizeof(struct crypto_rfc4543_req_ctx) +
		ALIGN(crypto_aead_reqsize(aead), crypto_tfm_ctx_alignment()) +
		align + GCM_AES_IV_SIZE);

	return 0;

err_free_aead:
	crypto_free_aead(aead);
	return err;
}

static void crypto_rfc4543_exit_tfm(struct crypto_aead *tfm)
{
	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(tfm);

	crypto_free_aead(ctx->child);
	crypto_put_default_null_skcipher();
}

static void crypto_rfc4543_free(struct aead_instance *inst)
{
	struct crypto_rfc4543_instance_ctx *ctx = aead_instance_ctx(inst);

	crypto_drop_aead(&ctx->aead);

	kfree(inst);
}

static int crypto_rfc4543_create(struct crypto_template *tmpl,
				struct rtattr **tb)
{
	u32 mask;
	struct aead_instance *inst;
	struct aead_alg *alg;
	struct crypto_rfc4543_instance_ctx *ctx;
	int err;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
	if (err)
		return err;

	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
	if (!inst)
		return -ENOMEM;

	ctx = aead_instance_ctx(inst);
	err = crypto_grab_aead(&ctx->aead, aead_crypto_instance(inst),
			       crypto_attr_alg_name(tb[1]), 0, mask);
	if (err)
		goto err_free_inst;

	alg = crypto_spawn_aead_alg(&ctx->aead);

	err = -EINVAL;

	/* Underlying IV size must be 12. */
	if (crypto_aead_alg_ivsize(alg) != GCM_AES_IV_SIZE)
		goto err_free_inst;

	/* Not a stream cipher? */
	if (alg->base.cra_blocksize != 1)
		goto err_free_inst;

	err = -ENAMETOOLONG;
	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
		     "rfc4543(%s)", alg->base.cra_name) >=
	    CRYPTO_MAX_ALG_NAME ||
	    snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
		     "rfc4543(%s)", alg->base.cra_driver_name) >=
	    CRYPTO_MAX_ALG_NAME)
		goto err_free_inst;

	inst->alg.base.cra_priority = alg->base.cra_priority;
	inst->alg.base.cra_blocksize = 1;
	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;

	inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc4543_ctx);

	inst->alg.ivsize = GCM_RFC4543_IV_SIZE;
	inst->alg.chunksize = crypto_aead_alg_chunksize(alg);
	inst->alg.maxauthsize = crypto_aead_alg_maxauthsize(alg);

	inst->alg.init = crypto_rfc4543_init_tfm;
	inst->alg.exit = crypto_rfc4543_exit_tfm;

	inst->alg.setkey = crypto_rfc4543_setkey;
	inst->alg.setauthsize = crypto_rfc4543_setauthsize;
	inst->alg.encrypt = crypto_rfc4543_encrypt;
	inst->alg.decrypt = crypto_rfc4543_decrypt;

	inst->free = crypto_rfc4543_free;

	err = aead_register_instance(tmpl, inst);
	if (err) {
err_free_inst:
		crypto_rfc4543_free(inst);
	}
	return err;
}

static struct crypto_template crypto_gcm_tmpls[] = {
	{
		.name = "gcm_base",
		.create = crypto_gcm_base_create,
		.module = THIS_MODULE,
	}, {
		.name = "gcm",
		.create = crypto_gcm_create,
		.module = THIS_MODULE,
	}, {
		.name = "rfc4106",
		.create = crypto_rfc4106_create,
		.module = THIS_MODULE,
	}, {
		.name = "rfc4543",
		.create = crypto_rfc4543_create,
		.module = THIS_MODULE,
	},
};

static int __init crypto_gcm_module_init(void)
{
	int err;

	gcm_zeroes = kzalloc(sizeof(*gcm_zeroes), GFP_KERNEL);
	if (!gcm_zeroes)
		return -ENOMEM;

	sg_init_one(&gcm_zeroes->sg, gcm_zeroes->buf, sizeof(gcm_zeroes->buf));

	err = crypto_register_templates(crypto_gcm_tmpls,
					ARRAY_SIZE(crypto_gcm_tmpls));
	if (err)
		kfree(gcm_zeroes);

	return err;
}

static void __exit crypto_gcm_module_exit(void)
{
	kfree(gcm_zeroes);
	crypto_unregister_templates(crypto_gcm_tmpls,
				    ARRAY_SIZE(crypto_gcm_tmpls));
}

subsys_initcall(crypto_gcm_module_init);
module_exit(crypto_gcm_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Galois/Counter Mode");
MODULE_AUTHOR("Mikko Herranen <mh1@iki.fi>");
MODULE_ALIAS_CRYPTO("gcm_base");
MODULE_ALIAS_CRYPTO("rfc4106");
MODULE_ALIAS_CRYPTO("rfc4543");
MODULE_ALIAS_CRYPTO("gcm");

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