Commit 357d065a authored by Daniel Axtens's avatar Daniel Axtens Committed by Herbert Xu
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crypto: vmx - ghash: do nosimd fallback manually 



VMX ghash was using a fallback that did not support interleaving simd
and nosimd operations, leading to failures in the extended test suite.

If I understood correctly, Eric's suggestion was to use the same
data format that the generic code uses, allowing us to call into it
with the same contexts. I wasn't able to get that to work - I think
there's a very different key structure and data layout being used.

So instead steal the arm64 approach and perform the fallback
operations directly if required.

Fixes: cc333cd6 ("crypto: vmx - Adding GHASH routines for VMX module")
Cc: stable@vger.kernel.org # v4.1+
Reported-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarDaniel Axtens <dja@axtens.net>
Acked-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 009b30ac

drivers/crypto/vmx/ghash.c

+86 −125
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/**

 * GHASH routines supporting VMX instructions on the Power 8

 *

 * Copyright (C) 2015 International Business Machines Inc.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; version 2 only.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 * Copyright (C) 2015, 2019 International Business Machines Inc.

 *

 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>

 *

 * Extended by Daniel Axtens <dja@axtens.net> to replace the fallback

 * mechanism. The new approach is based on arm64 code, which is:

 *   Copyright (C) 2014 - 2018 Linaro Ltd. <ard.biesheuvel@linaro.org>

 */



#include <linux/types.h>
@@ -38,70 +30,25 @@ void gcm_ghash_p8(u64 Xi[2], const u128 htable[16], 
		  const u8 *in, size_t len);



struct p8_ghash_ctx {

	/* key used by vector asm */

	u128 htable[16];

	struct crypto_shash *fallback;

	/* key used by software fallback */

	be128 key;

};



struct p8_ghash_desc_ctx {

	u64 shash[2];

	u8 buffer[GHASH_DIGEST_SIZE];

	int bytes;

	struct shash_desc fallback_desc;

};



static int p8_ghash_init_tfm(struct crypto_tfm *tfm)

{

	const char *alg = "ghash-generic";

	struct crypto_shash *fallback;

	struct crypto_shash *shash_tfm = __crypto_shash_cast(tfm);

	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);



	fallback = crypto_alloc_shash(alg, 0, CRYPTO_ALG_NEED_FALLBACK);

	if (IS_ERR(fallback)) {

		printk(KERN_ERR

		       "Failed to allocate transformation for '%s': %ld\n",

		       alg, PTR_ERR(fallback));

		return PTR_ERR(fallback);

	}



	crypto_shash_set_flags(fallback,

			       crypto_shash_get_flags((struct crypto_shash

						       *) tfm));



	/* Check if the descsize defined in the algorithm is still enough. */

	if (shash_tfm->descsize < sizeof(struct p8_ghash_desc_ctx)

	    + crypto_shash_descsize(fallback)) {

		printk(KERN_ERR

		       "Desc size of the fallback implementation (%s) does not match the expected value: %lu vs %u\n",

		       alg,

		       shash_tfm->descsize - sizeof(struct p8_ghash_desc_ctx),

		       crypto_shash_descsize(fallback));

		return -EINVAL;

	}

	ctx->fallback = fallback;



	return 0;

}



static void p8_ghash_exit_tfm(struct crypto_tfm *tfm)

{

	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);



	if (ctx->fallback) {

		crypto_free_shash(ctx->fallback);

		ctx->fallback = NULL;

	}

}



static int p8_ghash_init(struct shash_desc *desc)

{

	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));

	struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);



	dctx->bytes = 0;

	memset(dctx->shash, 0, GHASH_DIGEST_SIZE);

	dctx->fallback_desc.tfm = ctx->fallback;

	return crypto_shash_init(&dctx->fallback_desc);

	return 0;

}



static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key,
@@ -119,7 +66,51 @@ static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key, 
	disable_kernel_vsx();

	pagefault_enable();

	preempt_enable();

	return crypto_shash_setkey(ctx->fallback, key, keylen);



	memcpy(&ctx->key, key, GHASH_BLOCK_SIZE);



	return 0;

}



static inline void __ghash_block(struct p8_ghash_ctx *ctx,

				 struct p8_ghash_desc_ctx *dctx)

{

	if (crypto_simd_usable()) {

		preempt_disable();

		pagefault_disable();

		enable_kernel_vsx();

		gcm_ghash_p8(dctx->shash, ctx->htable,

				dctx->buffer, GHASH_DIGEST_SIZE);

		disable_kernel_vsx();

		pagefault_enable();

		preempt_enable();

	} else {

		crypto_xor((u8 *)dctx->shash, dctx->buffer, GHASH_BLOCK_SIZE);

		gf128mul_lle((be128 *)dctx->shash, &ctx->key);

	}

}



static inline void __ghash_blocks(struct p8_ghash_ctx *ctx,

				  struct p8_ghash_desc_ctx *dctx,

				  const u8 *src, unsigned int srclen)

{

	if (crypto_simd_usable()) {

		preempt_disable();

		pagefault_disable();

		enable_kernel_vsx();

		gcm_ghash_p8(dctx->shash, ctx->htable,

				src, srclen);

		disable_kernel_vsx();

		pagefault_enable();

		preempt_enable();

	} else {

		while (srclen >= GHASH_BLOCK_SIZE) {

			crypto_xor((u8 *)dctx->shash, src, GHASH_BLOCK_SIZE);

			gf128mul_lle((be128 *)dctx->shash, &ctx->key);

			srclen -= GHASH_BLOCK_SIZE;

			src += GHASH_BLOCK_SIZE;

		}

	}

}



static int p8_ghash_update(struct shash_desc *desc,
@@ -129,10 +120,6 @@ static int p8_ghash_update(struct shash_desc *desc, 
	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));

	struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);



	if (!crypto_simd_usable()) {

		return crypto_shash_update(&dctx->fallback_desc, src,

					   srclen);

	} else {

	if (dctx->bytes) {

		if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {

			memcpy(dctx->buffer + dctx->bytes, src,
@@ -142,27 +129,16 @@ static int p8_ghash_update(struct shash_desc *desc, 
		}

		memcpy(dctx->buffer + dctx->bytes, src,

			GHASH_DIGEST_SIZE - dctx->bytes);

			preempt_disable();

			pagefault_disable();

			enable_kernel_vsx();

			gcm_ghash_p8(dctx->shash, ctx->htable,

				     dctx->buffer, GHASH_DIGEST_SIZE);

			disable_kernel_vsx();

			pagefault_enable();

			preempt_enable();



		__ghash_block(ctx, dctx);



		src += GHASH_DIGEST_SIZE - dctx->bytes;

		srclen -= GHASH_DIGEST_SIZE - dctx->bytes;

		dctx->bytes = 0;

	}

	len = srclen & ~(GHASH_DIGEST_SIZE - 1);

	if (len) {

			preempt_disable();

			pagefault_disable();

			enable_kernel_vsx();

			gcm_ghash_p8(dctx->shash, ctx->htable, src, len);

			disable_kernel_vsx();

			pagefault_enable();

			preempt_enable();

		__ghash_blocks(ctx, dctx, src, len);

		src += len;

		srclen -= len;

	}
@@ -172,7 +148,6 @@ static int p8_ghash_update(struct shash_desc *desc, 
	}

	return 0;

}

}



static int p8_ghash_final(struct shash_desc *desc, u8 *out)

{
@@ -180,26 +155,15 @@ static int p8_ghash_final(struct shash_desc *desc, u8 *out) 
	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));

	struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);



	if (!crypto_simd_usable()) {

		return crypto_shash_final(&dctx->fallback_desc, out);

	} else {

	if (dctx->bytes) {

		for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)

			dctx->buffer[i] = 0;

			preempt_disable();

			pagefault_disable();

			enable_kernel_vsx();

			gcm_ghash_p8(dctx->shash, ctx->htable,

				     dctx->buffer, GHASH_DIGEST_SIZE);

			disable_kernel_vsx();

			pagefault_enable();

			preempt_enable();

		__ghash_block(ctx, dctx);

		dctx->bytes = 0;

	}

	memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);

	return 0;

}

}



struct shash_alg p8_ghash_alg = {

	.digestsize = GHASH_DIGEST_SIZE,
@@ -213,11 +177,8 @@ struct shash_alg p8_ghash_alg = { 
		 .cra_name = "ghash",

		 .cra_driver_name = "p8_ghash",

		 .cra_priority = 1000,

		 .cra_flags = CRYPTO_ALG_NEED_FALLBACK,

		 .cra_blocksize = GHASH_BLOCK_SIZE,

		 .cra_ctxsize = sizeof(struct p8_ghash_ctx),

		 .cra_module = THIS_MODULE,

		 .cra_init = p8_ghash_init_tfm,

		 .cra_exit = p8_ghash_exit_tfm,

	},

};

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