From a2b1118052c41ca92cbc2366e77b2f0ff3b054ba Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 18 Oct 2023 22:53:36 -0700 Subject: crypto: xcbc - remove unnecessary alignment logic The xcbc template is setting its alignmask to that of its underlying 'cipher'. Yet, it doesn't care itself about how its inputs and outputs are aligned, which is ostensibly the point of the alignmask. Instead, xcbc actually just uses its alignmask itself to runtime-align certain fields in its tfm and desc contexts appropriately for its underlying cipher. That is almost entirely pointless too, though, since xcbc is already using the cipher API functions that handle alignment themselves, and few ciphers set a nonzero alignmask anyway. Also, even without runtime alignment, an alignment of at least 4 bytes can be guaranteed. Thus, at best this code is optimizing for the rare case of ciphers that set an alignmask >= 7, at the cost of hurting the common cases. Therefore, this patch removes the manual alignment code from xcbc and makes it stop setting an alignmask. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu --- crypto/xcbc.c | 32 ++++++++++---------------------- 1 file changed, 10 insertions(+), 22 deletions(-) (limited to 'crypto') diff --git a/crypto/xcbc.c b/crypto/xcbc.c index 6074c5c1da49..a9e8ee9c1949 100644 --- a/crypto/xcbc.c +++ b/crypto/xcbc.c @@ -27,7 +27,7 @@ static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101, */ struct xcbc_tfm_ctx { struct crypto_cipher *child; - u8 ctx[]; + u8 consts[]; }; /* @@ -43,7 +43,7 @@ struct xcbc_tfm_ctx { */ struct xcbc_desc_ctx { unsigned int len; - u8 ctx[]; + u8 odds[]; }; #define XCBC_BLOCKSIZE 16 @@ -51,9 +51,8 @@ struct xcbc_desc_ctx { static int crypto_xcbc_digest_setkey(struct crypto_shash *parent, const u8 *inkey, unsigned int keylen) { - unsigned long alignmask = crypto_shash_alignmask(parent); struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent); - u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); + u8 *consts = ctx->consts; int err = 0; u8 key1[XCBC_BLOCKSIZE]; int bs = sizeof(key1); @@ -71,10 +70,9 @@ static int crypto_xcbc_digest_setkey(struct crypto_shash *parent, static int crypto_xcbc_digest_init(struct shash_desc *pdesc) { - unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm); struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); int bs = crypto_shash_blocksize(pdesc->tfm); - u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs; + u8 *prev = &ctx->odds[bs]; ctx->len = 0; memset(prev, 0, bs); @@ -86,12 +84,11 @@ static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p, unsigned int len) { struct crypto_shash *parent = pdesc->tfm; - unsigned long alignmask = crypto_shash_alignmask(parent); struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent); struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); struct crypto_cipher *tfm = tctx->child; int bs = crypto_shash_blocksize(parent); - u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); + u8 *odds = ctx->odds; u8 *prev = odds + bs; /* checking the data can fill the block */ @@ -132,13 +129,11 @@ static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p, static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out) { struct crypto_shash *parent = pdesc->tfm; - unsigned long alignmask = crypto_shash_alignmask(parent); struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent); struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); struct crypto_cipher *tfm = tctx->child; int bs = crypto_shash_blocksize(parent); - u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1); - u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); + u8 *odds = ctx->odds; u8 *prev = odds + bs; unsigned int offset = 0; @@ -157,7 +152,7 @@ static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out) } crypto_xor(prev, odds, bs); - crypto_xor(prev, consts + offset, bs); + crypto_xor(prev, &tctx->consts[offset], bs); crypto_cipher_encrypt_one(tfm, out, prev); @@ -191,7 +186,6 @@ static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb) struct shash_instance *inst; struct crypto_cipher_spawn *spawn; struct crypto_alg *alg; - unsigned long alignmask; u32 mask; int err; @@ -218,21 +212,15 @@ static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb) if (err) goto err_free_inst; - alignmask = alg->cra_alignmask | 3; - inst->alg.base.cra_alignmask = alignmask; inst->alg.base.cra_priority = alg->cra_priority; inst->alg.base.cra_blocksize = alg->cra_blocksize; + inst->alg.base.cra_ctxsize = sizeof(struct xcbc_tfm_ctx) + + alg->cra_blocksize * 2; inst->alg.digestsize = alg->cra_blocksize; - inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx), - crypto_tfm_ctx_alignment()) + - (alignmask & - ~(crypto_tfm_ctx_alignment() - 1)) + + inst->alg.descsize = sizeof(struct xcbc_desc_ctx) + alg->cra_blocksize * 2; - inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx), - alignmask + 1) + - alg->cra_blocksize * 2; inst->alg.base.cra_init = xcbc_init_tfm; inst->alg.base.cra_exit = xcbc_exit_tfm; -- cgit v1.2.3-70-g09d2