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crypto: hmac - Prehash ipad/opad
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This patch uses crypto_shash_export/crypto_shash_import to prehash
ipad/opad to speed up hmac.  This is partly based on a similar patch
by Steffen Klassert.

Signed-off-by: Herbert Xu <[email protected]>
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@herbertx
herbertx committed Jul 24, 2009
1 parent 7b4ffcf commit 0b767b4
Showing 1 changed file with 62 additions and 46 deletions.
108 changes: 62 additions & 46 deletions crypto/hmac.c
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@
#include <linux/string.h>

struct hmac_ctx {
struct shash_desc *desc;
struct crypto_shash *hash;
};

static inline void *align_ptr(void *p, unsigned int align)
Expand All @@ -38,8 +38,7 @@ static inline void *align_ptr(void *p, unsigned int align)
static inline struct hmac_ctx *hmac_ctx(struct crypto_shash *tfm)
{
return align_ptr(crypto_shash_ctx_aligned(tfm) +
crypto_shash_blocksize(tfm) * 2 +
crypto_shash_digestsize(tfm),
crypto_shash_statesize(tfm) * 2,
crypto_tfm_ctx_alignment());
}

Expand All @@ -48,28 +47,33 @@ static int hmac_setkey(struct crypto_shash *parent,
{
int bs = crypto_shash_blocksize(parent);
int ds = crypto_shash_digestsize(parent);
int ss = crypto_shash_statesize(parent);
char *ipad = crypto_shash_ctx_aligned(parent);
char *opad = ipad + bs;
char *digest = opad + bs;
struct hmac_ctx *ctx = align_ptr(digest + ds,
char *opad = ipad + ss;
struct hmac_ctx *ctx = align_ptr(opad + ss,
crypto_tfm_ctx_alignment());
struct crypto_shash *hash = ctx->hash;
struct {
struct shash_desc shash;
char ctx[crypto_shash_descsize(hash)];
} desc;
unsigned int i;

desc.shash.tfm = hash;
desc.shash.flags = crypto_shash_get_flags(parent) &
CRYPTO_TFM_REQ_MAY_SLEEP;

if (keylen > bs) {
int err;

ctx->desc->flags = crypto_shash_get_flags(parent) &
CRYPTO_TFM_REQ_MAY_SLEEP;

err = crypto_shash_digest(ctx->desc, inkey, keylen, digest);
err = crypto_shash_digest(&desc.shash, inkey, keylen, ipad);
if (err)
return err;

inkey = digest;
keylen = ds;
}
} else
memcpy(ipad, inkey, keylen);

memcpy(ipad, inkey, keylen);
memset(ipad + keylen, 0, bs - keylen);
memcpy(opad, ipad, bs);

Expand All @@ -78,24 +82,37 @@ static int hmac_setkey(struct crypto_shash *parent,
opad[i] ^= 0x5c;
}

return 0;
return crypto_shash_init(&desc.shash) ?:
crypto_shash_update(&desc.shash, ipad, bs) ?:
crypto_shash_export(&desc.shash, ipad) ?:
crypto_shash_init(&desc.shash) ?:
crypto_shash_update(&desc.shash, opad, bs) ?:
crypto_shash_export(&desc.shash, opad);
}

static int hmac_init(struct shash_desc *pdesc)
static int hmac_export(struct shash_desc *pdesc, void *out)
{
struct shash_desc *desc = shash_desc_ctx(pdesc);

desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

return crypto_shash_export(desc, out);
}

static int hmac_import(struct shash_desc *pdesc, const void *in)
{
struct crypto_shash *parent = pdesc->tfm;
int bs = crypto_shash_blocksize(parent);
int ds = crypto_shash_digestsize(parent);
char *ipad = crypto_shash_ctx_aligned(parent);
struct hmac_ctx *ctx = align_ptr(ipad + bs * 2 + ds,
crypto_tfm_ctx_alignment());
struct shash_desc *desc = shash_desc_ctx(pdesc);
struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);

desc->tfm = ctx->desc->tfm;
desc->tfm = ctx->hash;
desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

return crypto_shash_init(desc) ?:
crypto_shash_update(desc, ipad, bs);
return crypto_shash_import(desc, in);
}

static int hmac_init(struct shash_desc *pdesc)
{
return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
}

static int hmac_update(struct shash_desc *pdesc,
Expand All @@ -111,33 +128,33 @@ static int hmac_update(struct shash_desc *pdesc,
static int hmac_final(struct shash_desc *pdesc, u8 *out)
{
struct crypto_shash *parent = pdesc->tfm;
int bs = crypto_shash_blocksize(parent);
int ds = crypto_shash_digestsize(parent);
char *opad = crypto_shash_ctx_aligned(parent) + bs;
char *digest = opad + bs;
int ss = crypto_shash_statesize(parent);
char *opad = crypto_shash_ctx_aligned(parent) + ss;
struct shash_desc *desc = shash_desc_ctx(pdesc);

desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

return crypto_shash_final(desc, digest) ?:
crypto_shash_digest(desc, opad, bs + ds, out);
return crypto_shash_final(desc, out) ?:
crypto_shash_import(desc, opad) ?:
crypto_shash_finup(desc, out, ds, out);
}

static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
unsigned int nbytes, u8 *out)
{

struct crypto_shash *parent = pdesc->tfm;
int bs = crypto_shash_blocksize(parent);
int ds = crypto_shash_digestsize(parent);
char *opad = crypto_shash_ctx_aligned(parent) + bs;
char *digest = opad + bs;
int ss = crypto_shash_statesize(parent);
char *opad = crypto_shash_ctx_aligned(parent) + ss;
struct shash_desc *desc = shash_desc_ctx(pdesc);

desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

return crypto_shash_finup(desc, data, nbytes, digest) ?:
crypto_shash_digest(desc, opad, bs + ds, out);
return crypto_shash_finup(desc, data, nbytes, out) ?:
crypto_shash_import(desc, opad) ?:
crypto_shash_finup(desc, out, ds, out);
}

static int hmac_init_tfm(struct crypto_tfm *tfm)
Expand All @@ -155,21 +172,14 @@ static int hmac_init_tfm(struct crypto_tfm *tfm)
parent->descsize = sizeof(struct shash_desc) +
crypto_shash_descsize(hash);

ctx->desc = kmalloc(parent->descsize, GFP_KERNEL);
if (!ctx->desc) {
crypto_free_shash(hash);
return -ENOMEM;
}

ctx->desc->tfm = hash;
ctx->hash = hash;
return 0;
}

static void hmac_exit_tfm(struct crypto_tfm *tfm)
{
struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
crypto_free_shash(ctx->desc->tfm);
kzfree(ctx->desc);
crypto_free_shash(ctx->hash);
}

static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
Expand All @@ -179,6 +189,7 @@ static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
struct shash_alg *salg;
int err;
int ds;
int ss;

err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
if (err)
Expand All @@ -190,8 +201,10 @@ static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)

err = -EINVAL;
ds = salg->digestsize;
ss = salg->statesize;
alg = &salg->base;
if (ds > alg->cra_blocksize)
if (ds > alg->cra_blocksize ||
ss < alg->cra_blocksize)
goto out_put_alg;

inst = shash_alloc_instance("hmac", alg);
Expand All @@ -208,11 +221,12 @@ static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
inst->alg.base.cra_blocksize = alg->cra_blocksize;
inst->alg.base.cra_alignmask = alg->cra_alignmask;

ss = ALIGN(ss, alg->cra_alignmask + 1);
inst->alg.digestsize = ds;
inst->alg.statesize = ss;

inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
ALIGN(alg->cra_blocksize * 2 + ds,
crypto_tfm_ctx_alignment());
ALIGN(ss * 2, crypto_tfm_ctx_alignment());

inst->alg.base.cra_init = hmac_init_tfm;
inst->alg.base.cra_exit = hmac_exit_tfm;
Expand All @@ -221,6 +235,8 @@ static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
inst->alg.update = hmac_update;
inst->alg.final = hmac_final;
inst->alg.finup = hmac_finup;
inst->alg.export = hmac_export;
inst->alg.import = hmac_import;
inst->alg.setkey = hmac_setkey;

err = shash_register_instance(tmpl, inst);
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