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[CRYPTO] authenc: Add givencrypt operation
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This patch implements the givencrypt function for authenc.  It simply
calls the givencrypt operation on the underlying cipher instead of encrypt.

Signed-off-by: Herbert Xu <[email protected]>
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@herbertx
herbertx committed Jan 10, 2008
1 parent 743edf5 commit e56dd56
Showing 1 changed file with 114 additions and 22 deletions.
136 changes: 114 additions & 22 deletions crypto/authenc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
*
*/

#include <crypto/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/authenc.h>
#include <crypto/scatterwalk.h>
Expand Down Expand Up @@ -87,6 +88,20 @@ static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
goto out;
}

static void authenc_chain(struct scatterlist *head, struct scatterlist *sg,
int chain)
{
if (chain) {
head->length += sg->length;
sg = scatterwalk_sg_next(sg);
}

if (sg)
scatterwalk_sg_chain(head, 2, sg);
else
sg_mark_end(head);
}

static u8 *crypto_authenc_hash(struct aead_request *req, unsigned int flags,
struct scatterlist *cipher,
unsigned int cryptlen)
Expand Down Expand Up @@ -127,27 +142,48 @@ static u8 *crypto_authenc_hash(struct aead_request *req, unsigned int flags,
return hash;
}

static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags)
static int crypto_authenc_genicv(struct aead_request *req, u8 *iv,
unsigned int flags)
{
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
struct scatterlist *dst = req->dst;
unsigned int cryptlen = req->cryptlen;
struct scatterlist cipher[2];
struct page *dstp;
unsigned int ivsize = crypto_aead_ivsize(authenc);
unsigned int cryptlen;
u8 *vdst;
u8 *hash;

hash = crypto_authenc_hash(req, flags, dst, cryptlen);
dstp = sg_page(dst);
vdst = PageHighMem(dstp) ? NULL : page_address(dstp) + dst->offset;

sg_init_table(cipher, 2);
sg_set_buf(cipher, iv, ivsize);
authenc_chain(cipher, dst, vdst == iv + ivsize);

cryptlen = req->cryptlen + ivsize;
hash = crypto_authenc_hash(req, flags, cipher, cryptlen);
if (IS_ERR(hash))
return PTR_ERR(hash);

scatterwalk_map_and_copy(hash, dst, cryptlen,
scatterwalk_map_and_copy(hash, cipher, cryptlen,
crypto_aead_authsize(authenc), 1);
return 0;
}

static void crypto_authenc_encrypt_done(struct crypto_async_request *req,
int err)
{
if (!err)
err = crypto_authenc_genicv(req->data, 0);
if (!err) {
struct aead_request *areq = req->data;
struct crypto_aead *authenc = crypto_aead_reqtfm(areq);
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
struct ablkcipher_request *abreq = aead_request_ctx(areq);
u8 *iv = (u8 *)(abreq + 1) +
crypto_ablkcipher_reqsize(ctx->enc);

err = crypto_authenc_genicv(areq, iv, 0);
}

aead_request_complete(req->data, err);
}
Expand All @@ -157,45 +193,99 @@ static int crypto_authenc_encrypt(struct aead_request *req)
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
struct ablkcipher_request *abreq = aead_request_ctx(req);
struct crypto_ablkcipher *enc = ctx->enc;
struct scatterlist *dst = req->dst;
unsigned int cryptlen = req->cryptlen;
u8 *iv = (u8 *)(abreq + 1) + crypto_ablkcipher_reqsize(enc);
int err;

ablkcipher_request_set_tfm(abreq, ctx->enc);
ablkcipher_request_set_tfm(abreq, enc);
ablkcipher_request_set_callback(abreq, aead_request_flags(req),
crypto_authenc_encrypt_done, req);
ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen,
req->iv);
ablkcipher_request_set_crypt(abreq, req->src, dst, cryptlen, req->iv);

memcpy(iv, req->iv, crypto_aead_ivsize(authenc));

err = crypto_ablkcipher_encrypt(abreq);
if (err)
return err;

return crypto_authenc_genicv(req, CRYPTO_TFM_REQ_MAY_SLEEP);
return crypto_authenc_genicv(req, iv, CRYPTO_TFM_REQ_MAY_SLEEP);
}

static void crypto_authenc_givencrypt_done(struct crypto_async_request *req,
int err)
{
if (!err) {
struct aead_givcrypt_request *greq = req->data;

err = crypto_authenc_genicv(&greq->areq, greq->giv, 0);
}

aead_request_complete(req->data, err);
}

static int crypto_authenc_givencrypt(struct aead_givcrypt_request *req)
{
struct crypto_aead *authenc = aead_givcrypt_reqtfm(req);
struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
struct aead_request *areq = &req->areq;
struct skcipher_givcrypt_request *greq = aead_request_ctx(areq);
u8 *iv = req->giv;
int err;

skcipher_givcrypt_set_tfm(greq, ctx->enc);
skcipher_givcrypt_set_callback(greq, aead_request_flags(areq),
crypto_authenc_givencrypt_done, areq);
skcipher_givcrypt_set_crypt(greq, areq->src, areq->dst, areq->cryptlen,
areq->iv);
skcipher_givcrypt_set_giv(greq, iv, req->seq);

err = crypto_skcipher_givencrypt(greq);
if (err)
return err;

return crypto_authenc_genicv(areq, iv, CRYPTO_TFM_REQ_MAY_SLEEP);
}

static int crypto_authenc_verify(struct aead_request *req,
struct scatterlist *cipher,
unsigned int cryptlen)
{
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
u8 *ohash;
u8 *ihash;
struct scatterlist *src = req->src;
unsigned int authsize;

ohash = crypto_authenc_hash(req, CRYPTO_TFM_REQ_MAY_SLEEP, src,
ohash = crypto_authenc_hash(req, CRYPTO_TFM_REQ_MAY_SLEEP, cipher,
cryptlen);
if (IS_ERR(ohash))
return PTR_ERR(ohash);

authsize = crypto_aead_authsize(authenc);
ihash = ohash + authsize;
scatterwalk_map_and_copy(ihash, src, cryptlen, authsize, 0);
scatterwalk_map_and_copy(ihash, cipher, cryptlen, authsize, 0);
return memcmp(ihash, ohash, authsize) ? -EBADMSG: 0;
}

static void crypto_authenc_decrypt_done(struct crypto_async_request *req,
int err)
static int crypto_authenc_iverify(struct aead_request *req, u8 *iv,
unsigned int cryptlen)
{
aead_request_complete(req->data, err);
struct crypto_aead *authenc = crypto_aead_reqtfm(req);
struct scatterlist *src = req->src;
struct scatterlist cipher[2];
struct page *srcp;
unsigned int ivsize = crypto_aead_ivsize(authenc);
u8 *vsrc;

srcp = sg_page(src);
vsrc = PageHighMem(srcp) ? NULL : page_address(srcp) + src->offset;

sg_init_table(cipher, 2);
sg_set_buf(cipher, iv, ivsize);
authenc_chain(cipher, src, vsrc == iv + ivsize);

return crypto_authenc_verify(req, cipher, cryptlen + ivsize);
}

static int crypto_authenc_decrypt(struct aead_request *req)
Expand All @@ -205,21 +295,21 @@ static int crypto_authenc_decrypt(struct aead_request *req)
struct ablkcipher_request *abreq = aead_request_ctx(req);
unsigned int cryptlen = req->cryptlen;
unsigned int authsize = crypto_aead_authsize(authenc);
u8 *iv = req->iv;
int err;

if (cryptlen < authsize)
return -EINVAL;
cryptlen -= authsize;

err = crypto_authenc_verify(req, cryptlen);
err = crypto_authenc_iverify(req, iv, cryptlen);
if (err)
return err;

ablkcipher_request_set_tfm(abreq, ctx->enc);
ablkcipher_request_set_callback(abreq, aead_request_flags(req),
crypto_authenc_decrypt_done, req);
ablkcipher_request_set_crypt(abreq, req->src, req->dst, cryptlen,
req->iv);
req->base.complete, req->base.data);
ablkcipher_request_set_crypt(abreq, req->src, req->dst, cryptlen, iv);

return crypto_ablkcipher_decrypt(abreq);
}
Expand Down Expand Up @@ -248,8 +338,9 @@ static int crypto_authenc_init_tfm(struct crypto_tfm *tfm)
(crypto_hash_alignmask(auth) &
~(crypto_tfm_ctx_alignment() - 1)) +
crypto_hash_digestsize(auth) * 2,
sizeof(struct ablkcipher_request) +
crypto_ablkcipher_reqsize(enc));
sizeof(struct skcipher_givcrypt_request) +
crypto_ablkcipher_reqsize(enc) +
crypto_ablkcipher_ivsize(enc));

spin_lock_init(&ctx->auth_lock);

Expand Down Expand Up @@ -347,6 +438,7 @@ static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb)
inst->alg.cra_aead.setkey = crypto_authenc_setkey;
inst->alg.cra_aead.encrypt = crypto_authenc_encrypt;
inst->alg.cra_aead.decrypt = crypto_authenc_decrypt;
inst->alg.cra_aead.givencrypt = crypto_authenc_givencrypt;

out:
crypto_mod_put(auth);
Expand Down

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