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linux/crypto/ccm.c
James Yonan 6bf37e5aa9 crypto: crypto_memneq - add equality testing of memory regions w/o timing leaks 
When comparing MAC hashes, AEAD authentication tags, or other hash
values in the context of authentication or integrity checking, it
is important not to leak timing information to a potential attacker,
i.e. when communication happens over a network.

Bytewise memory comparisons (such as memcmp) are usually optimized so
that they return a nonzero value as soon as a mismatch is found. E.g,
on x86_64/i5 for 512 bytes this can be ~50 cyc for a full mismatch
and up to ~850 cyc for a full match (cold). This early-return behavior
can leak timing information as a side channel, allowing an attacker to
iteratively guess the correct result.

This patch adds a new method crypto_memneq ("memory not equal to each
other") to the crypto API that compares memory areas of the same length
in roughly "constant time" (cache misses could change the timing, but
since they don't reveal information about the content of the strings
being compared, they are effectively benign). Iow, best and worst case
behaviour take the same amount of time to complete (in contrast to
memcmp).

Note that crypto_memneq (unlike memcmp) can only be used to test for
equality or inequality, NOT for lexicographical order. This, however,
is not an issue for its use-cases within the crypto API.

We tried to locate all of the places in the crypto API where memcmp was
being used for authentication or integrity checking, and convert them
over to crypto_memneq.

crypto_memneq is declared noinline, placed in its own source file,
and compiled with optimizations that might increase code size disabled
("Os") because a smart compiler (or LTO) might notice that the return
value is always compared against zero/nonzero, and might then
reintroduce the same early-return optimization that we are trying to
avoid.

Using #pragma or __attribute__ optimization annotations of the code
for disabling optimization was avoided as it seems to be considered
broken or unmaintained for long time in GCC [1]. Therefore, we work
around that by specifying the compile flag for memneq.o directly in
the Makefile. We found that this seems to be most appropriate.

As we use ("Os"), this patch also provides a loop-free "fast-path" for
frequently used 16 byte digests. Similarly to kernel library string
functions, leave an option for future even further optimized architecture
specific assembler implementations.

This was a joint work of James Yonan and Daniel Borkmann. Also thanks
for feedback from Florian Weimer on this and earlier proposals [2].

  [1] http://gcc.gnu.org/ml/gcc/2012-07/msg00211.html
  [2] https://lkml.org/lkml/2013/2/10/131

Signed-off-by: James Yonan <james@openvpn.net>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2013-10-07 14:17:06 +08:00

883 lines
21 KiB
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/*
* CCM: Counter with CBC-MAC
*
* (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
*
* 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; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "internal.h"
struct ccm_instance_ctx {
struct crypto_skcipher_spawn ctr;
struct crypto_spawn cipher;
};
struct crypto_ccm_ctx {
struct crypto_cipher *cipher;
struct crypto_ablkcipher *ctr;
};
struct crypto_rfc4309_ctx {
struct crypto_aead *child;
u8 nonce[3];
};
struct crypto_ccm_req_priv_ctx {
u8 odata[16];
u8 idata[16];
u8 auth_tag[16];
u32 ilen;
u32 flags;
struct scatterlist src[2];
struct scatterlist dst[2];
struct ablkcipher_request abreq;
};
static inline struct crypto_ccm_req_priv_ctx *crypto_ccm_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 set_msg_len(u8 *block, unsigned int msglen, int csize)
{
__be32 data;
memset(block, 0, csize);
block += csize;
if (csize >= 4)
csize = 4;
else if (msglen > (1 << (8 * csize)))
return -EOVERFLOW;
data = cpu_to_be32(msglen);
memcpy(block - csize, (u8 *)&data + 4 - csize, csize);
return 0;
}
static int crypto_ccm_setkey(struct crypto_aead *aead, const u8 *key,
unsigned int keylen)
{
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_ablkcipher *ctr = ctx->ctr;
struct crypto_cipher *tfm = ctx->cipher;
int err = 0;
crypto_ablkcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
crypto_ablkcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
CRYPTO_TFM_REQ_MASK);
err = crypto_ablkcipher_setkey(ctr, key, keylen);
crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctr) &
CRYPTO_TFM_RES_MASK);
if (err)
goto out;
crypto_cipher_clear_flags(tfm, CRYPTO_TFM_REQ_MASK);
crypto_cipher_set_flags(tfm, crypto_aead_get_flags(aead) &
CRYPTO_TFM_REQ_MASK);
err = crypto_cipher_setkey(tfm, key, keylen);
crypto_aead_set_flags(aead, crypto_cipher_get_flags(tfm) &
CRYPTO_TFM_RES_MASK);
out:
return err;
}
static int crypto_ccm_setauthsize(struct crypto_aead *tfm,
unsigned int authsize)
{
switch (authsize) {
case 4:
case 6:
case 8:
case 10:
case 12:
case 14:
case 16:
break;
default:
return -EINVAL;
}
return 0;
}
static int format_input(u8 *info, struct aead_request *req,
unsigned int cryptlen)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
unsigned int lp = req->iv[0];
unsigned int l = lp + 1;
unsigned int m;
m = crypto_aead_authsize(aead);
memcpy(info, req->iv, 16);
/* format control info per RFC 3610 and
* NIST Special Publication 800-38C
*/
*info |= (8 * ((m - 2) / 2));
if (req->assoclen)
*info |= 64;
return set_msg_len(info + 16 - l, cryptlen, l);
}
static int format_adata(u8 *adata, unsigned int a)
{
int len = 0;
/* add control info for associated data
* RFC 3610 and NIST Special Publication 800-38C
*/
if (a < 65280) {
*(__be16 *)adata = cpu_to_be16(a);
len = 2;
} else {
*(__be16 *)adata = cpu_to_be16(0xfffe);
*(__be32 *)&adata[2] = cpu_to_be32(a);
len = 6;
}
return len;
}
static void compute_mac(struct crypto_cipher *tfm, u8 *data, int n,
struct crypto_ccm_req_priv_ctx *pctx)
{
unsigned int bs = 16;
u8 *odata = pctx->odata;
u8 *idata = pctx->idata;
int datalen, getlen;
datalen = n;
/* first time in here, block may be partially filled. */
getlen = bs - pctx->ilen;
if (datalen >= getlen) {
memcpy(idata + pctx->ilen, data, getlen);
crypto_xor(odata, idata, bs);
crypto_cipher_encrypt_one(tfm, odata, odata);
datalen -= getlen;
data += getlen;
pctx->ilen = 0;
}
/* now encrypt rest of data */
while (datalen >= bs) {
crypto_xor(odata, data, bs);
crypto_cipher_encrypt_one(tfm, odata, odata);
datalen -= bs;
data += bs;
}
/* check and see if there's leftover data that wasn't
* enough to fill a block.
*/
if (datalen) {
memcpy(idata + pctx->ilen, data, datalen);
pctx->ilen += datalen;
}
}
static void get_data_to_compute(struct crypto_cipher *tfm,
struct crypto_ccm_req_priv_ctx *pctx,
struct scatterlist *sg, unsigned int len)
{
struct scatter_walk walk;
u8 *data_src;
int n;
scatterwalk_start(&walk, sg);
while (len) {
n = scatterwalk_clamp(&walk, len);
if (!n) {
scatterwalk_start(&walk, sg_next(walk.sg));
n = scatterwalk_clamp(&walk, len);
}
data_src = scatterwalk_map(&walk);
compute_mac(tfm, data_src, n, pctx);
len -= n;
scatterwalk_unmap(data_src);
scatterwalk_advance(&walk, n);
scatterwalk_done(&walk, 0, len);
if (len)
crypto_yield(pctx->flags);
}
/* any leftover needs padding and then encrypted */
if (pctx->ilen) {
int padlen;
u8 *odata = pctx->odata;
u8 *idata = pctx->idata;
padlen = 16 - pctx->ilen;
memset(idata + pctx->ilen, 0, padlen);
crypto_xor(odata, idata, 16);
crypto_cipher_encrypt_one(tfm, odata, odata);
pctx->ilen = 0;
}
}
static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain,
unsigned int cryptlen)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
struct crypto_cipher *cipher = ctx->cipher;
unsigned int assoclen = req->assoclen;
u8 *odata = pctx->odata;
u8 *idata = pctx->idata;
int err;
/* format control data for input */
err = format_input(odata, req, cryptlen);
if (err)
goto out;
/* encrypt first block to use as start in computing mac */
crypto_cipher_encrypt_one(cipher, odata, odata);
/* format associated data and compute into mac */
if (assoclen) {
pctx->ilen = format_adata(idata, assoclen);
get_data_to_compute(cipher, pctx, req->assoc, req->assoclen);
} else {
pctx->ilen = 0;
}
/* compute plaintext into mac */
get_data_to_compute(cipher, pctx, plain, cryptlen);
out:
return err;
}
static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err)
{
struct aead_request *req = areq->data;
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
u8 *odata = pctx->odata;
if (!err)
scatterwalk_map_and_copy(odata, req->dst, req->cryptlen,
crypto_aead_authsize(aead), 1);
aead_request_complete(req, err);
}
static inline int crypto_ccm_check_iv(const u8 *iv)
{
/* 2 <= L <= 8, so 1 <= L' <= 7. */
if (1 > iv[0] || iv[0] > 7)
return -EINVAL;
return 0;
}
static int crypto_ccm_encrypt(struct aead_request *req)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
struct ablkcipher_request *abreq = &pctx->abreq;
struct scatterlist *dst;
unsigned int cryptlen = req->cryptlen;
u8 *odata = pctx->odata;
u8 *iv = req->iv;
int err;
err = crypto_ccm_check_iv(iv);
if (err)
return err;
pctx->flags = aead_request_flags(req);
err = crypto_ccm_auth(req, req->src, cryptlen);
if (err)
return err;
/* Note: rfc 3610 and NIST 800-38C require counter of
* zero to encrypt auth tag.
*/
memset(iv + 15 - iv[0], 0, iv[0] + 1);
sg_init_table(pctx->src, 2);
sg_set_buf(pctx->src, odata, 16);
scatterwalk_sg_chain(pctx->src, 2, req->src);
dst = pctx->src;
if (req->src != req->dst) {
sg_init_table(pctx->dst, 2);
sg_set_buf(pctx->dst, odata, 16);
scatterwalk_sg_chain(pctx->dst, 2, req->dst);
dst = pctx->dst;
}
ablkcipher_request_set_tfm(abreq, ctx->ctr);
ablkcipher_request_set_callback(abreq, pctx->flags,
crypto_ccm_encrypt_done, req);
ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
err = crypto_ablkcipher_encrypt(abreq);
if (err)
return err;
/* copy authtag to end of dst */
scatterwalk_map_and_copy(odata, req->dst, cryptlen,
crypto_aead_authsize(aead), 1);
return err;
}
static void crypto_ccm_decrypt_done(struct crypto_async_request *areq,
int err)
{
struct aead_request *req = areq->data;
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
struct crypto_aead *aead = crypto_aead_reqtfm(req);
unsigned int authsize = crypto_aead_authsize(aead);
unsigned int cryptlen = req->cryptlen - authsize;
if (!err) {
err = crypto_ccm_auth(req, req->dst, cryptlen);
if (!err && crypto_memneq(pctx->auth_tag, pctx->odata, authsize))
err = -EBADMSG;
}
aead_request_complete(req, err);
}
static int crypto_ccm_decrypt(struct aead_request *req)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
struct ablkcipher_request *abreq = &pctx->abreq;
struct scatterlist *dst;
unsigned int authsize = crypto_aead_authsize(aead);
unsigned int cryptlen = req->cryptlen;
u8 *authtag = pctx->auth_tag;
u8 *odata = pctx->odata;
u8 *iv = req->iv;
int err;
if (cryptlen < authsize)
return -EINVAL;
cryptlen -= authsize;
err = crypto_ccm_check_iv(iv);
if (err)
return err;
pctx->flags = aead_request_flags(req);
scatterwalk_map_and_copy(authtag, req->src, cryptlen, authsize, 0);
memset(iv + 15 - iv[0], 0, iv[0] + 1);
sg_init_table(pctx->src, 2);
sg_set_buf(pctx->src, authtag, 16);
scatterwalk_sg_chain(pctx->src, 2, req->src);
dst = pctx->src;
if (req->src != req->dst) {
sg_init_table(pctx->dst, 2);
sg_set_buf(pctx->dst, authtag, 16);
scatterwalk_sg_chain(pctx->dst, 2, req->dst);
dst = pctx->dst;
}
ablkcipher_request_set_tfm(abreq, ctx->ctr);
ablkcipher_request_set_callback(abreq, pctx->flags,
crypto_ccm_decrypt_done, req);
ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
err = crypto_ablkcipher_decrypt(abreq);
if (err)
return err;
err = crypto_ccm_auth(req, req->dst, cryptlen);
if (err)
return err;
/* verify */
if (crypto_memneq(authtag, odata, authsize))
return -EBADMSG;
return err;
}
static int crypto_ccm_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct ccm_instance_ctx *ictx = crypto_instance_ctx(inst);
struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_cipher *cipher;
struct crypto_ablkcipher *ctr;
unsigned long align;
int err;
cipher = crypto_spawn_cipher(&ictx->cipher);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctr = crypto_spawn_skcipher(&ictx->ctr);
err = PTR_ERR(ctr);
if (IS_ERR(ctr))
goto err_free_cipher;
ctx->cipher = cipher;
ctx->ctr = ctr;
align = crypto_tfm_alg_alignmask(tfm);
align &= ~(crypto_tfm_ctx_alignment() - 1);
tfm->crt_aead.reqsize = align +
sizeof(struct crypto_ccm_req_priv_ctx) +
crypto_ablkcipher_reqsize(ctr);
return 0;
err_free_cipher:
crypto_free_cipher(cipher);
return err;
}
static void crypto_ccm_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_cipher(ctx->cipher);
crypto_free_ablkcipher(ctx->ctr);
}
static struct crypto_instance *crypto_ccm_alloc_common(struct rtattr **tb,
const char *full_name,
const char *ctr_name,
const char *cipher_name)
{
struct crypto_attr_type *algt;
struct crypto_instance *inst;
struct crypto_alg *ctr;
struct crypto_alg *cipher;
struct ccm_instance_ctx *ictx;
int err;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return ERR_CAST(algt);
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return ERR_PTR(-EINVAL);
cipher = crypto_alg_mod_lookup(cipher_name, CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
if (IS_ERR(cipher))
return ERR_CAST(cipher);
err = -EINVAL;
if (cipher->cra_blocksize != 16)
goto out_put_cipher;
inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
err = -ENOMEM;
if (!inst)
goto out_put_cipher;
ictx = crypto_instance_ctx(inst);
err = crypto_init_spawn(&ictx->cipher, cipher, inst,
CRYPTO_ALG_TYPE_MASK);
if (err)
goto err_free_inst;
crypto_set_skcipher_spawn(&ictx->ctr, inst);
err = crypto_grab_skcipher(&ictx->ctr, ctr_name, 0,
crypto_requires_sync(algt->type,
algt->mask));
if (err)
goto err_drop_cipher;
ctr = crypto_skcipher_spawn_alg(&ictx->ctr);
/* Not a stream cipher? */
err = -EINVAL;
if (ctr->cra_blocksize != 1)
goto err_drop_ctr;
/* We want the real thing! */
if (ctr->cra_ablkcipher.ivsize != 16)
goto err_drop_ctr;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"ccm_base(%s,%s)", ctr->cra_driver_name,
cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
goto err_drop_ctr;
memcpy(inst->alg.cra_name, full_name, CRYPTO_MAX_ALG_NAME);
inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
inst->alg.cra_flags |= ctr->cra_flags & CRYPTO_ALG_ASYNC;
inst->alg.cra_priority = cipher->cra_priority + ctr->cra_priority;
inst->alg.cra_blocksize = 1;
inst->alg.cra_alignmask = cipher->cra_alignmask | ctr->cra_alignmask |
(__alignof__(u32) - 1);
inst->alg.cra_type = &crypto_aead_type;
inst->alg.cra_aead.ivsize = 16;
inst->alg.cra_aead.maxauthsize = 16;
inst->alg.cra_ctxsize = sizeof(struct crypto_ccm_ctx);
inst->alg.cra_init = crypto_ccm_init_tfm;
inst->alg.cra_exit = crypto_ccm_exit_tfm;
inst->alg.cra_aead.setkey = crypto_ccm_setkey;
inst->alg.cra_aead.setauthsize = crypto_ccm_setauthsize;
inst->alg.cra_aead.encrypt = crypto_ccm_encrypt;
inst->alg.cra_aead.decrypt = crypto_ccm_decrypt;
out:
crypto_mod_put(cipher);
return inst;
err_drop_ctr:
crypto_drop_skcipher(&ictx->ctr);
err_drop_cipher:
crypto_drop_spawn(&ictx->cipher);
err_free_inst:
kfree(inst);
out_put_cipher:
inst = ERR_PTR(err);
goto out;
}
static struct crypto_instance *crypto_ccm_alloc(struct rtattr **tb)
{
const char *cipher_name;
char ctr_name[CRYPTO_MAX_ALG_NAME];
char full_name[CRYPTO_MAX_ALG_NAME];
cipher_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(cipher_name))
return ERR_CAST(cipher_name);
if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
cipher_name) >= CRYPTO_MAX_ALG_NAME)
return ERR_PTR(-ENAMETOOLONG);
if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >=
CRYPTO_MAX_ALG_NAME)
return ERR_PTR(-ENAMETOOLONG);
return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
}
static void crypto_ccm_free(struct crypto_instance *inst)
{
struct ccm_instance_ctx *ctx = crypto_instance_ctx(inst);
crypto_drop_spawn(&ctx->cipher);
crypto_drop_skcipher(&ctx->ctr);
kfree(inst);
}
static struct crypto_template crypto_ccm_tmpl = {
.name = "ccm",
.alloc = crypto_ccm_alloc,
.free = crypto_ccm_free,
.module = THIS_MODULE,
};
static struct crypto_instance *crypto_ccm_base_alloc(struct rtattr **tb)
{
const char *ctr_name;
const char *cipher_name;
char full_name[CRYPTO_MAX_ALG_NAME];
ctr_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(ctr_name))
return ERR_CAST(ctr_name);
cipher_name = crypto_attr_alg_name(tb[2]);
if (IS_ERR(cipher_name))
return ERR_CAST(cipher_name);
if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)",
ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME)
return ERR_PTR(-ENAMETOOLONG);
return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
}
static struct crypto_template crypto_ccm_base_tmpl = {
.name = "ccm_base",
.alloc = crypto_ccm_base_alloc,
.free = crypto_ccm_free,
.module = THIS_MODULE,
};
static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
unsigned int keylen)
{
struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
struct crypto_aead *child = ctx->child;
int err;
if (keylen < 3)
return -EINVAL;
keylen -= 3;
memcpy(ctx->nonce, key + keylen, 3);
crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
err = crypto_aead_setkey(child, key, keylen);
crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
CRYPTO_TFM_RES_MASK);
return err;
}
static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
unsigned int authsize)
{
struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
switch (authsize) {
case 8:
case 12:
case 16:
break;
default:
return -EINVAL;
}
return crypto_aead_setauthsize(ctx->child, authsize);
}
static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
{
struct aead_request *subreq = aead_request_ctx(req);
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_aead *child = ctx->child;
u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
crypto_aead_alignmask(child) + 1);
/* L' */
iv[0] = 3;
memcpy(iv + 1, ctx->nonce, 3);
memcpy(iv + 4, req->iv, 8);
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, req->src, req->dst, req->cryptlen, iv);
aead_request_set_assoc(subreq, req->assoc, req->assoclen);
return subreq;
}
static int crypto_rfc4309_encrypt(struct aead_request *req)
{
req = crypto_rfc4309_crypt(req);
return crypto_aead_encrypt(req);
}
static int crypto_rfc4309_decrypt(struct aead_request *req)
{
req = crypto_rfc4309_crypt(req);
return crypto_aead_decrypt(req);
}
static int crypto_rfc4309_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst);
struct crypto_rfc4309_ctx *ctx = crypto_tfm_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);
tfm->crt_aead.reqsize = sizeof(struct aead_request) +
ALIGN(crypto_aead_reqsize(aead),
crypto_tfm_ctx_alignment()) +
align + 16;
return 0;
}
static void crypto_rfc4309_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_aead(ctx->child);
}
static struct crypto_instance *crypto_rfc4309_alloc(struct rtattr **tb)
{
struct crypto_attr_type *algt;
struct crypto_instance *inst;
struct crypto_aead_spawn *spawn;
struct crypto_alg *alg;
const char *ccm_name;
int err;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return ERR_CAST(algt);
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return ERR_PTR(-EINVAL);
ccm_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(ccm_name))
return ERR_CAST(ccm_name);
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return ERR_PTR(-ENOMEM);
spawn = crypto_instance_ctx(inst);
crypto_set_aead_spawn(spawn, inst);
err = crypto_grab_aead(spawn, ccm_name, 0,
crypto_requires_sync(algt->type, algt->mask));
if (err)
goto out_free_inst;
alg = crypto_aead_spawn_alg(spawn);
err = -EINVAL;
/* We only support 16-byte blocks. */
if (alg->cra_aead.ivsize != 16)
goto out_drop_alg;
/* Not a stream cipher? */
if (alg->cra_blocksize != 1)
goto out_drop_alg;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
"rfc4309(%s)", alg->cra_name) >= CRYPTO_MAX_ALG_NAME ||
snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"rfc4309(%s)", alg->cra_driver_name) >=
CRYPTO_MAX_ALG_NAME)
goto out_drop_alg;
inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
inst->alg.cra_priority = alg->cra_priority;
inst->alg.cra_blocksize = 1;
inst->alg.cra_alignmask = alg->cra_alignmask;
inst->alg.cra_type = &crypto_nivaead_type;
inst->alg.cra_aead.ivsize = 8;
inst->alg.cra_aead.maxauthsize = 16;
inst->alg.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);
inst->alg.cra_init = crypto_rfc4309_init_tfm;
inst->alg.cra_exit = crypto_rfc4309_exit_tfm;
inst->alg.cra_aead.setkey = crypto_rfc4309_setkey;
inst->alg.cra_aead.setauthsize = crypto_rfc4309_setauthsize;
inst->alg.cra_aead.encrypt = crypto_rfc4309_encrypt;
inst->alg.cra_aead.decrypt = crypto_rfc4309_decrypt;
inst->alg.cra_aead.geniv = "seqiv";
out:
return inst;
out_drop_alg:
crypto_drop_aead(spawn);
out_free_inst:
kfree(inst);
inst = ERR_PTR(err);
goto out;
}
static void crypto_rfc4309_free(struct crypto_instance *inst)
{
crypto_drop_spawn(crypto_instance_ctx(inst));
kfree(inst);
}
static struct crypto_template crypto_rfc4309_tmpl = {
.name = "rfc4309",
.alloc = crypto_rfc4309_alloc,
.free = crypto_rfc4309_free,
.module = THIS_MODULE,
};
static int __init crypto_ccm_module_init(void)
{
int err;
err = crypto_register_template(&crypto_ccm_base_tmpl);
if (err)
goto out;
err = crypto_register_template(&crypto_ccm_tmpl);
if (err)
goto out_undo_base;
err = crypto_register_template(&crypto_rfc4309_tmpl);
if (err)
goto out_undo_ccm;
out:
return err;
out_undo_ccm:
crypto_unregister_template(&crypto_ccm_tmpl);
out_undo_base:
crypto_unregister_template(&crypto_ccm_base_tmpl);
goto out;
}
static void __exit crypto_ccm_module_exit(void)
{
crypto_unregister_template(&crypto_rfc4309_tmpl);
crypto_unregister_template(&crypto_ccm_tmpl);
crypto_unregister_template(&crypto_ccm_base_tmpl);
}
module_init(crypto_ccm_module_init);
module_exit(crypto_ccm_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Counter with CBC MAC");
MODULE_ALIAS("ccm_base");
MODULE_ALIAS("rfc4309");
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