[CRYPTO] ctr: Refactor into ctr and rfc3686
As discussed previously, this patch moves the basic CTR functionality
into a chainable algorithm called ctr. The IPsec-specific variant of
it is now placed on top with the name rfc3686.
So ctr(aes) gives a chainable cipher with IV size 16 while the IPsec
variant will be called rfc3686(ctr(aes)). This patch also adjusts
gcm accordingly.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/ctr.c b/crypto/ctr.c
index 57da7d0..1052b31 100644
--- a/crypto/ctr.c
+++ b/crypto/ctr.c
@@ -11,6 +11,7 @@
*/
#include <crypto/algapi.h>
+#include <crypto/ctr.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
@@ -19,16 +20,13 @@
#include <linux/scatterlist.h>
#include <linux/slab.h>
-struct ctr_instance_ctx {
- struct crypto_spawn alg;
- unsigned int noncesize;
- unsigned int ivsize;
- unsigned int countersize;
-};
-
struct crypto_ctr_ctx {
struct crypto_cipher *child;
- u8 *nonce;
+};
+
+struct crypto_rfc3686_ctx {
+ struct crypto_blkcipher *child;
+ u8 nonce[CTR_RFC3686_NONCE_SIZE];
};
static int crypto_ctr_setkey(struct crypto_tfm *parent, const u8 *key,
@@ -36,18 +34,7 @@
{
struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(parent);
struct crypto_cipher *child = ctx->child;
- struct ctr_instance_ctx *ictx =
- crypto_instance_ctx(crypto_tfm_alg_instance(parent));
- unsigned int noncelen = ictx->noncesize;
- int err = 0;
-
- /* the nonce is stored in bytes at end of key */
- if (keylen < noncelen)
- return -EINVAL;
-
- memcpy(ctx->nonce, key + (keylen - noncelen), noncelen);
-
- keylen -= noncelen;
+ int err;
crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
@@ -60,11 +47,13 @@
}
static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
- struct crypto_cipher *tfm, u8 *ctrblk,
- unsigned int countersize)
+ struct crypto_cipher *tfm)
{
unsigned int bsize = crypto_cipher_blocksize(tfm);
- u8 *keystream = ctrblk + bsize;
+ unsigned long alignmask = crypto_cipher_alignmask(tfm);
+ u8 *ctrblk = walk->iv;
+ u8 tmp[bsize + alignmask];
+ u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
unsigned int nbytes = walk->nbytes;
@@ -72,15 +61,17 @@
crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
crypto_xor(keystream, src, nbytes);
memcpy(dst, keystream, nbytes);
+
+ crypto_inc(ctrblk, bsize);
}
static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
- struct crypto_cipher *tfm, u8 *ctrblk,
- unsigned int countersize)
+ struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_encrypt;
unsigned int bsize = crypto_cipher_blocksize(tfm);
+ u8 *ctrblk = walk->iv;
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
unsigned int nbytes = walk->nbytes;
@@ -91,7 +82,7 @@
crypto_xor(dst, src, bsize);
/* increment counter in counterblock */
- crypto_inc(ctrblk + bsize - countersize, countersize);
+ crypto_inc(ctrblk, bsize);
src += bsize;
dst += bsize;
@@ -101,15 +92,17 @@
}
static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
- struct crypto_cipher *tfm, u8 *ctrblk,
- unsigned int countersize)
+ struct crypto_cipher *tfm)
{
void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
crypto_cipher_alg(tfm)->cia_encrypt;
unsigned int bsize = crypto_cipher_blocksize(tfm);
+ unsigned long alignmask = crypto_cipher_alignmask(tfm);
unsigned int nbytes = walk->nbytes;
+ u8 *ctrblk = walk->iv;
u8 *src = walk->src.virt.addr;
- u8 *keystream = ctrblk + bsize;
+ u8 tmp[bsize + alignmask];
+ u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
do {
/* create keystream */
@@ -117,7 +110,7 @@
crypto_xor(src, keystream, bsize);
/* increment counter in counterblock */
- crypto_inc(ctrblk + bsize - countersize, countersize);
+ crypto_inc(ctrblk, bsize);
src += bsize;
} while ((nbytes -= bsize) >= bsize);
@@ -134,41 +127,22 @@
struct crypto_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm);
struct crypto_cipher *child = ctx->child;
unsigned int bsize = crypto_cipher_blocksize(child);
- struct ctr_instance_ctx *ictx =
- crypto_instance_ctx(crypto_tfm_alg_instance(&tfm->base));
- unsigned long alignmask = crypto_cipher_alignmask(child) |
- (__alignof__(u32) - 1);
- u8 cblk[bsize * 2 + alignmask];
- u8 *counterblk = (u8 *)ALIGN((unsigned long)cblk, alignmask + 1);
int err;
blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt_block(desc, &walk, bsize);
- /* set up counter block */
- memset(counterblk, 0 , bsize);
- memcpy(counterblk, ctx->nonce, ictx->noncesize);
- memcpy(counterblk + ictx->noncesize, walk.iv, ictx->ivsize);
-
- /* initialize counter portion of counter block */
- crypto_inc(counterblk + bsize - ictx->countersize, ictx->countersize);
-
while (walk.nbytes >= bsize) {
if (walk.src.virt.addr == walk.dst.virt.addr)
- nbytes = crypto_ctr_crypt_inplace(&walk, child,
- counterblk,
- ictx->countersize);
+ nbytes = crypto_ctr_crypt_inplace(&walk, child);
else
- nbytes = crypto_ctr_crypt_segment(&walk, child,
- counterblk,
- ictx->countersize);
+ nbytes = crypto_ctr_crypt_segment(&walk, child);
err = blkcipher_walk_done(desc, &walk, nbytes);
}
if (walk.nbytes) {
- crypto_ctr_crypt_final(&walk, child, counterblk,
- ictx->countersize);
+ crypto_ctr_crypt_final(&walk, child);
err = blkcipher_walk_done(desc, &walk, 0);
}
@@ -178,15 +152,11 @@
static int crypto_ctr_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
- struct ctr_instance_ctx *ictx = crypto_instance_ctx(inst);
+ struct crypto_spawn *spawn = crypto_instance_ctx(inst);
struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_cipher *cipher;
- ctx->nonce = kzalloc(ictx->noncesize, GFP_KERNEL);
- if (!ctx->nonce)
- return -ENOMEM;
-
- cipher = crypto_spawn_cipher(&ictx->alg);
+ cipher = crypto_spawn_cipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
@@ -199,7 +169,6 @@
{
struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
- kfree(ctx->nonce);
crypto_free_cipher(ctx->child);
}
@@ -207,10 +176,6 @@
{
struct crypto_instance *inst;
struct crypto_alg *alg;
- struct ctr_instance_ctx *ictx;
- unsigned int noncesize;
- unsigned int ivsize;
- unsigned int countersize;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
@@ -222,71 +187,28 @@
if (IS_ERR(alg))
return ERR_PTR(PTR_ERR(alg));
- err = crypto_attr_u32(tb[2], &noncesize);
- if (err)
- goto out_put_alg;
-
- err = crypto_attr_u32(tb[3], &ivsize);
- if (err)
- goto out_put_alg;
-
- err = crypto_attr_u32(tb[4], &countersize);
- if (err)
- goto out_put_alg;
-
- /* verify size of nonce + iv + counter
- * counter must be >= 4 bytes.
- */
+ /* Block size must be >= 4 bytes. */
err = -EINVAL;
- if (((noncesize + ivsize + countersize) < alg->cra_blocksize) ||
- ((noncesize + ivsize) > alg->cra_blocksize) ||
- (countersize > alg->cra_blocksize) || (countersize < 4))
+ if (alg->cra_blocksize < 4)
goto out_put_alg;
/* If this is false we'd fail the alignment of crypto_inc. */
- if ((alg->cra_blocksize - countersize) % 4)
+ if (alg->cra_blocksize % 4)
goto out_put_alg;
- inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
- err = -ENOMEM;
- if (!inst)
- goto out_put_alg;
+ inst = crypto_alloc_instance("ctr", alg);
+ if (IS_ERR(inst))
+ goto out;
- err = -ENAMETOOLONG;
- if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
- "ctr(%s,%u,%u,%u)", alg->cra_name, noncesize,
- ivsize, countersize) >= CRYPTO_MAX_ALG_NAME) {
- goto err_free_inst;
- }
-
- if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
- "ctr(%s,%u,%u,%u)", alg->cra_driver_name, noncesize,
- ivsize, countersize) >= CRYPTO_MAX_ALG_NAME) {
- goto err_free_inst;
- }
-
- ictx = crypto_instance_ctx(inst);
- ictx->noncesize = noncesize;
- ictx->ivsize = ivsize;
- ictx->countersize = countersize;
-
- err = crypto_init_spawn(&ictx->alg, alg, inst,
- CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
- if (err)
- goto err_free_inst;
-
- err = 0;
inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
inst->alg.cra_priority = alg->cra_priority;
inst->alg.cra_blocksize = 1;
inst->alg.cra_alignmask = alg->cra_alignmask | (__alignof__(u32) - 1);
inst->alg.cra_type = &crypto_blkcipher_type;
- inst->alg.cra_blkcipher.ivsize = ivsize;
- inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize
- + noncesize;
- inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize
- + noncesize;
+ inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
+ inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
+ inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
inst->alg.cra_ctxsize = sizeof(struct crypto_ctr_ctx);
@@ -297,24 +219,18 @@
inst->alg.cra_blkcipher.encrypt = crypto_ctr_crypt;
inst->alg.cra_blkcipher.decrypt = crypto_ctr_crypt;
-err_free_inst:
- if (err)
- kfree(inst);
+out:
+ crypto_mod_put(alg);
+ return inst;
out_put_alg:
- crypto_mod_put(alg);
-
- if (err)
- inst = ERR_PTR(err);
-
- return inst;
+ inst = ERR_PTR(err);
+ goto out;
}
static void crypto_ctr_free(struct crypto_instance *inst)
{
- struct ctr_instance_ctx *ictx = crypto_instance_ctx(inst);
-
- crypto_drop_spawn(&ictx->alg);
+ crypto_drop_spawn(crypto_instance_ctx(inst));
kfree(inst);
}
@@ -325,13 +241,174 @@
.module = THIS_MODULE,
};
+static int crypto_rfc3686_setkey(struct crypto_tfm *parent, const u8 *key,
+ unsigned int keylen)
+{
+ struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(parent);
+ struct crypto_blkcipher *child = ctx->child;
+ int err;
+
+ /* the nonce is stored in bytes at end of key */
+ if (keylen < CTR_RFC3686_NONCE_SIZE)
+ return -EINVAL;
+
+ memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
+ CTR_RFC3686_NONCE_SIZE);
+
+ keylen -= CTR_RFC3686_NONCE_SIZE;
+
+ crypto_blkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+ crypto_blkcipher_set_flags(child, crypto_tfm_get_flags(parent) &
+ CRYPTO_TFM_REQ_MASK);
+ err = crypto_blkcipher_setkey(child, key, keylen);
+ crypto_tfm_set_flags(parent, crypto_blkcipher_get_flags(child) &
+ CRYPTO_TFM_RES_MASK);
+
+ return err;
+}
+
+static int crypto_rfc3686_crypt(struct blkcipher_desc *desc,
+ struct scatterlist *dst,
+ struct scatterlist *src, unsigned int nbytes)
+{
+ struct crypto_blkcipher *tfm = desc->tfm;
+ struct crypto_rfc3686_ctx *ctx = crypto_blkcipher_ctx(tfm);
+ struct crypto_blkcipher *child = ctx->child;
+ unsigned long alignmask = crypto_blkcipher_alignmask(tfm);
+ u8 ivblk[CTR_RFC3686_BLOCK_SIZE + alignmask];
+ u8 *iv = PTR_ALIGN(ivblk + 0, alignmask + 1);
+ u8 *info = desc->info;
+ int err;
+
+ /* set up counter block */
+ memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
+ memcpy(iv + CTR_RFC3686_NONCE_SIZE, info, CTR_RFC3686_IV_SIZE);
+
+ /* initialize counter portion of counter block */
+ *(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
+ cpu_to_be32(1);
+
+ desc->tfm = child;
+ desc->info = iv;
+ err = crypto_blkcipher_encrypt_iv(desc, dst, src, nbytes);
+ desc->tfm = tfm;
+ desc->info = info;
+
+ return err;
+}
+
+static int crypto_rfc3686_init_tfm(struct crypto_tfm *tfm)
+{
+ struct crypto_instance *inst = (void *)tfm->__crt_alg;
+ struct crypto_spawn *spawn = crypto_instance_ctx(inst);
+ struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
+ struct crypto_blkcipher *cipher;
+
+ cipher = crypto_spawn_blkcipher(spawn);
+ if (IS_ERR(cipher))
+ return PTR_ERR(cipher);
+
+ ctx->child = cipher;
+
+ return 0;
+}
+
+static void crypto_rfc3686_exit_tfm(struct crypto_tfm *tfm)
+{
+ struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ crypto_free_blkcipher(ctx->child);
+}
+
+static struct crypto_instance *crypto_rfc3686_alloc(struct rtattr **tb)
+{
+ struct crypto_instance *inst;
+ struct crypto_alg *alg;
+ int err;
+
+ err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
+ if (err)
+ return ERR_PTR(err);
+
+ alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_BLKCIPHER,
+ CRYPTO_ALG_TYPE_MASK);
+ err = PTR_ERR(alg);
+ if (IS_ERR(alg))
+ return ERR_PTR(err);
+
+ /* We only support 16-byte blocks. */
+ err = -EINVAL;
+ if (alg->cra_blkcipher.ivsize != CTR_RFC3686_BLOCK_SIZE)
+ goto out_put_alg;
+
+ /* Not a stream cipher? */
+ if (alg->cra_blocksize != 1)
+ goto out_put_alg;
+
+ inst = crypto_alloc_instance("rfc3686", alg);
+ if (IS_ERR(inst))
+ goto out;
+
+ inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
+ inst->alg.cra_priority = alg->cra_priority;
+ inst->alg.cra_blocksize = 1;
+ inst->alg.cra_alignmask = alg->cra_alignmask;
+ inst->alg.cra_type = &crypto_blkcipher_type;
+
+ inst->alg.cra_blkcipher.ivsize = CTR_RFC3686_IV_SIZE;
+ inst->alg.cra_blkcipher.min_keysize = alg->cra_blkcipher.min_keysize
+ + CTR_RFC3686_NONCE_SIZE;
+ inst->alg.cra_blkcipher.max_keysize = alg->cra_blkcipher.max_keysize
+ + CTR_RFC3686_NONCE_SIZE;
+
+ inst->alg.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
+
+ inst->alg.cra_init = crypto_rfc3686_init_tfm;
+ inst->alg.cra_exit = crypto_rfc3686_exit_tfm;
+
+ inst->alg.cra_blkcipher.setkey = crypto_rfc3686_setkey;
+ inst->alg.cra_blkcipher.encrypt = crypto_rfc3686_crypt;
+ inst->alg.cra_blkcipher.decrypt = crypto_rfc3686_crypt;
+
+out:
+ crypto_mod_put(alg);
+ return inst;
+
+out_put_alg:
+ inst = ERR_PTR(err);
+ goto out;
+}
+
+static struct crypto_template crypto_rfc3686_tmpl = {
+ .name = "rfc3686",
+ .alloc = crypto_rfc3686_alloc,
+ .free = crypto_ctr_free,
+ .module = THIS_MODULE,
+};
+
static int __init crypto_ctr_module_init(void)
{
- return crypto_register_template(&crypto_ctr_tmpl);
+ int err;
+
+ err = crypto_register_template(&crypto_ctr_tmpl);
+ if (err)
+ goto out;
+
+ err = crypto_register_template(&crypto_rfc3686_tmpl);
+ if (err)
+ goto out_drop_ctr;
+
+out:
+ return err;
+
+out_drop_ctr:
+ crypto_unregister_template(&crypto_ctr_tmpl);
+ goto out;
}
static void __exit crypto_ctr_module_exit(void)
{
+ crypto_unregister_template(&crypto_rfc3686_tmpl);
crypto_unregister_template(&crypto_ctr_tmpl);
}
@@ -340,3 +417,4 @@
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("CTR Counter block mode");
+MODULE_ALIAS("rfc3686");