Hi Herbert,
On Nov 26, 2007 9:21 PM, Herbert Xu <[EMAIL PROTECTED]> wrote:
> Here is my attempt at fixing it and optimising it a bit more.
> The idea is that we should only process partial blocks when
> we're at the end. Otherwise we should do whole blocks.
Great patch! I like it more than mine as it captures the essence of
the problem better.
> Please let me know if this works or not.
It works if we change the following:
(1.) both crypto_ctr_crypt_segment() and crypto_ctr_crypt_inplace()
returns "nbytes" instead of 0;
(2.) blkcipher_walk_done() is called with 0 and not "nbytes" after
crypto_ctr_crypt_final().
The final patch (combining yours and the two fixes) is attached to this email.
> Oh any chance you could post a tcrypt patch for the large test?
Sure. I will send it separately. But it will cause considerable bloat
in tcrypt.ko.
One question: Can we use crypto_cipher_encrypt_one() in both
_segment() and _inplace()? It reads better than the function pointer
fn().
Regards,
Swee Heng
diff --git a/crypto/ctr.c b/crypto/ctr.c
index 47e044a..57da7d0 100644
--- a/crypto/ctr.c
+++ b/crypto/ctr.c
@@ -59,6 +59,21 @@ static int crypto_ctr_setkey(struct crypto_tfm *parent,
const u8 *key,
return err;
}
+static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
+ struct crypto_cipher *tfm, u8 *ctrblk,
+ unsigned int countersize)
+{
+ unsigned int bsize = crypto_cipher_blocksize(tfm);
+ u8 *keystream = ctrblk + bsize;
+ u8 *src = walk->src.virt.addr;
+ u8 *dst = walk->dst.virt.addr;
+ unsigned int nbytes = walk->nbytes;
+
+ crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
+ crypto_xor(keystream, src, nbytes);
+ memcpy(dst, keystream, nbytes);
+}
+
static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
struct crypto_cipher *tfm, u8 *ctrblk,
unsigned int countersize)
@@ -66,35 +81,23 @@ static int crypto_ctr_crypt_segment(struct blkcipher_walk
*walk,
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) |
- (__alignof__(u32) - 1);
- u8 ks[bsize + alignmask];
- u8 *keystream = (u8 *)ALIGN((unsigned long)ks, alignmask + 1);
u8 *src = walk->src.virt.addr;
u8 *dst = walk->dst.virt.addr;
unsigned int nbytes = walk->nbytes;
do {
/* create keystream */
- fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
- crypto_xor(keystream, src, min(nbytes, bsize));
-
- /* copy result into dst */
- memcpy(dst, keystream, min(nbytes, bsize));
+ fn(crypto_cipher_tfm(tfm), dst, ctrblk);
+ crypto_xor(dst, src, bsize);
/* increment counter in counterblock */
crypto_inc(ctrblk + bsize - countersize, countersize);
- if (nbytes < bsize)
- break;
-
src += bsize;
dst += bsize;
- nbytes -= bsize;
-
- } while (nbytes);
+ } while ((nbytes -= bsize) >= bsize);
- return 0;
+ return nbytes;
}
static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
@@ -104,30 +107,22 @@ static int crypto_ctr_crypt_inplace(struct blkcipher_walk
*walk,
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) |
- (__alignof__(u32) - 1);
unsigned int nbytes = walk->nbytes;
u8 *src = walk->src.virt.addr;
- u8 ks[bsize + alignmask];
- u8 *keystream = (u8 *)ALIGN((unsigned long)ks, alignmask + 1);
+ u8 *keystream = ctrblk + bsize;
do {
/* create keystream */
fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
- crypto_xor(src, keystream, min(nbytes, bsize));
+ crypto_xor(src, keystream, bsize);
/* increment counter in counterblock */
crypto_inc(ctrblk + bsize - countersize, countersize);
- if (nbytes < bsize)
- break;
-
src += bsize;
- nbytes -= bsize;
-
- } while (nbytes);
+ } while ((nbytes -= bsize) >= bsize);
- return 0;
+ return nbytes;
}
static int crypto_ctr_crypt(struct blkcipher_desc *desc,
@@ -143,7 +138,7 @@ static int crypto_ctr_crypt(struct blkcipher_desc *desc,
crypto_instance_ctx(crypto_tfm_alg_instance(&tfm->base));
unsigned long alignmask = crypto_cipher_alignmask(child) |
(__alignof__(u32) - 1);
- u8 cblk[bsize + alignmask];
+ u8 cblk[bsize * 2 + alignmask];
u8 *counterblk = (u8 *)ALIGN((unsigned long)cblk, alignmask + 1);
int err;
@@ -158,7 +153,7 @@ static int crypto_ctr_crypt(struct blkcipher_desc *desc,
/* initialize counter portion of counter block */
crypto_inc(counterblk + bsize - ictx->countersize, ictx->countersize);
- while (walk.nbytes) {
+ while (walk.nbytes >= bsize) {
if (walk.src.virt.addr == walk.dst.virt.addr)
nbytes = crypto_ctr_crypt_inplace(&walk, child,
counterblk,
@@ -170,6 +165,13 @@ static int crypto_ctr_crypt(struct blkcipher_desc *desc,
err = blkcipher_walk_done(desc, &walk, nbytes);
}
+
+ if (walk.nbytes) {
+ crypto_ctr_crypt_final(&walk, child, counterblk,
+ ictx->countersize);
+ err = blkcipher_walk_done(desc, &walk, 0);
+ }
+
return err;
}
@@ -277,7 +279,7 @@ static struct crypto_instance *crypto_ctr_alloc(struct
rtattr **tb)
inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
inst->alg.cra_priority = alg->cra_priority;
inst->alg.cra_blocksize = 1;
- inst->alg.cra_alignmask = __alignof__(u32) - 1;
+ inst->alg.cra_alignmask = alg->cra_alignmask | (__alignof__(u32) - 1);
inst->alg.cra_type = &crypto_blkcipher_type;
inst->alg.cra_blkcipher.ivsize = ivsize;
