On Wed, Oct 03, 2007 at 06:17:08PM -0500, Joy Latten wrote:
>
> Since the last block of data to CTR may be a partial block, I changed
> the following in crypto_ctr_crypt_segment(),
Good catch. In that case we can probably merge in_place and
_segment into one function.
> while (walk.nbytes) {
> if (walk.src.virt.addr == walk.dst.virt.addr)
> nbytes = crypto_ctr_crypt_inplace(&walk, ctx,
> counterblk,
> countersize);
> else
> nbytes = crypto_ctr_crypt_segment(&walk, ctx
> counterblk,
> countersize);
>
> err = blkcipher_walk_done(desc, &walk, nbytes);
> }
>
> I assumed that if there is a partial block, it will occur at the
> very end of all the data. However, looking at this loop, I wondered
Good point. We need to change the blkcipher helper so that it
lets you walk by a specified block size instead of the block
size of the algorithm.
The following patch should let you get the desired result if
you call blkcipher_walk_virt_block and specify the underlying
block size.
> > > + u8 counterblk[bsize];
> >
> > This needs to be aligned by the underlying mask and at least 4.
> >
> Ok, sorry I missed that.
> However, I don't understand what the check
> for 4 is for... my bsize should be at least 4?
Depending on the compiler a u8 might only be byte-aligned
regardless of its size.
The 4 is because xor/ctr_inc will access the data in words.
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
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--
[CRYPTO] blkcipher: Added blkcipher_walk_virt_block
This patch adds the helper blkcipher_walk_virt_block which is similar to
blkcipher_walk_virt but uses a supplied block size instead of the block
size of the block cipher. This is useful for CTR where the block size is
1 but we still want to walk by the block size of the underlying cipher.
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
index 1b2a14a..77ee73b 100644
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -84,8 +84,6 @@ static inline unsigned int blkcipher_done_slow(struct crypto_blkcipher *tfm,
static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
unsigned int n)
{
- n = walk->nbytes - n;
-
if (walk->flags & BLKCIPHER_WALK_COPY) {
blkcipher_map_dst(walk);
memcpy(walk->dst.virt.addr, walk->page, n);
@@ -109,13 +107,15 @@ int blkcipher_walk_done(struct blkcipher_desc *desc,
unsigned int nbytes = 0;
if (likely(err >= 0)) {
- unsigned int bsize = crypto_blkcipher_blocksize(tfm);
- unsigned int n;
+ unsigned int n = walk->nbytes - err;
if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
- n = blkcipher_done_fast(walk, err);
- else
- n = blkcipher_done_slow(tfm, walk, bsize);
+ n = blkcipher_done_fast(walk, n);
+ else if (WARN_ON(err)) {
+ err = -EINVAL;
+ goto err;
+ } else
+ n = blkcipher_done_slow(tfm, walk, n);
nbytes = walk->total - n;
err = 0;
@@ -132,6 +132,7 @@ int blkcipher_walk_done(struct blkcipher_desc *desc,
return blkcipher_walk_next(desc, walk);
}
+err:
if (walk->iv != desc->info)
memcpy(desc->info, walk->iv, crypto_blkcipher_ivsize(tfm));
if (walk->buffer != walk->page)
@@ -225,12 +226,12 @@ static int blkcipher_walk_next(struct blkcipher_desc *desc,
{
struct crypto_blkcipher *tfm = desc->tfm;
unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
- unsigned int bsize = crypto_blkcipher_blocksize(tfm);
+ unsigned int bsize;
unsigned int n;
int err;
n = walk->total;
- if (unlikely(n < bsize)) {
+ if (unlikely(n < crypto_blkcipher_blocksize(tfm))) {
desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
return blkcipher_walk_done(desc, walk, -EINVAL);
}
@@ -247,6 +248,7 @@ static int blkcipher_walk_next(struct blkcipher_desc *desc,
}
}
+ bsize = min(walk->blocksize, n);
n = scatterwalk_clamp(&walk->in, n);
n = scatterwalk_clamp(&walk->out, n);
@@ -277,7 +279,7 @@ static inline int blkcipher_copy_iv(struct blkcipher_walk *walk,
struct crypto_blkcipher *tfm,
unsigned int alignmask)
{
- unsigned bs = crypto_blkcipher_blocksize(tfm);
+ unsigned bs = walk->blocksize;
unsigned int ivsize = crypto_blkcipher_ivsize(tfm);
unsigned aligned_bs = ALIGN(bs, alignmask + 1);
unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
@@ -302,6 +304,7 @@ int blkcipher_walk_virt(struct blkcipher_desc *desc,
struct blkcipher_walk *walk)
{
walk->flags &= ~BLKCIPHER_WALK_PHYS;
+ walk->blocksize = crypto_blkcipher_blocksize(desc->tfm);
return blkcipher_walk_first(desc, walk);
}
EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
@@ -310,6 +313,7 @@ int blkcipher_walk_phys(struct blkcipher_desc *desc,
struct blkcipher_walk *walk)
{
walk->flags |= BLKCIPHER_WALK_PHYS;
+ walk->blocksize = crypto_blkcipher_blocksize(desc->tfm);
return blkcipher_walk_first(desc, walk);
}
EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
@@ -342,6 +346,16 @@ static int blkcipher_walk_first(struct blkcipher_desc *desc,
return blkcipher_walk_next(desc, walk);
}
+int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
+ struct blkcipher_walk *walk,
+ unsigned int blocksize)
+{
+ walk->flags &= ~BLKCIPHER_WALK_PHYS;
+ walk->blocksize = blocksize;
+ return blkcipher_walk_first(desc, walk);
+}
+EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
+
static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{
diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index 4af72dc..b9b05d3 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -91,6 +91,7 @@ struct blkcipher_walk {
u8 *iv;
int flags;
+ unsigned int blocksize;
};
extern const struct crypto_type crypto_ablkcipher_type;
@@ -129,6 +130,9 @@ int blkcipher_walk_virt(struct blkcipher_desc *desc,
struct blkcipher_walk *walk);
int blkcipher_walk_phys(struct blkcipher_desc *desc,
struct blkcipher_walk *walk);
+int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
+ struct blkcipher_walk *walk,
+ unsigned int blocksize);
static inline void *crypto_tfm_ctx_aligned(struct crypto_tfm *tfm)
{
-
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