[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@gondor.apana.org.au>
diff --git a/crypto/blkcipher.c b/crypto/blkcipher.c
index 3d05586..f6c67f9 100644
--- a/crypto/blkcipher.c
+++ b/crypto/blkcipher.c
@@ -84,8 +84,6 @@
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 @@
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 @@
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 @@
{
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 @@
}
}
+ bsize = min(walk->blocksize, n);
n = scatterwalk_clamp(&walk->in, n);
n = scatterwalk_clamp(&walk->out, n);
@@ -277,7 +279,7 @@
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 @@
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 @@
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 @@
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)
{