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crypto: algapi - make crypto_xor() take separate dst and src arguments

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There are quite a number of occurrences in the kernel of the pattern

  if (dst != src)
          memcpy(dst, src, walk.total % AES_BLOCK_SIZE);
  crypto_xor(dst, final, walk.total % AES_BLOCK_SIZE);

or

  crypto_xor(keystream, src, nbytes);
  memcpy(dst, keystream, nbytes);

where crypto_xor() is preceded or followed by a memcpy() invocation
that is only there because crypto_xor() uses its output parameter as
one of the inputs. To avoid having to add new instances of this pattern
in the arm64 code, which will be refactored to implement non-SIMD
fallbacks, add an alternative implementation called crypto_xor_cpy(),
taking separate input and output arguments. This removes the need for
the separate memcpy().

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ard Biesheuvel
2017-07-24 11:28:04 +01:00
committed by Herbert Xu
parent a7c391f04f
commit 45fe93dff2
14 changed files with 42 additions and 40 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
crypto/pcbc.c
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@@ -55,8 +55,7 @@ static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,
do {
crypto_xor(iv, src, bsize);
crypto_cipher_encrypt_one(tfm, dst, iv);
memcpy(iv, dst, bsize);
crypto_xor(iv, src, bsize);
crypto_xor_cpy(iv, dst, src, bsize);
src += bsize;
dst += bsize;
@@ -79,8 +78,7 @@ static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,
memcpy(tmpbuf, src, bsize);
crypto_xor(iv, src, bsize);
crypto_cipher_encrypt_one(tfm, src, iv);
memcpy(iv, tmpbuf, bsize);
crypto_xor(iv, src, bsize);
crypto_xor_cpy(iv, tmpbuf, src, bsize);
src += bsize;
} while ((nbytes -= bsize) >= bsize);
@@ -127,8 +125,7 @@ static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,
do {
crypto_cipher_decrypt_one(tfm, dst, src);
crypto_xor(dst, iv, bsize);
memcpy(iv, src, bsize);
crypto_xor(iv, dst, bsize);
crypto_xor_cpy(iv, dst, src, bsize);
src += bsize;
dst += bsize;
@@ -153,8 +150,7 @@ static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,
memcpy(tmpbuf, src, bsize);
crypto_cipher_decrypt_one(tfm, src, src);
crypto_xor(src, iv, bsize);
memcpy(iv, tmpbuf, bsize);
crypto_xor(iv, src, bsize);
crypto_xor_cpy(iv, src, tmpbuf, bsize);
src += bsize;
} while ((nbytes -= bsize) >= bsize);