From 95477377995aefa2ec1654a9a3777bd57ea99146 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Wed, 6 Jul 2005 13:52:09 -0700 Subject: [PATCH] [CRYPTO] Add alignmask for low-level cipher implementations The VIA Padlock device requires the input and output buffers to be aligned on 16-byte boundaries. This patch adds the alignmask attribute for low-level cipher implementations to indicate their alignment requirements. The mid-level crypt() function will copy the input/output buffers if they are not aligned correctly before they are passed to the low-level implementation. Strictly speaking, some of the software implementations require the buffers to be aligned on 4-byte boundaries as they do 32-bit loads. However, it is not clear whether it is better to copy the buffers or pay the penalty for unaligned loads/stores. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- crypto/api.c | 6 ++++++ crypto/cipher.c | 43 +++++++++++++++++++++++++++++++++++------- crypto/scatterwalk.h | 6 ++++++ include/linux/crypto.h | 1 + 4 files changed, 49 insertions(+), 7 deletions(-) diff --git a/crypto/api.c b/crypto/api.c index 394169a8577..f55856b2199 100644 --- a/crypto/api.c +++ b/crypto/api.c @@ -168,6 +168,12 @@ int crypto_register_alg(struct crypto_alg *alg) { int ret = 0; struct crypto_alg *q; + + if (alg->cra_alignmask & (alg->cra_alignmask + 1)) + return -EINVAL; + + if (alg->cra_alignmask > PAGE_SIZE) + return -EINVAL; down_write(&crypto_alg_sem); diff --git a/crypto/cipher.c b/crypto/cipher.c index 54c4a560070..85eb12f8e56 100644 --- a/crypto/cipher.c +++ b/crypto/cipher.c @@ -41,8 +41,10 @@ static unsigned int crypt_slow(const struct cipher_desc *desc, struct scatter_walk *in, struct scatter_walk *out, unsigned int bsize) { - u8 src[bsize]; - u8 dst[bsize]; + unsigned int alignmask = desc->tfm->__crt_alg->cra_alignmask; + u8 buffer[bsize * 2 + alignmask]; + u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); + u8 *dst = src + bsize; unsigned int n; n = scatterwalk_copychunks(src, in, bsize, 0); @@ -59,15 +61,24 @@ static unsigned int crypt_slow(const struct cipher_desc *desc, static inline unsigned int crypt_fast(const struct cipher_desc *desc, struct scatter_walk *in, struct scatter_walk *out, - unsigned int nbytes) + unsigned int nbytes, u8 *tmp) { u8 *src, *dst; src = in->data; dst = scatterwalk_samebuf(in, out) ? src : out->data; + if (tmp) { + memcpy(tmp, in->data, nbytes); + src = tmp; + dst = tmp; + } + nbytes = desc->prfn(desc, dst, src, nbytes); + if (tmp) + memcpy(out->data, tmp, nbytes); + scatterwalk_advance(in, nbytes); scatterwalk_advance(out, nbytes); @@ -87,6 +98,8 @@ static int crypt(const struct cipher_desc *desc, struct scatter_walk walk_in, walk_out; struct crypto_tfm *tfm = desc->tfm; const unsigned int bsize = crypto_tfm_alg_blocksize(tfm); + unsigned int alignmask = tfm->__crt_alg->cra_alignmask; + unsigned long buffer = 0; if (!nbytes) return 0; @@ -100,16 +113,27 @@ static int crypt(const struct cipher_desc *desc, scatterwalk_start(&walk_out, dst); for(;;) { - unsigned int n; + unsigned int n = nbytes; + u8 *tmp = NULL; + + if (!scatterwalk_aligned(&walk_in, alignmask) || + !scatterwalk_aligned(&walk_out, alignmask)) { + if (!buffer) { + buffer = __get_free_page(GFP_ATOMIC); + if (!buffer) + n = 0; + } + tmp = (u8 *)buffer; + } scatterwalk_map(&walk_in, 0); scatterwalk_map(&walk_out, 1); - n = scatterwalk_clamp(&walk_in, nbytes); + n = scatterwalk_clamp(&walk_in, n); n = scatterwalk_clamp(&walk_out, n); if (likely(n >= bsize)) - n = crypt_fast(desc, &walk_in, &walk_out, n); + n = crypt_fast(desc, &walk_in, &walk_out, n, tmp); else n = crypt_slow(desc, &walk_in, &walk_out, bsize); @@ -119,10 +143,15 @@ static int crypt(const struct cipher_desc *desc, scatterwalk_done(&walk_out, 1, nbytes); if (!nbytes) - return 0; + break; crypto_yield(tfm); } + + if (buffer) + free_page(buffer); + + return 0; } static unsigned int cbc_process_encrypt(const struct cipher_desc *desc, diff --git a/crypto/scatterwalk.h b/crypto/scatterwalk.h index 5495bb97081..e79925c474a 100644 --- a/crypto/scatterwalk.h +++ b/crypto/scatterwalk.h @@ -55,6 +55,12 @@ static inline void scatterwalk_advance(struct scatter_walk *walk, walk->len_this_segment -= nbytes; } +static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk, + unsigned int alignmask) +{ + return !(walk->offset & alignmask); +} + void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg); int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, size_t nbytes, int out); void scatterwalk_map(struct scatter_walk *walk, int out); diff --git a/include/linux/crypto.h b/include/linux/crypto.h index 26ce01c2574..ac9d49beecd 100644 --- a/include/linux/crypto.h +++ b/include/linux/crypto.h @@ -124,6 +124,7 @@ struct crypto_alg { u32 cra_flags; unsigned int cra_blocksize; unsigned int cra_ctxsize; + unsigned int cra_alignmask; const char cra_name[CRYPTO_MAX_ALG_NAME]; union { -- 2.20.1