[CRYPTO] Add support for low-level multi-block operations
[linux-2.6.git] / crypto / cipher.c
index f434ce7..54c4a56 100644 (file)
@@ -4,6 +4,7 @@
  * Cipher operations.
  *
  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
 #include "internal.h"
 #include "scatterwalk.h"
 
-typedef void (cryptfn_t)(void *, u8 *, const u8 *);
-typedef void (procfn_t)(struct crypto_tfm *, u8 *,
-                        u8*, cryptfn_t, void *);
-
 static inline void xor_64(u8 *a, const u8 *b)
 {
        ((u32 *)a)[0] ^= ((u32 *)b)[0];
@@ -39,63 +36,57 @@ static inline void xor_128(u8 *a, const u8 *b)
        ((u32 *)a)[2] ^= ((u32 *)b)[2];
        ((u32 *)a)[3] ^= ((u32 *)b)[3];
 }
-static inline void *prepare_src(struct scatter_walk *walk, int bsize,
-                               void *tmp, int in_place)
+
+static unsigned int crypt_slow(const struct cipher_desc *desc,
+                              struct scatter_walk *in,
+                              struct scatter_walk *out, unsigned int bsize)
 {
-       void *src = walk->data;
-       int n = bsize;
+       u8 src[bsize];
+       u8 dst[bsize];
+       unsigned int n;
 
-       if (unlikely(scatterwalk_across_pages(walk, bsize))) {
-               src = tmp;
-               n = scatterwalk_copychunks(src, walk, bsize, 0);
-       }
-       scatterwalk_advance(walk, n);
-       return src;
-}
+       n = scatterwalk_copychunks(src, in, bsize, 0);
+       scatterwalk_advance(in, n);
 
-static inline void *prepare_dst(struct scatter_walk *walk, int bsize,
-                               void *tmp, int in_place)
-{
-       void *dst = walk->data;
+       desc->prfn(desc, dst, src, bsize);
 
-       if (unlikely(scatterwalk_across_pages(walk, bsize)) || in_place)
-               dst = tmp;
-       return dst;
-}
+       n = scatterwalk_copychunks(dst, out, bsize, 1);
+       scatterwalk_advance(out, n);
 
-static inline void complete_src(struct scatter_walk *walk, int bsize,
-                               void *src, int in_place)
-{
+       return bsize;
 }
 
-static inline void complete_dst(struct scatter_walk *walk, int bsize,
-                               void *dst, int in_place)
+static inline unsigned int crypt_fast(const struct cipher_desc *desc,
+                                     struct scatter_walk *in,
+                                     struct scatter_walk *out,
+                                     unsigned int nbytes)
 {
-       int n = bsize;
+       u8 *src, *dst;
+
+       src = in->data;
+       dst = scatterwalk_samebuf(in, out) ? src : out->data;
+
+       nbytes = desc->prfn(desc, dst, src, nbytes);
 
-       if (unlikely(scatterwalk_across_pages(walk, bsize)))
-               n = scatterwalk_copychunks(dst, walk, bsize, 1);
-       else if (in_place)
-               memcpy(walk->data, dst, bsize);
-       scatterwalk_advance(walk, n);
+       scatterwalk_advance(in, nbytes);
+       scatterwalk_advance(out, nbytes);
+
+       return nbytes;
 }
 
 /* 
  * Generic encrypt/decrypt wrapper for ciphers, handles operations across
  * multiple page boundaries by using temporary blocks.  In user context,
- * the kernel is given a chance to schedule us once per block.
+ * the kernel is given a chance to schedule us once per page.
  */
-static int crypt(struct crypto_tfm *tfm,
+static int crypt(const struct cipher_desc *desc,
                 struct scatterlist *dst,
                 struct scatterlist *src,
-                 unsigned int nbytes, cryptfn_t crfn,
-                 procfn_t prfn, void *info)
+                unsigned int nbytes)
 {
        struct scatter_walk walk_in, walk_out;
+       struct crypto_tfm *tfm = desc->tfm;
        const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
-       u8 tmp_src[bsize];
-       u8 tmp_dst[bsize];
 
        if (!nbytes)
                return 0;
@@ -109,29 +100,20 @@ static int crypt(struct crypto_tfm *tfm,
        scatterwalk_start(&walk_out, dst);
 
        for(;;) {
-               u8 *src_p, *dst_p;
-               int in_place;
+               unsigned int n;
 
                scatterwalk_map(&walk_in, 0);
                scatterwalk_map(&walk_out, 1);
 
-               in_place = scatterwalk_samebuf(&walk_in, &walk_out);
-
-               do {
-                       src_p = prepare_src(&walk_in, bsize, tmp_src,
-                                           in_place);
-                       dst_p = prepare_dst(&walk_out, bsize, tmp_dst,
-                                           in_place);
-
-                       prfn(tfm, dst_p, src_p, crfn, info);
+               n = scatterwalk_clamp(&walk_in, nbytes);
+               n = scatterwalk_clamp(&walk_out, n);
 
-                       complete_src(&walk_in, bsize, src_p, in_place);
-                       complete_dst(&walk_out, bsize, dst_p, in_place);
+               if (likely(n >= bsize))
+                       n = crypt_fast(desc, &walk_in, &walk_out, n);
+               else
+                       n = crypt_slow(desc, &walk_in, &walk_out, bsize);
 
-                       nbytes -= bsize;
-               } while (nbytes &&
-                        !scatterwalk_across_pages(&walk_in, bsize) &&
-                        !scatterwalk_across_pages(&walk_out, bsize));
+               nbytes -= n;
 
                scatterwalk_done(&walk_in, 0, nbytes);
                scatterwalk_done(&walk_out, 1, nbytes);
@@ -143,30 +125,78 @@ static int crypt(struct crypto_tfm *tfm,
        }
 }
 
-static void cbc_process_encrypt(struct crypto_tfm *tfm, u8 *dst, u8 *src,
-                               cryptfn_t fn, void *info)
+static unsigned int cbc_process_encrypt(const struct cipher_desc *desc,
+                                       u8 *dst, const u8 *src,
+                                       unsigned int nbytes)
 {
-       u8 *iv = info;
+       struct crypto_tfm *tfm = desc->tfm;
+       void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
+       int bsize = crypto_tfm_alg_blocksize(tfm);
+
+       void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
+       u8 *iv = desc->info;
+       unsigned int done = 0;
+
+       do {
+               xor(iv, src);
+               fn(crypto_tfm_ctx(tfm), dst, iv);
+               memcpy(iv, dst, bsize);
 
-       tfm->crt_u.cipher.cit_xor_block(iv, src);
-       fn(crypto_tfm_ctx(tfm), dst, iv);
-       memcpy(iv, dst, crypto_tfm_alg_blocksize(tfm));
+               src += bsize;
+               dst += bsize;
+       } while ((done += bsize) < nbytes);
+
+       return done;
 }
 
-static void cbc_process_decrypt(struct crypto_tfm *tfm, u8 *dst, u8 *src,
-                               cryptfn_t fn, void *info)
+static unsigned int cbc_process_decrypt(const struct cipher_desc *desc,
+                                       u8 *dst, const u8 *src,
+                                       unsigned int nbytes)
 {
-       u8 *iv = info;
+       struct crypto_tfm *tfm = desc->tfm;
+       void (*xor)(u8 *, const u8 *) = tfm->crt_u.cipher.cit_xor_block;
+       int bsize = crypto_tfm_alg_blocksize(tfm);
+
+       u8 stack[src == dst ? bsize : 0];
+       u8 *buf = stack;
+       u8 **dst_p = src == dst ? &buf : &dst;
+
+       void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
+       u8 *iv = desc->info;
+       unsigned int done = 0;
+
+       do {
+               u8 *tmp_dst = *dst_p;
 
-       fn(crypto_tfm_ctx(tfm), dst, src);
-       tfm->crt_u.cipher.cit_xor_block(dst, iv);
-       memcpy(iv, src, crypto_tfm_alg_blocksize(tfm));
+               fn(crypto_tfm_ctx(tfm), tmp_dst, src);
+               xor(tmp_dst, iv);
+               memcpy(iv, src, bsize);
+               if (tmp_dst != dst)
+                       memcpy(dst, tmp_dst, bsize);
+
+               src += bsize;
+               dst += bsize;
+       } while ((done += bsize) < nbytes);
+
+       return done;
 }
 
-static void ecb_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
-                       cryptfn_t fn, void *info)
+static unsigned int ecb_process(const struct cipher_desc *desc, u8 *dst,
+                               const u8 *src, unsigned int nbytes)
 {
-       fn(crypto_tfm_ctx(tfm), dst, src);
+       struct crypto_tfm *tfm = desc->tfm;
+       int bsize = crypto_tfm_alg_blocksize(tfm);
+       void (*fn)(void *, u8 *, const u8 *) = desc->crfn;
+       unsigned int done = 0;
+
+       do {
+               fn(crypto_tfm_ctx(tfm), dst, src);
+
+               src += bsize;
+               dst += bsize;
+       } while ((done += bsize) < nbytes);
+
+       return done;
 }
 
 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
@@ -185,9 +215,14 @@ static int ecb_encrypt(struct crypto_tfm *tfm,
                       struct scatterlist *dst,
                        struct scatterlist *src, unsigned int nbytes)
 {
-       return crypt(tfm, dst, src, nbytes,
-                    tfm->__crt_alg->cra_cipher.cia_encrypt,
-                    ecb_process, NULL);
+       struct cipher_desc desc;
+       struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
+
+       desc.tfm = tfm;
+       desc.crfn = cipher->cia_encrypt;
+       desc.prfn = cipher->cia_encrypt_ecb ?: ecb_process;
+
+       return crypt(&desc, dst, src, nbytes);
 }
 
 static int ecb_decrypt(struct crypto_tfm *tfm,
@@ -195,9 +230,14 @@ static int ecb_decrypt(struct crypto_tfm *tfm,
                        struct scatterlist *src,
                       unsigned int nbytes)
 {
-       return crypt(tfm, dst, src, nbytes,
-                    tfm->__crt_alg->cra_cipher.cia_decrypt,
-                    ecb_process, NULL);
+       struct cipher_desc desc;
+       struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
+
+       desc.tfm = tfm;
+       desc.crfn = cipher->cia_decrypt;
+       desc.prfn = cipher->cia_decrypt_ecb ?: ecb_process;
+
+       return crypt(&desc, dst, src, nbytes);
 }
 
 static int cbc_encrypt(struct crypto_tfm *tfm,
@@ -205,9 +245,15 @@ static int cbc_encrypt(struct crypto_tfm *tfm,
                        struct scatterlist *src,
                       unsigned int nbytes)
 {
-       return crypt(tfm, dst, src, nbytes,
-                    tfm->__crt_alg->cra_cipher.cia_encrypt,
-                    cbc_process_encrypt, tfm->crt_cipher.cit_iv);
+       struct cipher_desc desc;
+       struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
+
+       desc.tfm = tfm;
+       desc.crfn = cipher->cia_encrypt;
+       desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
+       desc.info = tfm->crt_cipher.cit_iv;
+
+       return crypt(&desc, dst, src, nbytes);
 }
 
 static int cbc_encrypt_iv(struct crypto_tfm *tfm,
@@ -215,9 +261,15 @@ static int cbc_encrypt_iv(struct crypto_tfm *tfm,
                           struct scatterlist *src,
                           unsigned int nbytes, u8 *iv)
 {
-       return crypt(tfm, dst, src, nbytes,
-                    tfm->__crt_alg->cra_cipher.cia_encrypt,
-                    cbc_process_encrypt, iv);
+       struct cipher_desc desc;
+       struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
+
+       desc.tfm = tfm;
+       desc.crfn = cipher->cia_encrypt;
+       desc.prfn = cipher->cia_encrypt_cbc ?: cbc_process_encrypt;
+       desc.info = iv;
+
+       return crypt(&desc, dst, src, nbytes);
 }
 
 static int cbc_decrypt(struct crypto_tfm *tfm,
@@ -225,9 +277,15 @@ static int cbc_decrypt(struct crypto_tfm *tfm,
                        struct scatterlist *src,
                       unsigned int nbytes)
 {
-       return crypt(tfm, dst, src, nbytes,
-                    tfm->__crt_alg->cra_cipher.cia_decrypt,
-                    cbc_process_decrypt, tfm->crt_cipher.cit_iv);
+       struct cipher_desc desc;
+       struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
+
+       desc.tfm = tfm;
+       desc.crfn = cipher->cia_decrypt;
+       desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
+       desc.info = tfm->crt_cipher.cit_iv;
+
+       return crypt(&desc, dst, src, nbytes);
 }
 
 static int cbc_decrypt_iv(struct crypto_tfm *tfm,
@@ -235,9 +293,15 @@ static int cbc_decrypt_iv(struct crypto_tfm *tfm,
                           struct scatterlist *src,
                           unsigned int nbytes, u8 *iv)
 {
-       return crypt(tfm, dst, src, nbytes,
-                    tfm->__crt_alg->cra_cipher.cia_decrypt,
-                    cbc_process_decrypt, iv);
+       struct cipher_desc desc;
+       struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
+
+       desc.tfm = tfm;
+       desc.crfn = cipher->cia_decrypt;
+       desc.prfn = cipher->cia_decrypt_cbc ?: cbc_process_decrypt;
+       desc.info = iv;
+
+       return crypt(&desc, dst, src, nbytes);
 }
 
 static int nocrypt(struct crypto_tfm *tfm,
@@ -336,6 +400,5 @@ out:
 
 void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
 {
-       if (tfm->crt_cipher.cit_iv)
-               kfree(tfm->crt_cipher.cit_iv);
+       kfree(tfm->crt_cipher.cit_iv);
 }