/* * Cryptographic API. * * 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 * Software Foundation; either version 2 of the License, or (at your option) * any later version. * */ #include <linux/compiler.h> #include <linux/kernel.h> #include <linux/crypto.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/string.h> #include <asm/scatterlist.h> #include "internal.h" #include "scatterwalk.h" static inline void xor_64(u8 *a, const u8 *b) { ((u32 *)a)[0] ^= ((u32 *)b)[0]; ((u32 *)a)[1] ^= ((u32 *)b)[1]; } static inline void xor_128(u8 *a, const u8 *b) { ((u32 *)a)[0] ^= ((u32 *)b)[0]; ((u32 *)a)[1] ^= ((u32 *)b)[1]; ((u32 *)a)[2] ^= ((u32 *)b)[2]; ((u32 *)a)[3] ^= ((u32 *)b)[3]; } static unsigned int crypt_slow(const struct cipher_desc *desc, struct scatter_walk *in, struct scatter_walk *out, unsigned int bsize) { unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm); 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); scatterwalk_advance(in, n); desc->prfn(desc, dst, src, bsize); n = scatterwalk_copychunks(dst, out, bsize, 1); scatterwalk_advance(out, n); return bsize; } static inline unsigned int crypt_fast(const struct cipher_desc *desc, struct scatter_walk *in, struct scatter_walk *out, 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); 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 page. */ static int crypt(const struct cipher_desc *desc, struct scatterlist *dst, struct scatterlist *src, 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); unsigned int alignmask = crypto_tfm_alg_alignmask(tfm); unsigned long buffer = 0; if (!nbytes) return 0; if (nbytes % bsize) { tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; return -EINVAL; } scatterwalk_start(&walk_in, src); scatterwalk_start(&walk_out, dst); for(;;) { 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, n); n = scatterwalk_clamp(&walk_out, n); if (likely(n >= bsize)) n = crypt_fast(desc, &walk_in, &walk_out, n, tmp); else n = crypt_slow(desc, &walk_in, &walk_out, bsize); nbytes -= n; scatterwalk_done(&walk_in, 0, nbytes); scatterwalk_done(&walk_out, 1, nbytes); if (!nbytes) break; crypto_yield(tfm); } if (buffer) free_page(buffer); return 0; } static int crypt_iv_unaligned(struct cipher_desc *desc, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { struct crypto_tfm *tfm = desc->tfm; unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); u8 *iv = desc->info; if (unlikely(((unsigned long)iv & alignmask))) { unsigned int ivsize = tfm->crt_cipher.cit_ivsize; u8 buffer[ivsize + alignmask]; u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); int err; desc->info = memcpy(tmp, iv, ivsize); err = crypt(desc, dst, src, nbytes); memcpy(iv, tmp, ivsize); return err; } return crypt(desc, dst, src, nbytes); } static unsigned int cbc_process_encrypt(const struct cipher_desc *desc, u8 *dst, const u8 *src, unsigned int nbytes) { 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; nbytes -= bsize; do { xor(iv, src); fn(crypto_tfm_ctx(tfm), dst, iv); memcpy(iv, dst, bsize); src += bsize; dst += bsize; } while ((done += bsize) <= nbytes); return done; } static unsigned int cbc_process_decrypt(const struct cipher_desc *desc, u8 *dst, const u8 *src, unsigned int nbytes) { 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; nbytes -= bsize; do { u8 *tmp_dst = *dst_p; 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 unsigned int ecb_process(const struct cipher_desc *desc, u8 *dst, const u8 *src, unsigned int nbytes) { 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; nbytes -= bsize; 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) { struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher; if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) { tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; return -EINVAL; } else return cia->cia_setkey(crypto_tfm_ctx(tfm), key, keylen, &tfm->crt_flags); } static int ecb_encrypt(struct crypto_tfm *tfm, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { 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, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { 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, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { 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, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes, u8 *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_iv_unaligned(&desc, dst, src, nbytes); } static int cbc_decrypt(struct crypto_tfm *tfm, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { 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, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes, u8 *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_iv_unaligned(&desc, dst, src, nbytes); } static int nocrypt(struct crypto_tfm *tfm, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes) { return -ENOSYS; } static int nocrypt_iv(struct crypto_tfm *tfm, struct scatterlist *dst, struct scatterlist *src, unsigned int nbytes, u8 *iv) { return -ENOSYS; } int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags) { u32 mode = flags & CRYPTO_TFM_MODE_MASK; tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB; return 0; } int crypto_init_cipher_ops(struct crypto_tfm *tfm) { int ret = 0; struct cipher_tfm *ops = &tfm->crt_cipher; ops->cit_setkey = setkey; switch (tfm->crt_cipher.cit_mode) { case CRYPTO_TFM_MODE_ECB: ops->cit_encrypt = ecb_encrypt; ops->cit_decrypt = ecb_decrypt; break; case CRYPTO_TFM_MODE_CBC: ops->cit_encrypt = cbc_encrypt; ops->cit_decrypt = cbc_decrypt; ops->cit_encrypt_iv = cbc_encrypt_iv; ops->cit_decrypt_iv = cbc_decrypt_iv; break; case CRYPTO_TFM_MODE_CFB: ops->cit_encrypt = nocrypt; ops->cit_decrypt = nocrypt; ops->cit_encrypt_iv = nocrypt_iv; ops->cit_decrypt_iv = nocrypt_iv; break; case CRYPTO_TFM_MODE_CTR: ops->cit_encrypt = nocrypt; ops->cit_decrypt = nocrypt; ops->cit_encrypt_iv = nocrypt_iv; ops->cit_decrypt_iv = nocrypt_iv; break; default: BUG(); } if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) { unsigned long align; unsigned long addr; switch (crypto_tfm_alg_blocksize(tfm)) { case 8: ops->cit_xor_block = xor_64; break; case 16: ops->cit_xor_block = xor_128; break; default: printk(KERN_WARNING "%s: block size %u not supported\n", crypto_tfm_alg_name(tfm), crypto_tfm_alg_blocksize(tfm)); ret = -EINVAL; goto out; } ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm); align = crypto_tfm_alg_alignmask(tfm) + 1; addr = (unsigned long)crypto_tfm_ctx(tfm); addr = ALIGN(addr, align); addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align); ops->cit_iv = (void *)addr; } out: return ret; } void crypto_exit_cipher_ops(struct crypto_tfm *tfm) { }