/* * Block chaining cipher operations. * * 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. * * Copyright (c) 2006 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/crypto.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/io.h> #include <linux/module.h> #include <linux/scatterlist.h> #include <linux/seq_file.h> #include <linux/slab.h> #include <linux/string.h> #include "internal.h" #include "scatterwalk.h" enum { BLKCIPHER_WALK_PHYS = 1 << 0, BLKCIPHER_WALK_SLOW = 1 << 1, BLKCIPHER_WALK_COPY = 1 << 2, BLKCIPHER_WALK_DIFF = 1 << 3, }; static int blkcipher_walk_next(struct blkcipher_desc *desc, struct blkcipher_walk *walk); static int blkcipher_walk_first(struct blkcipher_desc *desc, struct blkcipher_walk *walk); static inline void blkcipher_map_src(struct blkcipher_walk *walk) { walk->src.virt.addr = scatterwalk_map(&walk->in, 0); } static inline void blkcipher_map_dst(struct blkcipher_walk *walk) { walk->dst.virt.addr = scatterwalk_map(&walk->out, 1); } static inline void blkcipher_unmap_src(struct blkcipher_walk *walk) { scatterwalk_unmap(walk->src.virt.addr, 0); } static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk) { scatterwalk_unmap(walk->dst.virt.addr, 1); } static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len) { if (offset_in_page(start + len) < len) return (u8 *)((unsigned long)(start + len) & PAGE_MASK); return start; } static inline unsigned int blkcipher_done_slow(struct crypto_blkcipher *tfm, struct blkcipher_walk *walk, unsigned int bsize) { u8 *addr; unsigned int alignmask = crypto_blkcipher_alignmask(tfm); addr = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1); addr = blkcipher_get_spot(addr, bsize); scatterwalk_copychunks(addr, &walk->out, bsize, 1); return bsize; } 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); blkcipher_unmap_dst(walk); } else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) { blkcipher_unmap_src(walk); if (walk->flags & BLKCIPHER_WALK_DIFF) blkcipher_unmap_dst(walk); } scatterwalk_advance(&walk->in, n); scatterwalk_advance(&walk->out, n); return n; } int blkcipher_walk_done(struct blkcipher_desc *desc, struct blkcipher_walk *walk, int err) { struct crypto_blkcipher *tfm = desc->tfm; unsigned int nbytes = 0; if (likely(err >= 0)) { unsigned int bsize = crypto_blkcipher_blocksize(tfm); unsigned int n; if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW))) n = blkcipher_done_fast(walk, err); else n = blkcipher_done_slow(tfm, walk, bsize); nbytes = walk->total - n; err = 0; } scatterwalk_done(&walk->in, 0, nbytes); scatterwalk_done(&walk->out, 1, nbytes); walk->total = nbytes; walk->nbytes = nbytes; if (nbytes) { crypto_yield(desc->flags); return blkcipher_walk_next(desc, walk); } if (walk->iv != desc->info) memcpy(desc->info, walk->iv, crypto_blkcipher_ivsize(tfm)); if (walk->buffer != walk->page) kfree(walk->buffer); if (walk->page) free_page((unsigned long)walk->page); return err; } EXPORT_SYMBOL_GPL(blkcipher_walk_done); static inline int blkcipher_next_slow(struct blkcipher_desc *desc, struct blkcipher_walk *walk, unsigned int bsize, unsigned int alignmask) { unsigned int n; if (walk->buffer) goto ok; walk->buffer = walk->page; if (walk->buffer) goto ok; n = bsize * 2 + (alignmask & ~(crypto_tfm_ctx_alignment() - 1)); walk->buffer = kmalloc(n, GFP_ATOMIC); if (!walk->buffer) return blkcipher_walk_done(desc, walk, -ENOMEM); ok: walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1); walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize); walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr + bsize, bsize); scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0); walk->nbytes = bsize; walk->flags |= BLKCIPHER_WALK_SLOW; return 0; } static inline int blkcipher_next_copy(struct blkcipher_walk *walk) { u8 *tmp = walk->page; blkcipher_map_src(walk); memcpy(tmp, walk->src.virt.addr, walk->nbytes); blkcipher_unmap_src(walk); walk->src.virt.addr = tmp; walk->dst.virt.addr = tmp; return 0; } static inline int blkcipher_next_fast(struct blkcipher_desc *desc, struct blkcipher_walk *walk) { unsigned long diff; walk->src.phys.page = scatterwalk_page(&walk->in); walk->src.phys.offset = offset_in_page(walk->in.offset); walk->dst.phys.page = scatterwalk_page(&walk->out); walk->dst.phys.offset = offset_in_page(walk->out.offset); if (walk->flags & BLKCIPHER_WALK_PHYS) return 0; diff = walk->src.phys.offset - walk->dst.phys.offset; diff |= walk->src.virt.page - walk->dst.virt.page; blkcipher_map_src(walk); walk->dst.virt.addr = walk->src.virt.addr; if (diff) { walk->flags |= BLKCIPHER_WALK_DIFF; blkcipher_map_dst(walk); } return 0; } static int blkcipher_walk_next(struct blkcipher_desc *desc, struct blkcipher_walk *walk) { struct crypto_blkcipher *tfm = desc->tfm; unsigned int alignmask = crypto_blkcipher_alignmask(tfm); unsigned int bsize = crypto_blkcipher_blocksize(tfm); unsigned int n; int err; n = walk->total; if (unlikely(n < bsize)) { desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; return blkcipher_walk_done(desc, walk, -EINVAL); } walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY | BLKCIPHER_WALK_DIFF); if (!scatterwalk_aligned(&walk->in, alignmask) || !scatterwalk_aligned(&walk->out, alignmask)) { walk->flags |= BLKCIPHER_WALK_COPY; if (!walk->page) { walk->page = (void *)__get_free_page(GFP_ATOMIC); if (!walk->page) n = 0; } } n = scatterwalk_clamp(&walk->in, n); n = scatterwalk_clamp(&walk->out, n); if (unlikely(n < bsize)) { err = blkcipher_next_slow(desc, walk, bsize, alignmask); goto set_phys_lowmem; } walk->nbytes = n; if (walk->flags & BLKCIPHER_WALK_COPY) { err = blkcipher_next_copy(walk); goto set_phys_lowmem; } return blkcipher_next_fast(desc, walk); set_phys_lowmem: if (walk->flags & BLKCIPHER_WALK_PHYS) { walk->src.phys.page = virt_to_page(walk->src.virt.addr); walk->dst.phys.page = virt_to_page(walk->dst.virt.addr); walk->src.phys.offset &= PAGE_SIZE - 1; walk->dst.phys.offset &= PAGE_SIZE - 1; } return err; } static inline int blkcipher_copy_iv(struct blkcipher_walk *walk, struct crypto_blkcipher *tfm, unsigned int alignmask) { unsigned bs = crypto_blkcipher_blocksize(tfm); unsigned int ivsize = crypto_blkcipher_ivsize(tfm); unsigned int size = bs * 2 + ivsize + max(bs, ivsize) - (alignmask + 1); u8 *iv; size += alignmask & ~(crypto_tfm_ctx_alignment() - 1); walk->buffer = kmalloc(size, GFP_ATOMIC); if (!walk->buffer) return -ENOMEM; iv = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1); iv = blkcipher_get_spot(iv, bs) + bs; iv = blkcipher_get_spot(iv, bs) + bs; iv = blkcipher_get_spot(iv, ivsize); walk->iv = memcpy(iv, walk->iv, ivsize); return 0; } int blkcipher_walk_virt(struct blkcipher_desc *desc, struct blkcipher_walk *walk) { walk->flags &= ~BLKCIPHER_WALK_PHYS; return blkcipher_walk_first(desc, walk); } EXPORT_SYMBOL_GPL(blkcipher_walk_virt); int blkcipher_walk_phys(struct blkcipher_desc *desc, struct blkcipher_walk *walk) { walk->flags |= BLKCIPHER_WALK_PHYS; return blkcipher_walk_first(desc, walk); } EXPORT_SYMBOL_GPL(blkcipher_walk_phys); static int blkcipher_walk_first(struct blkcipher_desc *desc, struct blkcipher_walk *walk) { struct crypto_blkcipher *tfm = desc->tfm; unsigned int alignmask = crypto_blkcipher_alignmask(tfm); walk->nbytes = walk->total; if (unlikely(!walk->total)) return 0; walk->buffer = NULL; walk->iv = desc->info; if (unlikely(((unsigned long)walk->iv & alignmask))) { int err = blkcipher_copy_iv(walk, tfm, alignmask); if (err) return err; } scatterwalk_start(&walk->in, walk->in.sg); scatterwalk_start(&walk->out, walk->out.sg); walk->page = NULL; return blkcipher_walk_next(desc, walk); } static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen) { struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher; if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) { tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; return -EINVAL; } return cipher->setkey(tfm, key, keylen); } static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg) { struct blkcipher_alg *cipher = &alg->cra_blkcipher; unsigned int len = alg->cra_ctxsize; if (cipher->ivsize) { len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1); len += cipher->ivsize; } return len; } static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm) { struct blkcipher_tfm *crt = &tfm->crt_blkcipher; struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1; unsigned long addr; if (alg->ivsize > PAGE_SIZE / 8) return -EINVAL; crt->setkey = setkey; crt->encrypt = alg->encrypt; crt->decrypt = alg->decrypt; addr = (unsigned long)crypto_tfm_ctx(tfm); addr = ALIGN(addr, align); addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align); crt->iv = (void *)addr; return 0; } static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg) __attribute_used__; static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg) { seq_printf(m, "type : blkcipher\n"); seq_printf(m, "blocksize : %u\n", alg->cra_blocksize); seq_printf(m, "min keysize : %u\n", alg->cra_blkcipher.min_keysize); seq_printf(m, "max keysize : %u\n", alg->cra_blkcipher.max_keysize); seq_printf(m, "ivsize : %u\n", alg->cra_blkcipher.ivsize); } const struct crypto_type crypto_blkcipher_type = { .ctxsize = crypto_blkcipher_ctxsize, .init = crypto_init_blkcipher_ops, #ifdef CONFIG_PROC_FS .show = crypto_blkcipher_show, #endif }; EXPORT_SYMBOL_GPL(crypto_blkcipher_type); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Generic block chaining cipher type");