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514 lines
14 KiB
514 lines
14 KiB
/*
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* Block chaining cipher operations.
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*
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* Generic encrypt/decrypt wrapper for ciphers, handles operations across
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* multiple page boundaries by using temporary blocks. In user context,
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* the kernel is given a chance to schedule us once per page.
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*
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* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <linux/crypto.h>
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#include <linux/errno.h>
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#include <linux/hardirq.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/scatterlist.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include "internal.h"
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#include "scatterwalk.h"
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enum {
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BLKCIPHER_WALK_PHYS = 1 << 0,
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BLKCIPHER_WALK_SLOW = 1 << 1,
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BLKCIPHER_WALK_COPY = 1 << 2,
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BLKCIPHER_WALK_DIFF = 1 << 3,
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};
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static int blkcipher_walk_next(struct blkcipher_desc *desc,
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struct blkcipher_walk *walk);
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static int blkcipher_walk_first(struct blkcipher_desc *desc,
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struct blkcipher_walk *walk);
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static inline void blkcipher_map_src(struct blkcipher_walk *walk)
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{
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walk->src.virt.addr = scatterwalk_map(&walk->in, 0);
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}
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static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
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{
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walk->dst.virt.addr = scatterwalk_map(&walk->out, 1);
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}
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static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
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{
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scatterwalk_unmap(walk->src.virt.addr, 0);
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}
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static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
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{
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scatterwalk_unmap(walk->dst.virt.addr, 1);
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}
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/* Get a spot of the specified length that does not straddle a page.
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* The caller needs to ensure that there is enough space for this operation.
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*/
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static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len)
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{
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u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
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return max(start, end_page);
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}
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static inline unsigned int blkcipher_done_slow(struct crypto_blkcipher *tfm,
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struct blkcipher_walk *walk,
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unsigned int bsize)
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{
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u8 *addr;
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unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
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addr = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1);
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addr = blkcipher_get_spot(addr, bsize);
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scatterwalk_copychunks(addr, &walk->out, bsize, 1);
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return bsize;
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}
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static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
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unsigned int n)
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{
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if (walk->flags & BLKCIPHER_WALK_COPY) {
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blkcipher_map_dst(walk);
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memcpy(walk->dst.virt.addr, walk->page, n);
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blkcipher_unmap_dst(walk);
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} else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
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blkcipher_unmap_src(walk);
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if (walk->flags & BLKCIPHER_WALK_DIFF)
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blkcipher_unmap_dst(walk);
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}
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scatterwalk_advance(&walk->in, n);
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scatterwalk_advance(&walk->out, n);
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return n;
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}
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int blkcipher_walk_done(struct blkcipher_desc *desc,
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struct blkcipher_walk *walk, int err)
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{
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struct crypto_blkcipher *tfm = desc->tfm;
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unsigned int nbytes = 0;
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if (likely(err >= 0)) {
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unsigned int n = walk->nbytes - err;
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if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
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n = blkcipher_done_fast(walk, n);
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else if (WARN_ON(err)) {
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err = -EINVAL;
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goto err;
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} else
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n = blkcipher_done_slow(tfm, walk, n);
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nbytes = walk->total - n;
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err = 0;
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}
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scatterwalk_done(&walk->in, 0, nbytes);
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scatterwalk_done(&walk->out, 1, nbytes);
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walk->total = nbytes;
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walk->nbytes = nbytes;
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if (nbytes) {
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crypto_yield(desc->flags);
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return blkcipher_walk_next(desc, walk);
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}
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err:
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if (walk->iv != desc->info)
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memcpy(desc->info, walk->iv, crypto_blkcipher_ivsize(tfm));
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if (walk->buffer != walk->page)
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kfree(walk->buffer);
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if (walk->page)
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free_page((unsigned long)walk->page);
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return err;
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}
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EXPORT_SYMBOL_GPL(blkcipher_walk_done);
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static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
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struct blkcipher_walk *walk,
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unsigned int bsize,
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unsigned int alignmask)
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{
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unsigned int n;
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unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
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if (walk->buffer)
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goto ok;
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walk->buffer = walk->page;
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if (walk->buffer)
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goto ok;
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n = aligned_bsize * 3 - (alignmask + 1) +
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(alignmask & ~(crypto_tfm_ctx_alignment() - 1));
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walk->buffer = kmalloc(n, GFP_ATOMIC);
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if (!walk->buffer)
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return blkcipher_walk_done(desc, walk, -ENOMEM);
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ok:
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walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
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alignmask + 1);
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walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
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walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr +
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aligned_bsize, bsize);
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scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
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walk->nbytes = bsize;
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walk->flags |= BLKCIPHER_WALK_SLOW;
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return 0;
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}
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static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
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{
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u8 *tmp = walk->page;
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blkcipher_map_src(walk);
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memcpy(tmp, walk->src.virt.addr, walk->nbytes);
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blkcipher_unmap_src(walk);
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walk->src.virt.addr = tmp;
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walk->dst.virt.addr = tmp;
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return 0;
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}
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static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
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struct blkcipher_walk *walk)
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{
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unsigned long diff;
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walk->src.phys.page = scatterwalk_page(&walk->in);
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walk->src.phys.offset = offset_in_page(walk->in.offset);
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walk->dst.phys.page = scatterwalk_page(&walk->out);
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walk->dst.phys.offset = offset_in_page(walk->out.offset);
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if (walk->flags & BLKCIPHER_WALK_PHYS)
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return 0;
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diff = walk->src.phys.offset - walk->dst.phys.offset;
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diff |= walk->src.virt.page - walk->dst.virt.page;
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blkcipher_map_src(walk);
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walk->dst.virt.addr = walk->src.virt.addr;
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if (diff) {
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walk->flags |= BLKCIPHER_WALK_DIFF;
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blkcipher_map_dst(walk);
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}
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return 0;
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}
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static int blkcipher_walk_next(struct blkcipher_desc *desc,
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struct blkcipher_walk *walk)
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{
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struct crypto_blkcipher *tfm = desc->tfm;
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unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
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unsigned int bsize;
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unsigned int n;
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int err;
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n = walk->total;
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if (unlikely(n < crypto_blkcipher_blocksize(tfm))) {
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desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
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return blkcipher_walk_done(desc, walk, -EINVAL);
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}
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walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
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BLKCIPHER_WALK_DIFF);
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if (!scatterwalk_aligned(&walk->in, alignmask) ||
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!scatterwalk_aligned(&walk->out, alignmask)) {
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walk->flags |= BLKCIPHER_WALK_COPY;
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if (!walk->page) {
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walk->page = (void *)__get_free_page(GFP_ATOMIC);
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if (!walk->page)
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n = 0;
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}
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}
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bsize = min(walk->blocksize, n);
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n = scatterwalk_clamp(&walk->in, n);
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n = scatterwalk_clamp(&walk->out, n);
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if (unlikely(n < bsize)) {
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err = blkcipher_next_slow(desc, walk, bsize, alignmask);
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goto set_phys_lowmem;
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}
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walk->nbytes = n;
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if (walk->flags & BLKCIPHER_WALK_COPY) {
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err = blkcipher_next_copy(walk);
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goto set_phys_lowmem;
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}
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return blkcipher_next_fast(desc, walk);
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set_phys_lowmem:
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if (walk->flags & BLKCIPHER_WALK_PHYS) {
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walk->src.phys.page = virt_to_page(walk->src.virt.addr);
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walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
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walk->src.phys.offset &= PAGE_SIZE - 1;
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walk->dst.phys.offset &= PAGE_SIZE - 1;
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}
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return err;
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}
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static inline int blkcipher_copy_iv(struct blkcipher_walk *walk,
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struct crypto_blkcipher *tfm,
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unsigned int alignmask)
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{
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unsigned bs = walk->blocksize;
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unsigned int ivsize = crypto_blkcipher_ivsize(tfm);
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unsigned aligned_bs = ALIGN(bs, alignmask + 1);
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unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
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(alignmask + 1);
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u8 *iv;
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size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
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walk->buffer = kmalloc(size, GFP_ATOMIC);
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if (!walk->buffer)
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return -ENOMEM;
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iv = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1);
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iv = blkcipher_get_spot(iv, bs) + aligned_bs;
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iv = blkcipher_get_spot(iv, bs) + aligned_bs;
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iv = blkcipher_get_spot(iv, ivsize);
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walk->iv = memcpy(iv, walk->iv, ivsize);
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return 0;
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}
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int blkcipher_walk_virt(struct blkcipher_desc *desc,
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struct blkcipher_walk *walk)
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{
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walk->flags &= ~BLKCIPHER_WALK_PHYS;
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walk->blocksize = crypto_blkcipher_blocksize(desc->tfm);
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return blkcipher_walk_first(desc, walk);
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}
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EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
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int blkcipher_walk_phys(struct blkcipher_desc *desc,
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struct blkcipher_walk *walk)
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{
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walk->flags |= BLKCIPHER_WALK_PHYS;
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walk->blocksize = crypto_blkcipher_blocksize(desc->tfm);
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return blkcipher_walk_first(desc, walk);
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}
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EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
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static int blkcipher_walk_first(struct blkcipher_desc *desc,
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struct blkcipher_walk *walk)
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{
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struct crypto_blkcipher *tfm = desc->tfm;
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unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
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if (WARN_ON_ONCE(in_irq()))
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return -EDEADLK;
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walk->nbytes = walk->total;
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if (unlikely(!walk->total))
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return 0;
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walk->buffer = NULL;
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walk->iv = desc->info;
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if (unlikely(((unsigned long)walk->iv & alignmask))) {
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int err = blkcipher_copy_iv(walk, tfm, alignmask);
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if (err)
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return err;
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}
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scatterwalk_start(&walk->in, walk->in.sg);
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scatterwalk_start(&walk->out, walk->out.sg);
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walk->page = NULL;
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return blkcipher_walk_next(desc, walk);
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}
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int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
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struct blkcipher_walk *walk,
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unsigned int blocksize)
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{
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walk->flags &= ~BLKCIPHER_WALK_PHYS;
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walk->blocksize = blocksize;
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return blkcipher_walk_first(desc, walk);
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}
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EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
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static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
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unsigned int keylen)
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{
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struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
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unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
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int ret;
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u8 *buffer, *alignbuffer;
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unsigned long absize;
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absize = keylen + alignmask;
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buffer = kmalloc(absize, GFP_ATOMIC);
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if (!buffer)
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return -ENOMEM;
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alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
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memcpy(alignbuffer, key, keylen);
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ret = cipher->setkey(tfm, alignbuffer, keylen);
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memset(alignbuffer, 0, keylen);
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kfree(buffer);
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return ret;
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}
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static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
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{
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struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
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unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
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if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
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tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
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return -EINVAL;
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}
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if ((unsigned long)key & alignmask)
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return setkey_unaligned(tfm, key, keylen);
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return cipher->setkey(tfm, key, keylen);
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}
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static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
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unsigned int keylen)
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{
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return setkey(crypto_ablkcipher_tfm(tfm), key, keylen);
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}
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static int async_encrypt(struct ablkcipher_request *req)
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{
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struct crypto_tfm *tfm = req->base.tfm;
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struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
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struct blkcipher_desc desc = {
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.tfm = __crypto_blkcipher_cast(tfm),
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.info = req->info,
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.flags = req->base.flags,
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};
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return alg->encrypt(&desc, req->dst, req->src, req->nbytes);
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}
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static int async_decrypt(struct ablkcipher_request *req)
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{
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struct crypto_tfm *tfm = req->base.tfm;
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struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
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struct blkcipher_desc desc = {
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.tfm = __crypto_blkcipher_cast(tfm),
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.info = req->info,
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.flags = req->base.flags,
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};
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return alg->decrypt(&desc, req->dst, req->src, req->nbytes);
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}
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static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type,
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u32 mask)
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{
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struct blkcipher_alg *cipher = &alg->cra_blkcipher;
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unsigned int len = alg->cra_ctxsize;
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type ^= CRYPTO_ALG_ASYNC;
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mask &= CRYPTO_ALG_ASYNC;
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if ((type & mask) && cipher->ivsize) {
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len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
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len += cipher->ivsize;
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}
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return len;
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}
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static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm)
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{
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struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
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struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
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crt->setkey = async_setkey;
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crt->encrypt = async_encrypt;
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crt->decrypt = async_decrypt;
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crt->ivsize = alg->ivsize;
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return 0;
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}
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static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm)
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{
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struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
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struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
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unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
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unsigned long addr;
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crt->setkey = setkey;
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crt->encrypt = alg->encrypt;
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crt->decrypt = alg->decrypt;
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addr = (unsigned long)crypto_tfm_ctx(tfm);
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addr = ALIGN(addr, align);
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addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
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crt->iv = (void *)addr;
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return 0;
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}
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static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
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{
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struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
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if (alg->ivsize > PAGE_SIZE / 8)
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return -EINVAL;
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type ^= CRYPTO_ALG_ASYNC;
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mask &= CRYPTO_ALG_ASYNC;
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if (type & mask)
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return crypto_init_blkcipher_ops_sync(tfm);
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else
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return crypto_init_blkcipher_ops_async(tfm);
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}
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static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
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__attribute__ ((unused));
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static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
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{
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seq_printf(m, "type : blkcipher\n");
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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");
|
|
|