cregit-Linux how code gets into the kernel

Release 4.8 crypto/blkcipher.c

Directory: crypto
/*
 * 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 <crypto/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/errno.h>
#include <linux/hardirq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/cryptouser.h>
#include <net/netlink.h>

#include "internal.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); }

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static inline void blkcipher_map_dst(struct blkcipher_walk *walk) { walk->dst.virt.addr = scatterwalk_map(&walk->out); }

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static inline void blkcipher_unmap_src(struct blkcipher_walk *walk) { scatterwalk_unmap(walk->src.virt.addr); }

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static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk) { scatterwalk_unmap(walk->dst.virt.addr); }

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/* Get a spot of the specified length that does not straddle a page. * The caller needs to ensure that there is enough space for this operation. */
static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len) { u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK); return max(start, end_page); }

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static inline unsigned int blkcipher_done_slow(struct blkcipher_walk *walk, unsigned int bsize) { u8 *addr; addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1); addr = blkcipher_get_spot(addr, bsize); scatterwalk_copychunks(addr, &walk->out, bsize, 1); return bsize; }

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static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk, unsigned int 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)) { if (walk->flags & BLKCIPHER_WALK_DIFF) blkcipher_unmap_dst(walk); blkcipher_unmap_src(walk); } scatterwalk_advance(&walk->in, n); scatterwalk_advance(&walk->out, n); return n; }

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int blkcipher_walk_done(struct blkcipher_desc *desc, struct blkcipher_walk *walk, int err) { unsigned int nbytes = 0; if (likely(err >= 0)) { unsigned int n = walk->nbytes - err; if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW))) n = blkcipher_done_fast(walk, n); else if (WARN_ON(err)) { err = -EINVAL; goto err; } else n = blkcipher_done_slow(walk, n); nbytes = walk->total - n; err = 0; } scatterwalk_done(&walk->in, 0, nbytes); scatterwalk_done(&walk->out, 1, nbytes); err: 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, walk->ivsize); if (walk->buffer != walk->page) kfree(walk->buffer); if (walk->page) free_page((unsigned long)walk->page); return err; }

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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; unsigned aligned_bsize = ALIGN(bsize, alignmask + 1); if (walk->buffer) goto ok; walk->buffer = walk->page; if (walk->buffer) goto ok; n = aligned_bsize * 3 - (alignmask + 1) + (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 + aligned_bsize, bsize); scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0); walk->nbytes = bsize; walk->flags |= BLKCIPHER_WALK_SLOW; return 0; }

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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; }

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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; }

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static int blkcipher_walk_next(struct blkcipher_desc *desc, struct blkcipher_walk *walk) { unsigned int bsize; unsigned int n; int err; n = walk->total; if (unlikely(n < walk->cipher_blocksize)) { desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN; return blkcipher_walk_done(desc, walk, -EINVAL); } bsize = min(walk->walk_blocksize, n); walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY | BLKCIPHER_WALK_DIFF); if (!scatterwalk_aligned(&walk->in, walk->alignmask) || !scatterwalk_aligned(&walk->out, walk->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, walk->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; }

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static inline int blkcipher_copy_iv(struct blkcipher_walk *walk) { unsigned bs = walk->walk_blocksize; unsigned aligned_bs = ALIGN(bs, walk->alignmask + 1); unsigned int size = aligned_bs * 2 + walk->ivsize + max(aligned_bs, walk->ivsize) - (walk->alignmask + 1); u8 *iv; size += walk->alignmask & ~(crypto_tfm_ctx_alignment() - 1); walk->buffer = kmalloc(size, GFP_ATOMIC); if (!walk->buffer) return -ENOMEM; iv = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1); iv = blkcipher_get_spot(iv, bs) + aligned_bs; iv = blkcipher_get_spot(iv, bs) + aligned_bs; iv = blkcipher_get_spot(iv, walk->ivsize); walk->iv = memcpy(iv, walk->iv, walk->ivsize); return 0; }

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int blkcipher_walk_virt(struct blkcipher_desc *desc, struct blkcipher_walk *walk) { walk->flags &= ~BLKCIPHER_WALK_PHYS; walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm); walk->cipher_blocksize = walk->walk_blocksize; walk->ivsize = crypto_blkcipher_ivsize(desc->tfm); walk->alignmask = crypto_blkcipher_alignmask(desc->tfm); return blkcipher_walk_first(desc, walk); }

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EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
int blkcipher_walk_phys(struct blkcipher_desc *desc, struct blkcipher_walk *walk) { walk->flags |= BLKCIPHER_WALK_PHYS; walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm); walk->cipher_blocksize = walk->walk_blocksize; walk->ivsize = crypto_blkcipher_ivsize(desc->tfm); walk->alignmask = crypto_blkcipher_alignmask(desc->tfm); return blkcipher_walk_first(desc, walk); }

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EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
static int blkcipher_walk_first(struct blkcipher_desc *desc, struct blkcipher_walk *walk) { if (WARN_ON_ONCE(in_irq())) return -EDEADLK; walk->iv = desc->info; walk->nbytes = walk->total; if (unlikely(!walk->total)) return 0; walk->buffer = NULL; if (unlikely(((unsigned long)walk->iv & walk->alignmask))) { int err = blkcipher_copy_iv(walk); 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); }

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int blkcipher_walk_virt_block(struct blkcipher_desc *desc, struct blkcipher_walk *walk, unsigned int blocksize) { walk->flags &= ~BLKCIPHER_WALK_PHYS; walk->walk_blocksize = blocksize; walk->cipher_blocksize = crypto_blkcipher_blocksize(desc->tfm); walk->ivsize = crypto_blkcipher_ivsize(desc->tfm); walk->alignmask = crypto_blkcipher_alignmask(desc->tfm); return blkcipher_walk_first(desc, walk); }

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EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
int blkcipher_aead_walk_virt_block(struct blkcipher_desc *desc, struct blkcipher_walk *walk, struct crypto_aead *tfm, unsigned int blocksize) { walk->flags &= ~BLKCIPHER_WALK_PHYS; walk->walk_blocksize = blocksize; walk->cipher_blocksize = crypto_aead_blocksize(tfm); walk->ivsize = crypto_aead_ivsize(tfm); walk->alignmask = crypto_aead_alignmask(tfm); return blkcipher_walk_first(desc, walk); }

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EXPORT_SYMBOL_GPL(blkcipher_aead_walk_virt_block);
static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen) { struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher; unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); int ret; u8 *buffer, *alignbuffer; unsigned long absize; absize = keylen + alignmask; buffer = kmalloc(absize, GFP_ATOMIC); if (!buffer) return -ENOMEM; alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1); memcpy(alignbuffer, key, keylen); ret = cipher->setkey(tfm, alignbuffer, keylen); memset(alignbuffer, 0, keylen); kfree(buffer); return ret; }

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static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen) { struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher; unsigned long alignmask = crypto_tfm_alg_alignmask(tfm); if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) { tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; return -EINVAL; } if ((unsigned long)key & alignmask) return setkey_unaligned(tfm, key, keylen); return cipher->setkey(tfm, key, keylen); }

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static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key, unsigned int keylen) { return setkey(crypto_ablkcipher_tfm(tfm), key, keylen); }

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static int async_encrypt(struct ablkcipher_request *req) { struct crypto_tfm *tfm = req->base.tfm; struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; struct blkcipher_desc desc = { .tfm = __crypto_blkcipher_cast(tfm), .info = req->info, .flags = req->base.flags, }; return alg->encrypt(&desc, req->dst, req->src, req->nbytes); }

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static int async_decrypt(struct ablkcipher_request *req) { struct crypto_tfm *tfm = req->base.tfm; struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; struct blkcipher_desc desc = { .tfm = __crypto_blkcipher_cast(tfm), .info = req->info, .flags = req->base.flags, }; return alg->decrypt(&desc, req->dst, req->src, req->nbytes); }

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static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type, u32 mask) { struct blkcipher_alg *cipher = &alg->cra_blkcipher; unsigned int len = alg->cra_ctxsize; if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK && cipher->ivsize) { len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1); len += cipher->ivsize; } return len; }

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static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm) { struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher; struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; crt->setkey = async_setkey; crt->encrypt = async_encrypt; crt->decrypt = async_decrypt; crt->base = __crypto_ablkcipher_cast(tfm); crt->ivsize = alg->ivsize; return 0; }

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static int crypto_init_blkcipher_ops_sync(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; 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; }

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static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask) { struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher; if (alg->ivsize > PAGE_SIZE / 8) return -EINVAL; if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK) return crypto_init_blkcipher_ops_sync(tfm); else return crypto_init_blkcipher_ops_async(tfm); }

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#ifdef CONFIG_NET
static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg) { struct crypto_report_blkcipher rblkcipher; strncpy(rblkcipher.type, "blkcipher", sizeof(rblkcipher.type)); strncpy(rblkcipher.geniv, alg->cra_blkcipher.geniv ?: "<default>", sizeof(rblkcipher.geniv)); rblkcipher.blocksize = alg->cra_blocksize; rblkcipher.min_keysize = alg->cra_blkcipher.min_keysize; rblkcipher.max_keysize = alg->cra_blkcipher.max_keysize; rblkcipher.ivsize = alg->cra_blkcipher.ivsize; if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER, sizeof(struct crypto_report_blkcipher