linux/crypto/ablkcipher.c

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/*
* Asynchronous block chaining cipher operations.
*
* This is the asynchronous version of blkcipher.c indicating completion
* via a callback.
*
* 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/internal/skcipher.h>
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rtnetlink.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/cryptouser.h>
#include <net/netlink.h>
#include <crypto/scatterwalk.h>
#include "internal.h"
static const char *skcipher_default_geniv __read_mostly;
struct ablkcipher_buffer {
struct list_head entry;
struct scatter_walk dst;
unsigned int len;
void *data;
};
enum {
ABLKCIPHER_WALK_SLOW = 1 << 0,
};
static inline void ablkcipher_buffer_write(struct ablkcipher_buffer *p)
{
scatterwalk_copychunks(p->data, &p->dst, p->len, 1);
}
void __ablkcipher_walk_complete(struct ablkcipher_walk *walk)
{
struct ablkcipher_buffer *p, *tmp;
list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
ablkcipher_buffer_write(p);
list_del(&p->entry);
kfree(p);
}
}
EXPORT_SYMBOL_GPL(__ablkcipher_walk_complete);
static inline void ablkcipher_queue_write(struct ablkcipher_walk *walk,
struct ablkcipher_buffer *p)
{
p->dst = walk->out;
list_add_tail(&p->entry, &walk->buffers);
}
/* 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 *ablkcipher_get_spot(u8 *start, unsigned int len)
{
u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
return max(start, end_page);
}
static inline unsigned int ablkcipher_done_slow(struct ablkcipher_walk *walk,
unsigned int bsize)
{
unsigned int n = bsize;
for (;;) {
unsigned int len_this_page = scatterwalk_pagelen(&walk->out);
if (len_this_page > n)
len_this_page = n;
scatterwalk_advance(&walk->out, n);
if (n == len_this_page)
break;
n -= len_this_page;
scatterwalk_start(&walk->out, scatterwalk_sg_next(walk->out.sg));
}
return bsize;
}
static inline unsigned int ablkcipher_done_fast(struct ablkcipher_walk *walk,
unsigned int n)
{
scatterwalk_advance(&walk->in, n);
scatterwalk_advance(&walk->out, n);
return n;
}
static int ablkcipher_walk_next(struct ablkcipher_request *req,
struct ablkcipher_walk *walk);
int ablkcipher_walk_done(struct ablkcipher_request *req,
struct ablkcipher_walk *walk, int err)
{
struct crypto_tfm *tfm = req->base.tfm;
unsigned int nbytes = 0;
if (likely(err >= 0)) {
unsigned int n = walk->nbytes - err;
if (likely(!(walk->flags & ABLKCIPHER_WALK_SLOW)))
n = ablkcipher_done_fast(walk, n);
else if (WARN_ON(err)) {
err = -EINVAL;
goto err;
} else
n = ablkcipher_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(req->base.flags);
return ablkcipher_walk_next(req, walk);
}
if (walk->iv != req->info)
memcpy(req->info, walk->iv, tfm->crt_ablkcipher.ivsize);
kfree(walk->iv_buffer);
return err;
}
EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
static inline int ablkcipher_next_slow(struct ablkcipher_request *req,
struct ablkcipher_walk *walk,
unsigned int bsize,
unsigned int alignmask,
void **src_p, void **dst_p)
{
unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
struct ablkcipher_buffer *p;
void *src, *dst, *base;
unsigned int n;
n = ALIGN(sizeof(struct ablkcipher_buffer), alignmask + 1);
n += (aligned_bsize * 3 - (alignmask + 1) +
(alignmask & ~(crypto_tfm_ctx_alignment() - 1)));
p = kmalloc(n, GFP_ATOMIC);
if (!p)
return ablkcipher_walk_done(req, walk, -ENOMEM);
base = p + 1;
dst = (u8 *)ALIGN((unsigned long)base, alignmask + 1);
src = dst = ablkcipher_get_spot(dst, bsize);
p->len = bsize;
p->data = dst;
scatterwalk_copychunks(src, &walk->in, bsize, 0);
ablkcipher_queue_write(walk, p);
walk->nbytes = bsize;
walk->flags |= ABLKCIPHER_WALK_SLOW;
*src_p = src;
*dst_p = dst;
return 0;
}
static inline int ablkcipher_copy_iv(struct ablkcipher_walk *walk,
struct crypto_tfm *tfm,
unsigned int alignmask)
{
unsigned bs = walk->blocksize;
unsigned int ivsize = tfm->crt_ablkcipher.ivsize;
unsigned aligned_bs = ALIGN(bs, alignmask + 1);
unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
(alignmask + 1);
u8 *iv;
size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
walk->iv_buffer = kmalloc(size, GFP_ATOMIC);
if (!walk->iv_buffer)
return -ENOMEM;
iv = (u8 *)ALIGN((unsigned long)walk->iv_buffer, alignmask + 1);
iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
iv = ablkcipher_get_spot(iv, ivsize);
walk->iv = memcpy(iv, walk->iv, ivsize);
return 0;
}
static inline int ablkcipher_next_fast(struct ablkcipher_request *req,
struct ablkcipher_walk *walk)
{
walk->src.page = scatterwalk_page(&walk->in);
walk->src.offset = offset_in_page(walk->in.offset);
walk->dst.page = scatterwalk_page(&walk->out);
walk->dst.offset = offset_in_page(walk->out.offset);
return 0;
}
static int ablkcipher_walk_next(struct ablkcipher_request *req,
struct ablkcipher_walk *walk)
{
struct crypto_tfm *tfm = req->base.tfm;
unsigned int alignmask, bsize, n;
void *src, *dst;
int err;
alignmask = crypto_tfm_alg_alignmask(tfm);
n = walk->total;
if (unlikely(n < crypto_tfm_alg_blocksize(tfm))) {
req->base.flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
return ablkcipher_walk_done(req, walk, -EINVAL);
}
walk->flags &= ~ABLKCIPHER_WALK_SLOW;
src = dst = NULL;
bsize = min(walk->blocksize, n);
n = scatterwalk_clamp(&walk->in, n);
n = scatterwalk_clamp(&walk->out, n);
if (n < bsize ||
!scatterwalk_aligned(&walk->in, alignmask) ||
!scatterwalk_aligned(&walk->out, alignmask)) {
err = ablkcipher_next_slow(req, walk, bsize, alignmask,
&src, &dst);
goto set_phys_lowmem;
}
walk->nbytes = n;
return ablkcipher_next_fast(req, walk);
set_phys_lowmem:
if (err >= 0) {
walk->src.page = virt_to_page(src);
walk->dst.page = virt_to_page(dst);
walk->src.offset = ((unsigned long)src & (PAGE_SIZE - 1));
walk->dst.offset = ((unsigned long)dst & (PAGE_SIZE - 1));
}
return err;
}
static int ablkcipher_walk_first(struct ablkcipher_request *req,
struct ablkcipher_walk *walk)
{
struct crypto_tfm *tfm = req->base.tfm;
unsigned int alignmask;
alignmask = crypto_tfm_alg_alignmask(tfm);
if (WARN_ON_ONCE(in_irq()))
return -EDEADLK;
walk->nbytes = walk->total;
if (unlikely(!walk->total))
return 0;
walk->iv_buffer = NULL;
walk->iv = req->info;
if (unlikely(((unsigned long)walk->iv & alignmask))) {
int err = ablkcipher_copy_iv(walk, tfm, alignmask);
if (err)
return err;
}
scatterwalk_start(&walk->in, walk->in.sg);
scatterwalk_start(&walk->out, walk->out.sg);
return ablkcipher_walk_next(req, walk);
}
int ablkcipher_walk_phys(struct ablkcipher_request *req,
struct ablkcipher_walk *walk)
{
walk->blocksize = crypto_tfm_alg_blocksize(req->base.tfm);
return ablkcipher_walk_first(req, walk);
}
EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
unsigned int keylen)
{
struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
unsigned long alignmask = crypto_ablkcipher_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;
}
static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
unsigned int keylen)
{
struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
crypto_ablkcipher_set_flags(tfm, 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);
}
static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
u32 mask)
{
return alg->cra_ctxsize;
}
int skcipher_null_givencrypt(struct skcipher_givcrypt_request *req)
{
return crypto_ablkcipher_encrypt(&req->creq);
}
int skcipher_null_givdecrypt(struct skcipher_givcrypt_request *req)
{
return crypto_ablkcipher_decrypt(&req->creq);
}
static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
u32 mask)
{
struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
if (alg->ivsize > PAGE_SIZE / 8)
return -EINVAL;
crt->setkey = setkey;
crt->encrypt = alg->encrypt;
crt->decrypt = alg->decrypt;
if (!alg->ivsize) {
crt->givencrypt = skcipher_null_givencrypt;
crt->givdecrypt = skcipher_null_givdecrypt;
}
crt->base = __crypto_ablkcipher_cast(tfm);
crt->ivsize = alg->ivsize;
return 0;
}
#ifdef CONFIG_NET
static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_blkcipher rblkcipher;
snprintf(rblkcipher.type, CRYPTO_MAX_ALG_NAME, "%s", "ablkcipher");
snprintf(rblkcipher.geniv, CRYPTO_MAX_ALG_NAME, "%s",
alg->cra_ablkcipher.geniv ?: "<default>");
rblkcipher.blocksize = alg->cra_blocksize;
rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
sizeof(struct crypto_report_blkcipher), &rblkcipher))
goto nla_put_failure;
return 0;
nla_put_failure:
return -EMSGSIZE;
}
#else
static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
{
return -ENOSYS;
}
#endif
static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
__attribute__ ((unused));
static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
{
struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
seq_printf(m, "type : ablkcipher\n");
seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
"yes" : "no");
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
seq_printf(m, "min keysize : %u\n", ablkcipher->min_keysize);
seq_printf(m, "max keysize : %u\n", ablkcipher->max_keysize);
seq_printf(m, "ivsize : %u\n", ablkcipher->ivsize);
seq_printf(m, "geniv : %s\n", ablkcipher->geniv ?: "<default>");
}
const struct crypto_type crypto_ablkcipher_type = {
.ctxsize = crypto_ablkcipher_ctxsize,
.init = crypto_init_ablkcipher_ops,
#ifdef CONFIG_PROC_FS
.show = crypto_ablkcipher_show,
#endif
.report = crypto_ablkcipher_report,
};
EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);
[CRYPTO] skcipher: Add givcrypt operations and givcipher type Different block cipher modes have different requirements for intialisation vectors. For example, CBC can use a simple randomly generated IV while modes such as CTR must use an IV generation mechanisms that give a stronger guarantee on the lack of collisions. Furthermore, disk encryption modes have their own IV generation algorithms. Up until now IV generation has been left to the users of the symmetric key cipher API. This is inconvenient as the number of block cipher modes increase because the user needs to be aware of which mode is supposed to be paired with which IV generation algorithm. Therefore it makes sense to integrate the IV generation into the crypto API. This patch takes the first step in that direction by creating two new ablkcipher operations, givencrypt and givdecrypt that generates an IV before performing the actual encryption or decryption. The operations are currently not exposed to the user. That will be done once the underlying functionality has actually been implemented. It also creates the underlying givcipher type. Algorithms that directly generate IVs would use it instead of ablkcipher. All other algorithms (including all existing ones) would generate a givcipher algorithm upon registration. This givcipher algorithm will be constructed from the geniv string that's stored in every algorithm. That string will locate a template which is instantiated by the blkcipher/ablkcipher algorithm in question to give a givcipher algorithm. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-12-17 14:51:27 +01:00
static int no_givdecrypt(struct skcipher_givcrypt_request *req)
{
return -ENOSYS;
}
static int crypto_init_givcipher_ops(struct crypto_tfm *tfm, u32 type,
u32 mask)
{
struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
if (alg->ivsize > PAGE_SIZE / 8)
return -EINVAL;
crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
alg->setkey : setkey;
[CRYPTO] skcipher: Add givcrypt operations and givcipher type Different block cipher modes have different requirements for intialisation vectors. For example, CBC can use a simple randomly generated IV while modes such as CTR must use an IV generation mechanisms that give a stronger guarantee on the lack of collisions. Furthermore, disk encryption modes have their own IV generation algorithms. Up until now IV generation has been left to the users of the symmetric key cipher API. This is inconvenient as the number of block cipher modes increase because the user needs to be aware of which mode is supposed to be paired with which IV generation algorithm. Therefore it makes sense to integrate the IV generation into the crypto API. This patch takes the first step in that direction by creating two new ablkcipher operations, givencrypt and givdecrypt that generates an IV before performing the actual encryption or decryption. The operations are currently not exposed to the user. That will be done once the underlying functionality has actually been implemented. It also creates the underlying givcipher type. Algorithms that directly generate IVs would use it instead of ablkcipher. All other algorithms (including all existing ones) would generate a givcipher algorithm upon registration. This givcipher algorithm will be constructed from the geniv string that's stored in every algorithm. That string will locate a template which is instantiated by the blkcipher/ablkcipher algorithm in question to give a givcipher algorithm. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-12-17 14:51:27 +01:00
crt->encrypt = alg->encrypt;
crt->decrypt = alg->decrypt;
crt->givencrypt = alg->givencrypt;
crt->givdecrypt = alg->givdecrypt ?: no_givdecrypt;
crt->base = __crypto_ablkcipher_cast(tfm);
[CRYPTO] skcipher: Add givcrypt operations and givcipher type Different block cipher modes have different requirements for intialisation vectors. For example, CBC can use a simple randomly generated IV while modes such as CTR must use an IV generation mechanisms that give a stronger guarantee on the lack of collisions. Furthermore, disk encryption modes have their own IV generation algorithms. Up until now IV generation has been left to the users of the symmetric key cipher API. This is inconvenient as the number of block cipher modes increase because the user needs to be aware of which mode is supposed to be paired with which IV generation algorithm. Therefore it makes sense to integrate the IV generation into the crypto API. This patch takes the first step in that direction by creating two new ablkcipher operations, givencrypt and givdecrypt that generates an IV before performing the actual encryption or decryption. The operations are currently not exposed to the user. That will be done once the underlying functionality has actually been implemented. It also creates the underlying givcipher type. Algorithms that directly generate IVs would use it instead of ablkcipher. All other algorithms (including all existing ones) would generate a givcipher algorithm upon registration. This givcipher algorithm will be constructed from the geniv string that's stored in every algorithm. That string will locate a template which is instantiated by the blkcipher/ablkcipher algorithm in question to give a givcipher algorithm. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-12-17 14:51:27 +01:00
crt->ivsize = alg->ivsize;
return 0;
}
#ifdef CONFIG_NET
static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_blkcipher rblkcipher;
snprintf(rblkcipher.type, CRYPTO_MAX_ALG_NAME, "%s", "givcipher");
snprintf(rblkcipher.geniv, CRYPTO_MAX_ALG_NAME, "%s",
alg->cra_ablkcipher.geniv ?: "<built-in>");
rblkcipher.blocksize = alg->cra_blocksize;
rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
sizeof(struct crypto_report_blkcipher), &rblkcipher))
goto nla_put_failure;
return 0;
nla_put_failure:
return -EMSGSIZE;
}
#else
static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
{
return -ENOSYS;
}
#endif
[CRYPTO] skcipher: Add givcrypt operations and givcipher type Different block cipher modes have different requirements for intialisation vectors. For example, CBC can use a simple randomly generated IV while modes such as CTR must use an IV generation mechanisms that give a stronger guarantee on the lack of collisions. Furthermore, disk encryption modes have their own IV generation algorithms. Up until now IV generation has been left to the users of the symmetric key cipher API. This is inconvenient as the number of block cipher modes increase because the user needs to be aware of which mode is supposed to be paired with which IV generation algorithm. Therefore it makes sense to integrate the IV generation into the crypto API. This patch takes the first step in that direction by creating two new ablkcipher operations, givencrypt and givdecrypt that generates an IV before performing the actual encryption or decryption. The operations are currently not exposed to the user. That will be done once the underlying functionality has actually been implemented. It also creates the underlying givcipher type. Algorithms that directly generate IVs would use it instead of ablkcipher. All other algorithms (including all existing ones) would generate a givcipher algorithm upon registration. This givcipher algorithm will be constructed from the geniv string that's stored in every algorithm. That string will locate a template which is instantiated by the blkcipher/ablkcipher algorithm in question to give a givcipher algorithm. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-12-17 14:51:27 +01:00
static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
__attribute__ ((unused));
static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
{
struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
seq_printf(m, "type : givcipher\n");
seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
"yes" : "no");
[CRYPTO] skcipher: Add givcrypt operations and givcipher type Different block cipher modes have different requirements for intialisation vectors. For example, CBC can use a simple randomly generated IV while modes such as CTR must use an IV generation mechanisms that give a stronger guarantee on the lack of collisions. Furthermore, disk encryption modes have their own IV generation algorithms. Up until now IV generation has been left to the users of the symmetric key cipher API. This is inconvenient as the number of block cipher modes increase because the user needs to be aware of which mode is supposed to be paired with which IV generation algorithm. Therefore it makes sense to integrate the IV generation into the crypto API. This patch takes the first step in that direction by creating two new ablkcipher operations, givencrypt and givdecrypt that generates an IV before performing the actual encryption or decryption. The operations are currently not exposed to the user. That will be done once the underlying functionality has actually been implemented. It also creates the underlying givcipher type. Algorithms that directly generate IVs would use it instead of ablkcipher. All other algorithms (including all existing ones) would generate a givcipher algorithm upon registration. This givcipher algorithm will be constructed from the geniv string that's stored in every algorithm. That string will locate a template which is instantiated by the blkcipher/ablkcipher algorithm in question to give a givcipher algorithm. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-12-17 14:51:27 +01:00
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
seq_printf(m, "min keysize : %u\n", ablkcipher->min_keysize);
seq_printf(m, "max keysize : %u\n", ablkcipher->max_keysize);
seq_printf(m, "ivsize : %u\n", ablkcipher->ivsize);
seq_printf(m, "geniv : %s\n", ablkcipher->geniv ?: "<built-in>");
[CRYPTO] skcipher: Add givcrypt operations and givcipher type Different block cipher modes have different requirements for intialisation vectors. For example, CBC can use a simple randomly generated IV while modes such as CTR must use an IV generation mechanisms that give a stronger guarantee on the lack of collisions. Furthermore, disk encryption modes have their own IV generation algorithms. Up until now IV generation has been left to the users of the symmetric key cipher API. This is inconvenient as the number of block cipher modes increase because the user needs to be aware of which mode is supposed to be paired with which IV generation algorithm. Therefore it makes sense to integrate the IV generation into the crypto API. This patch takes the first step in that direction by creating two new ablkcipher operations, givencrypt and givdecrypt that generates an IV before performing the actual encryption or decryption. The operations are currently not exposed to the user. That will be done once the underlying functionality has actually been implemented. It also creates the underlying givcipher type. Algorithms that directly generate IVs would use it instead of ablkcipher. All other algorithms (including all existing ones) would generate a givcipher algorithm upon registration. This givcipher algorithm will be constructed from the geniv string that's stored in every algorithm. That string will locate a template which is instantiated by the blkcipher/ablkcipher algorithm in question to give a givcipher algorithm. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-12-17 14:51:27 +01:00
}
const struct crypto_type crypto_givcipher_type = {
.ctxsize = crypto_ablkcipher_ctxsize,
.init = crypto_init_givcipher_ops,
#ifdef CONFIG_PROC_FS
.show = crypto_givcipher_show,
#endif
.report = crypto_givcipher_report,
[CRYPTO] skcipher: Add givcrypt operations and givcipher type Different block cipher modes have different requirements for intialisation vectors. For example, CBC can use a simple randomly generated IV while modes such as CTR must use an IV generation mechanisms that give a stronger guarantee on the lack of collisions. Furthermore, disk encryption modes have their own IV generation algorithms. Up until now IV generation has been left to the users of the symmetric key cipher API. This is inconvenient as the number of block cipher modes increase because the user needs to be aware of which mode is supposed to be paired with which IV generation algorithm. Therefore it makes sense to integrate the IV generation into the crypto API. This patch takes the first step in that direction by creating two new ablkcipher operations, givencrypt and givdecrypt that generates an IV before performing the actual encryption or decryption. The operations are currently not exposed to the user. That will be done once the underlying functionality has actually been implemented. It also creates the underlying givcipher type. Algorithms that directly generate IVs would use it instead of ablkcipher. All other algorithms (including all existing ones) would generate a givcipher algorithm upon registration. This givcipher algorithm will be constructed from the geniv string that's stored in every algorithm. That string will locate a template which is instantiated by the blkcipher/ablkcipher algorithm in question to give a givcipher algorithm. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-12-17 14:51:27 +01:00
};
EXPORT_SYMBOL_GPL(crypto_givcipher_type);
const char *crypto_default_geniv(const struct crypto_alg *alg)
{
if (((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
alg->cra_ablkcipher.ivsize) !=
alg->cra_blocksize)
return "chainiv";
return alg->cra_flags & CRYPTO_ALG_ASYNC ?
"eseqiv" : skcipher_default_geniv;
}
static int crypto_givcipher_default(struct crypto_alg *alg, u32 type, u32 mask)
{
struct rtattr *tb[3];
struct {
struct rtattr attr;
struct crypto_attr_type data;
} ptype;
struct {
struct rtattr attr;
struct crypto_attr_alg data;
} palg;
struct crypto_template *tmpl;
struct crypto_instance *inst;
struct crypto_alg *larval;
const char *geniv;
int err;
larval = crypto_larval_lookup(alg->cra_driver_name,
(type & ~CRYPTO_ALG_TYPE_MASK) |
CRYPTO_ALG_TYPE_GIVCIPHER,
mask | CRYPTO_ALG_TYPE_MASK);
err = PTR_ERR(larval);
if (IS_ERR(larval))
goto out;
err = -EAGAIN;
if (!crypto_is_larval(larval))
goto drop_larval;
ptype.attr.rta_len = sizeof(ptype);
ptype.attr.rta_type = CRYPTOA_TYPE;
ptype.data.type = type | CRYPTO_ALG_GENIV;
/* GENIV tells the template that we're making a default geniv. */
ptype.data.mask = mask | CRYPTO_ALG_GENIV;
tb[0] = &ptype.attr;
palg.attr.rta_len = sizeof(palg);
palg.attr.rta_type = CRYPTOA_ALG;
/* Must use the exact name to locate ourselves. */
memcpy(palg.data.name, alg->cra_driver_name, CRYPTO_MAX_ALG_NAME);
tb[1] = &palg.attr;
tb[2] = NULL;
if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_BLKCIPHER)
geniv = alg->cra_blkcipher.geniv;
else
geniv = alg->cra_ablkcipher.geniv;
if (!geniv)
geniv = crypto_default_geniv(alg);
tmpl = crypto_lookup_template(geniv);
err = -ENOENT;
if (!tmpl)
goto kill_larval;
inst = tmpl->alloc(tb);
err = PTR_ERR(inst);
if (IS_ERR(inst))
goto put_tmpl;
if ((err = crypto_register_instance(tmpl, inst))) {
tmpl->free(inst);
goto put_tmpl;
}
/* Redo the lookup to use the instance we just registered. */
err = -EAGAIN;
put_tmpl:
crypto_tmpl_put(tmpl);
kill_larval:
crypto_larval_kill(larval);
drop_larval:
crypto_mod_put(larval);
out:
crypto_mod_put(alg);
return err;
}
struct crypto_alg *crypto_lookup_skcipher(const char *name, u32 type, u32 mask)
{
struct crypto_alg *alg;
alg = crypto_alg_mod_lookup(name, type, mask);
if (IS_ERR(alg))
return alg;
if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_GIVCIPHER)
return alg;
if (!((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
alg->cra_ablkcipher.ivsize))
return alg;
crypto_mod_put(alg);
alg = crypto_alg_mod_lookup(name, type | CRYPTO_ALG_TESTED,
mask & ~CRYPTO_ALG_TESTED);
if (IS_ERR(alg))
return alg;
if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_GIVCIPHER) {
if ((alg->cra_flags ^ type ^ ~mask) & CRYPTO_ALG_TESTED) {
crypto_mod_put(alg);
alg = ERR_PTR(-ENOENT);
}
return alg;
}
BUG_ON(!((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
alg->cra_ablkcipher.ivsize));
return ERR_PTR(crypto_givcipher_default(alg, type, mask));
}
EXPORT_SYMBOL_GPL(crypto_lookup_skcipher);
int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn, const char *name,
u32 type, u32 mask)
{
struct crypto_alg *alg;
int err;
type = crypto_skcipher_type(type);
mask = crypto_skcipher_mask(mask);
alg = crypto_lookup_skcipher(name, type, mask);
if (IS_ERR(alg))
return PTR_ERR(alg);
err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
crypto_mod_put(alg);
return err;
}
EXPORT_SYMBOL_GPL(crypto_grab_skcipher);
struct crypto_ablkcipher *crypto_alloc_ablkcipher(const char *alg_name,
u32 type, u32 mask)
{
struct crypto_tfm *tfm;
int err;
type = crypto_skcipher_type(type);
mask = crypto_skcipher_mask(mask);
for (;;) {
struct crypto_alg *alg;
alg = crypto_lookup_skcipher(alg_name, type, mask);
if (IS_ERR(alg)) {
err = PTR_ERR(alg);
goto err;
}
tfm = __crypto_alloc_tfm(alg, type, mask);
if (!IS_ERR(tfm))
return __crypto_ablkcipher_cast(tfm);
crypto_mod_put(alg);
err = PTR_ERR(tfm);
err:
if (err != -EAGAIN)
break;
if (signal_pending(current)) {
err = -EINTR;
break;
}
}
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(crypto_alloc_ablkcipher);
static int __init skcipher_module_init(void)
{
skcipher_default_geniv = num_possible_cpus() > 1 ?
"eseqiv" : "chainiv";
return 0;
}
static void skcipher_module_exit(void)
{
}
module_init(skcipher_module_init);
module_exit(skcipher_module_exit);