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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-11-27 12:04:22 +08:00
linux-next/crypto/ablkcipher.c
Mathias Krause 9a5467bf7b crypto: user - fix info leaks in report API
Three errors resulting in kernel memory disclosure:

1/ The structures used for the netlink based crypto algorithm report API
are located on the stack. As snprintf() does not fill the remainder of
the buffer with null bytes, those stack bytes will be disclosed to users
of the API. Switch to strncpy() to fix this.

2/ crypto_report_one() does not initialize all field of struct
crypto_user_alg. Fix this to fix the heap info leak.

3/ For the module name we should copy only as many bytes as
module_name() returns -- not as much as the destination buffer could
hold. But the current code does not and therefore copies random data
from behind the end of the module name, as the module name is always
shorter than CRYPTO_MAX_ALG_NAME.

Also switch to use strncpy() to copy the algorithm's name and
driver_name. They are strings, after all.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2013-02-19 20:27:03 +08:00

726 lines
18 KiB
C

/*
* 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;
strncpy(rblkcipher.type, "ablkcipher", sizeof(rblkcipher.type));
strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<default>",
sizeof(rblkcipher.geniv));
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);
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;
crt->encrypt = alg->encrypt;
crt->decrypt = alg->decrypt;
crt->givencrypt = alg->givencrypt;
crt->givdecrypt = alg->givdecrypt ?: no_givdecrypt;
crt->base = __crypto_ablkcipher_cast(tfm);
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;
strncpy(rblkcipher.type, "givcipher", sizeof(rblkcipher.type));
strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<built-in>",
sizeof(rblkcipher.geniv));
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
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");
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>");
}
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,
};
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);