linux/crypto/lskcipher.c
Eric Biggers 7ec0a09d4e crypto: skcipher - fix weak key check for lskciphers
When an algorithm of the new "lskcipher" type is exposed through the
"skcipher" API, calls to crypto_skcipher_setkey() don't pass on the
CRYPTO_TFM_REQ_FORBID_WEAK_KEYS flag to the lskcipher.  This causes
self-test failures for ecb(des), as weak keys are not rejected anymore.
Fix this.

Fixes: 31865c4c4d ("crypto: skcipher - Add lskcipher")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2023-10-20 13:39:26 +08:00

635 lines
17 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Linear symmetric key cipher operations.
*
* Generic encrypt/decrypt wrapper for ciphers.
*
* Copyright (c) 2023 Herbert Xu <herbert@gondor.apana.org.au>
*/
#include <linux/cryptouser.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <net/netlink.h>
#include "skcipher.h"
static inline struct crypto_lskcipher *__crypto_lskcipher_cast(
struct crypto_tfm *tfm)
{
return container_of(tfm, struct crypto_lskcipher, base);
}
static inline struct lskcipher_alg *__crypto_lskcipher_alg(
struct crypto_alg *alg)
{
return container_of(alg, struct lskcipher_alg, co.base);
}
static inline struct crypto_istat_cipher *lskcipher_get_stat(
struct lskcipher_alg *alg)
{
return skcipher_get_stat_common(&alg->co);
}
static inline int crypto_lskcipher_errstat(struct lskcipher_alg *alg, int err)
{
struct crypto_istat_cipher *istat = lskcipher_get_stat(alg);
if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
return err;
if (err)
atomic64_inc(&istat->err_cnt);
return err;
}
static int lskcipher_setkey_unaligned(struct crypto_lskcipher *tfm,
const u8 *key, unsigned int keylen)
{
unsigned long alignmask = crypto_lskcipher_alignmask(tfm);
struct lskcipher_alg *cipher = crypto_lskcipher_alg(tfm);
u8 *buffer, *alignbuffer;
unsigned long absize;
int ret;
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);
kfree_sensitive(buffer);
return ret;
}
int crypto_lskcipher_setkey(struct crypto_lskcipher *tfm, const u8 *key,
unsigned int keylen)
{
unsigned long alignmask = crypto_lskcipher_alignmask(tfm);
struct lskcipher_alg *cipher = crypto_lskcipher_alg(tfm);
if (keylen < cipher->co.min_keysize || keylen > cipher->co.max_keysize)
return -EINVAL;
if ((unsigned long)key & alignmask)
return lskcipher_setkey_unaligned(tfm, key, keylen);
else
return cipher->setkey(tfm, key, keylen);
}
EXPORT_SYMBOL_GPL(crypto_lskcipher_setkey);
static int crypto_lskcipher_crypt_unaligned(
struct crypto_lskcipher *tfm, const u8 *src, u8 *dst, unsigned len,
u8 *iv, int (*crypt)(struct crypto_lskcipher *tfm, const u8 *src,
u8 *dst, unsigned len, u8 *iv, bool final))
{
unsigned ivsize = crypto_lskcipher_ivsize(tfm);
unsigned bs = crypto_lskcipher_blocksize(tfm);
unsigned cs = crypto_lskcipher_chunksize(tfm);
int err;
u8 *tiv;
u8 *p;
BUILD_BUG_ON(MAX_CIPHER_BLOCKSIZE > PAGE_SIZE ||
MAX_CIPHER_ALIGNMASK >= PAGE_SIZE);
tiv = kmalloc(PAGE_SIZE, GFP_ATOMIC);
if (!tiv)
return -ENOMEM;
memcpy(tiv, iv, ivsize);
p = kmalloc(PAGE_SIZE, GFP_ATOMIC);
err = -ENOMEM;
if (!p)
goto out;
while (len >= bs) {
unsigned chunk = min((unsigned)PAGE_SIZE, len);
int err;
if (chunk > cs)
chunk &= ~(cs - 1);
memcpy(p, src, chunk);
err = crypt(tfm, p, p, chunk, tiv, true);
if (err)
goto out;
memcpy(dst, p, chunk);
src += chunk;
dst += chunk;
len -= chunk;
}
err = len ? -EINVAL : 0;
out:
memcpy(iv, tiv, ivsize);
kfree_sensitive(p);
kfree_sensitive(tiv);
return err;
}
static int crypto_lskcipher_crypt(struct crypto_lskcipher *tfm, const u8 *src,
u8 *dst, unsigned len, u8 *iv,
int (*crypt)(struct crypto_lskcipher *tfm,
const u8 *src, u8 *dst,
unsigned len, u8 *iv,
bool final))
{
unsigned long alignmask = crypto_lskcipher_alignmask(tfm);
struct lskcipher_alg *alg = crypto_lskcipher_alg(tfm);
int ret;
if (((unsigned long)src | (unsigned long)dst | (unsigned long)iv) &
alignmask) {
ret = crypto_lskcipher_crypt_unaligned(tfm, src, dst, len, iv,
crypt);
goto out;
}
ret = crypt(tfm, src, dst, len, iv, true);
out:
return crypto_lskcipher_errstat(alg, ret);
}
int crypto_lskcipher_encrypt(struct crypto_lskcipher *tfm, const u8 *src,
u8 *dst, unsigned len, u8 *iv)
{
struct lskcipher_alg *alg = crypto_lskcipher_alg(tfm);
if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
struct crypto_istat_cipher *istat = lskcipher_get_stat(alg);
atomic64_inc(&istat->encrypt_cnt);
atomic64_add(len, &istat->encrypt_tlen);
}
return crypto_lskcipher_crypt(tfm, src, dst, len, iv, alg->encrypt);
}
EXPORT_SYMBOL_GPL(crypto_lskcipher_encrypt);
int crypto_lskcipher_decrypt(struct crypto_lskcipher *tfm, const u8 *src,
u8 *dst, unsigned len, u8 *iv)
{
struct lskcipher_alg *alg = crypto_lskcipher_alg(tfm);
if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
struct crypto_istat_cipher *istat = lskcipher_get_stat(alg);
atomic64_inc(&istat->decrypt_cnt);
atomic64_add(len, &istat->decrypt_tlen);
}
return crypto_lskcipher_crypt(tfm, src, dst, len, iv, alg->decrypt);
}
EXPORT_SYMBOL_GPL(crypto_lskcipher_decrypt);
static int crypto_lskcipher_crypt_sg(struct skcipher_request *req,
int (*crypt)(struct crypto_lskcipher *tfm,
const u8 *src, u8 *dst,
unsigned len, u8 *iv,
bool final))
{
struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
struct crypto_lskcipher **ctx = crypto_skcipher_ctx(skcipher);
struct crypto_lskcipher *tfm = *ctx;
struct skcipher_walk walk;
int err;
err = skcipher_walk_virt(&walk, req, false);
while (walk.nbytes) {
err = crypt(tfm, walk.src.virt.addr, walk.dst.virt.addr,
walk.nbytes, walk.iv, walk.nbytes == walk.total);
err = skcipher_walk_done(&walk, err);
}
return err;
}
int crypto_lskcipher_encrypt_sg(struct skcipher_request *req)
{
struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
struct crypto_lskcipher **ctx = crypto_skcipher_ctx(skcipher);
struct lskcipher_alg *alg = crypto_lskcipher_alg(*ctx);
return crypto_lskcipher_crypt_sg(req, alg->encrypt);
}
int crypto_lskcipher_decrypt_sg(struct skcipher_request *req)
{
struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
struct crypto_lskcipher **ctx = crypto_skcipher_ctx(skcipher);
struct lskcipher_alg *alg = crypto_lskcipher_alg(*ctx);
return crypto_lskcipher_crypt_sg(req, alg->decrypt);
}
static void crypto_lskcipher_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_lskcipher *skcipher = __crypto_lskcipher_cast(tfm);
struct lskcipher_alg *alg = crypto_lskcipher_alg(skcipher);
alg->exit(skcipher);
}
static int crypto_lskcipher_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_lskcipher *skcipher = __crypto_lskcipher_cast(tfm);
struct lskcipher_alg *alg = crypto_lskcipher_alg(skcipher);
if (alg->exit)
skcipher->base.exit = crypto_lskcipher_exit_tfm;
if (alg->init)
return alg->init(skcipher);
return 0;
}
static void crypto_lskcipher_free_instance(struct crypto_instance *inst)
{
struct lskcipher_instance *skcipher =
container_of(inst, struct lskcipher_instance, s.base);
skcipher->free(skcipher);
}
static void __maybe_unused crypto_lskcipher_show(
struct seq_file *m, struct crypto_alg *alg)
{
struct lskcipher_alg *skcipher = __crypto_lskcipher_alg(alg);
seq_printf(m, "type : lskcipher\n");
seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
seq_printf(m, "min keysize : %u\n", skcipher->co.min_keysize);
seq_printf(m, "max keysize : %u\n", skcipher->co.max_keysize);
seq_printf(m, "ivsize : %u\n", skcipher->co.ivsize);
seq_printf(m, "chunksize : %u\n", skcipher->co.chunksize);
}
static int __maybe_unused crypto_lskcipher_report(
struct sk_buff *skb, struct crypto_alg *alg)
{
struct lskcipher_alg *skcipher = __crypto_lskcipher_alg(alg);
struct crypto_report_blkcipher rblkcipher;
memset(&rblkcipher, 0, sizeof(rblkcipher));
strscpy(rblkcipher.type, "lskcipher", sizeof(rblkcipher.type));
strscpy(rblkcipher.geniv, "<none>", sizeof(rblkcipher.geniv));
rblkcipher.blocksize = alg->cra_blocksize;
rblkcipher.min_keysize = skcipher->co.min_keysize;
rblkcipher.max_keysize = skcipher->co.max_keysize;
rblkcipher.ivsize = skcipher->co.ivsize;
return nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
sizeof(rblkcipher), &rblkcipher);
}
static int __maybe_unused crypto_lskcipher_report_stat(
struct sk_buff *skb, struct crypto_alg *alg)
{
struct lskcipher_alg *skcipher = __crypto_lskcipher_alg(alg);
struct crypto_istat_cipher *istat;
struct crypto_stat_cipher rcipher;
istat = lskcipher_get_stat(skcipher);
memset(&rcipher, 0, sizeof(rcipher));
strscpy(rcipher.type, "cipher", sizeof(rcipher.type));
rcipher.stat_encrypt_cnt = atomic64_read(&istat->encrypt_cnt);
rcipher.stat_encrypt_tlen = atomic64_read(&istat->encrypt_tlen);
rcipher.stat_decrypt_cnt = atomic64_read(&istat->decrypt_cnt);
rcipher.stat_decrypt_tlen = atomic64_read(&istat->decrypt_tlen);
rcipher.stat_err_cnt = atomic64_read(&istat->err_cnt);
return nla_put(skb, CRYPTOCFGA_STAT_CIPHER, sizeof(rcipher), &rcipher);
}
static const struct crypto_type crypto_lskcipher_type = {
.extsize = crypto_alg_extsize,
.init_tfm = crypto_lskcipher_init_tfm,
.free = crypto_lskcipher_free_instance,
#ifdef CONFIG_PROC_FS
.show = crypto_lskcipher_show,
#endif
#if IS_ENABLED(CONFIG_CRYPTO_USER)
.report = crypto_lskcipher_report,
#endif
#ifdef CONFIG_CRYPTO_STATS
.report_stat = crypto_lskcipher_report_stat,
#endif
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_MASK,
.type = CRYPTO_ALG_TYPE_LSKCIPHER,
.tfmsize = offsetof(struct crypto_lskcipher, base),
};
static void crypto_lskcipher_exit_tfm_sg(struct crypto_tfm *tfm)
{
struct crypto_lskcipher **ctx = crypto_tfm_ctx(tfm);
crypto_free_lskcipher(*ctx);
}
int crypto_init_lskcipher_ops_sg(struct crypto_tfm *tfm)
{
struct crypto_lskcipher **ctx = crypto_tfm_ctx(tfm);
struct crypto_alg *calg = tfm->__crt_alg;
struct crypto_lskcipher *skcipher;
if (!crypto_mod_get(calg))
return -EAGAIN;
skcipher = crypto_create_tfm(calg, &crypto_lskcipher_type);
if (IS_ERR(skcipher)) {
crypto_mod_put(calg);
return PTR_ERR(skcipher);
}
*ctx = skcipher;
tfm->exit = crypto_lskcipher_exit_tfm_sg;
return 0;
}
int crypto_grab_lskcipher(struct crypto_lskcipher_spawn *spawn,
struct crypto_instance *inst,
const char *name, u32 type, u32 mask)
{
spawn->base.frontend = &crypto_lskcipher_type;
return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_grab_lskcipher);
struct crypto_lskcipher *crypto_alloc_lskcipher(const char *alg_name,
u32 type, u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_lskcipher_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_lskcipher);
static int lskcipher_prepare_alg(struct lskcipher_alg *alg)
{
struct crypto_alg *base = &alg->co.base;
int err;
err = skcipher_prepare_alg_common(&alg->co);
if (err)
return err;
if (alg->co.chunksize & (alg->co.chunksize - 1))
return -EINVAL;
base->cra_type = &crypto_lskcipher_type;
base->cra_flags |= CRYPTO_ALG_TYPE_LSKCIPHER;
return 0;
}
int crypto_register_lskcipher(struct lskcipher_alg *alg)
{
struct crypto_alg *base = &alg->co.base;
int err;
err = lskcipher_prepare_alg(alg);
if (err)
return err;
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_lskcipher);
void crypto_unregister_lskcipher(struct lskcipher_alg *alg)
{
crypto_unregister_alg(&alg->co.base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_lskcipher);
int crypto_register_lskciphers(struct lskcipher_alg *algs, int count)
{
int i, ret;
for (i = 0; i < count; i++) {
ret = crypto_register_lskcipher(&algs[i]);
if (ret)
goto err;
}
return 0;
err:
for (--i; i >= 0; --i)
crypto_unregister_lskcipher(&algs[i]);
return ret;
}
EXPORT_SYMBOL_GPL(crypto_register_lskciphers);
void crypto_unregister_lskciphers(struct lskcipher_alg *algs, int count)
{
int i;
for (i = count - 1; i >= 0; --i)
crypto_unregister_lskcipher(&algs[i]);
}
EXPORT_SYMBOL_GPL(crypto_unregister_lskciphers);
int lskcipher_register_instance(struct crypto_template *tmpl,
struct lskcipher_instance *inst)
{
int err;
if (WARN_ON(!inst->free))
return -EINVAL;
err = lskcipher_prepare_alg(&inst->alg);
if (err)
return err;
return crypto_register_instance(tmpl, lskcipher_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(lskcipher_register_instance);
static int lskcipher_setkey_simple(struct crypto_lskcipher *tfm, const u8 *key,
unsigned int keylen)
{
struct crypto_lskcipher *cipher = lskcipher_cipher_simple(tfm);
crypto_lskcipher_clear_flags(cipher, CRYPTO_TFM_REQ_MASK);
crypto_lskcipher_set_flags(cipher, crypto_lskcipher_get_flags(tfm) &
CRYPTO_TFM_REQ_MASK);
return crypto_lskcipher_setkey(cipher, key, keylen);
}
static int lskcipher_init_tfm_simple(struct crypto_lskcipher *tfm)
{
struct lskcipher_instance *inst = lskcipher_alg_instance(tfm);
struct crypto_lskcipher **ctx = crypto_lskcipher_ctx(tfm);
struct crypto_lskcipher_spawn *spawn;
struct crypto_lskcipher *cipher;
spawn = lskcipher_instance_ctx(inst);
cipher = crypto_spawn_lskcipher(spawn);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
*ctx = cipher;
return 0;
}
static void lskcipher_exit_tfm_simple(struct crypto_lskcipher *tfm)
{
struct crypto_lskcipher **ctx = crypto_lskcipher_ctx(tfm);
crypto_free_lskcipher(*ctx);
}
static void lskcipher_free_instance_simple(struct lskcipher_instance *inst)
{
crypto_drop_lskcipher(lskcipher_instance_ctx(inst));
kfree(inst);
}
/**
* lskcipher_alloc_instance_simple - allocate instance of simple block cipher
*
* Allocate an lskcipher_instance for a simple block cipher mode of operation,
* e.g. cbc or ecb. The instance context will have just a single crypto_spawn,
* that for the underlying cipher. The {min,max}_keysize, ivsize, blocksize,
* alignmask, and priority are set from the underlying cipher but can be
* overridden if needed. The tfm context defaults to
* struct crypto_lskcipher *, and default ->setkey(), ->init(), and
* ->exit() methods are installed.
*
* @tmpl: the template being instantiated
* @tb: the template parameters
*
* Return: a pointer to the new instance, or an ERR_PTR(). The caller still
* needs to register the instance.
*/
struct lskcipher_instance *lskcipher_alloc_instance_simple(
struct crypto_template *tmpl, struct rtattr **tb)
{
u32 mask;
struct lskcipher_instance *inst;
struct crypto_lskcipher_spawn *spawn;
char ecb_name[CRYPTO_MAX_ALG_NAME];
struct lskcipher_alg *cipher_alg;
const char *cipher_name;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_LSKCIPHER, &mask);
if (err)
return ERR_PTR(err);
cipher_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(cipher_name))
return ERR_CAST(cipher_name);
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return ERR_PTR(-ENOMEM);
spawn = lskcipher_instance_ctx(inst);
err = crypto_grab_lskcipher(spawn,
lskcipher_crypto_instance(inst),
cipher_name, 0, mask);
ecb_name[0] = 0;
if (err == -ENOENT && !!memcmp(tmpl->name, "ecb", 4)) {
err = -ENAMETOOLONG;
if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
cipher_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
err = crypto_grab_lskcipher(spawn,
lskcipher_crypto_instance(inst),
ecb_name, 0, mask);
}
if (err)
goto err_free_inst;
cipher_alg = crypto_lskcipher_spawn_alg(spawn);
err = crypto_inst_setname(lskcipher_crypto_instance(inst), tmpl->name,
&cipher_alg->co.base);
if (err)
goto err_free_inst;
if (ecb_name[0]) {
int len;
err = -EINVAL;
len = strscpy(ecb_name, &cipher_alg->co.base.cra_name[4],
sizeof(ecb_name));
if (len < 2)
goto err_free_inst;
if (ecb_name[len - 1] != ')')
goto err_free_inst;
ecb_name[len - 1] = 0;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.co.base.cra_name, CRYPTO_MAX_ALG_NAME,
"%s(%s)", tmpl->name, ecb_name) >=
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
if (strcmp(ecb_name, cipher_name) &&
snprintf(inst->alg.co.base.cra_driver_name,
CRYPTO_MAX_ALG_NAME,
"%s(%s)", tmpl->name, cipher_name) >=
CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
} else {
/* Don't allow nesting. */
err = -ELOOP;
if ((cipher_alg->co.base.cra_flags & CRYPTO_ALG_INSTANCE))
goto err_free_inst;
}
err = -EINVAL;
if (cipher_alg->co.ivsize)
goto err_free_inst;
inst->free = lskcipher_free_instance_simple;
/* Default algorithm properties, can be overridden */
inst->alg.co.base.cra_blocksize = cipher_alg->co.base.cra_blocksize;
inst->alg.co.base.cra_alignmask = cipher_alg->co.base.cra_alignmask;
inst->alg.co.base.cra_priority = cipher_alg->co.base.cra_priority;
inst->alg.co.min_keysize = cipher_alg->co.min_keysize;
inst->alg.co.max_keysize = cipher_alg->co.max_keysize;
inst->alg.co.ivsize = cipher_alg->co.base.cra_blocksize;
/* Use struct crypto_lskcipher * by default, can be overridden */
inst->alg.co.base.cra_ctxsize = sizeof(struct crypto_lskcipher *);
inst->alg.setkey = lskcipher_setkey_simple;
inst->alg.init = lskcipher_init_tfm_simple;
inst->alg.exit = lskcipher_exit_tfm_simple;
return inst;
err_free_inst:
lskcipher_free_instance_simple(inst);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(lskcipher_alloc_instance_simple);