linux/crypto/akcipher.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Public Key Encryption
*
* Copyright (c) 2015, Intel Corporation
* Authors: Tadeusz Struk <tadeusz.struk@intel.com>
*/
#include <crypto/internal/akcipher.h>
#include <linux/cryptouser.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <net/netlink.h>
#include "internal.h"
#define CRYPTO_ALG_TYPE_AHASH_MASK 0x0000000e
static int __maybe_unused crypto_akcipher_report(
struct sk_buff *skb, struct crypto_alg *alg)
{
struct crypto_report_akcipher rakcipher;
crypto: user - clean up report structure copying There have been a pretty ridiculous number of issues with initializing the report structures that are copied to userspace by NETLINK_CRYPTO. Commit 4473710df1f8 ("crypto: user - Prepare for CRYPTO_MAX_ALG_NAME expansion") replaced some strncpy()s with strlcpy()s, thereby introducing information leaks. Later two other people tried to replace other strncpy()s with strlcpy() too, which would have introduced even more information leaks: - https://lore.kernel.org/patchwork/patch/954991/ - https://patchwork.kernel.org/patch/10434351/ Commit cac5818c25d0 ("crypto: user - Implement a generic crypto statistics") also uses the buggy strlcpy() approach and therefore leaks uninitialized memory to userspace. A fix was proposed, but it was originally incomplete. Seeing as how apparently no one can get this right with the current approach, change all the reporting functions to: - Start by memsetting the report structure to 0. This guarantees it's always initialized, regardless of what happens later. - Initialize all strings using strscpy(). This is safe after the memset, ensures null termination of long strings, avoids unnecessary work, and avoids the -Wstringop-truncation warnings from gcc. - Use sizeof(var) instead of sizeof(type). This is more robust against copy+paste errors. For simplicity, also reuse the -EMSGSIZE return value from nla_put(). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-11-04 05:56:03 +08:00
memset(&rakcipher, 0, sizeof(rakcipher));
crypto: user - clean up report structure copying There have been a pretty ridiculous number of issues with initializing the report structures that are copied to userspace by NETLINK_CRYPTO. Commit 4473710df1f8 ("crypto: user - Prepare for CRYPTO_MAX_ALG_NAME expansion") replaced some strncpy()s with strlcpy()s, thereby introducing information leaks. Later two other people tried to replace other strncpy()s with strlcpy() too, which would have introduced even more information leaks: - https://lore.kernel.org/patchwork/patch/954991/ - https://patchwork.kernel.org/patch/10434351/ Commit cac5818c25d0 ("crypto: user - Implement a generic crypto statistics") also uses the buggy strlcpy() approach and therefore leaks uninitialized memory to userspace. A fix was proposed, but it was originally incomplete. Seeing as how apparently no one can get this right with the current approach, change all the reporting functions to: - Start by memsetting the report structure to 0. This guarantees it's always initialized, regardless of what happens later. - Initialize all strings using strscpy(). This is safe after the memset, ensures null termination of long strings, avoids unnecessary work, and avoids the -Wstringop-truncation warnings from gcc. - Use sizeof(var) instead of sizeof(type). This is more robust against copy+paste errors. For simplicity, also reuse the -EMSGSIZE return value from nla_put(). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-11-04 05:56:03 +08:00
strscpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
crypto: user - clean up report structure copying There have been a pretty ridiculous number of issues with initializing the report structures that are copied to userspace by NETLINK_CRYPTO. Commit 4473710df1f8 ("crypto: user - Prepare for CRYPTO_MAX_ALG_NAME expansion") replaced some strncpy()s with strlcpy()s, thereby introducing information leaks. Later two other people tried to replace other strncpy()s with strlcpy() too, which would have introduced even more information leaks: - https://lore.kernel.org/patchwork/patch/954991/ - https://patchwork.kernel.org/patch/10434351/ Commit cac5818c25d0 ("crypto: user - Implement a generic crypto statistics") also uses the buggy strlcpy() approach and therefore leaks uninitialized memory to userspace. A fix was proposed, but it was originally incomplete. Seeing as how apparently no one can get this right with the current approach, change all the reporting functions to: - Start by memsetting the report structure to 0. This guarantees it's always initialized, regardless of what happens later. - Initialize all strings using strscpy(). This is safe after the memset, ensures null termination of long strings, avoids unnecessary work, and avoids the -Wstringop-truncation warnings from gcc. - Use sizeof(var) instead of sizeof(type). This is more robust against copy+paste errors. For simplicity, also reuse the -EMSGSIZE return value from nla_put(). Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-11-04 05:56:03 +08:00
return nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
sizeof(rakcipher), &rakcipher);
}
static void crypto_akcipher_show(struct seq_file *m, struct crypto_alg *alg)
__maybe_unused;
static void crypto_akcipher_show(struct seq_file *m, struct crypto_alg *alg)
{
seq_puts(m, "type : akcipher\n");
}
static void crypto_akcipher_exit_tfm(struct crypto_tfm *tfm)
{
struct crypto_akcipher *akcipher = __crypto_akcipher_tfm(tfm);
struct akcipher_alg *alg = crypto_akcipher_alg(akcipher);
alg->exit(akcipher);
}
static int crypto_akcipher_init_tfm(struct crypto_tfm *tfm)
{
struct crypto_akcipher *akcipher = __crypto_akcipher_tfm(tfm);
struct akcipher_alg *alg = crypto_akcipher_alg(akcipher);
if (alg->exit)
akcipher->base.exit = crypto_akcipher_exit_tfm;
if (alg->init)
return alg->init(akcipher);
return 0;
}
static void crypto_akcipher_free_instance(struct crypto_instance *inst)
{
struct akcipher_instance *akcipher = akcipher_instance(inst);
akcipher->free(akcipher);
}
static int __maybe_unused crypto_akcipher_report_stat(
struct sk_buff *skb, struct crypto_alg *alg)
{
struct akcipher_alg *akcipher = __crypto_akcipher_alg(alg);
struct crypto_istat_akcipher *istat;
struct crypto_stat_akcipher rakcipher;
istat = akcipher_get_stat(akcipher);
memset(&rakcipher, 0, sizeof(rakcipher));
strscpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
rakcipher.stat_encrypt_cnt = atomic64_read(&istat->encrypt_cnt);
rakcipher.stat_encrypt_tlen = atomic64_read(&istat->encrypt_tlen);
rakcipher.stat_decrypt_cnt = atomic64_read(&istat->decrypt_cnt);
rakcipher.stat_decrypt_tlen = atomic64_read(&istat->decrypt_tlen);
rakcipher.stat_sign_cnt = atomic64_read(&istat->sign_cnt);
rakcipher.stat_verify_cnt = atomic64_read(&istat->verify_cnt);
rakcipher.stat_err_cnt = atomic64_read(&istat->err_cnt);
return nla_put(skb, CRYPTOCFGA_STAT_AKCIPHER,
sizeof(rakcipher), &rakcipher);
}
static const struct crypto_type crypto_akcipher_type = {
.extsize = crypto_alg_extsize,
.init_tfm = crypto_akcipher_init_tfm,
.free = crypto_akcipher_free_instance,
#ifdef CONFIG_PROC_FS
.show = crypto_akcipher_show,
#endif
#if IS_ENABLED(CONFIG_CRYPTO_USER)
.report = crypto_akcipher_report,
#endif
#ifdef CONFIG_CRYPTO_STATS
.report_stat = crypto_akcipher_report_stat,
#endif
.maskclear = ~CRYPTO_ALG_TYPE_MASK,
.maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
.type = CRYPTO_ALG_TYPE_AKCIPHER,
.tfmsize = offsetof(struct crypto_akcipher, base),
};
int crypto_grab_akcipher(struct crypto_akcipher_spawn *spawn,
struct crypto_instance *inst,
const char *name, u32 type, u32 mask)
{
spawn->base.frontend = &crypto_akcipher_type;
return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_grab_akcipher);
struct crypto_akcipher *crypto_alloc_akcipher(const char *alg_name, u32 type,
u32 mask)
{
return crypto_alloc_tfm(alg_name, &crypto_akcipher_type, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_alloc_akcipher);
static void akcipher_prepare_alg(struct akcipher_alg *alg)
{
struct crypto_istat_akcipher *istat = akcipher_get_stat(alg);
struct crypto_alg *base = &alg->base;
base->cra_type = &crypto_akcipher_type;
base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
base->cra_flags |= CRYPTO_ALG_TYPE_AKCIPHER;
if (IS_ENABLED(CONFIG_CRYPTO_STATS))
memset(istat, 0, sizeof(*istat));
}
static int akcipher_default_op(struct akcipher_request *req)
{
return -ENOSYS;
}
static int akcipher_default_set_key(struct crypto_akcipher *tfm,
const void *key, unsigned int keylen)
{
return -ENOSYS;
}
int crypto_register_akcipher(struct akcipher_alg *alg)
{
struct crypto_alg *base = &alg->base;
if (!alg->sign)
alg->sign = akcipher_default_op;
if (!alg->verify)
alg->verify = akcipher_default_op;
if (!alg->encrypt)
alg->encrypt = akcipher_default_op;
if (!alg->decrypt)
alg->decrypt = akcipher_default_op;
if (!alg->set_priv_key)
alg->set_priv_key = akcipher_default_set_key;
akcipher_prepare_alg(alg);
return crypto_register_alg(base);
}
EXPORT_SYMBOL_GPL(crypto_register_akcipher);
void crypto_unregister_akcipher(struct akcipher_alg *alg)
{
crypto_unregister_alg(&alg->base);
}
EXPORT_SYMBOL_GPL(crypto_unregister_akcipher);
int akcipher_register_instance(struct crypto_template *tmpl,
struct akcipher_instance *inst)
{
if (WARN_ON(!inst->free))
return -EINVAL;
akcipher_prepare_alg(&inst->alg);
return crypto_register_instance(tmpl, akcipher_crypto_instance(inst));
}
EXPORT_SYMBOL_GPL(akcipher_register_instance);
int crypto_akcipher_sync_prep(struct crypto_akcipher_sync_data *data)
{
unsigned int reqsize = crypto_akcipher_reqsize(data->tfm);
struct akcipher_request *req;
struct scatterlist *sg;
unsigned int mlen;
unsigned int len;
u8 *buf;
if (data->dst)
mlen = max(data->slen, data->dlen);
else
mlen = data->slen + data->dlen;
len = sizeof(*req) + reqsize + mlen;
if (len < mlen)
return -EOVERFLOW;
req = kzalloc(len, GFP_KERNEL);
if (!req)
return -ENOMEM;
data->req = req;
akcipher_request_set_tfm(req, data->tfm);
buf = (u8 *)(req + 1) + reqsize;
data->buf = buf;
memcpy(buf, data->src, data->slen);
sg = &data->sg;
sg_init_one(sg, buf, mlen);
akcipher_request_set_crypt(req, sg, data->dst ? sg : NULL,
data->slen, data->dlen);
crypto_init_wait(&data->cwait);
akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
crypto_req_done, &data->cwait);
return 0;
}
EXPORT_SYMBOL_GPL(crypto_akcipher_sync_prep);
int crypto_akcipher_sync_post(struct crypto_akcipher_sync_data *data, int err)
{
err = crypto_wait_req(err, &data->cwait);
if (data->dst)
memcpy(data->dst, data->buf, data->dlen);
data->dlen = data->req->dst_len;
kfree_sensitive(data->req);
return err;
}
EXPORT_SYMBOL_GPL(crypto_akcipher_sync_post);
int crypto_akcipher_sync_encrypt(struct crypto_akcipher *tfm,
const void *src, unsigned int slen,
void *dst, unsigned int dlen)
{
struct crypto_akcipher_sync_data data = {
.tfm = tfm,
.src = src,
.dst = dst,
.slen = slen,
.dlen = dlen,
};
return crypto_akcipher_sync_prep(&data) ?:
crypto_akcipher_sync_post(&data,
crypto_akcipher_encrypt(data.req));
}
EXPORT_SYMBOL_GPL(crypto_akcipher_sync_encrypt);
int crypto_akcipher_sync_decrypt(struct crypto_akcipher *tfm,
const void *src, unsigned int slen,
void *dst, unsigned int dlen)
{
struct crypto_akcipher_sync_data data = {
.tfm = tfm,
.src = src,
.dst = dst,
.slen = slen,
.dlen = dlen,
};
return crypto_akcipher_sync_prep(&data) ?:
crypto_akcipher_sync_post(&data,
crypto_akcipher_decrypt(data.req)) ?:
data.dlen;
}
EXPORT_SYMBOL_GPL(crypto_akcipher_sync_decrypt);
static void crypto_exit_akcipher_ops_sig(struct crypto_tfm *tfm)
{
struct crypto_akcipher **ctx = crypto_tfm_ctx(tfm);
crypto_free_akcipher(*ctx);
}
int crypto_init_akcipher_ops_sig(struct crypto_tfm *tfm)
{
struct crypto_akcipher **ctx = crypto_tfm_ctx(tfm);
struct crypto_alg *calg = tfm->__crt_alg;
struct crypto_akcipher *akcipher;
if (!crypto_mod_get(calg))
return -EAGAIN;
akcipher = crypto_create_tfm(calg, &crypto_akcipher_type);
if (IS_ERR(akcipher)) {
crypto_mod_put(calg);
return PTR_ERR(akcipher);
}
*ctx = akcipher;
tfm->exit = crypto_exit_akcipher_ops_sig;
return 0;
}
EXPORT_SYMBOL_GPL(crypto_init_akcipher_ops_sig);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Generic public key cipher type");