linux/crypto/rsa-pkcs1pad.c

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/*
* RSA padding templates.
*
* Copyright (c) 2015 Intel Corporation
*
* 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/algapi.h>
#include <crypto/akcipher.h>
#include <crypto/internal/akcipher.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/random.h>
struct pkcs1pad_ctx {
struct crypto_akcipher *child;
unsigned int key_size;
};
struct pkcs1pad_request {
struct akcipher_request child_req;
struct scatterlist in_sg[3], out_sg[2];
uint8_t *in_buf, *out_buf;
};
static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
unsigned int keylen)
{
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
int err, size;
err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
if (!err) {
/* Find out new modulus size from rsa implementation */
size = crypto_akcipher_maxsize(ctx->child);
ctx->key_size = size > 0 ? size : 0;
if (size <= 0)
err = size;
}
return err;
}
static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
unsigned int keylen)
{
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
int err, size;
err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
if (!err) {
/* Find out new modulus size from rsa implementation */
size = crypto_akcipher_maxsize(ctx->child);
ctx->key_size = size > 0 ? size : 0;
if (size <= 0)
err = size;
}
return err;
}
static int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
{
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
/*
* The maximum destination buffer size for the encrypt/sign operations
* will be the same as for RSA, even though it's smaller for
* decrypt/verify.
*/
return ctx->key_size ?: -EINVAL;
}
static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
struct scatterlist *next)
{
int nsegs = next ? 1 : 0;
if (offset_in_page(buf) + len <= PAGE_SIZE) {
nsegs += 1;
sg_init_table(sg, nsegs);
sg_set_buf(sg, buf, len);
} else {
nsegs += 2;
sg_init_table(sg, nsegs);
sg_set_buf(sg + 0, buf, PAGE_SIZE - offset_in_page(buf));
sg_set_buf(sg + 1, buf + PAGE_SIZE - offset_in_page(buf),
offset_in_page(buf) + len - PAGE_SIZE);
}
if (next)
sg_chain(sg, nsegs, next);
}
static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
size_t pad_len = ctx->key_size - req_ctx->child_req.dst_len;
size_t chunk_len, pad_left;
struct sg_mapping_iter miter;
if (!err) {
if (pad_len) {
sg_miter_start(&miter, req->dst,
sg_nents_for_len(req->dst, pad_len),
SG_MITER_ATOMIC | SG_MITER_TO_SG);
pad_left = pad_len;
while (pad_left) {
sg_miter_next(&miter);
chunk_len = min(miter.length, pad_left);
memset(miter.addr, 0, chunk_len);
pad_left -= chunk_len;
}
sg_miter_stop(&miter);
}
sg_pcopy_from_buffer(req->dst,
sg_nents_for_len(req->dst, ctx->key_size),
req_ctx->out_buf, req_ctx->child_req.dst_len,
pad_len);
}
req->dst_len = ctx->key_size;
kfree(req_ctx->in_buf);
kzfree(req_ctx->out_buf);
return err;
}
static void pkcs1pad_encrypt_sign_complete_cb(
struct crypto_async_request *child_async_req, int err)
{
struct akcipher_request *req = child_async_req->data;
struct crypto_async_request async_req;
if (err == -EINPROGRESS)
return;
async_req.data = req->base.data;
async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
async_req.flags = child_async_req->flags;
req->base.complete(&async_req,
pkcs1pad_encrypt_sign_complete(req, err));
}
static int pkcs1pad_encrypt(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
int err;
unsigned int i, ps_end;
if (!ctx->key_size)
return -EINVAL;
if (req->src_len > ctx->key_size - 11)
return -EOVERFLOW;
if (req->dst_len < ctx->key_size) {
req->dst_len = ctx->key_size;
return -EOVERFLOW;
}
if (ctx->key_size > PAGE_SIZE)
return -ENOTSUPP;
/*
* Replace both input and output to add the padding in the input and
* the potential missing leading zeros in the output.
*/
req_ctx->child_req.src = req_ctx->in_sg;
req_ctx->child_req.src_len = ctx->key_size - 1;
req_ctx->child_req.dst = req_ctx->out_sg;
req_ctx->child_req.dst_len = ctx->key_size;
req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
GFP_KERNEL : GFP_ATOMIC);
if (!req_ctx->in_buf)
return -ENOMEM;
ps_end = ctx->key_size - req->src_len - 2;
req_ctx->in_buf[0] = 0x02;
for (i = 1; i < ps_end; i++)
req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
req_ctx->in_buf[ps_end] = 0x00;
pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
ctx->key_size - 1 - req->src_len, req->src);
req_ctx->out_buf = kmalloc(ctx->key_size,
(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
GFP_KERNEL : GFP_ATOMIC);
if (!req_ctx->out_buf) {
kfree(req_ctx->in_buf);
return -ENOMEM;
}
pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
ctx->key_size, NULL);
akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
pkcs1pad_encrypt_sign_complete_cb, req);
err = crypto_akcipher_encrypt(&req_ctx->child_req);
if (err != -EINPROGRESS &&
(err != -EBUSY ||
!(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
return pkcs1pad_encrypt_sign_complete(req, err);
return err;
}
static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
unsigned int pos;
if (err == -EOVERFLOW)
/* Decrypted value had no leading 0 byte */
err = -EINVAL;
if (err)
goto done;
if (req_ctx->child_req.dst_len != ctx->key_size - 1) {
err = -EINVAL;
goto done;
}
if (req_ctx->out_buf[0] != 0x02) {
err = -EINVAL;
goto done;
}
for (pos = 1; pos < req_ctx->child_req.dst_len; pos++)
if (req_ctx->out_buf[pos] == 0x00)
break;
if (pos < 9 || pos == req_ctx->child_req.dst_len) {
err = -EINVAL;
goto done;
}
pos++;
if (req->dst_len < req_ctx->child_req.dst_len - pos)
err = -EOVERFLOW;
req->dst_len = req_ctx->child_req.dst_len - pos;
if (!err)
sg_copy_from_buffer(req->dst,
sg_nents_for_len(req->dst, req->dst_len),
req_ctx->out_buf + pos, req->dst_len);
done:
kzfree(req_ctx->out_buf);
return err;
}
static void pkcs1pad_decrypt_complete_cb(
struct crypto_async_request *child_async_req, int err)
{
struct akcipher_request *req = child_async_req->data;
struct crypto_async_request async_req;
if (err == -EINPROGRESS)
return;
async_req.data = req->base.data;
async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
async_req.flags = child_async_req->flags;
req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
}
static int pkcs1pad_decrypt(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
int err;
if (!ctx->key_size || req->src_len != ctx->key_size)
return -EINVAL;
if (ctx->key_size > PAGE_SIZE)
return -ENOTSUPP;
/* Reuse input buffer, output to a new buffer */
req_ctx->child_req.src = req->src;
req_ctx->child_req.src_len = req->src_len;
req_ctx->child_req.dst = req_ctx->out_sg;
req_ctx->child_req.dst_len = ctx->key_size - 1;
req_ctx->out_buf = kmalloc(ctx->key_size - 1,
(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
GFP_KERNEL : GFP_ATOMIC);
if (!req_ctx->out_buf)
return -ENOMEM;
pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
ctx->key_size - 1, NULL);
akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
pkcs1pad_decrypt_complete_cb, req);
err = crypto_akcipher_decrypt(&req_ctx->child_req);
if (err != -EINPROGRESS &&
(err != -EBUSY ||
!(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
return pkcs1pad_decrypt_complete(req, err);
return err;
}
static int pkcs1pad_sign(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
int err;
unsigned int ps_end;
if (!ctx->key_size)
return -EINVAL;
if (req->src_len > ctx->key_size - 11)
return -EOVERFLOW;
if (req->dst_len < ctx->key_size) {
req->dst_len = ctx->key_size;
return -EOVERFLOW;
}
if (ctx->key_size > PAGE_SIZE)
return -ENOTSUPP;
/*
* Replace both input and output to add the padding in the input and
* the potential missing leading zeros in the output.
*/
req_ctx->child_req.src = req_ctx->in_sg;
req_ctx->child_req.src_len = ctx->key_size - 1;
req_ctx->child_req.dst = req_ctx->out_sg;
req_ctx->child_req.dst_len = ctx->key_size;
req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
GFP_KERNEL : GFP_ATOMIC);
if (!req_ctx->in_buf)
return -ENOMEM;
ps_end = ctx->key_size - req->src_len - 2;
req_ctx->in_buf[0] = 0x01;
memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
req_ctx->in_buf[ps_end] = 0x00;
pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
ctx->key_size - 1 - req->src_len, req->src);
req_ctx->out_buf = kmalloc(ctx->key_size,
(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
GFP_KERNEL : GFP_ATOMIC);
if (!req_ctx->out_buf) {
kfree(req_ctx->in_buf);
return -ENOMEM;
}
pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
ctx->key_size, NULL);
akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
pkcs1pad_encrypt_sign_complete_cb, req);
err = crypto_akcipher_sign(&req_ctx->child_req);
if (err != -EINPROGRESS &&
(err != -EBUSY ||
!(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
return pkcs1pad_encrypt_sign_complete(req, err);
return err;
}
static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
unsigned int pos;
if (err == -EOVERFLOW)
/* Decrypted value had no leading 0 byte */
err = -EINVAL;
if (err)
goto done;
if (req_ctx->child_req.dst_len != ctx->key_size - 1) {
err = -EINVAL;
goto done;
}
if (req_ctx->out_buf[0] != 0x01) {
err = -EINVAL;
goto done;
}
for (pos = 1; pos < req_ctx->child_req.dst_len; pos++)
if (req_ctx->out_buf[pos] != 0xff)
break;
if (pos < 9 || pos == req_ctx->child_req.dst_len ||
req_ctx->out_buf[pos] != 0x00) {
err = -EINVAL;
goto done;
}
pos++;
if (req->dst_len < req_ctx->child_req.dst_len - pos)
err = -EOVERFLOW;
req->dst_len = req_ctx->child_req.dst_len - pos;
if (!err)
sg_copy_from_buffer(req->dst,
sg_nents_for_len(req->dst, req->dst_len),
req_ctx->out_buf + pos, req->dst_len);
done:
kzfree(req_ctx->out_buf);
return err;
}
static void pkcs1pad_verify_complete_cb(
struct crypto_async_request *child_async_req, int err)
{
struct akcipher_request *req = child_async_req->data;
struct crypto_async_request async_req;
if (err == -EINPROGRESS)
return;
async_req.data = req->base.data;
async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
async_req.flags = child_async_req->flags;
req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
}
/*
* The verify operation is here for completeness similar to the verification
* defined in RFC2313 section 10.2 except that block type 0 is not accepted,
* as in RFC2437. RFC2437 section 9.2 doesn't define any operation to
* retrieve the DigestInfo from a signature, instead the user is expected
* to call the sign operation to generate the expected signature and compare
* signatures instead of the message-digests.
*/
static int pkcs1pad_verify(struct akcipher_request *req)
{
struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
int err;
if (!ctx->key_size || req->src_len != ctx->key_size)
return -EINVAL;
if (ctx->key_size > PAGE_SIZE)
return -ENOTSUPP;
/* Reuse input buffer, output to a new buffer */
req_ctx->child_req.src = req->src;
req_ctx->child_req.src_len = req->src_len;
req_ctx->child_req.dst = req_ctx->out_sg;
req_ctx->child_req.dst_len = ctx->key_size - 1;
req_ctx->out_buf = kmalloc(ctx->key_size - 1,
(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
GFP_KERNEL : GFP_ATOMIC);
if (!req_ctx->out_buf)
return -ENOMEM;
pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
ctx->key_size - 1, NULL);
akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
pkcs1pad_verify_complete_cb, req);
err = crypto_akcipher_verify(&req_ctx->child_req);
if (err != -EINPROGRESS &&
(err != -EBUSY ||
!(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
return pkcs1pad_verify_complete(req, err);
return err;
}
static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
{
struct akcipher_instance *inst = akcipher_alg_instance(tfm);
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
struct crypto_akcipher *child_tfm;
child_tfm = crypto_spawn_akcipher(akcipher_instance_ctx(inst));
if (IS_ERR(child_tfm))
return PTR_ERR(child_tfm);
ctx->child = child_tfm;
return 0;
}
static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
{
struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
crypto_free_akcipher(ctx->child);
}
static void pkcs1pad_free(struct akcipher_instance *inst)
{
struct crypto_akcipher_spawn *spawn = akcipher_instance_ctx(inst);
crypto_drop_akcipher(spawn);
kfree(inst);
}
static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
{
struct crypto_attr_type *algt;
struct akcipher_instance *inst;
struct crypto_akcipher_spawn *spawn;
struct akcipher_alg *rsa_alg;
const char *rsa_alg_name;
int err;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return PTR_ERR(algt);
if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
return -EINVAL;
rsa_alg_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(rsa_alg_name))
return PTR_ERR(rsa_alg_name);
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return -ENOMEM;
spawn = akcipher_instance_ctx(inst);
crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
crypto_requires_sync(algt->type, algt->mask));
if (err)
goto out_free_inst;
rsa_alg = crypto_spawn_akcipher_alg(spawn);
err = -ENAMETOOLONG;
if (snprintf(inst->alg.base.cra_name,
CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
rsa_alg->base.cra_name) >=
CRYPTO_MAX_ALG_NAME ||
snprintf(inst->alg.base.cra_driver_name,
CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
rsa_alg->base.cra_driver_name) >=
CRYPTO_MAX_ALG_NAME)
goto out_drop_alg;
inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
inst->alg.init = pkcs1pad_init_tfm;
inst->alg.exit = pkcs1pad_exit_tfm;
inst->alg.encrypt = pkcs1pad_encrypt;
inst->alg.decrypt = pkcs1pad_decrypt;
inst->alg.sign = pkcs1pad_sign;
inst->alg.verify = pkcs1pad_verify;
inst->alg.set_pub_key = pkcs1pad_set_pub_key;
inst->alg.set_priv_key = pkcs1pad_set_priv_key;
inst->alg.max_size = pkcs1pad_get_max_size;
inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
inst->free = pkcs1pad_free;
err = akcipher_register_instance(tmpl, inst);
if (err)
goto out_drop_alg;
return 0;
out_drop_alg:
crypto_drop_akcipher(spawn);
out_free_inst:
kfree(inst);
return err;
}
struct crypto_template rsa_pkcs1pad_tmpl = {
.name = "pkcs1pad",
.create = pkcs1pad_create,
.module = THIS_MODULE,
};