diff options
Diffstat (limited to 'crypto/rsa-pkcs1pad.c')
| -rw-r--r-- | crypto/rsa-pkcs1pad.c | 379 |
1 files changed, 379 insertions, 0 deletions
diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c new file mode 100644 index 000000000..50bdb18e7 --- /dev/null +++ b/crypto/rsa-pkcs1pad.c @@ -0,0 +1,379 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * RSA padding templates. + * + * Copyright (c) 2015 Intel Corporation + */ + +#include <crypto/algapi.h> +#include <crypto/akcipher.h> +#include <crypto/internal/akcipher.h> +#include <crypto/internal/rsa.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/random.h> +#include <linux/scatterlist.h> + +struct pkcs1pad_ctx { + struct crypto_akcipher *child; + unsigned int key_size; +}; + +struct pkcs1pad_inst_ctx { + struct crypto_akcipher_spawn spawn; +}; + +struct pkcs1pad_request { + struct scatterlist in_sg[2], out_sg[1]; + uint8_t *in_buf, *out_buf; + struct akcipher_request child_req; +}; + +static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key, + unsigned int keylen) +{ + struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm); + + return rsa_set_key(ctx->child, &ctx->key_size, RSA_PUB, key, keylen); +} + +static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key, + unsigned int keylen) +{ + struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm); + + return rsa_set_key(ctx->child, &ctx->key_size, RSA_PRIV, key, keylen); +} + +static unsigned 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 operation + * will be the same as for RSA, even though it's smaller for + * decrypt. + */ + + return ctx->key_size; +} + +static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len, + struct scatterlist *next) +{ + int nsegs = next ? 2 : 1; + + sg_init_table(sg, nsegs); + sg_set_buf(sg, buf, len); + + if (next) + sg_chain(sg, nsegs, next); +} + +static int pkcs1pad_encrypt_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 pad_len; + unsigned int len; + u8 *out_buf; + + if (err) + goto out; + + len = req_ctx->child_req.dst_len; + pad_len = ctx->key_size - len; + + /* Four billion to one */ + if (likely(!pad_len)) + goto out; + + out_buf = kzalloc(ctx->key_size, GFP_ATOMIC); + err = -ENOMEM; + if (!out_buf) + goto out; + + sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len), + out_buf + pad_len, len); + sg_copy_from_buffer(req->dst, + sg_nents_for_len(req->dst, ctx->key_size), + out_buf, ctx->key_size); + kfree_sensitive(out_buf); + +out: + req->dst_len = ctx->key_size; + + kfree(req_ctx->in_buf); + + return err; +} + +static void pkcs1pad_encrypt_complete_cb(void *data, int err) +{ + struct akcipher_request *req = data; + + if (err == -EINPROGRESS) + goto out; + + err = pkcs1pad_encrypt_complete(req, err); + +out: + akcipher_request_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; + } + + req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len, + GFP_KERNEL); + 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] = get_random_u32_inclusive(1, 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); + + akcipher_request_set_tfm(&req_ctx->child_req, ctx->child); + akcipher_request_set_callback(&req_ctx->child_req, req->base.flags, + pkcs1pad_encrypt_complete_cb, req); + + /* Reuse output buffer */ + akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg, + req->dst, ctx->key_size - 1, req->dst_len); + + err = crypto_akcipher_encrypt(&req_ctx->child_req); + if (err != -EINPROGRESS && err != -EBUSY) + return pkcs1pad_encrypt_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 dst_len; + unsigned int pos; + u8 *out_buf; + + if (err) + goto done; + + err = -EINVAL; + dst_len = req_ctx->child_req.dst_len; + if (dst_len < ctx->key_size - 1) + goto done; + + out_buf = req_ctx->out_buf; + if (dst_len == ctx->key_size) { + if (out_buf[0] != 0x00) + /* Decrypted value had no leading 0 byte */ + goto done; + + dst_len--; + out_buf++; + } + + if (out_buf[0] != 0x02) + goto done; + + for (pos = 1; pos < dst_len; pos++) + if (out_buf[pos] == 0x00) + break; + if (pos < 9 || pos == dst_len) + goto done; + pos++; + + err = 0; + + if (req->dst_len < dst_len - pos) + err = -EOVERFLOW; + req->dst_len = dst_len - pos; + + if (!err) + sg_copy_from_buffer(req->dst, + sg_nents_for_len(req->dst, req->dst_len), + out_buf + pos, req->dst_len); + +done: + kfree_sensitive(req_ctx->out_buf); + + return err; +} + +static void pkcs1pad_decrypt_complete_cb(void *data, int err) +{ + struct akcipher_request *req = data; + + if (err == -EINPROGRESS) + goto out; + + err = pkcs1pad_decrypt_complete(req, err); + +out: + akcipher_request_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; + + req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL); + if (!req_ctx->out_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_decrypt_complete_cb, req); + + /* Reuse input buffer, output to a new buffer */ + akcipher_request_set_crypt(&req_ctx->child_req, req->src, + req_ctx->out_sg, req->src_len, + ctx->key_size); + + err = crypto_akcipher_decrypt(&req_ctx->child_req); + if (err != -EINPROGRESS && err != -EBUSY) + return pkcs1pad_decrypt_complete(req, err); + + return err; +} + +static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm) +{ + struct akcipher_instance *inst = akcipher_alg_instance(tfm); + struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst); + struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm); + struct crypto_akcipher *child_tfm; + + child_tfm = crypto_spawn_akcipher(&ictx->spawn); + if (IS_ERR(child_tfm)) + return PTR_ERR(child_tfm); + + ctx->child = child_tfm; + + akcipher_set_reqsize(tfm, sizeof(struct pkcs1pad_request) + + crypto_akcipher_reqsize(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 pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst); + struct crypto_akcipher_spawn *spawn = &ctx->spawn; + + crypto_drop_akcipher(spawn); + kfree(inst); +} + +static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb) +{ + u32 mask; + struct akcipher_instance *inst; + struct pkcs1pad_inst_ctx *ctx; + struct akcipher_alg *rsa_alg; + int err; + + err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AKCIPHER, &mask); + if (err) + return err; + + inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); + if (!inst) + return -ENOMEM; + + ctx = akcipher_instance_ctx(inst); + + err = crypto_grab_akcipher(&ctx->spawn, akcipher_crypto_instance(inst), + crypto_attr_alg_name(tb[1]), 0, mask); + if (err) + goto err_free_inst; + + rsa_alg = crypto_spawn_akcipher_alg(&ctx->spawn); + + if (strcmp(rsa_alg->base.cra_name, "rsa") != 0) { + err = -EINVAL; + goto err_free_inst; + } + + err = -ENAMETOOLONG; + if (snprintf(inst->alg.base.cra_name, + CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)", + rsa_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME) + goto err_free_inst; + + if (snprintf(inst->alg.base.cra_driver_name, + CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)", + rsa_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) + goto err_free_inst; + + 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.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->free = pkcs1pad_free; + + err = akcipher_register_instance(tmpl, inst); + if (err) { +err_free_inst: + pkcs1pad_free(inst); + } + return err; +} + +struct crypto_template rsa_pkcs1pad_tmpl = { + .name = "pkcs1pad", + .create = pkcs1pad_create, + .module = THIS_MODULE, +}; + +MODULE_ALIAS_CRYPTO("pkcs1pad"); |