diff options
Diffstat (limited to 'crypto/rsassa-pkcs1.c')
| -rw-r--r-- | crypto/rsassa-pkcs1.c | 422 |
1 files changed, 422 insertions, 0 deletions
diff --git a/crypto/rsassa-pkcs1.c b/crypto/rsassa-pkcs1.c new file mode 100644 index 000000000000..779c080fc013 --- /dev/null +++ b/crypto/rsassa-pkcs1.c @@ -0,0 +1,422 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * RSA Signature Scheme with Appendix - PKCS #1 v1.5 (RFC 8017 sec 8.2) + * + * https://www.rfc-editor.org/rfc/rfc8017#section-8.2 + * + * Copyright (c) 2015 - 2024 Intel Corporation + */ + +#include <linux/module.h> +#include <linux/scatterlist.h> +#include <crypto/akcipher.h> +#include <crypto/algapi.h> +#include <crypto/sig.h> +#include <crypto/internal/akcipher.h> +#include <crypto/internal/rsa.h> +#include <crypto/internal/sig.h> + +/* + * Full Hash Prefix for EMSA-PKCS1-v1_5 encoding method (RFC 9580 table 24) + * + * RSA keys are usually much larger than the hash of the message to be signed. + * The hash is therefore prepended by the Full Hash Prefix and a 0xff padding. + * The Full Hash Prefix is an ASN.1 SEQUENCE containing the hash algorithm OID. + * + * https://www.rfc-editor.org/rfc/rfc9580#table-24 + */ + +static const u8 hash_prefix_md5[] = { + 0x30, 0x20, 0x30, 0x0c, 0x06, 0x08, /* SEQUENCE (SEQUENCE (OID */ + 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* <algorithm>, */ + 0x05, 0x00, 0x04, 0x10 /* NULL), OCTET STRING <hash>) */ +}; + +static const u8 hash_prefix_sha1[] = { + 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, + 0x2b, 0x0e, 0x03, 0x02, 0x1a, + 0x05, 0x00, 0x04, 0x14 +}; + +static const u8 hash_prefix_rmd160[] = { + 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, + 0x2b, 0x24, 0x03, 0x02, 0x01, + 0x05, 0x00, 0x04, 0x14 +}; + +static const u8 hash_prefix_sha224[] = { + 0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, + 0x05, 0x00, 0x04, 0x1c +}; + +static const u8 hash_prefix_sha256[] = { + 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, + 0x05, 0x00, 0x04, 0x20 +}; + +static const u8 hash_prefix_sha384[] = { + 0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, + 0x05, 0x00, 0x04, 0x30 +}; + +static const u8 hash_prefix_sha512[] = { + 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, + 0x05, 0x00, 0x04, 0x40 +}; + +static const u8 hash_prefix_sha3_256[] = { + 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x08, + 0x05, 0x00, 0x04, 0x20 +}; + +static const u8 hash_prefix_sha3_384[] = { + 0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x09, + 0x05, 0x00, 0x04, 0x30 +}; + +static const u8 hash_prefix_sha3_512[] = { + 0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, + 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x0a, + 0x05, 0x00, 0x04, 0x40 +}; + +static const struct hash_prefix { + const char *name; + const u8 *data; + size_t size; +} hash_prefixes[] = { +#define _(X) { #X, hash_prefix_##X, sizeof(hash_prefix_##X) } + _(md5), + _(sha1), + _(rmd160), + _(sha256), + _(sha384), + _(sha512), + _(sha224), +#undef _ +#define _(X) { "sha3-" #X, hash_prefix_sha3_##X, sizeof(hash_prefix_sha3_##X) } + _(256), + _(384), + _(512), +#undef _ + { NULL } +}; + +static const struct hash_prefix *rsassa_pkcs1_find_hash_prefix(const char *name) +{ + const struct hash_prefix *p; + + for (p = hash_prefixes; p->name; p++) + if (strcmp(name, p->name) == 0) + return p; + return NULL; +} + +struct rsassa_pkcs1_ctx { + struct crypto_akcipher *child; + unsigned int key_size; +}; + +struct rsassa_pkcs1_inst_ctx { + struct crypto_akcipher_spawn spawn; + const struct hash_prefix *hash_prefix; +}; + +static int rsassa_pkcs1_sign(struct crypto_sig *tfm, + const void *src, unsigned int slen, + void *dst, unsigned int dlen) +{ + struct sig_instance *inst = sig_alg_instance(tfm); + struct rsassa_pkcs1_inst_ctx *ictx = sig_instance_ctx(inst); + const struct hash_prefix *hash_prefix = ictx->hash_prefix; + struct rsassa_pkcs1_ctx *ctx = crypto_sig_ctx(tfm); + unsigned int child_reqsize = crypto_akcipher_reqsize(ctx->child); + struct akcipher_request *child_req __free(kfree_sensitive) = NULL; + struct scatterlist in_sg[2], out_sg; + struct crypto_wait cwait; + unsigned int pad_len; + unsigned int ps_end; + unsigned int len; + u8 *in_buf; + int err; + + if (!ctx->key_size) + return -EINVAL; + + if (dlen < ctx->key_size) + return -EOVERFLOW; + + if (slen + hash_prefix->size > ctx->key_size - 11) + return -EOVERFLOW; + + child_req = kmalloc(sizeof(*child_req) + child_reqsize + + ctx->key_size - 1 - slen, GFP_KERNEL); + if (!child_req) + return -ENOMEM; + + /* RFC 8017 sec 8.2.1 step 1 - EMSA-PKCS1-v1_5 encoding generation */ + in_buf = (u8 *)(child_req + 1) + child_reqsize; + ps_end = ctx->key_size - hash_prefix->size - slen - 2; + in_buf[0] = 0x01; + memset(in_buf + 1, 0xff, ps_end - 1); + in_buf[ps_end] = 0x00; + memcpy(in_buf + ps_end + 1, hash_prefix->data, hash_prefix->size); + + /* RFC 8017 sec 8.2.1 step 2 - RSA signature */ + crypto_init_wait(&cwait); + sg_init_table(in_sg, 2); + sg_set_buf(&in_sg[0], in_buf, ctx->key_size - 1 - slen); + sg_set_buf(&in_sg[1], src, slen); + sg_init_one(&out_sg, dst, dlen); + akcipher_request_set_tfm(child_req, ctx->child); + akcipher_request_set_crypt(child_req, in_sg, &out_sg, + ctx->key_size - 1, dlen); + akcipher_request_set_callback(child_req, CRYPTO_TFM_REQ_MAY_SLEEP, + crypto_req_done, &cwait); + + err = crypto_akcipher_decrypt(child_req); + err = crypto_wait_req(err, &cwait); + if (err) + return err; + + len = child_req->dst_len; + pad_len = ctx->key_size - len; + + /* Four billion to one */ + if (unlikely(pad_len)) { + memmove(dst + pad_len, dst, len); + memset(dst, 0, pad_len); + } + + return 0; +} + +static int rsassa_pkcs1_verify(struct crypto_sig *tfm, + const void *src, unsigned int slen, + const void *digest, unsigned int dlen) +{ + struct sig_instance *inst = sig_alg_instance(tfm); + struct rsassa_pkcs1_inst_ctx *ictx = sig_instance_ctx(inst); + const struct hash_prefix *hash_prefix = ictx->hash_prefix; + struct rsassa_pkcs1_ctx *ctx = crypto_sig_ctx(tfm); + unsigned int child_reqsize = crypto_akcipher_reqsize(ctx->child); + struct akcipher_request *child_req __free(kfree_sensitive) = NULL; + struct scatterlist in_sg, out_sg; + struct crypto_wait cwait; + unsigned int dst_len; + unsigned int pos; + u8 *out_buf; + int err; + + /* RFC 8017 sec 8.2.2 step 1 - length checking */ + if (!ctx->key_size || + slen != ctx->key_size || + !dlen) + return -EINVAL; + + /* RFC 8017 sec 8.2.2 step 2 - RSA verification */ + child_req = kmalloc(sizeof(*child_req) + child_reqsize + ctx->key_size, + GFP_KERNEL); + if (!child_req) + return -ENOMEM; + + out_buf = (u8 *)(child_req + 1) + child_reqsize; + + crypto_init_wait(&cwait); + sg_init_one(&in_sg, src, slen); + sg_init_one(&out_sg, out_buf, ctx->key_size); + akcipher_request_set_tfm(child_req, ctx->child); + akcipher_request_set_crypt(child_req, &in_sg, &out_sg, + slen, ctx->key_size); + akcipher_request_set_callback(child_req, CRYPTO_TFM_REQ_MAY_SLEEP, + crypto_req_done, &cwait); + + err = crypto_akcipher_encrypt(child_req); + err = crypto_wait_req(err, &cwait); + if (err) + return err; + + /* RFC 8017 sec 8.2.2 step 3 - EMSA-PKCS1-v1_5 encoding verification */ + dst_len = child_req->dst_len; + if (dst_len < ctx->key_size - 1) + return -EINVAL; + + if (dst_len == ctx->key_size) { + if (out_buf[0] != 0x00) + /* Encrypted value had no leading 0 byte */ + return -EINVAL; + + dst_len--; + out_buf++; + } + + if (out_buf[0] != 0x01) + return -EBADMSG; + + for (pos = 1; pos < dst_len; pos++) + if (out_buf[pos] != 0xff) + break; + + if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00) + return -EBADMSG; + pos++; + + if (hash_prefix->size > dst_len - pos) + return -EBADMSG; + if (crypto_memneq(out_buf + pos, hash_prefix->data, hash_prefix->size)) + return -EBADMSG; + pos += hash_prefix->size; + + /* RFC 8017 sec 8.2.2 step 4 - comparison of digest with out_buf */ + if (dlen != dst_len - pos) + return -EKEYREJECTED; + if (memcmp(digest, out_buf + pos, dlen) != 0) + return -EKEYREJECTED; + + return 0; +} + +static unsigned int rsassa_pkcs1_max_size(struct crypto_sig *tfm) +{ + struct rsassa_pkcs1_ctx *ctx = crypto_sig_ctx(tfm); + + return ctx->key_size; +} + +static int rsassa_pkcs1_set_pub_key(struct crypto_sig *tfm, + const void *key, unsigned int keylen) +{ + struct rsassa_pkcs1_ctx *ctx = crypto_sig_ctx(tfm); + + return rsa_set_key(ctx->child, &ctx->key_size, RSA_PUB, key, keylen); +} + +static int rsassa_pkcs1_set_priv_key(struct crypto_sig *tfm, + const void *key, unsigned int keylen) +{ + struct rsassa_pkcs1_ctx *ctx = crypto_sig_ctx(tfm); + + return rsa_set_key(ctx->child, &ctx->key_size, RSA_PRIV, key, keylen); +} + +static int rsassa_pkcs1_init_tfm(struct crypto_sig *tfm) +{ + struct sig_instance *inst = sig_alg_instance(tfm); + struct rsassa_pkcs1_inst_ctx *ictx = sig_instance_ctx(inst); + struct rsassa_pkcs1_ctx *ctx = crypto_sig_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; + + return 0; +} + +static void rsassa_pkcs1_exit_tfm(struct crypto_sig *tfm) +{ + struct rsassa_pkcs1_ctx *ctx = crypto_sig_ctx(tfm); + + crypto_free_akcipher(ctx->child); +} + +static void rsassa_pkcs1_free(struct sig_instance *inst) +{ + struct rsassa_pkcs1_inst_ctx *ctx = sig_instance_ctx(inst); + struct crypto_akcipher_spawn *spawn = &ctx->spawn; + + crypto_drop_akcipher(spawn); + kfree(inst); +} + +static int rsassa_pkcs1_create(struct crypto_template *tmpl, struct rtattr **tb) +{ + struct rsassa_pkcs1_inst_ctx *ctx; + struct akcipher_alg *rsa_alg; + struct sig_instance *inst; + const char *hash_name; + u32 mask; + int err; + + err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SIG, &mask); + if (err) + return err; + + inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); + if (!inst) + return -ENOMEM; + + ctx = sig_instance_ctx(inst); + + err = crypto_grab_akcipher(&ctx->spawn, sig_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; + } + + hash_name = crypto_attr_alg_name(tb[2]); + if (IS_ERR(hash_name)) { + err = PTR_ERR(hash_name); + goto err_free_inst; + } + + ctx->hash_prefix = rsassa_pkcs1_find_hash_prefix(hash_name); + if (!ctx->hash_prefix) { + err = -EINVAL; + goto err_free_inst; + } + + err = -ENAMETOOLONG; + if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, + "pkcs1(%s,%s)", rsa_alg->base.cra_name, + hash_name) >= CRYPTO_MAX_ALG_NAME) + goto err_free_inst; + + if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, + "pkcs1(%s,%s)", rsa_alg->base.cra_driver_name, + hash_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 rsassa_pkcs1_ctx); + + inst->alg.init = rsassa_pkcs1_init_tfm; + inst->alg.exit = rsassa_pkcs1_exit_tfm; + + inst->alg.sign = rsassa_pkcs1_sign; + inst->alg.verify = rsassa_pkcs1_verify; + inst->alg.max_size = rsassa_pkcs1_max_size; + inst->alg.set_pub_key = rsassa_pkcs1_set_pub_key; + inst->alg.set_priv_key = rsassa_pkcs1_set_priv_key; + + inst->free = rsassa_pkcs1_free; + + err = sig_register_instance(tmpl, inst); + if (err) { +err_free_inst: + rsassa_pkcs1_free(inst); + } + return err; +} + +struct crypto_template rsassa_pkcs1_tmpl = { + .name = "pkcs1", + .create = rsassa_pkcs1_create, + .module = THIS_MODULE, +}; + +MODULE_ALIAS_CRYPTO("pkcs1"); |