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-rw-r--r--crypto/rsa.c395
1 files changed, 395 insertions, 0 deletions
diff --git a/crypto/rsa.c b/crypto/rsa.c
new file mode 100644
index 000000000..b9cd11fb7
--- /dev/null
+++ b/crypto/rsa.c
@@ -0,0 +1,395 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* RSA asymmetric public-key algorithm [RFC3447]
+ *
+ * Copyright (c) 2015, Intel Corporation
+ * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
+ */
+
+#include <linux/fips.h>
+#include <linux/module.h>
+#include <linux/mpi.h>
+#include <crypto/internal/rsa.h>
+#include <crypto/internal/akcipher.h>
+#include <crypto/akcipher.h>
+#include <crypto/algapi.h>
+
+struct rsa_mpi_key {
+ MPI n;
+ MPI e;
+ MPI d;
+ MPI p;
+ MPI q;
+ MPI dp;
+ MPI dq;
+ MPI qinv;
+};
+
+/*
+ * RSAEP function [RFC3447 sec 5.1.1]
+ * c = m^e mod n;
+ */
+static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m)
+{
+ /* (1) Validate 0 <= m < n */
+ if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
+ return -EINVAL;
+
+ /* (2) c = m^e mod n */
+ return mpi_powm(c, m, key->e, key->n);
+}
+
+/*
+ * RSADP function [RFC3447 sec 5.1.2]
+ * m_1 = c^dP mod p;
+ * m_2 = c^dQ mod q;
+ * h = (m_1 - m_2) * qInv mod p;
+ * m = m_2 + q * h;
+ */
+static int _rsa_dec_crt(const struct rsa_mpi_key *key, MPI m_or_m1_or_h, MPI c)
+{
+ MPI m2, m12_or_qh;
+ int ret = -ENOMEM;
+
+ /* (1) Validate 0 <= c < n */
+ if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)
+ return -EINVAL;
+
+ m2 = mpi_alloc(0);
+ m12_or_qh = mpi_alloc(0);
+ if (!m2 || !m12_or_qh)
+ goto err_free_mpi;
+
+ /* (2i) m_1 = c^dP mod p */
+ ret = mpi_powm(m_or_m1_or_h, c, key->dp, key->p);
+ if (ret)
+ goto err_free_mpi;
+
+ /* (2i) m_2 = c^dQ mod q */
+ ret = mpi_powm(m2, c, key->dq, key->q);
+ if (ret)
+ goto err_free_mpi;
+
+ /* (2iii) h = (m_1 - m_2) * qInv mod p */
+ mpi_sub(m12_or_qh, m_or_m1_or_h, m2);
+ mpi_mulm(m_or_m1_or_h, m12_or_qh, key->qinv, key->p);
+
+ /* (2iv) m = m_2 + q * h */
+ mpi_mul(m12_or_qh, key->q, m_or_m1_or_h);
+ mpi_addm(m_or_m1_or_h, m2, m12_or_qh, key->n);
+
+ ret = 0;
+
+err_free_mpi:
+ mpi_free(m12_or_qh);
+ mpi_free(m2);
+ return ret;
+}
+
+static inline struct rsa_mpi_key *rsa_get_key(struct crypto_akcipher *tfm)
+{
+ return akcipher_tfm_ctx(tfm);
+}
+
+static int rsa_enc(struct akcipher_request *req)
+{
+ struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
+ const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
+ MPI m, c = mpi_alloc(0);
+ int ret = 0;
+ int sign;
+
+ if (!c)
+ return -ENOMEM;
+
+ if (unlikely(!pkey->n || !pkey->e)) {
+ ret = -EINVAL;
+ goto err_free_c;
+ }
+
+ ret = -ENOMEM;
+ m = mpi_read_raw_from_sgl(req->src, req->src_len);
+ if (!m)
+ goto err_free_c;
+
+ ret = _rsa_enc(pkey, c, m);
+ if (ret)
+ goto err_free_m;
+
+ ret = mpi_write_to_sgl(c, req->dst, req->dst_len, &sign);
+ if (ret)
+ goto err_free_m;
+
+ if (sign < 0)
+ ret = -EBADMSG;
+
+err_free_m:
+ mpi_free(m);
+err_free_c:
+ mpi_free(c);
+ return ret;
+}
+
+static int rsa_dec(struct akcipher_request *req)
+{
+ struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
+ const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
+ MPI c, m = mpi_alloc(0);
+ int ret = 0;
+ int sign;
+
+ if (!m)
+ return -ENOMEM;
+
+ if (unlikely(!pkey->n || !pkey->d)) {
+ ret = -EINVAL;
+ goto err_free_m;
+ }
+
+ ret = -ENOMEM;
+ c = mpi_read_raw_from_sgl(req->src, req->src_len);
+ if (!c)
+ goto err_free_m;
+
+ ret = _rsa_dec_crt(pkey, m, c);
+ if (ret)
+ goto err_free_c;
+
+ ret = mpi_write_to_sgl(m, req->dst, req->dst_len, &sign);
+ if (ret)
+ goto err_free_c;
+
+ if (sign < 0)
+ ret = -EBADMSG;
+err_free_c:
+ mpi_free(c);
+err_free_m:
+ mpi_free(m);
+ return ret;
+}
+
+static void rsa_free_mpi_key(struct rsa_mpi_key *key)
+{
+ mpi_free(key->d);
+ mpi_free(key->e);
+ mpi_free(key->n);
+ mpi_free(key->p);
+ mpi_free(key->q);
+ mpi_free(key->dp);
+ mpi_free(key->dq);
+ mpi_free(key->qinv);
+ key->d = NULL;
+ key->e = NULL;
+ key->n = NULL;
+ key->p = NULL;
+ key->q = NULL;
+ key->dp = NULL;
+ key->dq = NULL;
+ key->qinv = NULL;
+}
+
+static int rsa_check_key_length(unsigned int len)
+{
+ switch (len) {
+ case 512:
+ case 1024:
+ case 1536:
+ if (fips_enabled)
+ return -EINVAL;
+ fallthrough;
+ case 2048:
+ case 3072:
+ case 4096:
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int rsa_check_exponent_fips(MPI e)
+{
+ MPI e_max = NULL;
+
+ /* check if odd */
+ if (!mpi_test_bit(e, 0)) {
+ return -EINVAL;
+ }
+
+ /* check if 2^16 < e < 2^256. */
+ if (mpi_cmp_ui(e, 65536) <= 0) {
+ return -EINVAL;
+ }
+
+ e_max = mpi_alloc(0);
+ if (!e_max)
+ return -ENOMEM;
+ mpi_set_bit(e_max, 256);
+
+ if (mpi_cmp(e, e_max) >= 0) {
+ mpi_free(e_max);
+ return -EINVAL;
+ }
+
+ mpi_free(e_max);
+ return 0;
+}
+
+static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
+ unsigned int keylen)
+{
+ struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
+ struct rsa_key raw_key = {0};
+ int ret;
+
+ /* Free the old MPI key if any */
+ rsa_free_mpi_key(mpi_key);
+
+ ret = rsa_parse_pub_key(&raw_key, key, keylen);
+ if (ret)
+ return ret;
+
+ mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
+ if (!mpi_key->e)
+ goto err;
+
+ mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
+ if (!mpi_key->n)
+ goto err;
+
+ if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
+ rsa_free_mpi_key(mpi_key);
+ return -EINVAL;
+ }
+
+ if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
+ rsa_free_mpi_key(mpi_key);
+ return -EINVAL;
+ }
+
+ return 0;
+
+err:
+ rsa_free_mpi_key(mpi_key);
+ return -ENOMEM;
+}
+
+static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
+ unsigned int keylen)
+{
+ struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
+ struct rsa_key raw_key = {0};
+ int ret;
+
+ /* Free the old MPI key if any */
+ rsa_free_mpi_key(mpi_key);
+
+ ret = rsa_parse_priv_key(&raw_key, key, keylen);
+ if (ret)
+ return ret;
+
+ mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz);
+ if (!mpi_key->d)
+ goto err;
+
+ mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
+ if (!mpi_key->e)
+ goto err;
+
+ mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
+ if (!mpi_key->n)
+ goto err;
+
+ mpi_key->p = mpi_read_raw_data(raw_key.p, raw_key.p_sz);
+ if (!mpi_key->p)
+ goto err;
+
+ mpi_key->q = mpi_read_raw_data(raw_key.q, raw_key.q_sz);
+ if (!mpi_key->q)
+ goto err;
+
+ mpi_key->dp = mpi_read_raw_data(raw_key.dp, raw_key.dp_sz);
+ if (!mpi_key->dp)
+ goto err;
+
+ mpi_key->dq = mpi_read_raw_data(raw_key.dq, raw_key.dq_sz);
+ if (!mpi_key->dq)
+ goto err;
+
+ mpi_key->qinv = mpi_read_raw_data(raw_key.qinv, raw_key.qinv_sz);
+ if (!mpi_key->qinv)
+ goto err;
+
+ if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
+ rsa_free_mpi_key(mpi_key);
+ return -EINVAL;
+ }
+
+ if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
+ rsa_free_mpi_key(mpi_key);
+ return -EINVAL;
+ }
+
+ return 0;
+
+err:
+ rsa_free_mpi_key(mpi_key);
+ return -ENOMEM;
+}
+
+static unsigned int rsa_max_size(struct crypto_akcipher *tfm)
+{
+ struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
+
+ return mpi_get_size(pkey->n);
+}
+
+static void rsa_exit_tfm(struct crypto_akcipher *tfm)
+{
+ struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
+
+ rsa_free_mpi_key(pkey);
+}
+
+static struct akcipher_alg rsa = {
+ .encrypt = rsa_enc,
+ .decrypt = rsa_dec,
+ .set_priv_key = rsa_set_priv_key,
+ .set_pub_key = rsa_set_pub_key,
+ .max_size = rsa_max_size,
+ .exit = rsa_exit_tfm,
+ .base = {
+ .cra_name = "rsa",
+ .cra_driver_name = "rsa-generic",
+ .cra_priority = 100,
+ .cra_module = THIS_MODULE,
+ .cra_ctxsize = sizeof(struct rsa_mpi_key),
+ },
+};
+
+static int __init rsa_init(void)
+{
+ int err;
+
+ err = crypto_register_akcipher(&rsa);
+ if (err)
+ return err;
+
+ err = crypto_register_template(&rsa_pkcs1pad_tmpl);
+ if (err) {
+ crypto_unregister_akcipher(&rsa);
+ return err;
+ }
+
+ return 0;
+}
+
+static void __exit rsa_exit(void)
+{
+ crypto_unregister_template(&rsa_pkcs1pad_tmpl);
+ crypto_unregister_akcipher(&rsa);
+}
+
+subsys_initcall(rsa_init);
+module_exit(rsa_exit);
+MODULE_ALIAS_CRYPTO("rsa");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("RSA generic algorithm");
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