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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Ignat Korchagin](/assets/img/avatar_default.png)
Changes from v1: * exported mpi_sub and mpi_mul, otherwise the build fails when RSA is a module The kernel RSA ASN.1 private key parser already supports only private keys with additional values to be used with the Chinese Remainder Theorem [1], but these values are currently not used. This rudimentary CRT implementation speeds up RSA private key operations for the following Go benchmark up to ~3x. This implementation also tries to minimise the allocation of additional MPIs, so existing MPIs are reused as much as possible (hence the variable names are a bit weird). The benchmark used: ``` package keyring_test import ( "crypto" "crypto/rand" "crypto/rsa" "crypto/x509" "io" "syscall" "testing" "unsafe" ) type KeySerial int32 type Keyring int32 const ( KEY_SPEC_PROCESS_KEYRING Keyring = -2 KEYCTL_PKEY_SIGN = 27 ) var ( keyTypeAsym = []byte("asymmetric\x00") sha256pkcs1 = []byte("enc=pkcs1 hash=sha256\x00") ) func (keyring Keyring) LoadAsym(desc string, payload []byte) (KeySerial, error) { cdesc := []byte(desc + "\x00") serial, _, errno := syscall.Syscall6(syscall.SYS_ADD_KEY, uintptr(unsafe.Pointer(&keyTypeAsym[0])), uintptr(unsafe.Pointer(&cdesc[0])), uintptr(unsafe.Pointer(&payload[0])), uintptr(len(payload)), uintptr(keyring), uintptr(0)) if errno == 0 { return KeySerial(serial), nil } return KeySerial(serial), errno } type pkeyParams struct { key_id KeySerial in_len uint32 out_or_in2_len uint32 __spare [7]uint32 } // the output signature buffer is an input parameter here, because we want to // avoid Go buffer allocation leaking into our benchmarks func (key KeySerial) Sign(info, digest, out []byte) error { var params pkeyParams params.key_id = key params.in_len = uint32(len(digest)) params.out_or_in2_len = uint32(len(out)) _, _, errno := syscall.Syscall6(syscall.SYS_KEYCTL, KEYCTL_PKEY_SIGN, uintptr(unsafe.Pointer(¶ms)), uintptr(unsafe.Pointer(&info[0])), uintptr(unsafe.Pointer(&digest[0])), uintptr(unsafe.Pointer(&out[0])), uintptr(0)) if errno == 0 { return nil } return errno } func BenchmarkSign(b *testing.B) { priv, err := rsa.GenerateKey(rand.Reader, 2048) if err != nil { b.Fatalf("failed to generate private key: %v", err) } pkcs8, err := x509.MarshalPKCS8PrivateKey(priv) if err != nil { b.Fatalf("failed to serialize the private key to PKCS8 blob: %v", err) } serial, err := KEY_SPEC_PROCESS_KEYRING.LoadAsym("test rsa key", pkcs8) if err != nil { b.Fatalf("failed to load the private key into the keyring: %v", err) } b.Logf("loaded test rsa key: %v", serial) digest := make([]byte, 32) _, err = io.ReadFull(rand.Reader, digest) if err != nil { b.Fatalf("failed to generate a random digest: %v", err) } sig := make([]byte, 256) for n := 0; n < b.N; n++ { err = serial.Sign(sha256pkcs1, digest, sig) if err != nil { b.Fatalf("failed to sign the digest: %v", err) } } err = rsa.VerifyPKCS1v15(&priv.PublicKey, crypto.SHA256, digest, sig) if err != nil { b.Fatalf("failed to verify the signature: %v", err) } } ``` [1]: https://en.wikipedia.org/wiki/RSA_(cryptosystem)#Using_the_Chinese_remainder_algorithm Signed-off-by: Ignat Korchagin <ignat@cloudflare.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
357 lines
6.8 KiB
C
357 lines
6.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* RSA asymmetric public-key algorithm [RFC3447]
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*
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* Copyright (c) 2015, Intel Corporation
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* Authors: Tadeusz Struk <tadeusz.struk@intel.com>
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*/
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#include <linux/fips.h>
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#include <linux/module.h>
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#include <linux/mpi.h>
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#include <crypto/internal/rsa.h>
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#include <crypto/internal/akcipher.h>
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#include <crypto/akcipher.h>
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#include <crypto/algapi.h>
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struct rsa_mpi_key {
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MPI n;
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MPI e;
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MPI d;
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MPI p;
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MPI q;
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MPI dp;
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MPI dq;
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MPI qinv;
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};
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/*
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* RSAEP function [RFC3447 sec 5.1.1]
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* c = m^e mod n;
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*/
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static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m)
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{
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/* (1) Validate 0 <= m < n */
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if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
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return -EINVAL;
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/* (2) c = m^e mod n */
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return mpi_powm(c, m, key->e, key->n);
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}
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/*
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* RSADP function [RFC3447 sec 5.1.2]
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* m_1 = c^dP mod p;
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* m_2 = c^dQ mod q;
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* h = (m_1 - m_2) * qInv mod p;
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* m = m_2 + q * h;
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*/
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static int _rsa_dec_crt(const struct rsa_mpi_key *key, MPI m_or_m1_or_h, MPI c)
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{
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MPI m2, m12_or_qh;
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int ret = -ENOMEM;
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/* (1) Validate 0 <= c < n */
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if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)
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return -EINVAL;
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m2 = mpi_alloc(0);
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m12_or_qh = mpi_alloc(0);
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if (!m2 || !m12_or_qh)
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goto err_free_mpi;
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/* (2i) m_1 = c^dP mod p */
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ret = mpi_powm(m_or_m1_or_h, c, key->dp, key->p);
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if (ret)
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goto err_free_mpi;
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/* (2i) m_2 = c^dQ mod q */
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ret = mpi_powm(m2, c, key->dq, key->q);
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if (ret)
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goto err_free_mpi;
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/* (2iii) h = (m_1 - m_2) * qInv mod p */
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mpi_sub(m12_or_qh, m_or_m1_or_h, m2);
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mpi_mulm(m_or_m1_or_h, m12_or_qh, key->qinv, key->p);
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/* (2iv) m = m_2 + q * h */
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mpi_mul(m12_or_qh, key->q, m_or_m1_or_h);
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mpi_addm(m_or_m1_or_h, m2, m12_or_qh, key->n);
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ret = 0;
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err_free_mpi:
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mpi_free(m12_or_qh);
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mpi_free(m2);
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return ret;
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}
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static inline struct rsa_mpi_key *rsa_get_key(struct crypto_akcipher *tfm)
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{
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return akcipher_tfm_ctx(tfm);
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}
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static int rsa_enc(struct akcipher_request *req)
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{
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struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
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const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
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MPI m, c = mpi_alloc(0);
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int ret = 0;
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int sign;
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if (!c)
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return -ENOMEM;
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if (unlikely(!pkey->n || !pkey->e)) {
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ret = -EINVAL;
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goto err_free_c;
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}
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ret = -ENOMEM;
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m = mpi_read_raw_from_sgl(req->src, req->src_len);
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if (!m)
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goto err_free_c;
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ret = _rsa_enc(pkey, c, m);
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if (ret)
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goto err_free_m;
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ret = mpi_write_to_sgl(c, req->dst, req->dst_len, &sign);
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if (ret)
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goto err_free_m;
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if (sign < 0)
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ret = -EBADMSG;
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err_free_m:
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mpi_free(m);
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err_free_c:
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mpi_free(c);
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return ret;
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}
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static int rsa_dec(struct akcipher_request *req)
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{
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struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
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const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
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MPI c, m = mpi_alloc(0);
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int ret = 0;
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int sign;
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if (!m)
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return -ENOMEM;
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if (unlikely(!pkey->n || !pkey->d)) {
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ret = -EINVAL;
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goto err_free_m;
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}
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ret = -ENOMEM;
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c = mpi_read_raw_from_sgl(req->src, req->src_len);
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if (!c)
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goto err_free_m;
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ret = _rsa_dec_crt(pkey, m, c);
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if (ret)
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goto err_free_c;
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ret = mpi_write_to_sgl(m, req->dst, req->dst_len, &sign);
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if (ret)
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goto err_free_c;
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if (sign < 0)
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ret = -EBADMSG;
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err_free_c:
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mpi_free(c);
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err_free_m:
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mpi_free(m);
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return ret;
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}
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static void rsa_free_mpi_key(struct rsa_mpi_key *key)
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{
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mpi_free(key->d);
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mpi_free(key->e);
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mpi_free(key->n);
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mpi_free(key->p);
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mpi_free(key->q);
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mpi_free(key->dp);
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mpi_free(key->dq);
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mpi_free(key->qinv);
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key->d = NULL;
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key->e = NULL;
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key->n = NULL;
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key->p = NULL;
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key->q = NULL;
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key->dp = NULL;
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key->dq = NULL;
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key->qinv = NULL;
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}
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static int rsa_check_key_length(unsigned int len)
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{
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switch (len) {
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case 512:
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case 1024:
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case 1536:
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if (fips_enabled)
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return -EINVAL;
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fallthrough;
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case 2048:
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case 3072:
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case 4096:
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return 0;
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}
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return -EINVAL;
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}
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static int rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
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unsigned int keylen)
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{
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struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
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struct rsa_key raw_key = {0};
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int ret;
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/* Free the old MPI key if any */
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rsa_free_mpi_key(mpi_key);
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ret = rsa_parse_pub_key(&raw_key, key, keylen);
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if (ret)
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return ret;
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mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
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if (!mpi_key->e)
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goto err;
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mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
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if (!mpi_key->n)
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goto err;
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if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
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rsa_free_mpi_key(mpi_key);
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return -EINVAL;
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}
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return 0;
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err:
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rsa_free_mpi_key(mpi_key);
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return -ENOMEM;
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}
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static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
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unsigned int keylen)
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{
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struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
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struct rsa_key raw_key = {0};
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int ret;
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/* Free the old MPI key if any */
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rsa_free_mpi_key(mpi_key);
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ret = rsa_parse_priv_key(&raw_key, key, keylen);
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if (ret)
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return ret;
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mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz);
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if (!mpi_key->d)
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goto err;
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mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
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if (!mpi_key->e)
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goto err;
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mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
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if (!mpi_key->n)
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goto err;
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mpi_key->p = mpi_read_raw_data(raw_key.p, raw_key.p_sz);
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if (!mpi_key->p)
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goto err;
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mpi_key->q = mpi_read_raw_data(raw_key.q, raw_key.q_sz);
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if (!mpi_key->q)
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goto err;
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mpi_key->dp = mpi_read_raw_data(raw_key.dp, raw_key.dp_sz);
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if (!mpi_key->dp)
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goto err;
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mpi_key->dq = mpi_read_raw_data(raw_key.dq, raw_key.dq_sz);
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if (!mpi_key->dq)
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goto err;
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mpi_key->qinv = mpi_read_raw_data(raw_key.qinv, raw_key.qinv_sz);
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if (!mpi_key->qinv)
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goto err;
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if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
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rsa_free_mpi_key(mpi_key);
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return -EINVAL;
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}
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return 0;
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err:
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rsa_free_mpi_key(mpi_key);
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return -ENOMEM;
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}
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static unsigned int rsa_max_size(struct crypto_akcipher *tfm)
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{
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struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
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return mpi_get_size(pkey->n);
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}
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static void rsa_exit_tfm(struct crypto_akcipher *tfm)
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{
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struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
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rsa_free_mpi_key(pkey);
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}
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static struct akcipher_alg rsa = {
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.encrypt = rsa_enc,
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.decrypt = rsa_dec,
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.set_priv_key = rsa_set_priv_key,
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.set_pub_key = rsa_set_pub_key,
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.max_size = rsa_max_size,
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.exit = rsa_exit_tfm,
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.base = {
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.cra_name = "rsa",
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.cra_driver_name = "rsa-generic",
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.cra_priority = 100,
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.cra_module = THIS_MODULE,
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.cra_ctxsize = sizeof(struct rsa_mpi_key),
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},
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};
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static int rsa_init(void)
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{
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int err;
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err = crypto_register_akcipher(&rsa);
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if (err)
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return err;
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err = crypto_register_template(&rsa_pkcs1pad_tmpl);
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if (err) {
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crypto_unregister_akcipher(&rsa);
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return err;
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}
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return 0;
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}
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static void rsa_exit(void)
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{
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crypto_unregister_template(&rsa_pkcs1pad_tmpl);
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crypto_unregister_akcipher(&rsa);
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}
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subsys_initcall(rsa_init);
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module_exit(rsa_exit);
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MODULE_ALIAS_CRYPTO("rsa");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("RSA generic algorithm");
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