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f145d411a6
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>
156 lines
3.4 KiB
C
156 lines
3.4 KiB
C
/* mpi-add.c - MPI functions
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* Copyright (C) 1994, 1996, 1998, 2001, 2002,
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* 2003 Free Software Foundation, Inc.
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*
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* This file is part of Libgcrypt.
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*
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* Note: This code is heavily based on the GNU MP Library.
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* Actually it's the same code with only minor changes in the
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* way the data is stored; this is to support the abstraction
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* of an optional secure memory allocation which may be used
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* to avoid revealing of sensitive data due to paging etc.
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*/
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#include "mpi-internal.h"
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/****************
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* Add the unsigned integer V to the mpi-integer U and store the
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* result in W. U and V may be the same.
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*/
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void mpi_add_ui(MPI w, MPI u, unsigned long v)
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{
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mpi_ptr_t wp, up;
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mpi_size_t usize, wsize;
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int usign, wsign;
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usize = u->nlimbs;
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usign = u->sign;
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wsign = 0;
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/* If not space for W (and possible carry), increase space. */
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wsize = usize + 1;
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if (w->alloced < wsize)
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mpi_resize(w, wsize);
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/* These must be after realloc (U may be the same as W). */
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up = u->d;
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wp = w->d;
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if (!usize) { /* simple */
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wp[0] = v;
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wsize = v ? 1:0;
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} else if (!usign) { /* mpi is not negative */
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mpi_limb_t cy;
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cy = mpihelp_add_1(wp, up, usize, v);
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wp[usize] = cy;
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wsize = usize + cy;
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} else {
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/* The signs are different. Need exact comparison to determine
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* which operand to subtract from which.
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*/
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if (usize == 1 && up[0] < v) {
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wp[0] = v - up[0];
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wsize = 1;
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} else {
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mpihelp_sub_1(wp, up, usize, v);
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/* Size can decrease with at most one limb. */
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wsize = usize - (wp[usize-1] == 0);
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wsign = 1;
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}
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}
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w->nlimbs = wsize;
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w->sign = wsign;
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}
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void mpi_add(MPI w, MPI u, MPI v)
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{
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mpi_ptr_t wp, up, vp;
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mpi_size_t usize, vsize, wsize;
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int usign, vsign, wsign;
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if (u->nlimbs < v->nlimbs) { /* Swap U and V. */
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usize = v->nlimbs;
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usign = v->sign;
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vsize = u->nlimbs;
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vsign = u->sign;
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wsize = usize + 1;
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RESIZE_IF_NEEDED(w, wsize);
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/* These must be after realloc (u or v may be the same as w). */
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up = v->d;
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vp = u->d;
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} else {
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usize = u->nlimbs;
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usign = u->sign;
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vsize = v->nlimbs;
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vsign = v->sign;
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wsize = usize + 1;
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RESIZE_IF_NEEDED(w, wsize);
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/* These must be after realloc (u or v may be the same as w). */
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up = u->d;
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vp = v->d;
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}
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wp = w->d;
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wsign = 0;
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if (!vsize) { /* simple */
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MPN_COPY(wp, up, usize);
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wsize = usize;
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wsign = usign;
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} else if (usign != vsign) { /* different sign */
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/* This test is right since USIZE >= VSIZE */
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if (usize != vsize) {
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mpihelp_sub(wp, up, usize, vp, vsize);
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wsize = usize;
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MPN_NORMALIZE(wp, wsize);
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wsign = usign;
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} else if (mpihelp_cmp(up, vp, usize) < 0) {
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mpihelp_sub_n(wp, vp, up, usize);
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wsize = usize;
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MPN_NORMALIZE(wp, wsize);
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if (!usign)
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wsign = 1;
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} else {
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mpihelp_sub_n(wp, up, vp, usize);
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wsize = usize;
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MPN_NORMALIZE(wp, wsize);
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if (usign)
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wsign = 1;
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}
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} else { /* U and V have same sign. Add them. */
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mpi_limb_t cy = mpihelp_add(wp, up, usize, vp, vsize);
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wp[usize] = cy;
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wsize = usize + cy;
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if (usign)
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wsign = 1;
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}
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w->nlimbs = wsize;
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w->sign = wsign;
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}
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EXPORT_SYMBOL_GPL(mpi_add);
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void mpi_sub(MPI w, MPI u, MPI v)
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{
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MPI vv = mpi_copy(v);
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vv->sign = !vv->sign;
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mpi_add(w, u, vv);
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mpi_free(vv);
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}
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EXPORT_SYMBOL_GPL(mpi_sub);
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void mpi_addm(MPI w, MPI u, MPI v, MPI m)
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{
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mpi_add(w, u, v);
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mpi_mod(w, w, m);
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}
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EXPORT_SYMBOL_GPL(mpi_addm);
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void mpi_subm(MPI w, MPI u, MPI v, MPI m)
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{
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mpi_sub(w, u, v);
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mpi_mod(w, w, m);
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}
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EXPORT_SYMBOL_GPL(mpi_subm);
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