diff options
author | Ignat Korchagin <ignat@cloudflare.com> | 2022-06-17 09:42:10 +0100 |
---|---|---|
committer | Herbert Xu <herbert@gondor.apana.org.au> | 2022-06-24 17:12:29 +0800 |
commit | f145d411a67efacc0731fc3f9c7b2d89fb62523a (patch) | |
tree | 92a526967e9a1329b5c52976612c8aa31d509811 /lib | |
parent | 1b05ece0c931536c0a38a9385e243a7962e933f6 (diff) |
crypto: rsa - implement Chinese Remainder Theorem for faster private key operations
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>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/mpi/mpi-add.c | 2 | ||||
-rw-r--r-- | lib/mpi/mpi-mul.c | 1 |
2 files changed, 2 insertions, 1 deletions
diff --git a/lib/mpi/mpi-add.c b/lib/mpi/mpi-add.c index 2cdae54c1bd0..9056fc5167fc 100644 --- a/lib/mpi/mpi-add.c +++ b/lib/mpi/mpi-add.c @@ -138,7 +138,7 @@ void mpi_sub(MPI w, MPI u, MPI v) mpi_add(w, u, vv); mpi_free(vv); } - +EXPORT_SYMBOL_GPL(mpi_sub); void mpi_addm(MPI w, MPI u, MPI v, MPI m) { diff --git a/lib/mpi/mpi-mul.c b/lib/mpi/mpi-mul.c index 8f5fa200f297..7f4eda8560dc 100644 --- a/lib/mpi/mpi-mul.c +++ b/lib/mpi/mpi-mul.c @@ -82,6 +82,7 @@ void mpi_mul(MPI w, MPI u, MPI v) if (tmp_limb) mpi_free_limb_space(tmp_limb); } +EXPORT_SYMBOL_GPL(mpi_mul); void mpi_mulm(MPI w, MPI u, MPI v, MPI m) { |