From: Filippo Valsorda <filippo@golang.org>
Date: Mon, 21 Nov 2022 22:24:58 +0000 (+0100)
Subject: crypto/internal/boring: tolerate empty ECDSA signatures
X-Git-Tag: go1.20rc1~115
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=6a72514076f6e2be54af267959e3098693e02980;p=gostls13.git

crypto/internal/boring: tolerate empty ECDSA signatures

VerifyASN1 became directly reachable without encoding/decoding in
CL 353849, so it's now possible for the signature to be empty.

Change-Id: I37d6400945ab541120180bf73335e0ec93322947
Reviewed-on: https://go-review.googlesource.com/c/go/+/452635
Reviewed-by: Roland Shoemaker <roland@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Auto-Submit: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
---

diff --git a/src/crypto/internal/boring/ecdsa.go b/src/crypto/internal/boring/ecdsa.go
index 284e7e9b69..e15f3682c7 100644
--- a/src/crypto/internal/boring/ecdsa.go
+++ b/src/crypto/internal/boring/ecdsa.go
@@ -11,7 +11,6 @@ import "C"
 import (
 	"errors"
 	"runtime"
-	"unsafe"
 )
 
 type ecdsaSignature struct {
@@ -124,7 +123,7 @@ func SignMarshalECDSA(priv *PrivateKeyECDSA, hash []byte) ([]byte, error) {
 	size := C._goboringcrypto_ECDSA_size(priv.key)
 	sig := make([]byte, size)
 	var sigLen C.uint
-	if C._goboringcrypto_ECDSA_sign(0, base(hash), C.size_t(len(hash)), (*C.uint8_t)(unsafe.Pointer(&sig[0])), &sigLen, priv.key) == 0 {
+	if C._goboringcrypto_ECDSA_sign(0, base(hash), C.size_t(len(hash)), base(sig), &sigLen, priv.key) == 0 {
 		return nil, fail("ECDSA_sign")
 	}
 	runtime.KeepAlive(priv)
@@ -132,7 +131,7 @@ func SignMarshalECDSA(priv *PrivateKeyECDSA, hash []byte) ([]byte, error) {
 }
 
 func VerifyECDSA(pub *PublicKeyECDSA, hash []byte, sig []byte) bool {
-	ok := C._goboringcrypto_ECDSA_verify(0, base(hash), C.size_t(len(hash)), (*C.uint8_t)(unsafe.Pointer(&sig[0])), C.size_t(len(sig)), pub.key) != 0
+	ok := C._goboringcrypto_ECDSA_verify(0, base(hash), C.size_t(len(hash)), base(sig), C.size_t(len(sig)), pub.key) != 0
 	runtime.KeepAlive(pub)
 	return ok
 }