fix bounds problem with eip196 ecmul, add test cases covering partial…

… scalar behavior

Signed-off-by: garyschulte <garyschulte@gmail.com>

bls12-381/src/test/resources/org/hyperledger/besu/nativelib/bls12_381/eip196_g1_mul.csv

@@ -102,3 +102,5 @@ input,result,gas,notes
 d2acf800b3ba0ff68ef8d5fd4d6c250d3e70b3bed17894f958579644c83fa9d485121d580e2b061c697e68f9502977680d6ad8e12b4f61e3e2a2252ce11428941f2a84b7f0a821cb8cc7699303bd4fec2247870562618fd8d6169072d9b33614,,6000,invalid input parameters, Failed to parse Fp element
 1c2cb2b4504b19c7e073679432e625f2706b7c4728cd9bd3ce36579f4de2f3902c8605f723ac2f73baa15eac674f62ab,,6000,invalid input parameters
 ,00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000,6000,
+1A87B0584CE92F4593D161480614F2989035225609F08058CCFA3D0F940FEBE31A2F3C951F6DADCC7EE9007DFF81504B0FCD6D7CF59996EFDC33D92BF7F9F8F60100000000000000000000000000000000,0x220cb1540fa85ba04d863dca86de9359a43ac9fc084aebb9f2a936d989abbb602ccdc6c020dd2cf78332132b3f1d1122391b515035623cd6f53d4aea24ea2466,6000,
+1A87B0584CE92F4593D161480614F2989035225609F08058CCFA3D0F940FEBE31A2F3C951F6DADCC7EE9007DFF81504B0FCD6D7CF59996EFDC33D92BF7F9F8F60000000000000000000000000000000100000000000000000000000000000000,1051acb0700ec6d42a88215852d582efbaef31529b6fcbc3277b5c1b300f5cf0135b2394bb45ab04b8bd7611bd2dfe1de6a4e6e2ccea1ea1955f577cd66af85b,6000,

gnark/gnark-jni/gnark-eip-196.go

@@ -18,7 +18,7 @@ import (
 )
 
 const (
-    EIP196PreallocateForResult = 256
+    EIP196PreallocateForResult = 128
     EIP196PreallocateForError = 256
 	EIP196PreallocateForScalar = 32 // scalar int is 32 byte
 	EIP196PreallocateForFp = 32  // field elements are 32 bytes
@@ -38,13 +38,20 @@ func eip196altbn128G1Add(javaInputBuf, javaOutputBuf, javaErrorBuf *C.char, cInp
     inputLen := int(cInputLen)
     errorLen := int(cErrorLen)
 
+
+    if (inputLen > 2*EIP196PreallocateForG1) {
+      // trunc if input too long
+      inputLen = 2*EIP196PreallocateForG1
+    }
+
     if inputLen < EIP196PreallocateForG1 {
         // if we do not have complete input, return 0
         return 0
     }
 
     // Convert error C pointers to Go slices
-    errorBuf := castBuffer(javaErrorBuf, errorLen)
+    errorBuf := castErrorBuffer(javaErrorBuf, errorLen)
+
 
     // Convert input C pointers to Go slices
     input := (*[2*EIP196PreallocateForG1]byte)(unsafe.Pointer(javaInputBuf))[:inputLen:inputLen]
@@ -89,18 +96,19 @@ func eip196altbn128G1Mul(javaInputBuf, javaOutputBuf, javaErrorBuf *C.char, cInp
     inputLen := int(cInputLen)
     errorLen := int(cErrorLen)
 
-    if inputLen == 0 {
-        return 0
-    }
-
     // Convert error C pointers to Go slices
-    errorBuf := castBuffer(javaErrorBuf, errorLen)
+    errorBuf := castErrorBuffer(javaErrorBuf, errorLen)
 
     if inputLen < EIP196PreallocateForG1 {
         // if we do not have complete input, return 0
         return 0
     }
 
+    if (inputLen > EIP196PreallocateForG1 + EIP196PreallocateForScalar) {
+      // trunc if input too long
+      inputLen = EIP196PreallocateForG1 + EIP196PreallocateForScalar
+    }
+
     // Convert input C pointers to Go slice
     input := (*[EIP196PreallocateForG1 + EIP196PreallocateForScalar]byte)(unsafe.Pointer(javaInputBuf))[:inputLen:inputLen]
 
@@ -114,12 +122,15 @@ func eip196altbn128G1Mul(javaInputBuf, javaOutputBuf, javaErrorBuf *C.char, cInp
     }
 
     // Convert byte slice to *big.Int
-    scalarEndIndex := 96;
-    if (scalarEndIndex > int(cInputLen)) {
-      scalarEndIndex = int(cInputLen)
+    scalarBytes := input[64:]
+    if (96 > int(cInputLen)) {
+      // if the input is truncated, copy the bytes to the high order portion of the scalar
+      scalarBytes = make([]byte, 32)
+      copy(scalarBytes[:], input[64:int(cInputLen)])
     }
+
     scalar := big.NewInt(0)
-    scalar.SetBytes(input[64:scalarEndIndex])
+    scalar.SetBytes(scalarBytes[:])
 
     // multiply g1 point by scalar
     result := p0.ScalarMultiplication(&p0, scalar)
@@ -140,7 +151,7 @@ func eip196altbn128Pairing(javaInputBuf, javaOutputBuf, javaErrorBuf *C.char, cI
     output := castBuffer(javaOutputBuf, outputLen)
 
     // Convert error C pointers to Go slices
-    errorBuf := castBuffer(javaErrorBuf, errorLen)
+    errorBuf := castErrorBuffer(javaErrorBuf, errorLen)
 
     if inputLen == 0 {
         output[31]=0x01
@@ -234,6 +245,14 @@ func castBuffer(javaOutputBuf *C.char, length int) []byte {
     return (*[EIP196PreallocateForResult]byte)(unsafe.Pointer(javaOutputBuf))[:bufSize:bufSize]
 }
 
+func castErrorBuffer(javaOutputBuf *C.char, length int) []byte {
+    bufSize := length
+    if bufSize < EIP196PreallocateForError {
+      bufSize = EIP196PreallocateForError
+    }
+    return (*[EIP196PreallocateForError]byte)(unsafe.Pointer(javaOutputBuf))[:bufSize:bufSize]
+}
+
 func main() {
 }
 

gnark/src/main/java/org/hyperledger/besu/nativelib/gnark/LibGnarkEIP196.java

@@ -6,7 +6,7 @@
 
 public class LibGnarkEIP196 {
 
-  public static final int EIP196_PREALLOCATE_FOR_RESULT_BYTES = 256; // includes error string
+  public static final int EIP196_PREALLOCATE_FOR_RESULT_BYTES = 128;
   public static final int EIP196_PREALLOCATE_FOR_ERROR_BYTES = 256; // includes error string
   @SuppressWarnings("WeakerAccess")
   public static final byte EIP196_ADD_OPERATION_RAW_VALUE = 1;

gnark/src/test/resources/org/hyperledger/besu/nativelib/gnark/eip196_g1_mul.csv

@@ -102,3 +102,5 @@ input,result,gas,notes
 d2acf800b3ba0ff68ef8d5fd4d6c250d3e70b3bed17894f958579644c83fa9d485121d580e2b061c697e68f9502977680d6ad8e12b4f61e3e2a2252ce11428941f2a84b7f0a821cb8cc7699303bd4fec2247870562618fd8d6169072d9b33614,,6000,invalid compressed coordinate
 1c2cb2b4504b19c7e073679432e625f2706b7c4728cd9bd3ce36579f4de2f3902c8605f723ac2f73baa15eac674f62ab,00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000,6000,invalid input parameters,
 ,00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000,6000,
+1A87B0584CE92F4593D161480614F2989035225609F08058CCFA3D0F940FEBE31A2F3C951F6DADCC7EE9007DFF81504B0FCD6D7CF59996EFDC33D92BF7F9F8F60100000000000000000000000000000000,0x220cb1540fa85ba04d863dca86de9359a43ac9fc084aebb9f2a936d989abbb602ccdc6c020dd2cf78332132b3f1d1122391b515035623cd6f53d4aea24ea2466,6000,
+1A87B0584CE92F4593D161480614F2989035225609F08058CCFA3D0F940FEBE31A2F3C951F6DADCC7EE9007DFF81504B0FCD6D7CF59996EFDC33D92BF7F9F8F60000000000000000000000000000000100000000000000000000000000000000,1051acb0700ec6d42a88215852d582efbaef31529b6fcbc3277b5c1b300f5cf0135b2394bb45ab04b8bd7611bd2dfe1de6a4e6e2ccea1ea1955f577cd66af85b,6000,