Merge pull request btcsuite#2233 from jharveyb/txid_string_check

wire: check TXID length before creating outpoint

wire/msgtx.go

@@ -229,6 +229,11 @@ func NewOutPointFromString(outpoint string) (*OutPoint, error) {
 	if len(parts) != 2 {
 		return nil, errors.New("outpoint should be of the form txid:index")
 	}
+
+	if len(parts[0]) != chainhash.MaxHashStringSize {
+		return nil, errors.New("outpoint txid should be 64 hex chars")
+	}
+
 	hash, err := chainhash.NewHashFromStr(parts[0])
 	if err != nil {
 		return nil, err

wire/msgtx_test.go

@@ -849,6 +849,15 @@ func TestTxOutPointFromString(t *testing.T) {
 			},
 			err: false,
 		},
+		{
+			name:  "normal outpoint 2 with 31-byte txid",
+			input: "c7762a68ff164352bd31fd95fa875204e811c09acef40ba781787eb28e3b55:42",
+			result: &OutPoint{
+				Hash:  hashFromStr("c7762a68ff164352bd31fd95fa875204e811c09acef40ba781787eb28e3b55"),
+				Index: 42,
+			},
+			err: true,
+		},
 		{
 			name:   "bad string",
 			input:  "not_outpoint_not_outpoint_not_outpoint",