From 63b5908f384a79966359f10864d6a5ff2ad97b4d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marco=20Trevisan=20=28Trevi=C3=B1o=29?= <mail@3v1n0.net>
Date: Thu, 13 Feb 2025 21:14:26 +0100
Subject: [PATCH] goodix: Read the header using byte reader

---
 libfprint/drivers/goodixmoc/goodix.c       | 10 +++---
 libfprint/drivers/goodixmoc/goodix_proto.c | 36 +++++++++++++++-------
 libfprint/drivers/goodixmoc/goodix_proto.h |  5 ++-
 3 files changed, 32 insertions(+), 19 deletions(-)

diff --git a/libfprint/drivers/goodixmoc/goodix.c b/libfprint/drivers/goodixmoc/goodix.c
index 2febb4ae..33e137f4 100644
--- a/libfprint/drivers/goodixmoc/goodix.c
+++ b/libfprint/drivers/goodixmoc/goodix.c
@@ -130,7 +130,7 @@ fp_cmd_receive_cb (FpiUsbTransfer *transfer,
   FpiDeviceGoodixMoc *self = FPI_DEVICE_GOODIXMOC (device);
   FpiByteReader reader = {0};
   CommandData *data = user_data;
-  int ret = -1, ssm_state = 0;
+  int ssm_state = 0;
   gxfp_cmd_response_t cmd_reponse = {0, };
   pack_header header;
   guint32 crc32_calc = 0;
@@ -156,8 +156,10 @@ fp_cmd_receive_cb (FpiUsbTransfer *transfer,
       return;
     }
 
-  ret = gx_proto_parse_header (transfer->buffer, transfer->actual_length, &header);
-  if (ret != 0)
+  reader.data = transfer->buffer;
+  reader.size = transfer->actual_length;
+
+  if (gx_proto_parse_header (&reader, &header) != 0)
     {
       fpi_ssm_mark_failed (transfer->ssm,
                            fpi_device_error_new_msg (FP_DEVICE_ERROR_PROTO,
@@ -165,8 +167,6 @@ fp_cmd_receive_cb (FpiUsbTransfer *transfer,
       return;
     }
 
-  reader.data = transfer->buffer;
-  reader.size = transfer->actual_length;
   if (!fpi_byte_reader_set_pos (&reader, PACKAGE_HEADER_SIZE + header.len))
     {
       fpi_ssm_mark_failed (transfer->ssm,
diff --git a/libfprint/drivers/goodixmoc/goodix_proto.c b/libfprint/drivers/goodixmoc/goodix_proto.c
index 67bbfe85..f0072b56 100644
--- a/libfprint/drivers/goodixmoc/goodix_proto.c
+++ b/libfprint/drivers/goodixmoc/goodix_proto.c
@@ -226,21 +226,35 @@ gx_proto_build_package (uint8_t       *ppackage,
 
 
 int
-gx_proto_parse_header (
-  uint8_t     *buffer,
-  uint32_t     buffer_len,
-  pack_header *pheader)
+gx_proto_parse_header (FpiByteReader *reader,
+                       pack_header   *pheader)
 {
-  if (!buffer || !pheader)
-    return -1;
-  if (buffer_len < PACKAGE_HEADER_SIZE + PACKAGE_CRC_SIZE)
+  if (!pheader)
     return -1;
 
-  memcpy (pheader, buffer, sizeof (pack_header));
-  pheader->len = GUINT16_FROM_LE (pheader->len);
-  if (buffer_len < pheader->len + PACKAGE_HEADER_SIZE)
-    return -1;
+  if (!fpi_byte_reader_get_uint8 (reader, &pheader->cmd0))
+    g_return_val_if_reached (-1);
+
+  if (!fpi_byte_reader_get_uint8 (reader, &pheader->cmd1))
+    g_return_val_if_reached (-1);
+
+  if (!fpi_byte_reader_get_uint8 (reader, &pheader->packagenum))
+    g_return_val_if_reached (-1);
+
+  if (!fpi_byte_reader_get_uint8 (reader, &pheader->reserved))
+    g_return_val_if_reached (-1);
+
+  if (!fpi_byte_reader_get_uint16_le (reader, &pheader->len))
+    g_return_val_if_reached (-1);
+
+  if (!fpi_byte_reader_get_uint8 (reader, &pheader->crc8))
+    g_return_val_if_reached (-1);
+
+  if (!fpi_byte_reader_get_uint8 (reader, &pheader->rev_crc8))
+    g_return_val_if_reached (-1);
+
   pheader->len -= PACKAGE_CRC_SIZE;
+
   return 0;
 }
 
diff --git a/libfprint/drivers/goodixmoc/goodix_proto.h b/libfprint/drivers/goodixmoc/goodix_proto.h
index 50a9a8b1..63024500 100644
--- a/libfprint/drivers/goodixmoc/goodix_proto.h
+++ b/libfprint/drivers/goodixmoc/goodix_proto.h
@@ -234,9 +234,8 @@ int gx_proto_build_package (uint8_t       *ppackage,
                             const uint8_t *payload,
                             uint32_t       payload_size);
 
-int gx_proto_parse_header (uint8_t     *buffer,
-                           uint32_t     buffer_len,
-                           pack_header *pheader);
+int gx_proto_parse_header (FpiByteReader *reader,
+                           pack_header   *pheader);
 
 int gx_proto_parse_body (uint16_t             cmd,
                          FpiByteReader       *byte_reader,