img3: hide low level img3 code and provide simpler img3_stitch_component() function

3 files changed, 63 insertions, 39 deletions

diff --git a/src/idevicerestore.c b/src/idevicerestore.c
index c799bc6..1ad62a9 100644
--- a/src/idevicerestore.c
+++ b/src/idevicerestore.c
@@ -1469,11 +1469,12 @@ int build_manifest_get_identity_count(plist_t build_manifest) {
 }
 
 int ipsw_get_component_by_path(const char* ipsw, plist_t tss, const char* component, const char* path, unsigned char** data, unsigned int* size) {
-	img3_file* img3 = NULL;
 	unsigned int component_size = 0;
 	unsigned char* component_data = NULL;
 	unsigned char* component_blob = NULL;
 	char* component_name = NULL;
+	unsigned char* stitched_component = NULL;
+	unsigned int stitched_component_size = 0;
 
 	component_name = strrchr(path, '/');
 	if (component_name != NULL)
@@ -1501,38 +1502,17 @@ int ipsw_get_component_by_path(const char* ipsw, plist_t tss, const char* compon
 		}
 
 		if (component_blob != NULL) {
-			/* parse current component as img3 */
-			img3 = img3_parse_file(component_data, component_size);
-			if (img3 == NULL) {
-				error("ERROR: Unable to parse IMG3: %s\n", component_name);
-				free(component_blob);
-				free(component_data);
-				return -1;
-			}
-
-			/* we no longer require the original data */
-			free(component_data);
-
 			info("Personalizing component %s...\n", component_name);
 
-			/* personalize the component using the blob */
-			if (img3_replace_signature(img3, component_blob) < 0) {
+			if (img3_stitch_component(component_data, component_size, component_blob, 64, &stitched_component, &stitched_component_size) < 0) {
 				error("ERROR: Unable to replace IMG3 signature\n");
 				free(component_blob);
-				img3_free(img3);
 				return -1;
 			}
 
-			/* get the img3 file as data */
-			if (img3_get_data(img3, &component_data, &component_size) < 0) {
-				error("ERROR: Unable to reconstruct IMG3\n");
-				free(component_blob);
-				img3_free(img3);
-				return -1;
-			}
-
-			/* cleanup */
-			img3_free(img3);
+			free(component_data);
+			component_data = stitched_component;
+			component_size = stitched_component_size;
 		} else {
 			info("Not personalizing component %s...\n", component_name);
 		}
diff --git a/src/img3.c b/src/img3.c
index 1fa1c66..ed7646d 100644
--- a/src/img3.c
+++ b/src/img3.c
@@ -29,7 +29,11 @@
 #include "common.h"
 #include "idevicerestore.h"
 
-img3_file* img3_parse_file(unsigned char* data, unsigned int size) {
+static void img3_free(img3_file* image);
+static img3_element* img3_parse_element(const unsigned char* data);
+static void img3_free_element(img3_element* element);
+
+static img3_file* img3_parse_file(const unsigned char* data, unsigned int size) {
 	unsigned int data_offset = 0;
 	img3_element* element;
 	img3_header* header = (img3_header*) data;
@@ -196,7 +200,7 @@ img3_file* img3_parse_file(unsigned char* data, unsigned int size) {
 	return image;
 }
 
-img3_element* img3_parse_element(unsigned char* data) {
+static img3_element* img3_parse_element(const unsigned char* data) {
 	img3_element_header* element_header = (img3_element_header*) data;
 	img3_element* element = (img3_element*) malloc(sizeof(img3_element));
 	if (element == NULL) {
@@ -218,7 +222,7 @@ img3_element* img3_parse_element(unsigned char* data) {
 	return element;
 }
 
-void img3_free(img3_file* image) {
+static void img3_free(img3_file* image) {
 	if (image != NULL) {
 		if (image->header != NULL) {
 			free(image->header);
@@ -234,7 +238,7 @@ void img3_free(img3_file* image) {
 	}
 }
 
-void img3_free_element(img3_element* element) {
+static void img3_free_element(img3_element* element) {
 	if (element != NULL) {
 		if (element->data != NULL) {
 			free(element->data);
@@ -245,7 +249,7 @@ void img3_free_element(img3_element* element) {
 	}
 }
 
-int img3_replace_signature(img3_file* image, unsigned char* signature) {
+static int img3_replace_signature(img3_file* image, const unsigned char* signature) {
 	int i, oldidx;
 	int offset = 0;
 	img3_element* ecid = img3_parse_element(&signature[offset]);
@@ -350,7 +354,7 @@ int img3_replace_signature(img3_file* image, unsigned char* signature) {
 	return 0;
 }
 
-int img3_get_data(img3_file* image, unsigned char** pdata, unsigned int* psize) {
+static int img3_get_data(img3_file* image, unsigned char** pdata, unsigned int* psize) {
 	int i;
 	int offset = 0;
 	int size = sizeof(img3_header);
@@ -397,3 +401,49 @@ int img3_get_data(img3_file* image, unsigned char** pdata, unsigned int* psize)
 	*psize = size;
 	return 0;
 }
+
+int img3_stitch_component(const unsigned char* component, unsigned int component_size, const unsigned char* blob, unsigned int blob_size, unsigned char** img3_data, unsigned int *img3_size)
+{
+	img3_file *img3 = NULL;
+	unsigned char* outbuf = NULL;
+	unsigned int outsize = 0;
+
+	if (!component || component_size == 0 || !blob || blob_size == 0 || !img3_data || !img3_size) {
+		return -1;
+	}
+	
+	/* parse current component as img3 */
+	img3 = img3_parse_file(component, component_size);
+	if (img3 == NULL) {
+		error("ERROR: Unable to parse IMG3 file\n");
+		return -1;
+	}
+
+	if (((img3_element_header*)blob)->full_size != blob_size) {
+		error("ERROR: the size %d embedded in the blob does not match the passed size of %d\n", ((img3_element_header*)blob)->full_size, blob_size);
+		img3_free(img3);
+		return -1;
+	}
+
+	/* personalize the component using the blob */
+	if (img3_replace_signature(img3, blob) < 0) {
+		error("ERROR: Unable to replace IMG3 signature\n");
+		img3_free(img3);
+		return -1;
+	}
+
+	/* get the img3 file as data */
+	if (img3_get_data(img3, &outbuf, &outsize) < 0) {
+		error("ERROR: Unable to reconstruct IMG3\n");
+		img3_free(img3);
+		return -1;
+	}
+
+	/* cleanup */
+	img3_free(img3);
+
+	*img3_data = outbuf;
+	*img3_size = outsize;
+
+	return 0;
+}
diff --git a/src/img3.h b/src/img3.h
index 1132162..d1119a6 100644
--- a/src/img3.h
+++ b/src/img3.h
@@ -95,13 +95,7 @@ typedef struct {
 	img3_element* unkn_element;*/
 } img3_file;
 
-void img3_free(img3_file* image);
-img3_element* img3_parse_element(unsigned char* data);
-void img3_free_element(img3_element* element);
-img3_file* img3_parse_file(unsigned char* data, unsigned int size);
-int img3_get_data(img3_file* image, unsigned char** pdata, unsigned int* psize);
-int img3_replace_signature(img3_file* image, unsigned char* signature);
-
+int img3_stitch_component(const unsigned char* component, unsigned int component_size, const unsigned char* blob, unsigned int blob_size, unsigned char** img3_data, unsigned int *img3_size);
 
 #ifdef __cplusplus
 }s