From 10fbbc8d6f405a9bc12706beaf645f27d174f799 Mon Sep 17 00:00:00 2001
From: amuliang <982632988@qq.com>
Date: Tue, 12 Dec 2023 01:05:48 +0800
Subject: [PATCH] =?UTF-8?q?png=E5=9B=BE=E7=89=87=E5=A2=9E=E5=8A=A0?=
 =?UTF-8?q?=E9=80=9A=E9=81=93=E6=A3=80=E6=B5=8B?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 README.md            |  10 +-
 ctf_analyze_image.py | 372 +++++--------------------------------------
 type/GIF.py          |  92 +++++++++++
 type/JPG.py          |  99 ++++++++++++
 type/PNG.py          | 238 +++++++++++++++++++++++++++
 5 files changed, 480 insertions(+), 331 deletions(-)
 create mode 100644 type/GIF.py
 create mode 100644 type/JPG.py
 create mode 100644 type/PNG.py

diff --git a/README.md b/README.md
index 8b92e79..76fd547 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,11 @@
 # ctf_analyze_image
 
-应对CTF中常见图片分析题
\ No newline at end of file
+应对CTF中常见图片分析题，暂时只支持PNG图片
+
+## 处理能力
+文件信息、文件头修复、文件尾修复、文件尺寸修复、填充数据识别、通道信息检测
+
+## 使用方法
+```
+python3 ctf_analyze_image.py test.png
+```
\ No newline at end of file
diff --git a/ctf_analyze_image.py b/ctf_analyze_image.py
index 1749762..4e0c8c4 100644
--- a/ctf_analyze_image.py
+++ b/ctf_analyze_image.py
@@ -6,345 +6,46 @@ import re
 import sys
 import time
 from PIL import Image
+from type.PNG import PNG
+# from type.JPG import JPG
+# from type.GIF import GIF
 
-
-class PNG:
-    def __init__(self):
-        pass
-
-    # 检测文件格式，返回百分比
-    @staticmethod
-    def test(data: bytearray):
-        return 100
-    
-    # 获取图片信息
-    @staticmethod
-    def get_info(data: bytearray):
-        text = b'tEXt'
-        index = data.find(text)
-        if index > 32:
-            length = int.from_bytes(data[index-4: index], byteorder='big')
-            chunk_data = data[index+4: index+4+length]
-            print('[*] 图像信息：')
-            print(bytes(chunk_data).split(b'\x00'))
-
-        info = chunk_data
-        return info
-    
-    def check_tail(data: bytearray):
-        changed = False
-        tail = None
-        iend = b'\x49\x45\x4E\x44\xAE\x42\x60\x82'
-        length = len(data)
-        index = data.find(iend)
-        if index == -1:
-            index = data.find(iend[0:4])
-            if index != -1:
-                index = index + 4
-        else:
-            index = index + 8
-
-        if index == -1:
-            print('[x] 缺少png文件格式结束标识符IEND')
-        elif index < 32:
-            print('[x] 缺少png文件格式结束标识符IEND位置貌似不太对')
-        else:
-            tail = data[index:]
-            if len(tail) > 0:
-                changed = True
-                print('[x] 检测到文件尾部有垃圾数据，已尝试修复')
-
-        return changed, data, tail
-    
-    # 修复文件头
-    @staticmethod
-    def repair_sig(data: bytearray):
-        changed = False
-        head = None
-        print('[*] 检测文件头')
-        sig = b'\x89\x50\x4E\x47\x0D\x0A\x1A\x0A'
-        index = data.find(sig)
-        if index > 0:
-            print('[x] 检测到文件头前有垃圾数据，已尝试修复')
-            head = bytes(data[:index])
-            data = data[index:]
-            changed = True
-        elif data[0:8] != sig:
-            print('[x] 检测到文件头异常，已尝试修复')
-            data[0:8] = sig
-            changed = True
-        return changed, data, head
-    
-    # 修复尺寸
-    @staticmethod
-    def repair_size(data: bytearray):
-        changed = False
-        print('[*] 检测文件尺寸')
-        chunk_begin = 8
-        data_begin = chunk_begin + 8
-        width_begin = data_begin
-        height_begin = data_begin + 4
-        length = int.from_bytes(data[chunk_begin:chunk_begin+4], byteorder='big')
-        ctype = data[chunk_begin+4: chunk_begin+8] # 应该为 b'\x49\x48\x44\x52'，即 b'IHDR'
-        chunk_data = data[data_begin: data_begin+length]
-        width = int.from_bytes(chunk_data[0:4], byteorder='big')
-        height = int.from_bytes(chunk_data[4:8], byteorder='big')
-        crc = int.from_bytes(data[data_begin+length:data_begin+length+4], byteorder='big')
-
-        if PNG.test_ihdr_chunk(ctype + chunk_data, crc):
-            print(' - 图片尺寸设置正确')
-        else:
-            b = False
-            if not b:
-                print('[x] 尝试修复图片宽度...')
-                chunk = ctype + chunk_data
-                for i in range(1, 2048):
-                    chunk[4:8] = i.to_bytes(4, byteorder='big')
-                    if PNG.test_ihdr_chunk(bytes(chunk), crc):
-                        width = i
-                        print(f'[*] 图片宽度修复成功，宽度值为{i}')
-                        data[width_begin: width_begin+4] = width.to_bytes(4, byteorder='big')
-                        changed = True
-                        b = True
-                        break
-            if not b:
-                print('[x] 尝试修复图片高度...')
-                chunk = ctype + chunk_data
-                for i in range(1, 2048):
-                    chunk[8:12] = i.to_bytes(4, byteorder='big')
-                    if PNG.test_ihdr_chunk(chunk, crc):
-                        height = i
-                        print(f'[*] 图片高度修复成功，宽度值为{i}')
-                        data[height_begin: height_begin+4] = width.to_bytes(4, byteorder='big')
-                        changed = True
-                        b = True
-                        break
-            if not b:
-                temp = input(f'当前宽度值为{width}，高度值为{height}，是否尝试将高度值设置为更高？可输入高度值或直接回车：')
-                if temp.isdigit():
-                    height = int(temp)
-                    data[height_begin: height_begin+4] = height.to_bytes(4, byteorder='big')
-                    print(f'[*] 已将图片高度设置为{height}')
-                    changed = True
-        return changed, data, width, height
-    
-    @staticmethod
-    def test_ihdr_chunk(chunk_data, crc):
-        crc32 = binascii.crc32(chunk_data) & 0xffffffff
-        return crc32 == crc
-
-class JPG:
-    def __init__(self):
-        pass
-
-    # 检测文件格式，返回百分比
-    @staticmethod
-    def test(data: bytearray):
-        return 100
-    
-    # 获取图片信息
-    @staticmethod
-    def get_info(data: bytearray):
-        info = {}
-        return info
-    
-    def check_tail(data: bytearray):
-        changed = False
-        tail = None
-        return changed, data, tail
-    
-    # 修复文件头
-    @staticmethod
-    def repair_sig(data: bytearray):
-        changed = False
-        head = None
-        print('[*] 检测文件头')
-        sig = b'\x89\x50\x4E\x47\x0D\x0A\x1A\x0A'
-        index = data.find(sig)
-        if index != -1:
-            print('[x] 检测到文件头前有垃圾数据，已尝试修复')
-            head = data[:index]
-            data = data[index:]
-            changed = True
-        elif data[0:8] != sig:
-            print('[x] 检测到文件头异常，已尝试修复')
-            data[0:8] = sig
-            changed = True
-        return changed, data, head
-    
-    # 修复尺寸
-    @staticmethod
-    def repair_size(data: bytearray):
-        changed = False
-        print('[*] 检测文件尺寸')
-        chunk_begin = 8
-        width_begin = chunk_begin + 8
-        height_begin = chunk_begin + 12
-        length = int.from_bytes(data[chunk_begin:chunk_begin+4], byteorder='big')
-        chunk_data = data[chunk_begin+4: chunk_begin+4+length]
-        ctype = chunk_data[0:4] # 应该为 b'\x49\x48\x44\x52'，即 b'IHDR'
-        width = int.from_bytes(chunk_data[4:8], byteorder='big')
-        height = int.from_bytes(chunk_data[8:12], byteorder='big')
-        crc = chunk_data[-4:]
-
-        if JPG.test_ihdr_chunk(chunk_data[:-4], crc):
-            print(' - 图片尺寸设置正确')
-        else:
-            if width == 0:
-                print('[x] 检测到图片宽度设置异常，尝试修复...')
-                for i in range(1, 2048):
-                    chunk_data[4:8] = i.to_bytes(4, byteorder='big')
-                    if JPG.test_ihdr_chunk(chunk_data[:-4], crc):
-                        width = i
-                        print(f'[*] 图片宽度修复成功，宽度值为{i}')
-                        data[width_begin: width_begin+4] = width.to_bytes(4, byteorder='big')
-                        changed = True
-                        break
-            if width == 0:
-                print('[x] 图片宽度修复失败')
-            
-            temp = input(f'当前宽度值为{width}，高度值为{height}，是否尝试将高度值设置为更高？可输入高度值或直接回车：')
-            if temp.isdigit():
-                height = int(temp)
-                data[height_begin: height_begin+4] = height.to_bytes(4, byteorder='big')
-                print(f'[*] 已将图片高度设置为{height}')
-                changed = True
-        return changed, data
-    
-    @staticmethod
-    def test_ihdr_chunk(chunk_data, crc):
-        crc32 = binascii.crc32(chunk_data) & 0xffffffff
-        return crc32 == crc
-
-class GIF:
-    def __init__(self):
-        pass
-
-    # 检测文件格式，返回百分比
-    @staticmethod
-    def test(data: bytearray):
-        return 100
-    
-    # 获取图片信息
-    @staticmethod
-    def get_info(data: bytearray):
-        info = {}
-        return info
-    
-    def check_tail(data: bytearray):
-        changed = False
-        tail = None
-        return changed, data, tail
-    
-    # 修复文件头
-    @staticmethod
-    def repair_sig(data: bytearray):
-        changed = False
-        head = None
-        print('[*] 检测文件头')
-        sig = b'\x89\x50\x4E\x47\x0D\x0A\x1A\x0A'
-        index = data.find(sig)
-        if index != -1:
-            print('[x] 检测到文件头前有垃圾数据，已尝试修复')
-            head = data[:index]
-            data = data[index:]
-            changed = True
-        elif data[0:8] != sig:
-            print('[x] 检测到文件头异常，已尝试修复')
-            data[0:8] = sig
-            changed = True
-        return changed, data, head
-    
-    # 修复尺寸
-    @staticmethod
-    def repair_size(data: bytearray):
-        changed = False
-        print('[*] 检测文件尺寸')
-        chunk_begin = 8
-        width_begin = chunk_begin + 8
-        height_begin = chunk_begin + 12
-        length = int.from_bytes(data[chunk_begin:chunk_begin+4], byteorder='big')
-        chunk_data = data[chunk_begin+4: chunk_begin+4+length]
-        ctype = chunk_data[0:4] # 应该为 b'\x49\x48\x44\x52'，即 b'IHDR'
-        width = int.from_bytes(chunk_data[4:8], byteorder='big')
-        height = int.from_bytes(chunk_data[8:12], byteorder='big')
-        crc = chunk_data[-4:]
-
-        if GIF.test_ihdr_chunk(chunk_data[:-4], crc):
-            print(' - 图片尺寸设置正确')
-        else:
-            if width == 0:
-                print('[x] 检测到图片宽度设置异常，尝试修复...')
-                for i in range(1, 2048):
-                    chunk_data[4:8] = i.to_bytes(4, byteorder='big')
-                    if GIF.test_ihdr_chunk(chunk_data[:-4], crc):
-                        width = i
-                        print(f'[*] 图片宽度修复成功，宽度值为{i}')
-                        data[width_begin: width_begin+4] = width.to_bytes(4, byteorder='big')
-                        changed = True
-                        break
-            if width == 0:
-                print('[x] 图片宽度修复失败')
-            
-            temp = input(f'当前宽度值为{width}，高度值为{height}，是否尝试将高度值设置为更高？可输入高度值或直接回车：')
-            if temp.isdigit():
-                height = int(temp)
-                data[height_begin: height_begin+4] = height.to_bytes(4, byteorder='big')
-                print(f'[*] 已将图片高度设置为{height}')
-                changed = True
-        return changed, data
-    
-    @staticmethod
-    def test_ihdr_chunk(chunk_data, crc):
-        crc32 = binascii.crc32(chunk_data) & 0xffffffff
-        return crc32 == crc
+types = [PNG] # 暂时先只处理PNG，其他的都没写好呢[PNG, JPG, GIF]
 
 
 def check_image_type(filename: str, data: bytearray):
     file_type1 = None
-    if re.match('.*\.png$',  filename.lower()):
-        file_type1 = 'png'
-    elif re.match('.*\.jpg$',  filename.lower()):
-        file_type1 = 'jpg'
-    elif re.match('.*\.gif$',  filename.lower()):
-        file_type1 = 'gif'
+    for model in types:
+        if re.match(f'.*\.{model.extension}$', filename.lower()):
+            file_type1 = model
+            break
 
     file_type2 = None
     weight = 0
-    weight2 = PNG.test(data)
-    if weight2 > weight:
-        file_type2 = 'png'
-        weight = weight2
-    weight2 = JPG.test(data)
-    if weight2 > weight:
-        file_type2 = 'jpg'
-        weight = weight2
-    weight2 = GIF.test(data)
-    if weight2 > weight:
-        file_type2 = 'gif'
-        weight = weight2
+    for model in types:
+        weight2 = model.test(data)
+        if weight2 > weight:
+            file_type2 = model
+            weight = weight2
     
     if file_type1 != None:
         if file_type1 == file_type2:
-            print(f'看起来文件格式是{file_type1}')
+            print(f'看起来文件格式是{file_type1.extension}')
         else:
-            print(f'文件名中格式是{file_type1}，但是解析文件头格式发现{weight}%是{file_type2}')
+            print(f'文件名中格式是{file_type1.extension}，但是解析文件头格式发现{weight}%是{file_type2.extension}')
     else:
         if file_type2 != None:
             file_type1 = file_type2
-            print(f'检测文件头认为文件格式{weight}%是{file_type2}')
+            print(f'检测文件头认为文件格式{weight}%是{file_type2.extension}')
         else:
             print('未检测到任何图片格式特征，该文件可能不是图片文件')
 
-    index = input('要指定文件格式吗？或者直接回车。(1、png  2、jpg  3、gif)：')
+    for i in range(len(types)):
+        print(f'    {i}、{types[i].extension}')
+    index = input('要指定文件格式吗？或者直接回车。请输入文件格式序号：')
     if index.isdigit():
         index = int(index)
-        if index == 1:
-            file_type1 = 'png'
-        elif index == 2:
-            file_type1 = 'jpg'
-        elif index == 3:
-            file_type1 = 'gif'
+        file_type1 = types[index]
 
     return file_type1
 
@@ -358,14 +59,7 @@ def main(filename: str):
         data = bytearray(f.read())
         
     # 确定文件格式
-    file_type = check_image_type(filename, data)
-    model = None
-    if file_type == 'png':
-        model = PNG
-    elif file_type == 'jpg':
-        model = JPG
-    elif file_type == 'gif':
-        model = GIF
+    model = check_image_type(filename, data)
 
     # 检测并修复
     changed = False
@@ -375,6 +69,16 @@ def main(filename: str):
         changed1, data, tail = model.check_tail(data)
         changed2, data, head = model.repair_sig(data)
         changed3, data, width, height = model.repair_size(data)
+        changed4, data, data_append = model.check_data(data)
+        checked_channel = False # 是否检测过RGB通道，如果没检测过，则下面还会尝试检测一遍
+        try:
+            # 尝试分析通道信息
+            changed5, data_r, data_g, data_b = model.check_channels(filename, width, height)
+            checked_channel = True
+        except Exception as e:
+            pass
+            #print('[x] 尝试打开图片失败，失败原因：' + str(e))
+
         changed = changed1 or changed2 or changed3
     else:
         print('[*] 未进行任何处理')
@@ -399,9 +103,16 @@ def main(filename: str):
             f = open(os.path.join(dirpath, 'head'), 'wb')
             f.write(head)
             f.close()
+        for i in range(len(data_append)):
+            f = open(os.path.join(dirpath, 'data_append_' + str(i)), 'wb')
+            f.write(data_append[i])
+            f.close()
         print(f'[*] 分析结果已保存到 {dirpath}')
-        # 尝试打开图片看一看
+        if not checked_channel:
+            # 尝试分析通道信息
+            changed5, data_r, data_g, data_b = model.check_channels(imagepath, width, height)
         try:
+            # 尝试打开图片看一看
             im = Image.open(imagepath)
             im.show()
         except Exception as e:
@@ -412,6 +123,7 @@ def main(filename: str):
     print('[*] 分析完成！')
 
 # 开始执行
-filename = sys.argv[1]
-# filename = 'G:\\1.png'
+if len(sys.argv) > 1:
+    filename = sys.argv[1]
+
 main(filename)
diff --git a/type/GIF.py b/type/GIF.py
new file mode 100644
index 0000000..a404e50
--- /dev/null
+++ b/type/GIF.py
@@ -0,0 +1,92 @@
+import binascii
+
+
+class GIF:
+    extension = 'gif'
+
+    def __init__(self):
+        pass
+
+    # 检测文件格式，返回百分比
+    @staticmethod
+    def test(data: bytearray):
+        return 100
+    
+    # 获取图片信息
+    @staticmethod
+    def get_info(data: bytearray):
+        info = {}
+        return info
+    
+    def check_tail(data: bytearray):
+        changed = False
+        tail = None
+        return changed, data, tail
+    
+    # 修复文件头
+    @staticmethod
+    def repair_sig(data: bytearray):
+        changed = False
+        head = None
+        print('[*] 检测文件头')
+        sig = b'\x89\x50\x4E\x47\x0D\x0A\x1A\x0A'
+        index = data.find(sig)
+        if index != -1:
+            print('[x] 检测到文件头前有垃圾数据，已尝试修复')
+            head = data[:index]
+            data = data[index:]
+            changed = True
+        elif data[0:8] != sig:
+            print('[x] 检测到文件头异常，已尝试修复')
+            data[0:8] = sig
+            changed = True
+        return changed, data, head
+    
+    # 修复尺寸
+    @staticmethod
+    def repair_size(data: bytearray):
+        changed = False
+        print('[*] 检测文件尺寸')
+        chunk_begin = 8
+        width_begin = chunk_begin + 8
+        height_begin = chunk_begin + 12
+        length = int.from_bytes(data[chunk_begin:chunk_begin+4], byteorder='big')
+        chunk_data = data[chunk_begin+4: chunk_begin+4+length]
+        ctype = chunk_data[0:4] # 应该为 b'\x49\x48\x44\x52'，即 b'IHDR'
+        width = int.from_bytes(chunk_data[4:8], byteorder='big')
+        height = int.from_bytes(chunk_data[8:12], byteorder='big')
+        crc = chunk_data[-4:]
+
+        if GIF.test_ihdr_chunk(chunk_data[:-4], crc):
+            print(' - 图片尺寸设置正确')
+        else:
+            if width == 0:
+                print('[x] 检测到图片宽度设置异常，尝试修复...')
+                for i in range(1, 2048):
+                    chunk_data[4:8] = i.to_bytes(4, byteorder='big')
+                    if GIF.test_ihdr_chunk(chunk_data[:-4], crc):
+                        width = i
+                        print(f'[*] 图片宽度修复成功，宽度值为{i}')
+                        data[width_begin: width_begin+4] = width.to_bytes(4, byteorder='big')
+                        changed = True
+                        break
+            if width == 0:
+                print('[x] 图片宽度修复失败')
+            
+            temp = input(f'当前宽度值为{width}，高度值为{height}，是否尝试将高度值设置为更高？可输入高度值或直接回车：')
+            if temp.isdigit():
+                height = int(temp)
+                data[height_begin: height_begin+4] = height.to_bytes(4, byteorder='big')
+                print(f'[*] 已将图片高度设置为{height}')
+                changed = True
+        return changed, data
+    
+    @staticmethod
+    def test_ihdr_chunk(chunk_data, crc):
+        crc32 = binascii.crc32(chunk_data) & 0xffffffff
+        return crc32 == crc
+    
+    @staticmethod
+    def check_data(data: bytearray):
+        return False, data, []
+
diff --git a/type/JPG.py b/type/JPG.py
new file mode 100644
index 0000000..a9247a9
--- /dev/null
+++ b/type/JPG.py
@@ -0,0 +1,99 @@
+import binascii
+
+
+class JPG:
+    extension = 'jpg'
+
+    def __init__(self):
+        pass
+
+    # 检测文件格式，返回百分比
+    @staticmethod
+    def test(data: bytearray):
+        rate = 0
+        if data.find(b'\xff\x') != -1:
+            rate = 100
+        else:
+            if data.find(b'IHDR') != -1:
+                rate = rate + 30
+            if data.find(b'IEND') != -1:
+                rate = rate + 30
+        return rate
+    
+    # 获取图片信息
+    @staticmethod
+    def get_info(data: bytearray):
+        info = {}
+        return info
+    
+    def check_tail(data: bytearray):
+        changed = False
+        tail = None
+        return changed, data, tail
+    
+    # 修复文件头
+    @staticmethod
+    def repair_sig(data: bytearray):
+        changed = False
+        head = None
+        print('[*] 检测文件头')
+        sig = b'\x89\x50\x4E\x47\x0D\x0A\x1A\x0A'
+        index = data.find(sig)
+        if index != -1:
+            print('[x] 检测到文件头前有垃圾数据，已尝试修复')
+            head = data[:index]
+            data = data[index:]
+            changed = True
+        elif data[0:8] != sig:
+            print('[x] 检测到文件头异常，已尝试修复')
+            data[0:8] = sig
+            changed = True
+        return changed, data, head
+    
+    # 修复尺寸
+    @staticmethod
+    def repair_size(data: bytearray):
+        changed = False
+        print('[*] 检测文件尺寸')
+        chunk_begin = 8
+        width_begin = chunk_begin + 8
+        height_begin = chunk_begin + 12
+        length = int.from_bytes(data[chunk_begin:chunk_begin+4], byteorder='big')
+        chunk_data = data[chunk_begin+4: chunk_begin+4+length]
+        ctype = chunk_data[0:4] # 应该为 b'\x49\x48\x44\x52'，即 b'IHDR'
+        width = int.from_bytes(chunk_data[4:8], byteorder='big')
+        height = int.from_bytes(chunk_data[8:12], byteorder='big')
+        crc = chunk_data[-4:]
+
+        if JPG.test_ihdr_chunk(chunk_data[:-4], crc):
+            print(' - 图片尺寸设置正确')
+        else:
+            if width == 0:
+                print('[x] 检测到图片宽度设置异常，尝试修复...')
+                for i in range(1, 2048):
+                    chunk_data[4:8] = i.to_bytes(4, byteorder='big')
+                    if JPG.test_ihdr_chunk(chunk_data[:-4], crc):
+                        width = i
+                        print(f'[*] 图片宽度修复成功，宽度值为{i}')
+                        data[width_begin: width_begin+4] = width.to_bytes(4, byteorder='big')
+                        changed = True
+                        break
+            if width == 0:
+                print('[x] 图片宽度修复失败')
+            
+            temp = input(f'当前宽度值为{width}，高度值为{height}，是否尝试将高度值设置为更高？可输入高度值或直接回车：')
+            if temp.isdigit():
+                height = int(temp)
+                data[height_begin: height_begin+4] = height.to_bytes(4, byteorder='big')
+                print(f'[*] 已将图片高度设置为{height}')
+                changed = True
+        return changed, data
+    
+    @staticmethod
+    def test_ihdr_chunk(chunk_data, crc):
+        crc32 = binascii.crc32(chunk_data) & 0xffffffff
+        return crc32 == crc
+
+    @staticmethod
+    def check_data(data: bytearray):
+        return False, data, []
\ No newline at end of file
diff --git a/type/PNG.py b/type/PNG.py
new file mode 100644
index 0000000..dc1cddf
--- /dev/null
+++ b/type/PNG.py
@@ -0,0 +1,238 @@
+import binascii
+import zlib
+from PIL import Image
+
+class PNG:
+    extension = 'png'
+    sig = b'\x89\x50\x4E\x47\x0D\x0A\x1A\x0A'
+
+    def __init__(self):
+        pass
+
+    # 检测文件格式，返回百分比
+    @staticmethod
+    def test(data: bytearray):
+        rate = 0
+        if data.find(PNG.sig) != -1:
+            rate = 100
+        else:
+            if data.find(b'IHDR') != -1:
+                rate = rate + 30
+            if data.find(b'IEND') != -1:
+                rate = rate + 30
+        return rate
+    
+    # 获取图片信息
+    @staticmethod
+    def get_info(data: bytearray):
+        text = b'tEXt'
+        index = data.find(text)
+        chunk_data = ''
+        if index > 32:
+            length = int.from_bytes(data[index-4: index], byteorder='big')
+            chunk_data = data[index+4: index+4+length]
+            print('[*] 图像信息：')
+            print(bytes(chunk_data).split(b'\x00'))
+
+        info = chunk_data
+        return info
+    
+    def check_tail(data: bytearray):
+        changed = False
+        tail = None
+        iend = b'\x49\x45\x4E\x44\xAE\x42\x60\x82'
+        length = len(data)
+        index = data.find(iend)
+        if index == -1:
+            index = data.find(iend[0:4])
+            if index != -1:
+                index = index + 4
+        else:
+            index = index + 8
+
+        if index == -1:
+            print('[x] 缺少png文件格式结束标识符IEND')
+        elif index < 32:
+            print('[x] 缺少png文件格式结束标识符IEND位置貌似不太对')
+        else:
+            tail = data[index:]
+            if len(tail) > 0:
+                changed = True
+                print('[x] 检测到文件尾部有垃圾数据，已尝试修复')
+
+        return changed, data, tail
+    
+    # 修复文件头
+    @staticmethod
+    def repair_sig(data: bytearray):
+        changed = False
+        head = None
+        print('[*] 检测文件头')
+        index = data.find(PNG.sig)
+        if index > 0:
+            # 如果能检测到文件头
+            print('[x] 检测到文件头前有垃圾数据，已尝试修复')
+            head = bytes(data[:index])
+            data = data[index:]
+            changed = True
+        elif data[0:8] != PNG.sig:
+            # 如果检测不到文件头，那么需要进一步确认有没有可能是被篡改或者缺失文件头，可以根据下一个chunk标记来辅助确认
+            index2 = data.find(b'IHDR')
+            if index2 != -1:
+                # 能检测到有图片尺寸信息的IHDR标记
+                if index2 == 12:
+                    # 说明文件头只是写的不对，直接替换
+                    data[0:8] = PNG.sig
+                elif index2 > 12:
+                    # 说明前面还是有垃圾数据
+                    head = bytes(data[:index2-4])
+                    data = bytearray(PNG.sig) + data[index2-4:]
+                    print('[x] 检测到文件头前有垃圾数据，已尝试修复')
+                elif index2 > 3 and index2 < 12:
+                    # 说明文件头长度不够
+                    data = bytearray(PNG.sig) + data[index2-4:]
+                print('[*] 检测到文件头异常，已尝试修复')
+                changed = True
+            else:
+                # 说明可能不是png图片了
+                print('[x] 未发现png图片特征，无法修复')
+        return changed, data, head
+    
+    # 修复尺寸
+    @staticmethod
+    def repair_size(data: bytearray):
+        changed = False
+        print('[*] 检测文件尺寸')
+        chunk_begin = 8
+        data_begin = chunk_begin + 8
+        width_begin = data_begin
+        height_begin = data_begin + 4
+        length = int.from_bytes(data[chunk_begin:chunk_begin+4], byteorder='big')
+        ctype = data[chunk_begin+4: chunk_begin+8] # 应该为 b'\x49\x48\x44\x52'，即 b'IHDR'
+        chunk_data = data[data_begin: data_begin+length]
+        width = int.from_bytes(chunk_data[0:4], byteorder='big')
+        height = int.from_bytes(chunk_data[4:8], byteorder='big')
+        crc = int.from_bytes(data[data_begin+length:data_begin+length+4], byteorder='big')
+
+        if PNG.test_ihdr_chunk(ctype + chunk_data, crc):
+            print(' - 图片尺寸设置正确')
+        else:
+            b = False
+            if not b:
+                print('[x] 尝试修复图片宽度...')
+                chunk = ctype + chunk_data
+                for i in range(1, 2048):
+                    chunk[4:8] = i.to_bytes(4, byteorder='big')
+                    if PNG.test_ihdr_chunk(bytes(chunk), crc):
+                        width = i
+                        print(f'[*] 图片宽度修复成功，宽度值为{i}')
+                        data[width_begin: width_begin+4] = width.to_bytes(4, byteorder='big')
+                        changed = True
+                        b = True
+                        break
+            if not b:
+                print('[x] 尝试修复图片高度...')
+                chunk = ctype + chunk_data
+                for i in range(1, 2048):
+                    chunk[8:12] = i.to_bytes(4, byteorder='big')
+                    if PNG.test_ihdr_chunk(chunk, crc):
+                        height = i
+                        print(f'[*] 图片高度修复成功，宽度值为{i}')
+                        data[height_begin: height_begin+4] = width.to_bytes(4, byteorder='big')
+                        changed = True
+                        b = True
+                        break
+            if not b:
+                temp = input(f'当前宽度值为{width}，高度值为{height}，是否尝试将高度值设置为更高？可输入高度值或直接回车：')
+                if temp.isdigit():
+                    height = int(temp)
+                    data[height_begin: height_begin+4] = height.to_bytes(4, byteorder='big')
+                    print(f'[*] 已将图片高度设置为{height}')
+                    changed = True
+        return changed, data, width, height
+    
+    @staticmethod
+    def test_ihdr_chunk(chunk_data, crc):
+        crc32 = binascii.crc32(chunk_data) & 0xffffffff
+        return crc32 == crc
+
+    @staticmethod
+    def check_data(data: bytearray):
+        idats = []
+        index = 0
+        print('[*] 检测IDAT数据块')
+        while True:
+            index = data.find(b'IDAT', index)
+            if index != -1:
+                length = int.from_bytes(data[index-4: index], byteorder='big')
+                data_begin = index + 4
+                idats.append((data_begin, length))
+                index = index + length + 8
+            else:
+                break
+        
+        changed = False
+        b = False
+        idat_append = []
+        for idat in idats:
+            if not b:
+                # 默认每个IDAT数据块最大为65445，如果出现一个数据块小于65445，说明数据块结束。如果后续又出现了IDAT数据块，则说明可能有异常数据
+                if idat[1] < 65445:
+                    b = True
+            else:
+                print('[x] 检测到异常IDAT数据块')
+                idat_data = data[idat[0]: idat[0]+idat[1]]
+                idat_result = binascii.hexlify(zlib.decompress(idat_data)) # 究竟是不是要这样处理有待研究
+                idat_append.append[idat_result]
+        
+        return changed, data, idat_append
+    
+    # 处理RGB三个通道
+    @staticmethod
+    def check_channels(filename: str, width: int, height: int):
+        image = Image.open(filename)
+        pixels_r = []
+        pixels_g = []
+        pixels_b = []
+        for y in range(height):
+            for x in range(width):
+                r, g, b = image.getpixel((x, y))
+                pixels_r.append(r)
+                pixels_g.append(g)
+                pixels_b.append(b)
+
+        data_r = PNG.check_channel(pixels_r, width, height, '红')
+        data_g = PNG.check_channel(pixels_g, width, height, '绿')
+        data_b = PNG.check_channel(pixels_b, width, height, '蓝')
+
+        return False, data_r, data_g, data_b 
+    
+    # 对单通道的处理方式
+    @staticmethod
+    def check_channel(channel: bytearray, width: int, height: int, channel_name):
+        data_set = set(channel)
+        value_len = len(data_set)
+
+        print('[*] 正在检测%s色通道'%channel_name)
+
+        # value_len为1说明所有像素都一样，不包含任何信息
+        if value_len == 1:
+            return False
+        
+        # value_len小于17说明有可能包含01的二进制信息，或者8、10、16进制信息
+        if value_len < 17:
+            print('[?] 通道颜色值仅有' + str(value_len) + '个值, 建议继续分析此通道信息')
+
+        # 说明应该不只是黑白信息，可能都为可打印字符
+        if value_len > 2 and value_len < 95:
+            # 提取出可打印字符
+            print_list = [chr(i) for i in channel if i > 31 and i < 127]
+            print_str = ''.join(print_list)
+            print('[?] 看看通道中这些可打印信息有没有用吧：' + print_str)
+            return print_str
+        
+        return False
+
+
+
+