Remove restrictions based on file extension when listing images and fix ELF header checks

gns3server/utils/images.py

@@ -45,7 +45,7 @@ def list_images(emulator_type):
 
         # We limit recursion to path outside the default images directory
         # the reason is in the default directory manage file organization and
-        # it should be flatten to keep things simple
+        # it should be flat to keep things simple
         recurse = True
         if os.path.commonprefix([directory, general_images_directory]) == general_images_directory:
             recurse = False
@@ -53,35 +53,51 @@ def list_images(emulator_type):
         directory = os.path.normpath(directory)
         for root, _, filenames in _os_walk(directory, recurse=recurse):
             for filename in filenames:
-                if filename not in files:
+                if filename in files:
+                    log.warning("File {} has already been found, skipping...".format(filename))
+                    continue
                 if filename.endswith(".md5sum") or filename.startswith("."):
                     continue
-                    elif ((filename.endswith(".image") or filename.endswith(".bin")) and emulator_type == "dynamips") \
+
-                            or ((filename.endswith(".bin") or filename.startswith("i86bi")) and emulator_type == "iou") \
-                            or (not filename.endswith(".bin") and not filename.endswith(".image") and emulator_type == "qemu"):
                 files.add(filename)
 
+                filesize = os.stat(os.path.join(root, filename)).st_size
+                if filesize < 7:
+                    log.warning("File {} is too small to be an image, skipping...".format(filename))
+                    continue
+
+                try:
+                    with open(os.path.join(root, filename), "rb") as f:
+                        # read the first 7 bytes of the file.
+                        elf_header_start = f.read(7)
+                    if emulator_type == "dynamips" and elf_header_start != b'\x7fELF\x01\x02\x01':
+                        # IOS images must start with the ELF magic number, be 32-bit, big endian and have an ELF version of 1
+                        log.warning("IOS image {} does not start with a valid ELF magic number, skipping...".format(filename))
+                        continue
+                    elif emulator_type == "iou" and elf_header_start != b'\x7fELF\x02\x01\x01' and elf_header_start != b'\x7fELF\x01\x01\x01':
+                        # IOU images must start with the ELF magic number, be 32-bit or 64-bit, little endian and have an ELF version of 1
+                        log.warning("IOU image {} does not start with a valid ELF magic number, skipping...".format(filename))
+                        continue
+                    elif emulator_type == "qemu" and elf_header_start[:4] == b'\x7fELF':
+                        # QEMU images should not start with an ELF magic number
+                        log.warning("QEMU image {} starts with an ELF magic number, skipping...".format(filename))
+                        continue
+
                     # It the image is located in the standard directory the path is relative
                     if os.path.commonprefix([root, default_directory]) != default_directory:
                         path = os.path.join(root, filename)
                     else:
                         path = os.path.relpath(os.path.join(root, filename), default_directory)
 
-                        try:
+                    images.append(
-                            if emulator_type in ["dynamips", "iou"]:
+                        {
-                                with open(os.path.join(root, filename), "rb") as f:
-                                    # read the first 7 bytes of the file.
-                                    elf_header_start = f.read(7)
-                                # valid IOU or IOS images must start with the ELF magic number, be 32-bit or 64-bit,
-                                # little endian and have an ELF version of 1
-                                if elf_header_start != b'\x7fELF\x02\x01\x01' and elf_header_start != b'\x7fELF\x01\x01\x01':
-                                    continue
-
-                            images.append({
                             "filename": filename,
                             "path": force_unix_path(path),
                             "md5sum": md5sum(os.path.join(root, filename)),
-                                "filesize": os.stat(os.path.join(root, filename)).st_size})
+                            "filesize": filesize
+                         }
+                    )
+
                 except OSError as e:
                     log.warning("Can't add image {}: {}".format(path, str(e)))
     return images

tests/utils/test_images.py

@@ -114,30 +114,49 @@ def test_remove_checksum(tmpdir):
 
 def test_list_images(tmpdir):
 
-    path1 = tmpdir / "images1" / "IOS" / "test1.image"
+    # IOS image in the images directory
-    path1.write(b'\x7fELF\x01\x01\x01', ensure=True)
+    ios_image_1 = tmpdir / "images1" / "IOS" / "ios_image_1.image"
-    path1 = force_unix_path(str(path1))
+    ios_image_1.write(b'\x7fELF\x01\x02\x01', ensure=True)
+    ios_image_1 = force_unix_path(str(ios_image_1))
 
-    path2 = tmpdir / "images2" / "test2.image"
+    # IOS image in an additional images path
-    path2.write(b'\x7fELF\x01\x01\x01', ensure=True)
+    ios_image_2 = tmpdir / "images2" / "ios_image_2.image"
-    path2 = force_unix_path(str(path2))
+    ios_image_2.write(b'\x7fELF\x01\x02\x01', ensure=True)
+    ios_image_2 = force_unix_path(str(ios_image_2))
 
-    # Invalid image because not a valid elf file
+    # Not a valid elf file
-    path = tmpdir / "images2" / "test_invalid.image"
+    not_elf_file = tmpdir / "images1" / "IOS" / "not_elf.image"
-    path.write(b'NOTANELF', ensure=True)
+    not_elf_file.write(b'NOTANELF', ensure=True)
+    not_elf_file = force_unix_path(str(not_elf_file))
+
+    # Invalid image because it is very small
+    small_file = tmpdir / "images1" / "too_small.image"
+    small_file.write(b'1', ensure=True)
 
     if sys.platform.startswith("linux"):
-        path3 = tmpdir / "images1" / "IOU" / "test3.bin"
+        # 64-bit IOU image
-        path3.write(b'\x7fELF\x02\x01\x01', ensure=True)
+        iou_image_1 = tmpdir / "images1" / "IOU" / "iou64.bin"
-        path3 = force_unix_path(str(path3))
+        iou_image_1.write(b'\x7fELF\x02\x01\x01', ensure=True)
+        iou_image_1 = force_unix_path(str(iou_image_1))
+        # 32-bit IOU image
+        iou_image_2 = tmpdir / "images1" / "IOU" / "iou32.bin"
+        iou_image_2.write(b'\x7fELF\x01\x01\x01', ensure=True) # 32-bit IOU image
+        iou_image_2 = force_unix_path(str(iou_image_2))
 
-    path4 = tmpdir / "images1" / "QEMU" / "test4.qcow2"
-    path4.write("1", ensure=True)
-    path4 = force_unix_path(str(path4))
 
-    path5 = tmpdir / "images1" / "QEMU" / "test4.qcow2.md5sum"
+    # Qemu image
-    path5.write("1", ensure=True)
+    qemu_image_1 = tmpdir / "images1" / "QEMU" / "qemu_image.qcow2"
-    path5 = force_unix_path(str(path5))
+    qemu_image_1.write("1234567", ensure=True)
+    qemu_image_1 = force_unix_path(str(qemu_image_1))
+
+    # ELF file inside the Qemu
+    elf_file = tmpdir / "images1" / "QEMU" / "elf_file.bin"
+    elf_file.write(b'\x7fELF\x02\x01\x01', ensure=True)  # ELF file
+    elf_file = force_unix_path(str(elf_file))
+
+    md5sum_file = tmpdir / "images1" / "QEMU" / "image.qcow2.md5sum"
+    md5sum_file.write("1", ensure=True)
+    md5sum_file = force_unix_path(str(md5sum_file))
 
     with patch("gns3server.config.Config.get_section_config", return_value={
             "images_path": str(tmpdir / "images1"),
@@ -146,34 +165,40 @@ def test_list_images(tmpdir):
 
         assert list_images("dynamips") == [
             {
-                'filename': 'test1.image',
+                'filename': 'ios_image_1.image',
                 'filesize': 7,
-                'md5sum': 'e573e8f5c93c6c00783f20c7a170aa6c',
+                'md5sum': 'b0d5aa897d937aced5a6b1046e8f7e2e',
-                'path': 'test1.image'
+                'path': 'ios_image_1.image'
             },
             {
-                'filename': 'test2.image',
+                'filename': 'ios_image_2.image',
                 'filesize': 7,
-                'md5sum': 'e573e8f5c93c6c00783f20c7a170aa6c',
+                'md5sum': 'b0d5aa897d937aced5a6b1046e8f7e2e',
-                'path': str(path2)
+                'path': str(ios_image_2)
             }
         ]
 
         if sys.platform.startswith("linux"):
             assert list_images("iou") == [
                 {
-                    'filename': 'test3.bin',
+                    'filename': 'iou64.bin',
                     'filesize': 7,
                     'md5sum': 'c73626d23469519894d58bc98bee9655',
-                    'path': 'test3.bin'
+                    'path': 'iou64.bin'
+                },
+                {
+                    'filename': 'iou32.bin',
+                    'filesize': 7,
+                    'md5sum': 'e573e8f5c93c6c00783f20c7a170aa6c',
+                    'path': 'iou32.bin'
                 }
             ]
 
         assert list_images("qemu") == [
             {
-                'filename': 'test4.qcow2',
+                'filename': 'qemu_image.qcow2',
-                'filesize': 1,
+                'filesize': 7,
-                'md5sum': 'c4ca4238a0b923820dcc509a6f75849b',
+                'md5sum': 'fcea920f7412b5da7be0cf42b8c93759',
-                'path': 'test4.qcow2'
+                'path': 'qemu_image.qcow2'
             }
         ]