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Remove restrictions based on file extension when listing images and f…
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…ix ELF header checks
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@grossmj
grossmj committed Nov 27, 2024
1 parent 83921a4 commit 3d58b43
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Showing 2 changed files with 104 additions and 63 deletions.
78 changes: 47 additions & 31 deletions gns3server/utils/images.py
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Original file line number Diff line number Diff line change
Expand Up @@ -45,45 +45,61 @@ 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

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.endswith(".md5sum") or filename.startswith("."):
if filename in files:
log.warning("File {} has already been found, skipping...".format(filename))
continue
if filename.endswith(".md5sum") or filename.startswith("."):
continue

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 ((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)

# 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:
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})
except OSError as e:
log.warning("Can't add image {}: {}".format(path, str(e)))
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)

images.append(
{
"filename": filename,
"path": force_unix_path(path),
"md5sum": md5sum(os.path.join(root, filename)),
"filesize": filesize
}
)

except OSError as e:
log.warning("Can't add image {}: {}".format(path, str(e)))
return images


Expand Down
89 changes: 57 additions & 32 deletions tests/utils/test_images.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -114,30 +114,49 @@ def test_remove_checksum(tmpdir):

def test_list_images(tmpdir):

path1 = tmpdir / "images1" / "IOS" / "test1.image"
path1.write(b'\x7fELF\x01\x01\x01', ensure=True)
path1 = force_unix_path(str(path1))

path2 = tmpdir / "images2" / "test2.image"
path2.write(b'\x7fELF\x01\x01\x01', ensure=True)
path2 = force_unix_path(str(path2))
# IOS image in the images directory
ios_image_1 = tmpdir / "images1" / "IOS" / "ios_image_1.image"
ios_image_1.write(b'\x7fELF\x01\x02\x01', ensure=True)
ios_image_1 = force_unix_path(str(ios_image_1))

# Invalid image because not a valid elf file
path = tmpdir / "images2" / "test_invalid.image"
path.write(b'NOTANELF', ensure=True)
# IOS image in an additional images path
ios_image_2 = tmpdir / "images2" / "ios_image_2.image"
ios_image_2.write(b'\x7fELF\x01\x02\x01', ensure=True)
ios_image_2 = force_unix_path(str(ios_image_2))

if sys.platform.startswith("linux"):
path3 = tmpdir / "images1" / "IOU" / "test3.bin"
path3.write(b'\x7fELF\x02\x01\x01', ensure=True)
path3 = force_unix_path(str(path3))
# Not a valid elf file
not_elf_file = tmpdir / "images1" / "IOS" / "not_elf.image"
not_elf_file.write(b'NOTANELF', ensure=True)
not_elf_file = force_unix_path(str(not_elf_file))

path4 = tmpdir / "images1" / "QEMU" / "test4.qcow2"
path4.write("1", ensure=True)
path4 = force_unix_path(str(path4))
# Invalid image because it is very small
small_file = tmpdir / "images1" / "too_small.image"
small_file.write(b'1', ensure=True)

path5 = tmpdir / "images1" / "QEMU" / "test4.qcow2.md5sum"
path5.write("1", ensure=True)
path5 = force_unix_path(str(path5))
if sys.platform.startswith("linux"):
# 64-bit IOU image
iou_image_1 = tmpdir / "images1" / "IOU" / "iou64.bin"
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))


# Qemu image
qemu_image_1 = tmpdir / "images1" / "QEMU" / "qemu_image.qcow2"
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"),
Expand All @@ -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',
'path': 'test1.image'
'md5sum': 'b0d5aa897d937aced5a6b1046e8f7e2e',
'path': 'ios_image_1.image'
},
{
'filename': 'test2.image',
'filename': 'ios_image_2.image',
'filesize': 7,
'md5sum': 'e573e8f5c93c6c00783f20c7a170aa6c',
'path': str(path2)
'md5sum': 'b0d5aa897d937aced5a6b1046e8f7e2e',
'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',
'filesize': 1,
'md5sum': 'c4ca4238a0b923820dcc509a6f75849b',
'path': 'test4.qcow2'
'filename': 'qemu_image.qcow2',
'filesize': 7,
'md5sum': 'fcea920f7412b5da7be0cf42b8c93759',
'path': 'qemu_image.qcow2'
}
]

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