Add support for ClamAV

This commit is contained in:
Mia Herkt 2022-12-12 07:25:30 +01:00
parent da30c8f8ff
commit a904922cbd
Signed by untrusted user: mia
GPG Key ID: 72E154B8622EC191
6 changed files with 167 additions and 1 deletions

22
0x0-vscan.service Normal file
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@ -0,0 +1,22 @@
[Unit]
Description=Scan 0x0 files with ClamAV
After=remote-fs.target clamd.service
[Service]
Type=oneshot
User=nullptr
WorkingDirectory=/path/to/0x0
BindPaths=/path/to/0x0
Environment=FLASK_APP=fhost
ExecStart=/usr/bin/flask vscan
ProtectProc=noaccess
ProtectSystem=strict
ProtectHome=tmpfs
PrivateTmp=true
PrivateUsers=true
ProtectKernelLogs=true
LockPersonality=true
[Install]
WantedBy=multi-user.target

9
0x0-vscan.timer Normal file
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@ -0,0 +1,9 @@
[Unit]
Description=Scan 0x0 files with ClamAV
[Timer]
OnCalendar=hourly
Persistent=true
[Install]
WantedBy=timers.target

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@ -59,6 +59,22 @@ the following:
* `PyAV <https://github.com/PyAV-Org/PyAV>`_
Virus Scanning
--------------
0x0 can scan its files with ClamAVs daemon. As this can take a long time
for larger files, this does not happen immediately but instead every time
you run the ``vscan`` command. It is recommended to configure a systemd
timer or cronjob to do this periodically. Examples are included::
0x0-vscan.service
0x0-vscan.timer
Remember to adjust your size limits in clamd.conf!
This feature requires the `clamd module <https://pypi.org/project/clamd/>`_.
Network Security Considerations
-------------------------------

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@ -22,7 +22,7 @@
from flask import Flask, abort, make_response, redirect, request, send_from_directory, url_for, Response, render_template
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from sqlalchemy import and_
from sqlalchemy import and_, or_
from jinja2.exceptions import *
from jinja2 import ChoiceLoader, FileSystemLoader
from hashlib import sha256
@ -32,6 +32,7 @@ import click
import os
import sys
import time
import datetime
import typing
import requests
import secrets
@ -70,6 +71,13 @@ app.config.update(
FHOST_UPLOAD_BLACKLIST = None,
NSFW_DETECT = False,
NSFW_THRESHOLD = 0.608,
VSCAN_SOCKET = None,
VSCAN_QUARANTINE_PATH = "quarantine",
VSCAN_IGNORE = [
"Eicar-Test-Signature",
"PUA.Win.Packer.XmMusicFile",
],
VSCAN_INTERVAL = datetime.timedelta(days=7),
URL_ALPHABET = "DEQhd2uFteibPwq0SWBInTpA_jcZL5GKz3YCR14Ulk87Jors9vNHgfaOmMXy6Vx-",
)
@ -131,6 +139,7 @@ class File(db.Model):
expiration = db.Column(db.BigInteger)
mgmt_token = db.Column(db.String)
secret = db.Column(db.String)
last_vscan = db.Column(db.DateTime)
def __init__(self, sha256, ext, mime, addr, expiration, mgmt_token):
self.sha256 = sha256
@ -591,3 +600,56 @@ def get_max_lifespan(filesize: int) -> int:
max_exp = app.config.get("FHOST_MAX_EXPIRATION", 365 * 24 * 60 * 60 * 1000)
max_size = app.config.get("MAX_CONTENT_LENGTH", 256 * 1024 * 1024)
return min_exp + int((-max_exp + min_exp) * (filesize / max_size - 1) ** 3)
def do_vscan(f):
if f["path"].is_file():
with open(f["path"], "rb") as scanf:
try:
f["result"] = list(app.config["VSCAN_SOCKET"].instream(scanf).values())[0]
except:
f["result"] = ("SCAN FAILED", None)
else:
f["result"] = ("FILE NOT FOUND", None)
return f
@app.cli.command("vscan")
def vscan():
if not app.config["VSCAN_SOCKET"]:
print("""Error: Virus scanning enabled but no connection method specified.
Please set VSCAN_SOCKET.""")
sys.exit(1)
qp = Path(app.config["VSCAN_QUARANTINE_PATH"])
qp.mkdir(parents=True, exist_ok=True)
from multiprocessing import Pool
with Pool() as p:
if isinstance(app.config["VSCAN_INTERVAL"], datetime.timedelta):
scandate = datetime.datetime.now() - app.config["VSCAN_INTERVAL"]
res = File.query.filter(or_(File.last_vscan < scandate,
File.last_vscan == None),
File.removed == False)
else:
res = File.query.filter(File.last_vscan == None, File.removed == False)
work = [{"path" : f.getpath(), "name" : f.getname(), "id" : f.id} for f in res]
results = []
for i, r in enumerate(p.imap_unordered(do_vscan, work)):
if r["result"][0] != "OK":
print(f"{r['name']}: {r['result'][0]} {r['result'][1] or ''}")
found = False
if r["result"][0] == "FOUND":
if not r["result"][1] in app.config["VSCAN_IGNORE"]:
r["path"].rename(qp / r["name"])
found = True
results.append({
"id" : r["id"],
"last_vscan" : None if r["result"][0] == "SCAN FAILED" else datetime.datetime.now(),
"removed" : found})
db.session.bulk_update_mappings(File, results)
db.session.commit()

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@ -168,6 +168,37 @@ NSFW_DETECT = False
NSFW_THRESHOLD = 0.608
# If you want to scan files for viruses using ClamAV, specify the socket used
# for connections here. You will need the clamd module.
# Since this can take a very long time on larger files, it is not done
# immediately but every time you run the vscan command. It is recommended to
# configure a systemd timer or cronjob to do this periodically.
# Remember to adjust your size limits in clamd.conf!
#
# Example:
# from clamd import ClamdUnixSocket
# VSCAN_SOCKET = ClamdUnixSocket("/run/clamav/clamd-socket")
# This is the directory that files flagged as malicious are moved to.
# Relative paths are resolved relative to the working directory
# of the 0x0 process.
VSCAN_QUARANTINE_PATH = "quarantine"
# Since updated virus definitions might catch some files that were previously
# reported as clean, you may want to rescan old files periodically.
# Set this to a datetime.timedelta to specify the frequency, or None to
# disable rescanning.
from datetime import timedelta
VSCAN_INTERVAL = timedelta(days=7)
# Some files flagged by ClamAV are usually not malicious, especially if the
# DetectPUA option is enabled in clamd.conf. This is a list of signatures
# that will be ignored.
VSCAN_IGNORE = [
"Eicar-Test-Signature",
"PUA.Win.Packer.XmMusicFile",
]
# A list of all characters which can appear in a URL
#
# If this list is too short, then URLs can very quickly become long.

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@ -0,0 +1,26 @@
"""add date of last virus scan
Revision ID: 5cee97aab219
Revises: e2e816056589
Create Date: 2022-12-10 16:39:56.388259
"""
# revision identifiers, used by Alembic.
revision = '5cee97aab219'
down_revision = 'e2e816056589'
from alembic import op
import sqlalchemy as sa
def upgrade():
# ### commands auto generated by Alembic - please adjust! ###
op.add_column('file', sa.Column('last_vscan', sa.DateTime(), nullable=True))
# ### end Alembic commands ###
def downgrade():
# ### commands auto generated by Alembic - please adjust! ###
op.drop_column('file', 'last_vscan')
# ### end Alembic commands ###