feat: security response headers

backend/open_webui/main.py

@@ -109,6 +109,7 @@ from starlette.middleware.base import BaseHTTPMiddleware
 from starlette.middleware.sessions import SessionMiddleware
 from starlette.responses import RedirectResponse, Response, StreamingResponse
 
+from open_webui.utils.security_headers import SecurityHeadersMiddleware
 
 from open_webui.utils.misc import (
     add_or_update_system_message,
@@ -789,6 +790,8 @@ app.add_middleware(
     allow_headers=["*"],
 )
 
+app.add_middleware(SecurityHeadersMiddleware)
+
 
 @app.middleware("http")
 async def commit_session_after_request(request: Request, call_next):

backend/open_webui/utils/security_headers.py

@@ -0,0 +1,119 @@
+import re
+import os
+
+from fastapi import Request
+from starlette.middleware.base import BaseHTTPMiddleware
+from typing import Dict
+
+class SecurityHeadersMiddleware(BaseHTTPMiddleware):
+    async def dispatch(self, request: Request, call_next):
+        response = await call_next(request)
+        response.headers.update(set_security_headers())
+        return response
+
+def set_security_headers() -> Dict[str, str]:
+    """
+    Sets security headers based on environment variables.
+
+    This function reads specific environment variables and uses their values
+    to set corresponding security headers. The headers that can be set are:
+    - cache-control
+    - strict-transport-security
+    - referrer-policy
+    - x-content-type-options
+    - x-download-options
+    - x-frame-options
+
+    Each environment variable is associated with a specific setter function
+    that constructs the header. If the environment variable is set, the
+    corresponding header is added to the options dictionary.
+
+    Returns:
+        dict: A dictionary containing the security headers and their values.
+    """
+    options = {}
+    header_setters = {
+        'CACHE_CONTROL': set_cache_control,
+        'HSTS': set_hsts,
+        'REFERRER_POLICY': set_referrer,
+        'XCONTENT_TYPE': set_xcontent_type,
+        'XDOWNLOAD_OPTIONS': set_xdownload_options,
+        'XFRAME_OPTIONS': set_xframe,
+        'XPERMITTED_CROSS_DOMAIN_POLICIES': set_xpermitted_cross_domain_policies,
+    }
+
+    for env_var, setter in header_setters.items():
+        value = os.environ.get(env_var, None)
+        if value:
+            header = setter(value)
+            if header:
+                options.update(header)
+
+    return options
+
+# Set HTTP Strict Transport Security(HSTS) response header
+def set_hsts(value: str):
+    pattern = r'^max-age=(\d+)(;includeSubDomains)?(;preload)?$'
+    match = re.match(pattern, value, re.IGNORECASE)
+    if not match:
+        return 'max-age=31536000;includeSubDomains'
+    return {
+        'Strict-Transport-Security': value
+    }
+
+# Set X-Frame-Options response header
+def set_xframe(value: str):
+    pattern = r'^(DENY|SAMEORIGIN)$'
+    match = re.match(pattern, value, re.IGNORECASE)
+    if not match:
+        value = 'DENY'
+    return {
+        "X-Frame-Options": value
+    }
+
+# Set Referrer-Policy response header
+def set_referrer(value: str):
+    pattern = r'^(no-referrer|no-referrer-when-downgrade|origin|origin-when-cross-origin|same-origin|strict-origin|strict-origin-when-cross-origin|unsafe-url)$'
+    match = re.match(pattern, value, re.IGNORECASE)
+    if not match:
+        value = 'no-referrer'
+    return {
+        'Referrer-Policy': value
+    }
+
+# Set Cache-Control response header
+def set_cache_control(value: str):
+    pattern = r'^(public|private|no-cache|no-store|must-revalidate|proxy-revalidate|max-age=\d+|s-maxage=\d+|no-transform|immutable)(,\s*(public|private|no-cache|no-store|must-revalidate|proxy-revalidate|max-age=\d+|s-maxage=\d+|no-transform|immutable))*$'
+    match = re.match(pattern, value, re.IGNORECASE)
+    if not match:
+        value = 'no-store, max-age=0'
+
+    return {
+        'Cache-Control': value
+    }
+
+# Set X-Download-Options response header
+def set_xdownload_options(value: str):
+    if value != 'noopen':
+        value = 'noopen'
+    return {
+        'X-Download-Options': value
+    }
+
+# Set X-Content-Type-Options response header
+def set_xcontent_type(value: str):
+    if value != 'nosniff':
+        value = 'nosniff'
+    return {
+        'X-Content-Type-Options': value
+    }
+
+# Set X-Permitted-Cross-Domain-Policies response header
+def set_xpermitted_cross_domain_policies(value: str):
+    pattern = r'^(none|master-only|by-content-type|by-ftp-filename)$'
+    match = re.match(pattern, value, re.IGNORECASE)
+    if not match:
+        value = 'none'
+    return {
+        'X-Permitted-Cross-Domain-Policies': value
+    }