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fix: Safe decode base64 data in case of incorrect padding

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This could possibly happen in case of corrupted/partial files. But for
the most part, if there's a missing trailing = or three at the end too.

Traceback:
Traceback (most recent call last):
  File "/home/frappe/frappe-bench/apps/frappe/frappe/app.py", line 68, in application
    response = frappe.api.handle()
  File "/home/frappe/frappe-bench/apps/frappe/frappe/api.py", line 55, in handle
    return frappe.handler.handle()
  File "/home/frappe/frappe-bench/apps/frappe/frappe/handler.py", line 31, in handle
    data = execute_cmd(cmd)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/handler.py", line 67, in execute_cmd
    return frappe.call(method, **frappe.form_dict)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/__init__.py", line 1208, in call
    return fn(*args, **newargs)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/desk/form/save.py", line 21, in savedocs
    doc.save()
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 285, in save
    return self._save(*args, **kwargs)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 307, in _save
    self.insert()
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 239, in insert
    self._validate()
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 499, in _validate
    self._extract_images_from_text_editor()
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/base_document.py", line 983, in _extract_images_from_text_editor
    extract_images_from_doc(self, df.fieldname)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/file/file.py", line 779, in extract_images_from_doc
    content = extract_images_from_html(doc, content)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/file/file.py", line 822, in extract_images_from_html
    content = re.sub(r']*src\s*=\s*["\'](?=data:)(.*?)["\']', _save_file, content)
  File "/home/frappe/frappe-bench/env/lib/python3.6/re.py", line 191, in sub
    return _compile(pattern, flags).sub(repl, string, count)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/file/file.py", line 814, in _save_file
    _file.save(ignore_permissions=True)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 285, in save
    return self._save(*args, **kwargs)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 307, in _save
    self.insert()
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 231, in insert
    self.run_method("before_insert")
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 860, in run_method
    out = Document.hook(fn)(self, *args, **kwargs)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 1158, in composer
    return composed(self, method, *args, **kwargs)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 1141, in runner
    add_to_return_value(self, fn(self, *args, **kwargs))
  File "/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py", line 854, in
    fn = lambda self, *args, **kwargs: getattr(self, method)(*args, **kwargs)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/file/file.py", line 56, in before_insert
    self.save_file(content=self.content, decode=self.decode)
  File "/home/frappe/frappe-bench/apps/frappe/frappe/core/doctype/file/file.py", line 436, in save_file
    self.content = base64.b64decode(self.content)
  File "/home/frappe/frappe-bench/env/lib/python3.6/base64.py", line 87, in b64decode
    return binascii.a2b_base64(s)
binascii.Error: Incorrect padding
This commit is contained in:
Gavin D'souza 2021-12-21 14:57:09 +05:30
parent df0ac2e666
commit b56e6fe4db
2 changed files with 20 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
frappe/core/doctype/file/file.py
View file

@ -29,6 +29,7 @@ from frappe import _, conf, safe_decode
from frappe.model.document import Document
from frappe.utils import call_hook_method, cint, cstr, encode, get_files_path, get_hook_method, random_string, strip
from frappe.utils.image import strip_exif_data, optimize_image
from frappe.utils.file_manager import safe_b64decode
class MaxFileSizeReachedError(frappe.ValidationError):
pass
@ -436,7 +437,7 @@ class File(Document):
if b"," in self.content:
self.content = self.content.split(b",")[1]
self.content = base64.b64decode(self.content)
self.content = safe_b64decode(self.content)
if not self.is_private:
self.is_private = 0
@ -852,7 +853,7 @@ def extract_images_from_html(doc, content, is_private=False):
content = content.encode("utf-8")
if b"," in content:
content = content.split(b",")[1]
content = base64.b64decode(content)
content = safe_b64decode(content)
content = optimize_image(content, mtype)

20
frappe/utils/file_manager.py
View file

@ -1,4 +1,4 @@
# Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
# Copyright (c) 2021, Frappe Technologies Pvt. Ltd. and Contributors
# License: MIT. See LICENSE
import frappe
@ -17,6 +17,20 @@ class MaxFileSizeReachedError(frappe.ValidationError):
pass
def safe_b64decode(binary: bytes) -> bytes:
"""Adds padding if doesn't already exist before decoding.
This attempts to avoid the `binascii.Error: Incorrect padding` error raised
when the number of trailing = is simply not enough :crie:. Although, it may
be an indication of corrupted data.
Refs:
* https://en.wikipedia.org/wiki/Base64
* https://stackoverflow.com/questions/2941995/python-ignore-incorrect-padding-error-when-base64-decoding
"""
return base64.b64decode(binary + b"===")
def get_file_url(file_data_name):
data = frappe.db.get_value("File", file_data_name, ["file_name", "file_url"], as_dict=True)
return data.file_url or data.file_name
@ -112,7 +126,7 @@ def get_uploaded_content():
if 'filedata' in frappe.form_dict:
if "," in frappe.form_dict.filedata:
frappe.form_dict.filedata = frappe.form_dict.filedata.rsplit(",", 1)[1]
frappe.uploaded_content = base64.b64decode(frappe.form_dict.filedata)
frappe.uploaded_content = safe_b64decode(frappe.form_dict.filedata)
frappe.uploaded_filename = frappe.form_dict.filename
return frappe.uploaded_filename, frappe.uploaded_content
else:
@ -126,7 +140,7 @@ def save_file(fname, content, dt, dn, folder=None, decode=False, is_private=0, d
if b"," in content:
content = content.split(b",")[1]
content = base64.b64decode(content)
content = safe_b64decode(content)
file_size = check_max_file_size(content)
content_hash = get_content_hash(content)