[FIX] snailmail: accurate error message when no access to the attachment

This revision follows
- odoo/odoo@5e81850ea64b533f0576c919a427820554096284
- odoo/enterprise@e484b4da0c8b70225e91cc66b64ac1b3a0bcc685

addons/snailmail/models/snailmail_letter.py

@@ -114,8 +114,15 @@ class SnailmailLetter(models.Model):
             'notification_status': 'ready',
         })
 
+        letter.attachment_id.check('read')
         return letter
 
+    def write(self, vals):
+        res = super().write(vals)
+        if 'attachment_id' in vals:
+            self.attachment_id.check('read')
+        return res
+
     def _fetch_attachment(self):
         """
         This method will check if we have any existent attachement matching the model

addons/snailmail/tests/__init__.py

+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from . import test_attachment_access

addons/snailmail/tests/test_attachment_access.py

+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+import base64
+
+from odoo.exceptions import AccessError
+from odoo.tests import SavepointCase
+
+
+class testAttachmentAccess(SavepointCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.user = cls.env['res.users'].create({
+            'name': "foo",
+            'login': "foo",
+            'email': "foo@bar.com",
+            'groups_id': [(6, 0, [
+                cls.env.ref('base.group_user').id,
+                cls.env.ref('base.group_partner_manager').id,
+            ])]
+        })
+        cls.letter_defaults = {
+            'model': cls.user.partner_id._name,
+            'res_id': cls.user.partner_id.id,
+            'partner_id': cls.user.partner_id.id,
+        }
+
+    def test_user_letter_attachment_without_res_fields(self):
+        """Test an employee can create a letter linked to an attachment without res_model/res_id"""
+        env_user = self.env(user=self.user)
+        # As user, create an attachment without res_model/res_id
+        attachment = env_user['ir.attachment'].create({'name': 'foo', 'datas': base64.b64encode(b'foo')})
+        # As user, create a snailmail.letter linked to that attachment
+        letter = env_user['snailmail.letter'].create({'attachment_id': attachment.id, **self.letter_defaults})
+        # As user, ensure the content of the attachment can be read through the letter
+        self.assertEqual(base64.b64decode(letter.attachment_datas), b'foo')
+        # As user, create another attachment without res_model/res_id
+        attachment_2 = env_user['ir.attachment'].create({'name': 'foo', 'datas': base64.b64encode(b'bar')})
+        # As user, change the attachment of the letter to this second attachment
+        letter.write({'attachment_id': attachment_2.id})
+        # As user, ensure the content of this second attachment can be read through the letter
+        self.assertEqual(base64.b64decode(letter.attachment_datas), b'bar')
+
+    def test_user_letter_attachment_without_res_fields_created_by_admin(self):
+        """Test an employee can read the content of the letter's attachment created by another user, the admin,
+        and the attachment does not have a res_model/res_id
+        """
+        # As admin, create an attachment without res_model/res_id
+        attachment = self.env['ir.attachment'].create({'name': 'foo', 'datas': base64.b64encode(b'foo')})
+        # As admin, create a snailmail.letter linked to that attachment
+        letter = self.env['snailmail.letter'].create({'attachment_id': attachment.id, **self.letter_defaults})
+
+        # As user, ensure the attachment itself cannot be read
+        attachment.invalidate_cache()
+        with self.assertRaises(AccessError):
+            attachment.with_user(self.user).datas
+        # But, as user, the content of the attachment can be read through the letter
+        self.assertEqual(base64.b64decode(letter.with_user(self.user).attachment_datas), b'foo')
+
+        # As admin, create a second attachment without res_model/res_id
+        attachment = self.env['ir.attachment'].create({'name': 'bar', 'datas': base64.b64encode(b'bar')})
+        # As admin, link this second attachment to the previously created letter (write instead of create)
+        letter.write({'attachment_id': attachment.id})
+
+        # As user ensure the attachment itself cannot be read
+        attachment.invalidate_cache()
+        with self.assertRaises(AccessError):
+            self.assertEqual(base64.b64decode(attachment.with_user(self.user).datas), b'bar')
+        # But, as user, the content of the attachment can be read through the letter
+        self.assertEqual(base64.b64decode(letter.with_user(self.user).attachment_datas), b'bar')
+
+    def test_user_read_unallowed_attachment(self):
+        """Test a user cannot access an attachment he is not supposed to through a snailmail.letter"""
+        # As admin, create an attachment for which you require the settings group to access
+        base_module = self.env.ref('base.module_base')
+        attachment_forbidden = self.env['ir.attachment'].create({
+            'name': 'foo', 'datas': base64.b64encode(b'foo'),
+            'res_model': base_module._name, 'res_id': base_module.id,
+        })
+        # As user, make sure this is indeed not possible to access that attachment data directly
+        attachment_forbidden.invalidate_cache()
+        with self.assertRaises(AccessError):
+            attachment_forbidden.with_user(self.user).datas
+        # As user, create a letter pointing to that attachment
+        # and make sure it raises an access error
+        with self.assertRaises(AccessError):
+            letter = self.env['snailmail.letter'].with_user(self.user).create({
+                'attachment_id': attachment_forbidden.id,
+                **self.letter_defaults,
+            })
+            letter.attachment_datas
+
+        # As user, update the attachment of an existing letter to the unallowed attachment
+        # and make sure it raises an access error
+        attachment_tmp = self.env['ir.attachment'].with_user(self.user).create({
+            'name': 'bar', 'datas': base64.b64encode(b'bar'),
+        })
+        letter = self.env['snailmail.letter'].with_user(self.user).create({
+            'attachment_id': attachment_tmp.id,
+            **self.letter_defaults,
+        })
+        with self.assertRaises(AccessError):
+            letter.write({'attachment_id': attachment_forbidden.id})
+            letter.attachment_datas