Описание
In the Linux kernel, the following vulnerability has been resolved: ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size smb_check_perm_dacl() validates that the DACL fits inside the NT security descriptor, but then bounds its two ACE walks by the remaining NTSD length (acl_size) rather than the DACL's declared size (pdacl_size). When pdacl->size is smaller than the trailing NTSD buffer, bytes after the declared DACL boundary - still inside the stored security descriptor - are parsed as ACEs during access checks. A crafted DACL can place an access-granting ACE beyond pdacl->size, and the current code accepts it during SMB2_CREATE access validation, while parse_dacl() and smb_inherit_dacl() stop at pdacl_size. Bound both ACE walks by pdacl_size to match the DACL boundary semantics used elsewhere in the server. Validation: - semantic KUnit harness shows the post-boundary ACE is selected before the fix and rejected (EACCES) after it - linux master (7.2-rc6), x86_64
Пакеты
| Пакет | Статус | Версия исправления | Релиз | Тип |
|---|---|---|---|---|
| linux | fixed | 7.2.6-1 | package |
Примечания
https://git.kernel.org/linus/79decd88dd3f0d42e7fb0689b1a7853bfa302459 (7.3-rc1)
Связанные уязвимости
(In the Linux kernel, the following vulnerability has been resolved: k ...)
In the Linux kernel, the following vulnerability has been resolved: ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size smb_check_perm_dacl() validates that the DACL fits inside the NT security descriptor, but then bounds its two ACE walks by the remaining NTSD length (acl_size) rather than the DACL's declared size (pdacl_size). When pdacl->size is smaller than the trailing NTSD buffer, bytes after the declared DACL boundary - still inside the stored security descriptor - are parsed as ACEs during access checks. A crafted DACL can place an access-granting ACE beyond pdacl->size, and the current code accepts it during SMB2_CREATE access validation, while parse_dacl() and smb_inherit_dacl() stop at pdacl_size. Bound both ACE walks by pdacl_size to match the DACL boundary semantics used elsewhere in the server. Validation: - semantic KUnit harness shows the post-boundary ACE is selected before the fix and rejected (EACCES) after it - linux master (7.2-rc6), x86_64
In the Linux kernel, the following vulnerability has been resolved: ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size smb_check_perm_dacl() validates that the DACL fits inside the NT security descriptor, but then bounds its two ACE walks by the remaining NTSD length (acl_size) rather than the DACL's declared size (pdacl_size). When pdacl->size is smaller than the trailing NTSD buffer, bytes after the declared DACL boundary - still inside the stored security descriptor - are parsed as ACEs during access checks. A crafted DACL can place an access-granting ACE beyond pdacl->size, and the current code accepts it during SMB2_CREATE access validation, while parse_dacl() and smb_inherit_dacl() stop at pdacl_size. Bound both ACE walks by pdacl_size to match the DACL boundary semantics used elsewhere in the server. Validation: - semantic KUnit harness shows the post-boundary ACE is selected before the fix and rejected (EACCES) after it - linux master (7.2-rc6), x86_64