Описание
In the Linux kernel, the following vulnerability has been resolved: afs: Remove setting of AS_RELEASE_ALWAYS for symlinks and mountpoints Regular AFS files correctly use afs_file_aops which have release_folio set as netfs_release_folio, so AS_RELEASE_ALWAYS is valid for them when fscache is enabled (set via afs_vnode_set_cache()). Symlinks and mountpoints in AFS use afs_dir_aops, which does not provide a release_folio callback. However, afs_apply_status() unconditionally calls mapping_set_release_always() for these. In such case when memory management code attempts to release folios, filemap_release_folio() checks folio_needs_release() which returns true due to AS_RELEASE_ALWAYS being set. Since there is no release_folio callback, it falls through to try_to_free_buffers(), which at present expects buffer_heads to be not null. For symlinks and mountpoints without buffer_heads, this causes pointer dereference. [dh: Added more bits that were missed]
Пакеты
| Пакет | Статус | Версия исправления | Релиз | Тип |
|---|---|---|---|---|
| linux | fixed | 7.1.5-1 | package | |
| linux | not-affected | trixie | package | |
| linux | not-affected | bookworm | package | |
| linux | not-affected | bullseye | package |
Примечания
https://git.kernel.org/linus/81e985b4c3a6cbcc443fcdcd3ebda7fcc845d459 (7.2-rc2)
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: afs: Remove setting of AS_RELEASE_ALWAYS for symlinks and mountpoints Regular AFS files correctly use afs_file_aops which have release_folio set as netfs_release_folio, so AS_RELEASE_ALWAYS is valid for them when fscache is enabled (set via afs_vnode_set_cache()). Symlinks and mountpoints in AFS use afs_dir_aops, which does not provide a release_folio callback. However, afs_apply_status() unconditionally calls mapping_set_release_always() for these. In such case when memory management code attempts to release folios, filemap_release_folio() checks folio_needs_release() which returns true due to AS_RELEASE_ALWAYS being set. Since there is no release_folio callback, it falls through to try_to_free_buffers(), which at present expects buffer_heads to be not null. For symlinks and mountpoints without buffer_heads, this causes pointer dereference. [dh: Added more bits that were missed]
In the Linux kernel, the following vulnerability has been resolved: afs: Remove setting of AS_RELEASE_ALWAYS for symlinks and mountpoints Regular AFS files correctly use afs_file_aops which have release_folio set as netfs_release_folio, so AS_RELEASE_ALWAYS is valid for them when fscache is enabled (set via afs_vnode_set_cache()). Symlinks and mountpoints in AFS use afs_dir_aops, which does not provide a release_folio callback. However, afs_apply_status() unconditionally calls mapping_set_release_always() for these. In such case when memory management code attempts to release folios, filemap_release_folio() checks folio_needs_release() which returns true due to AS_RELEASE_ALWAYS being set. Since there is no release_folio callback, it falls through to try_to_free_buffers(), which at present expects buffer_heads to be not null. For symlinks and mountpoints without buffer_heads, this causes pointer dereference. [dh: Added more bits that were missed]
In the Linux kernel, the following vulnerability has been resolved: afs: Remove setting of AS_RELEASE_ALWAYS for symlinks and mountpoints Regular AFS files correctly use afs_file_aops which have release_folio set as netfs_release_folio, so AS_RELEASE_ALWAYS is valid for them when fscache is enabled (set via afs_vnode_set_cache()). Symlinks and mountpoints in AFS use afs_dir_aops, which does not provide a release_folio callback. However, afs_apply_status() unconditionally calls mapping_set_release_always() for these. In such case when memory management code attempts to release folios, filemap_release_folio() checks folio_needs_release() which returns true due to AS_RELEASE_ALWAYS being set. Since there is no release_folio callback, it falls through to try_to_free_buffers(), which at present expects buffer_heads to be not null. For symlinks and mountpoints without buffer_heads, this causes pointer dereference. [dh: Added more bits that were missed]
In the Linux kernel, the following vulnerability has been resolved: afs: Remove setting of AS_RELEASE_ALWAYS for symlinks and mountpoints Regular AFS files correctly use afs_file_aops which have release_folio set as netfs_release_folio, so AS_RELEASE_ALWAYS is valid for them when fscache is enabled (set via afs_vnode_set_cache()). Symlinks and mountpoints in AFS use afs_dir_aops, which does not provide a release_folio callback. However, afs_apply_status() unconditionally calls mapping_set_release_always() for these. In such case when memory management code attempts to release folios, filemap_release_folio() checks folio_needs_release() which returns true due to AS_RELEASE_ALWAYS being set. Since there is no release_folio callback, it falls through to try_to_free_buffers(), which at present expects buffer_heads to be not null. For symlinks and mountpoints without buffer_heads, this causes pointer dereference. [dh: Added more bits that were missed]