On 6/15/26 15:19, Zhang Cen wrote: > f2fs_acl_count() only validates the aggregate ACL xattr length. A > malformed ACL can still place ACL_USER or ACL_GROUP in a slot that only > contains struct f2fs_acl_entry_short bytes, and f2fs_acl_from_disk() > then reads entry->e_id before verifying that a full entry fits. > > Require a short entry before reading e_tag and e_perm, and require a > full entry before reading e_id for ACL_USER and ACL_GROUP. Return > -EFSCORRUPTED from these new truncated-entry checks, while keeping the > pre-existing -EINVAL paths unchanged. > > Validation reproduced this kernel report: > KASAN slab-out-of-bounds in __f2fs_get_acl+0x6fb/0x7e0 > RIP: 0033:0x7f4b835ea7aa > The buggy address belongs to the object at ffff888114589960 which belongs > to the cache kmalloc-8 of size 8 > The buggy address is located 0 bytes to the right of allocated 8-byte > region [ffff888114589960, ffff888114589968) > Read of size 4 > Call trace: > dump_stack_lvl+0x66/0xa0 (?:?) > print_report+0xce/0x630 (?:?) > __f2fs_get_acl+0x6fb/0x7e0 (fs/f2fs/acl.c:169) > srso_alias_return_thunk+0x5/0xfbef5 (?:?) > __virt_addr_valid+0x224/0x430 (?:?) > kasan_report+0xe0/0x110 (?:?) > __f2fs_get_acl+0x5/0x7e0 (fs/f2fs/acl.c:169) > __get_acl+0x281/0x380 (?:?) > vfs_get_acl+0x10b/0x190 (?:?) > do_get_acl+0x2a/0x410 (?:?) > do_get_acl+0x9/0x410 (?:?) > do_getxattr+0xe8/0x260 (?:?) > filename_getxattr+0xd1/0x140 (?:?) > do_getname+0x2d/0x2d0 (?:?) > path_getxattrat+0x16c/0x200 (?:?) > lock_release+0xc8/0x290 (?:?) > cgroup_update_frozen+0x9d/0x320 (?:?) > lockdep_hardirqs_on_prepare+0xea/0x1a0 (?:?) > trace_hardirqs_on+0x1a/0x170 (?:?) > _raw_spin_unlock_irq+0x28/0x50 (?:?) > do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87) > entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?) >
Cc: [email protected] > Fixes: af48b85b8cd3 ("f2fs: add xattr and acl functionalities") > Assisted-by: Codex:gpt-5.5 > Signed-off-by: Zhang Cen <[email protected]> Reviewed-by: Chao Yu <[email protected]> Thanks, _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
