f2fs: fix UAF in f2fs_available_free_memory
if2fs_fill_super -> f2fs_build_segment_manager -> create_discard_cmd_control -> f2fs_start_discard_thread It invokes kthread_run to create a thread and run issue_discard_thread. However, if f2fs_build_node_manager fails, the control flow goes to free_nm and calls f2fs_destroy_node_manager. This function will free sbi->nm_info. However, if issue_discard_thread accesses sbi->nm_info after the deallocation, but before the f2fs_stop_discard_thread, it will cause UAF(Use-after-free). -> f2fs_destroy_segment_manager -> destroy_discard_cmd_control -> f2fs_stop_discard_thread Fix this by stopping discard thread before f2fs_destroy_node_manager. Note that, the commit d6d2b491 introduces the call of f2fs_available_free_memory into issue_discard_thread. Cc: stable@vger.kernel.org Fixes: d6d2b491 ("f2fs: allow to change discard policy based on cached discard cmds") Signed-off-by:Dongliang Mu <mudongliangabcd@gmail.com> Reviewed-by:
Chao Yu <chao@kernel.org> Signed-off-by:
Jaegeuk Kim <jaegeuk@kernel.org>
parent
e3b49ea3
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