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authorDongliang Mu <mudongliangabcd@gmail.com>2021-11-04 16:22:01 +0800
committerJaegeuk Kim <jaegeuk@kernel.org>2021-11-09 08:23:17 -0800
commit5429c9dbc9025f9a166f64e22e3a69c94fd5b29b (patch)
tree2197c2964b98c5eea5f6d05d72c378fb6bd1b508 /fs/f2fs
parente3b49ea36802053f312013fd4ccb6e59920a9f76 (diff)
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 d6d2b491a82e1 introduces the call of f2fs_available_free_memory into issue_discard_thread. Cc: stable@vger.kernel.org Fixes: d6d2b491a82e ("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>
Diffstat (limited to 'fs/f2fs')
-rw-r--r--fs/f2fs/super.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 75f706b91ebf..60cb2ede4fdd 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4385,6 +4385,8 @@ free_node_inode:
free_stats:
f2fs_destroy_stats(sbi);
free_nm:
+ /* stop discard thread before destroying node manager */
+ f2fs_stop_discard_thread(sbi);
f2fs_destroy_node_manager(sbi);
free_sm:
f2fs_destroy_segment_manager(sbi);