From 37223bec6285b788903b1d443e9e3b1dc5e2c50d Mon Sep 17 00:00:00 2001 From: zzzzzzzzzy9 Date: Tue, 1 Jul 2025 17:30:32 +0800 Subject: [PATCH] nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors commit d18b05eda7fa77f02114f15b02c009f28ee42346 upstream. The error handling in nilfs_empty_dir() when a directory folio/page read fails is incorrect, as in the old ext2 implementation, and if the folio/page cannot be read or nilfs_check_folio() fails, it will falsely determine the directory as empty and corrupt the file system. In addition, since nilfs_empty_dir() does not immediately return on a failed folio/page read, but continues to loop, this can cause a long loop with I/O if i_size of the directory's inode is also corrupted, causing the log writer thread to wait and hang, as reported by syzbot. Fix these issues by making nilfs_empty_dir() immediately return a false value (0) if it fails to get a directory folio/page. Link: https://lkml.kernel.org/r/20240604134255.7165-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi Reported-by: syzbot+c8166c541d3971bf6c87@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c8166c541d3971bf6c87 Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations") Tested-by: Ryusuke Konishi Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin Fixes: CVE-2024-39469 Signed-off-by: zzzzzzzzzy9 Reviewed-by: Huang Jian Link: https://gitee.com/anolis/embedded-kernel/pulls/971 --- fs/nilfs2/dir.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c index 54f6eff6ddac..7e6f266894d0 100644 --- a/fs/nilfs2/dir.c +++ b/fs/nilfs2/dir.c @@ -664,7 +664,7 @@ int nilfs_empty_dir(struct inode *inode) kaddr = nilfs_get_page(inode, i, &page); if (IS_ERR(kaddr)) - continue; + return 0; de = (struct nilfs_dir_entry *)kaddr; kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1); -- Gitee