From 74261e72c383a83882dbe87b10cac4e19e7aeae3 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Wed, 19 Oct 2016 12:43:07 +0200 Subject: [PATCH] ubifs: Abort readdir upon error commit c83ed4c9dbb358b9e7707486e167e940d48bfeed upstream. If UBIFS is facing an error while walking a directory, it reports this error and ubifs_readdir() returns the error code. But the VFS readdir logic does not make the getdents system call fail in all cases. When the readdir cursor indicates that more entries are present, the system call will just return and the libc wrapper will try again since it also knows that more entries are present. This causes the libc wrapper to busy loop for ever when a directory is corrupted on UBIFS. A common approach do deal with corrupted directory entries is skipping them by setting the cursor to the next entry. On UBIFS this approach is not possible since we cannot compute the next directory entry cursor position without reading the current entry. So all we can do is setting the cursor to the "no more entries" position and make getdents exit. Signed-off-by: Richard Weinberger [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- fs/ubifs/dir.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index aaebf0f21ab5..ca4eb9427bdc 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -356,7 +356,7 @@ static unsigned int vfs_dent_type(uint8_t type) */ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir) { - int err, over = 0; + int err = 0, over = 0; loff_t pos = file->f_pos; struct qstr nm; union ubifs_key key; @@ -475,16 +475,14 @@ static int ubifs_readdir(struct file *file, void *dirent, filldir_t filldir) } out: - if (err != -ENOENT) { + if (err != -ENOENT) ubifs_err("cannot find next direntry, error %d", err); - return err; - } kfree(file->private_data); file->private_data = NULL; /* 2 is a special value indicating that there are no more direntries */ file->f_pos = 2; - return 0; + return err; } static loff_t ubifs_dir_llseek(struct file *file, loff_t offset, int origin) -- 2.39.2