On 11/23, Sheng Yong wrote:
> Hi, Jaegeuk and Chao,
>
> On 2018/11/15 15:50, Jaegeuk Kim wrote:
> > If namelen is corrupted to have very long value, fill_dentries can copy
> > wrong memory area.
> >
> Is there any scenario that could hit this corruption? Or this is triggered
> by fuzzing injection?
Hi Sheng,
It's from a fuzzing test.
Thanks,
>
> thanks,
> Sheng Yong
>
> > Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
> > ---
> > fs/f2fs/dir.c | 12 +++++++++++-
> > 1 file changed, 11 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
> > index bacc667950b6..c0c845da12fa 100644
> > --- a/fs/f2fs/dir.c
> > +++ b/fs/f2fs/dir.c
> > @@ -808,6 +808,17 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct
> > f2fs_dentry_ptr *d,
> > de_name.name = d->filename[bit_pos];
> > de_name.len = le16_to_cpu(de->name_len);
> > + /* check memory boundary before moving forward */
> > + bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
> > + if (unlikely(bit_pos > d->max)) {
> > + f2fs_msg(sbi->sb, KERN_WARNING,
> > + "%s: corrupted namelen=%d, run fsck to fix.",
> > + __func__, le16_to_cpu(de->name_len));
> > + set_sbi_flag(sbi, SBI_NEED_FSCK);
> > + err = -EINVAL;
> > + goto out;
> > + }
> > +
> > if (f2fs_encrypted_inode(d->inode)) {
> > int save_len = fstr->len;
> > @@ -830,7 +841,6 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct
> > f2fs_dentry_ptr *d,
> > if (readdir_ra)
> > f2fs_ra_node_page(sbi, le32_to_cpu(de->ino));
> > - bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
> > ctx->pos = start_pos + bit_pos;
> > }
> > out:
> >
