From 7d9dfa1dd7f42bfb043c6090e22d0d77ff34b255 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Fri, 12 Feb 2016 14:29:28 -0800 Subject: [PATCH] f2fs: avoid garbage lenghs in dentries This patch fixes to eliminate garbage name lengths in dentries in order to provide correct answers of readdir. For example, if a valid dentry consists of: bitmap : 1 1 1 1 len : 32 0 x 0, readdir can start with second bit_pos having len = 0. Or, it can start with third bit_pos having garbage. In both of cases, we should avoid to try filling dentries. So, this patch not only removes any garbage length, but also avoid entering zero length case in readdir. Signed-off-by: Jaegeuk Kim --- 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 8950fc3cc2f7..ca41b2a77849 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -511,8 +511,12 @@ void f2fs_update_dentry(nid_t ino, umode_t mode, struct f2fs_dentry_ptr *d, memcpy(d->filename[bit_pos], name->name, name->len); de->ino = cpu_to_le32(ino); set_de_type(de, mode); - for (i = 0; i < slots; i++) + for (i = 0; i < slots; i++) { test_and_set_bit_le(bit_pos + i, (void *)d->bitmap); + /* avoid wrong garbage data for readdir */ + if (i) + (de + i)->name_len = 0; + } } /* @@ -792,6 +796,12 @@ bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d, break; de = &d->dentry[bit_pos]; + if (de->name_len == 0) { + bit_pos++; + ctx->pos = start_pos + bit_pos; + continue; + } + if (de->file_type < F2FS_FT_MAX) d_type = f2fs_filetype_table[de->file_type]; else -- 2.20.1