From 4e240d1bab1ead280ddf5eb05058dba6bbd57d10 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Wed, 14 Nov 2018 12:40:30 -0800 Subject: f2fs: check memory boundary by insane namelen If namelen is corrupted to have very long value, fill_dentries can copy wrong memory area. Reviewed-by: Chao Yu 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 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: -- cgit v1.2.3