Re: [PATCH] btrfs: fix uninitialized pointer free on add_inode_ref

[Filipe Manana]

On Wed, Oct 9, 2024 at 9:17 AM Roi Martin <jroi.martin@xxxxxxxxx> wrote:
>
> The "add_inode_ref" function does not initializes the "name" struct
> when it is declared.  If any of the following calls to
> "read_one_inode" returns NULL,
>
>         dir = read_one_inode(root, parent_objectid);
>         if (!dir) {
>                 ret = -ENOENT;
>                 goto out;
>         }
>
>         inode = read_one_inode(root, inode_objectid);
>         if (!inode) {
>                 ret = -EIO;
>                 goto out;
>         }
>
> then "name.name" would be freed on "out" before being initialized.
>
> out:
>         ...
>         kfree(name.name);
>
> This issue was reported by Coverity with CID 1526744.
>
> Signed-off-by: Roi Martin <jroi.martin@xxxxxxxxx>

Fixes: e43eec81c5167b65 ("btrfs: use struct qstr instead of name and
namelen pairs")

Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx>

Looks good, thanks.

> ---
>  fs/btrfs/tree-log.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index e2ed2a791f8f..35c452bab1ca 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -1374,7 +1374,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
>         struct inode *inode = NULL;
>         unsigned long ref_ptr;
>         unsigned long ref_end;
> -       struct fscrypt_str name;
> +       struct fscrypt_str name = { 0 };
>         int ret;
>         int log_ref_ver = 0;
>         u64 parent_objectid;
>
> base-commit: 75b607fab38d149f232f01eae5e6392b394dd659
> --
> 2.46.0
>
>