Re: [PATCH 3/4] fs/hfsplus: Set grub errno to prevent NULL pointer access

[Vladimir 'phcoder' Serbinenko]

On Thu, Apr 20, 2023 at 8:00 PM Lidong Chen <lidong.chen@oracle.com> wrote:
>
> When an invalid node size is detected in grub_hfsplus_mount(), data pinter
> is freed. Thus, file->data is not set. The code should also set the
> grub error when that happens to indicate an error and to avoid accessing
> the unintialized file->data in grub_file_close().
file->data is set to NULL in grub_file_open as part of zalloc. What
sets it to something else?
>
> Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
> ---
>  grub-core/fs/hfsplus.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/grub-core/fs/hfsplus.c b/grub-core/fs/hfsplus.c
> index 9c1f12574..cf13e8a63 100644
> --- a/grub-core/fs/hfsplus.c
> +++ b/grub-core/fs/hfsplus.c
> @@ -357,7 +357,10 @@ grub_hfsplus_mount (grub_disk_t disk)
>                           (header.key_compare == 
> GRUB_HFSPLUSX_BINARYCOMPARE));
>
>    if (data->catalog_tree.nodesize < 2)
> -    goto fail;
> +    {
> +      grub_error (GRUB_ERR_BAD_FS, "invalid catalog node size");
> +      goto fail;
> +    }
>
>    if (grub_hfsplus_read_file (&data->extoverflow_tree.file, 0, 0,
>                               sizeof (struct grub_hfsplus_btnode),
> @@ -374,7 +377,10 @@ grub_hfsplus_mount (grub_disk_t disk)
>    data->extoverflow_tree.nodesize = grub_be_to_cpu16 (header.nodesize);
>
>    if (data->extoverflow_tree.nodesize < 2)
> -    goto fail;
> +    {
> +      grub_error (GRUB_ERR_BAD_FS, "invalid extents overflow node size");
> +      goto fail;
> +    }
>
>    data->extoverflow_tree_ready = 1;
>
> --
> 2.39.1
>
>
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-- 
Regards
Vladimir 'phcoder' Serbinenko