Bug#891773: [PATCH] ieee1275: Fix crash in of_path_of_nvme when of_path is empty

[James Clarke]

On Thu, Mar 01, 2018 at 05:00:28PM +0100, John Paul Adrian Glaubitz wrote:
> The of_path_of_nvme function (commit 2391d57, ieee1275: add nvme
> support within ofpath) introduced a functional regression:
>
> On systems which are not based on Open Firmware but have at
> least one NVME device, find_obppath will return an empty path
> and appending the disk name to of_path will therefore result
> in a crash. Thus, when of_path is empty, just return the
> disk name in of_path_of_nvme.
>
> Signed-off-by: John Paul Adrian Glaubitz <glaubitz at physik.fu-berlin.de>
> ---
>  grub-core/osdep/linux/ofpath.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/grub-core/osdep/linux/ofpath.c b/grub-core/osdep/linux/ofpath.c
> index 1c30e7233..da0000f0f 100644
> --- a/grub-core/osdep/linux/ofpath.c
> +++ b/grub-core/osdep/linux/ofpath.c
> @@ -389,8 +389,13 @@ of_path_of_nvme(const char *sys_devname __attribute__((unused)),
>      }
>  
>    of_path = find_obppath (sysfs_path);
> +
> +  if(of_path)
> +    strcat (of_path, disk);
> +  else
> +    of_path = strdup(disk);
> +

Whitespace issues aside, should it not be returning NULL if of_path is
NULL, like the other users of find_obppath, such as of_path_of_scsi?
This should restore the behaviour from before of_path_of_nvme was added,
as grub_util_devname_to_ofpath would have previously returned NULL due
to the unknown type?

James

>    free (sysfs_path);
> -  strcat (of_path, disk);
>    return of_path;
>  }
>  
> -- 
> 2.16.2