Re: [PATCH 1/2] pstore: fix NULL pointer fault if get NULL prz in ramoops_get_next_prz

[Kees Cook]

On Mon, Mar 10, 2014 at 11:15 PM, Liu ShuoX <shuox.liu@xxxxxxxxx> wrote:
> These two patches are applied on top of patches:
> https://lkml.org/lkml/2014/3/3/368
> It has been added in -mm tree. Below is the first patch, and i will
> send the second by replying this one.
>
> From: Liu ShuoX <shuox.liu@xxxxxxxxx>
>
> ramoops_get_next_prz get the prz according the paramters. If it get a
> uninitialized prz, access its members by following
> persistent_ram_old_size(prz)
> will cause a NULL pointer crash.
> Ex: if ftrace_size is 0, fprz will be NULL.
>
> Fix it by return NULL in advance.
>
> Signed-off-by: Liu ShuoX <shuox.liu@xxxxxxxxx>

Thanks!

Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>

-Kees

> ---
>  fs/pstore/ram.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> index 1daed28..6f96d8c 100644
> --- a/fs/pstore/ram.c
> +++ b/fs/pstore/ram.c
> @@ -119,6 +119,8 @@ ramoops_get_next_prz(struct persistent_ram_zone *przs[],
> uint *c, uint max,
>                 return NULL;
>         prz = przs[i];
> +       if (!prz)
> +               return NULL;
>         /* Update old/shadowed buffer. */
>         if (update)
> --
> 1.8.3.2



-- 
Kees Cook
Chrome OS Security
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