On Fri, Aug 08, 2014 at 12:53:16AM -0700, Kees Cook wrote:
> To avoid potential format string expansion via module parameters,
> do not use the zpool type directly in request_module() without a
> format string. Additionally, to avoid arbitrary modules being loaded
> via zpool API (e.g. via the zswap_zpool_type module parameter) add a
> "zpool-" prefix to the requested module, as well as module aliases for
> the existing zpool types (zbud and zsmalloc).
I didn't know that request_module() did string expansion.
Thanks for the fix!
Acked-by: Seth Jennings <sjennings@xxxxxxxxxxxxxx>
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
> mm/zbud.c | 1 +
> mm/zpool.c | 2 +-
> mm/zsmalloc.c | 1 +
> 3 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/mm/zbud.c b/mm/zbud.c
> index a05790b1915e..aa74f7addab1 100644
> --- a/mm/zbud.c
> +++ b/mm/zbud.c
> @@ -619,3 +619,4 @@ module_exit(exit_zbud);
> MODULE_LICENSE("GPL");
> MODULE_AUTHOR("Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx>");
> MODULE_DESCRIPTION("Buddy Allocator for Compressed Pages");
> +MODULE_ALIAS("zpool-zbud");
> diff --git a/mm/zpool.c b/mm/zpool.c
> index e40612a1df00..739cdf0d183a 100644
> --- a/mm/zpool.c
> +++ b/mm/zpool.c
> @@ -150,7 +150,7 @@ struct zpool *zpool_create_pool(char *type, gfp_t gfp, struct zpool_ops *ops)
> driver = zpool_get_driver(type);
>
> if (!driver) {
> - request_module(type);
> + request_module("zpool-%s", type);
> driver = zpool_get_driver(type);
> }
>
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 4e2fc83cb394..36af729eb3f6 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -1199,3 +1199,4 @@ module_exit(zs_exit);
>
> MODULE_LICENSE("Dual BSD/GPL");
> MODULE_AUTHOR("Nitin Gupta <ngupta@xxxxxxxxxx>");
> +MODULE_ALIAS("zpool-zsmalloc");
> --
> 1.9.1
>
>
> --
> Kees Cook
> Chrome OS Security
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