Re: [PATCH] dm: writecache: Use 2-factor allocator arguments

Kees Cook
2018-06-27T21:48:15Z

On Mon, Jun 18, 2018 at 10:50 AM, Kees Cook <keescook@chromium.org> wrote:
> This adjusts the allocator calls to use the 2-factor argument style, as
> already done treewide for better defense against allocator overflows.
> Additionally adjusts style nit to avoid assignments in test expressions.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>

Friendly ping -- I'd like to make sure this makes it into 4.18. All
other 2-factor allocations have been fixed in the kernel.

-Kees

> ---
> drivers/md/dm-writecache.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
> index 5961c7794ef3..7773f4c75701 100644
> --- a/drivers/md/dm-writecache.c
> +++ b/drivers/md/dm-writecache.c
> @@ -259,7 +259,7 @@ static int persistent_memory_claim(struct dm_writecache *wc)
> if (da != p) {
> long i;
> wc->memory_map = NULL;
> - pages = kvmalloc(p * sizeof(struct page *), GFP_KERNEL);
> + pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
> if (!pages) {
> r = -ENOMEM;
> goto err2;
> @@ -859,7 +859,8 @@ static int writecache_alloc_entries(struct dm_writecache *wc)
>
> if (wc->entries)
> return 0;
> - wc->entries = vmalloc(sizeof(struct wc_entry) * wc->n_blocks);
> + wc->entries = vmalloc(array_size(sizeof(struct wc_entry),
> + wc->n_blocks));
> if (!wc->entries)
> return -ENOMEM;
> for (b = 0; b < wc->n_blocks; b++) {
> @@ -1480,10 +1481,13 @@ static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba
> bio_set_dev(&wb->bio, wc->dev->bdev);
> wb->bio.bi_iter.bi_sector = read_original_sector(wc, e);
> wb->page_offset = PAGE_SIZE;
> - if (max_pages <= WB_LIST_INLINE ||
> - unlikely(!(wb->wc_list = kmalloc(max_pages * sizeof(struct wc_entry *),
> - GFP_NOIO | __GFP_NORETRY |
> - __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
> + if (max_pages > WB_LIST_INLINE)
> + wb->wc_list = kmalloc_array(max_pages,
> + sizeof(struct wc_entry *),
> + GFP_NOIO | __GFP_NORETRY |
> + __GFP_NOMEMALLOC |
> + __GFP_NOWARN);
> + if (max_pages <= WB_LIST_INLINE || !wb->wc_list) {
> wb->wc_list = wb->wc_list_inline;
> max_pages = WB_LIST_INLINE;
> }
> --
> 2.17.0
>
>
> --
> Kees Cook
> Pixel Security