[PREVIEW] [PATCH] staging: erofs: fix potential overflow in z_erofs_vle_normalaccess_readpage{,s}

[Chao Yu]

On 2018/8/23 17:19, Gao Xiang wrote:
> As Dan reported in the LKP mailing list:
> https://lists.01.org/pipermail/kbuild-all/2018-August/051558.html
> 
> New smatch warnings:
> drivers/staging/erofs/unzip_vle.c:1359 z_erofs_vle_normalaccess_readpages() warn: should '()->index << 12' be a 64 bit type?
> 
> Old smatch warnings:
> drivers/staging/erofs/unzip_vle.c:1322 z_erofs_vle_normalaccess_readpage() warn: should 'page->index << 12' be a 64 bit type?
> 
> It needs to cast variable's type to erofs_off_t before left shifting.
> 
> Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
> Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com>

Reviewed-by: Chao Yu <yuchao0 at huawei.com>

> ---
> 
> Hi Chao,
> 
> This patch is based on
> `staging: erofs: fix potential overflow in erofs_grab_bio()'
> in order to avoid patch conflict when rebasing.
> 
> I think it is better to rearrange the commit order in the erofs branch and
> it needs to be sent separately in advance to Greg.

Agreed, let me add this into erofs branch later.

Thanks,

> 
> Thanks,
> Gao Xiang
> 
>  drivers/staging/erofs/unzip_vle.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c
> index 6c4c928..22f9a02 100644
> --- a/drivers/staging/erofs/unzip_vle.c
> +++ b/drivers/staging/erofs/unzip_vle.c
> @@ -1314,7 +1314,7 @@ static int z_erofs_vle_normalaccess_readpage(struct file *file,
>  	LIST_HEAD(pagepool);
>  
>  #if (EROFS_FS_ZIP_CACHE_LVL >= 2)
> -	f.cachedzone_la = page->index << PAGE_SHIFT;
> +	f.cachedzone_la = (erofs_off_t)page->index << PAGE_SHIFT;
>  #endif
>  	err = z_erofs_do_read_page(&f, page, &pagepool);
>  	(void)z_erofs_vle_work_iter_end(&f.builder);
> @@ -1347,7 +1347,7 @@ static inline int __z_erofs_vle_normalaccess_readpages(
>  	LIST_HEAD(pagepool);
>  
>  #if (EROFS_FS_ZIP_CACHE_LVL >= 2)
> -	f.cachedzone_la = lru_to_page(pages)->index << PAGE_SHIFT;
> +	f.cachedzone_la = (erofs_off_t)lru_to_page(pages)->index << PAGE_SHIFT;
>  #endif
>  	for (; nr_pages; --nr_pages) {
>  		struct page *page = lru_to_page(pages);
>