linux-hardening - Re: [PATCH] fs/ntfs3: use kcalloc() instead of kzalloc()

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Message-ID: <bb7a8d29-d80d-41b0-8dde-2aba44c3fd90@embeddedor.com>
Date: Sat, 10 Feb 2024 22:31:49 -0600
From: "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To: Lenko Donchev <lenko.donchev@...il.com>,
 Konstantin Komarov <almaz.alexandrovich@...agon-software.com>,
 "Gustavo A. R. Silva" <gustavoars@...nel.org>
Cc: ntfs3@...ts.linux.dev, linux-kernel@...r.kernel.org,
 linux-hardening@...r.kernel.org
Subject: Re: [PATCH] fs/ntfs3: use kcalloc() instead of kzalloc()



On 2/10/24 19:53, Lenko Donchev wrote:
> We are trying to get rid of all multiplications from allocation
> functions to prevent integer overflows[1]. Here the multiplication is
> obviously safe, but using kcalloc() is more appropriate and improves
> readability. This patch has no effect on runtime behavior.
> 
> Link: https://github.com/KSPP/linux/issues/162 [1]
> Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [2]
> 
> Signed-off-by: Lenko Donchev <lenko.donchev@...il.com>
> ---
>   fs/ntfs3/frecord.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/ntfs3/frecord.c b/fs/ntfs3/frecord.c
> index 3b42938a9d3b..d435446537ca 100644
> --- a/fs/ntfs3/frecord.c
> +++ b/fs/ntfs3/frecord.c
> @@ -2636,7 +2636,7 @@ int ni_read_frame(struct ntfs_inode *ni, u64 frame_vbo, struct page **pages,
>   		goto out1;
>   	}
>   
> -	pages_disk = kzalloc(npages_disk * sizeof(struct page *), GFP_NOFS);
> +	pages_disk = kcalloc(npages_disk, sizeof(struct page *), GFP_NOFS);

`sizeof(*pages_disk)` is preferable over `sizeof(struct page *)`

Thanks
--
Gustavo

>   	if (!pages_disk) {
>   		err = -ENOMEM;
>   		goto out2;