linux-kernel - Re: [PATCH] btrfs: compression: Adjust cb->compressed

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <4dd1e595-21c2-4a6c-a7b9-e7c945d3a7a2@embeddedor.com>
Date: Sat, 26 Apr 2025 00:55:21 -0600
From: "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To: Kees Cook <kees@...nel.org>, Chris Mason <clm@...com>
Cc: Josef Bacik <josef@...icpanda.com>, David Sterba <dsterba@...e.com>,
 linux-btrfs@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-hardening@...r.kernel.org
Subject: Re: [PATCH] btrfs: compression: Adjust cb->compressed_folios
 allocation type



On 26/04/25 00:23, Kees Cook wrote:
> In preparation for making the kmalloc family of allocators type aware,
> we need to make sure that the returned type from the allocation matches
> the type of the variable being assigned. (Before, the allocator would
> always return "void *", which can be implicitly cast to any pointer type.)
> 
> The assigned type is "struct folio **" but the returned type will be
> "struct page **". These are the same allocation size (pointer size), but
> the types don't match. Adjust the allocation type to match the assignment.
> 
> Signed-off-by: Kees Cook <kees@...nel.org>
> ---
> Cc: Chris Mason <clm@...com>
> Cc: Josef Bacik <josef@...icpanda.com>
> Cc: David Sterba <dsterba@...e.com>
> Cc: <linux-btrfs@...r.kernel.org>
> ---
>   fs/btrfs/compression.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
> index e7f8ee5d48a4..7f11ef559be6 100644
> --- a/fs/btrfs/compression.c
> +++ b/fs/btrfs/compression.c
> @@ -606,7 +606,7 @@ void btrfs_submit_compressed_read(struct btrfs_bio *bbio)
>   	free_extent_map(em);
>   
>   	cb->nr_folios = DIV_ROUND_UP(compressed_len, PAGE_SIZE);
> -	cb->compressed_folios = kcalloc(cb->nr_folios, sizeof(struct page *), GFP_NOFS);
> +	cb->compressed_folios = kcalloc(cb->nr_folios, sizeof(struct folio *), GFP_NOFS);

Why not `sizeof(*cb->compressed_folios)` as in other patches? :)

-Gustavo