[PATCH] CIPSO: Fix unaligned memory access in cipso_v4_gentag_hdr

[Ondrej Mosnacek]

On Thu, Mar 4, 2021 at 10:09 PM Seergey Nazarov <s-nazarov at yandex.ru> wrote:
> We need to use put_unaligned when writing 32-bit DOI value
> in cipso_v4_gentag_hdr to avoid unaligned memory access.
>
> Signed-off-by: Sergey Nazarov <s-nazarov at yandex.ru>
> ---
>  net/ipv4/cipso_ipv4.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
> index 471d33a..28dfe40 100644
> --- a/net/ipv4/cipso_ipv4.c
> +++ b/net/ipv4/cipso_ipv4.c
> @@ -1162,7 +1162,7 @@ static void cipso_v4_gentag_hdr(const struct
> cipso_v4_doi *doi_def,
>  {
>         buf[0] = IPOPT_CIPSO;
>         buf[1] = CIPSO_V4_HDR_LEN + len;
> -       *(__be32 *)&buf[2] = htonl(doi_def->doi);
> +       put_unaligned_be32(doi_def->doi, (__be32 *)&buf[2]);

I think you can now also drop the cast, since put_unaligned_be32()
expects a void *.

>  }
>
>  /**
> --
> 1.8.3.1
>
>

-- 
Ondrej Mosnacek
Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.