# Re: \[PATCH v2\] CIPSO: Fix unaligned memory access in cipso\_v4\_gentag\_hdr

- From: Paul Moore \<paul@paul-moore.com\>
- Date: 2021-03-05 16:43:31 
- List: linux-security-module
- Page: https://ratatoskr.run/linux-security-module/2021/03/11197856
- Thread: https://ratatoskr.run/linux-security-module/2021/03/11197848/t.md

```text
On Fri, Mar 5, 2021 at 3:05 AM Sergey Nazarov [ref] wrote:
>
> We need to use put_unaligned when writing 32-bit DOI value
> in cipso_v4_gentag_hdr to avoid unaligned memory access.
>
> v2: unneeded type cast removed as Ondrej Mosnacek suggested.
>
> Signed-off-by: Sergey Nazarov <redacted>
> ---
>  net/ipv4/cipso_ipv4.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Acked-by: Paul Moore <paul@paul-moore.com>

> diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
> index 471d33a..6e59902 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, &buf[2]);
>  }
>
>  /**
> --
> 1.8.3.1

-- 
paul moore
www.paul-moore.com
```