Re: [PATCH] net/scm: Fix typo in SCM_RIGHTS compat refactoring

[Christian Brauner]

On Fri, Aug 07, 2020 at 11:20:05AM -0700, Kees Cook wrote:
> When refactoring the SCM_RIGHTS code, I accidentally mis-merged my
> native/compat diffs, which entirely broke using SCM_RIGHTS in compat
> mode. Use the correct helper.
> 
> Reported-by: Christian Zigotzky <chzigotzky@xxxxxxxxxxx>
> Link: https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-August/216156.html
> Reported-by: "Alex Xu (Hello71)" <alex_y_xu@xxxxxxxx>
> Link: https://lore.kernel.org/lkml/1596812929.lz7fuo8r2w.none@localhost/
> Suggested-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
> Fixes: c0029de50982 ("net/scm: Regularize compat handling of scm_detach_fds()")
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---

Oh fun,

Acked-by: Christian Brauner <christian.brauner@xxxxxxxxxx>

Thanks for fixing this quickly, Kees! I already built stuff on top of
the notifier fd injection work we did this cycle so it's great that we
don't have to revert this!



>  net/compat.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/compat.c b/net/compat.c
> index 703acb51c698..95ce707a30a3 100644
> --- a/net/compat.c
> +++ b/net/compat.c
> @@ -294,7 +294,7 @@ void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm)
>  		(struct compat_cmsghdr __user *)msg->msg_control;
>  	unsigned int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
>  	int fdmax = min_t(int, scm_max_fds_compat(msg), scm->fp->count);
> -	int __user *cmsg_data = CMSG_USER_DATA(cm);
> +	int __user *cmsg_data = CMSG_COMPAT_DATA(cm);
>  	int err = 0, i;
>  
>  	for (i = 0; i < fdmax; i++) {
> -- 
> 2.25.1
> 
> 
> -- 
> Kees Cook