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Date:   Fri, 7 Aug 2020 21:46:11 +0200
From:   Christian Brauner <christian.brauner@ubuntu.com>
To:     Kees Cook <keescook@chromium.org>
Cc:     Christian Zigotzky <chzigotzky@xenosoft.de>,
        "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>,
        Thadeu Lima de Souza Cascardo <cascardo@canonical.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Aleksa Sarai <cyphar@cyphar.com>,
        Chris Palmer <palmer@google.com>,
        Christoph Hellwig <hch@lst.de>,
        Matt Denton <mpdenton@google.com>,
        Robert Sesek <rsesek@google.com>,
        Sargun Dhillon <sargun@sargun.me>,
        Shuah Khan <shuah@kernel.org>, Tycho Andersen <tycho@tycho.ws>,
        Will Deacon <will@kernel.org>, Will Drewry <wad@chromium.org>,
        Yonghong Song <yhs@fb.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net/scm: Fix typo in SCM_RIGHTS compat refactoring
Message-ID: <20200807194611.zduj77nrobm3ibpr@wittgenstein>
References: <202008071117.56ADE58@keescook>
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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@xenosoft.de>
> Link: https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-August/216156.html
> Reported-by: "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>
> Link: https://lore.kernel.org/lkml/1596812929.lz7fuo8r2w.none@localhost/
> Suggested-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
> Fixes: c0029de50982 ("net/scm: Regularize compat handling of scm_detach_fds()")
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---

Oh fun,

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

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