linux-kernel - Re: [PATCH] fs: split receive_fd_replace from __receive

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

Message-ID: <YHkGodVOpc/kg3V8@zeniv-ca.linux.org.uk>
Date:   Fri, 16 Apr 2021 03:38:09 +0000
From:   Al Viro <viro@...iv.linux.org.uk>
To:     Christoph Hellwig <hch@....de>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Kees Cook <keescook@...omium.org>,
        Andy Lutomirski <luto@...capital.net>,
        Will Drewry <wad@...omium.org>
Subject: Re: [PATCH] fs: split receive_fd_replace from __receive_fd

On Thu, Mar 25, 2021 at 09:22:09AM +0100, Christoph Hellwig wrote:
> receive_fd_replace shares almost no code with the general case, so split
> it out.  Also remove the "Bump the sock usage counts" comment from
> both copies, as that is now what __receive_sock actually does.

Nice, except that you've misread that, er, lovely API.  This

> -static inline int receive_fd_replace(int fd, struct file *file, unsigned int o_flags)
> -{
> -	return __receive_fd(fd, file, NULL, o_flags);
> +	return __receive_fd(file, NULL, o_flags);
>  }

can get called with negative fd (in which case it turns into an alias for
receive_fd(), of course).  As the result, that ioctl got broken in case
when SECCOMP_ADDFD_FLAG_SETFD is not set.  Trivially fixed by having the
only caller check the damn condition and call either receive_fd_replace()
or receive_fd().