netdev - Re: [PATCH net-next v7 1/4] scm: add SO_PASSPIDFD and SCM

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: <20230901205145.10640-A-hca@linux.ibm.com>
Date: Fri, 1 Sep 2023 22:51:45 +0200
From: Heiko Carstens <hca@...ux.ibm.com>
To: Kuniyuki Iwashima <kuniyu@...zon.com>
Cc: aleksandr.mikhalitsyn@...onical.com, arnd@...db.de, bluca@...ian.org,
        brauner@...nel.org, davem@...emloft.net, dsahern@...nel.org,
        edumazet@...gle.com, keescook@...omium.org, kuba@...nel.org,
        ldv@...ace.io, leon@...nel.org, linux-arch@...r.kernel.org,
        linux-kernel@...r.kernel.org, mzxreary@...inter.de,
        netdev@...r.kernel.org, pabeni@...hat.com
Subject: Re: [PATCH net-next v7 1/4] scm: add SO_PASSPIDFD and SCM_PIDFD

On Fri, Sep 01, 2023 at 01:33:22PM -0700, Kuniyuki Iwashima wrote:
> From: Heiko Carstens <hca@...ux.ibm.com>
> Date: Fri, 1 Sep 2023 22:05:17 +0200
> > On Thu, Jun 08, 2023 at 10:26:25PM +0200, Alexander Mikhalitsyn wrote:
> > > +	if ((msg->msg_controllen <= sizeof(struct cmsghdr)) ||
> > > +	    (msg->msg_controllen - sizeof(struct cmsghdr)) < sizeof(int)) {
> > > +		msg->msg_flags |= MSG_CTRUNC;
> > > +		return;
> > > +	}
> > 
> > This does not work for compat tasks since the size of struct cmsghdr (aka
> > struct compat_cmsghdr) is differently. If the check from put_cmsg() is
> > open-coded here, then also a different check for compat tasks needs to be
> > added.
> > 
> > Discovered this because I was wondering why strace compat tests fail; it
> > seems because of this.
> > 
> > See https://github.com/strace/strace/blob/master/tests/scm_pidfd.c
> > 
> > For compat tasks recvmsg() returns with msg_flags=MSG_CTRUNC since the
> > above code expects a larger buffer than is necessary.
> 
> Can you test this ?

Works for me.

Tested-by: Heiko Carstens <hca@...ux.ibm.com>