On Wed, May 12, 2021 at 06:35:57PM +0200, Philippe Mathieu-Daudé wrote: > On 5/12/21 5:36 PM, Daniel P. Berrangé wrote: > > The CMSG_LEN and CMSG_SPACE macros must not be assumed to return the > > same value. The msg_controllen field must be initialized using > > CMSG_SPACE when using SCM_RIGHTS. > > > > This ought to fix any FD receive issues users might be hitting on > > 64-bit FeeBSD / NetBSD platforms. The flaw was noticed first in > > GNULIB > > > > https://lists.gnu.org/archive/html/bug-gnulib/2021-02/msg00066.html > > > > and QEMU's code has the same logic bug. > > > > Reviewed-by: Connor Kuehl <cku...@redhat.com> > > Signed-off-by: Daniel P. Berrangé <berra...@redhat.com> > > --- > > net/tap.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/net/tap.c b/net/tap.c > > index bae895e287..276a9077fc 100644 > > --- a/net/tap.c > > +++ b/net/tap.c > > @@ -467,7 +467,7 @@ static int recv_fd(int c) > > cmsg->cmsg_level = SOL_SOCKET; > > cmsg->cmsg_type = SCM_RIGHTS; > > cmsg->cmsg_len = CMSG_LEN(sizeof(fd)); > > - msg.msg_controllen = cmsg->cmsg_len; > > + msg.msg_controllen = CMSG_SPACE(sizeof(fd)); > > > > iov.iov_base = req; > > iov.iov_len = sizeof(req); > > > > Possibly more:
Ewwwww, yes :-( Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
