Date: Fri, 31 Mar 2023 20:20:58 +0200 From: Mateusz Guzik <mjguzik@gmail.com> To: Gleb Smirnoff <glebius@freebsd.org> Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: f5a365e51fee - main - inet6: protect address manipulation with a lock Message-ID: <CAGudoHEO-ODEqpZmj1qCwyaptFHMORe0pOPfpw46Dot2zjHK%2BQ@mail.gmail.com> In-Reply-To: <ZCciivj8ciSkj8ph@FreeBSD.org> References: <202303300847.32U8l1UM004219@gitrepo.freebsd.org> <ZCciivj8ciSkj8ph@FreeBSD.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On 3/31/23, Gleb Smirnoff <glebius@freebsd.org> wrote:
> Mateusz,
>
> On Thu, Mar 30, 2023 at 08:47:01AM +0000, Mateusz Guzik wrote:
> M> diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c
> M> index 27dc3550177c..3d967e9a40c7 100644
> M> --- a/sys/netinet6/in6.c
> M> +++ b/sys/netinet6/in6.c
> M> @@ -168,6 +168,9 @@ static void in6_leave_proxy_ndp_mc(struct ifnet *,
> const struct in6_addr *);
> M> #define ifa2ia6(ifa) ((struct in6_ifaddr *)(ifa))
> M> #define ia62ifa(ia6) (&((ia6)->ia_ifa))
> M>
> M> +static struct sx in6_control_sx;
> M> +SX_SYSINIT(in6_control_sx, &in6_control_sx, "in6_control");
> M> +
> M> void
> M> in6_newaddrmsg(struct in6_ifaddr *ia, int cmd)
> M> {
> M> @@ -254,6 +257,7 @@ in6_control(struct socket *so, u_long cmd, void
> *data,
> M> struct in6_aliasreq *ifra = (struct in6_aliasreq *)data;
> M> struct sockaddr_in6 *sa6;
> M> int error;
> M> + bool control_locked = false;
> M>
> M> /*
> M> * Compat to make pre-10.x ifconfig(8) operable.
> M> @@ -411,6 +415,8 @@ in6_control(struct socket *so, u_long cmd, void
> *data,
> M> if (td != NULL && (error = prison_check_ip6(td->td_ucred,
> M> &sa6->sin6_addr)) != 0)
> M> return (error);
> M> + sx_xlock(&in6_control_sx);
> M> + control_locked = true;
> M> ia = in6ifa_ifpwithaddr(ifp, &sa6->sin6_addr);
> M> } else
> M> ia = NULL;
> M> @@ -582,6 +588,9 @@ in6_control(struct socket *so, u_long cmd, void
> *data,
> M>
> M> error = 0;
> M> out:
> M> + if (control_locked)
> M> + sx_xunlock(&in6_control_sx);
> M> +
> M> if (ia != NULL)
> M> ifa_free(&ia->ia_ifa);
> M> return (error);
>
> Why do you prefer a bool over using sx_xlocked()?
>
It does not read from the lock
but now that you mention it, perhaps i should assert it is not taken
in the else clause
--
Mateusz Guzik <mjguzik gmail.com>
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAGudoHEO-ODEqpZmj1qCwyaptFHMORe0pOPfpw46Dot2zjHK%2BQ>