From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ido Schimmel Date: Mon, 27 Jul 2020 12:15:05 +0000 Subject: Re: [PATCH 19/26] net/ipv6: switch ipv6_flowlabel_opt to sockptr_t Message-Id: <20200727121505.GA1804864@shredder> List-Id: References: <20200723060908.50081-1-hch@lst.de> <20200723060908.50081-20-hch@lst.de> In-Reply-To: <20200723060908.50081-20-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Hellwig Cc: "David S. Miller" , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Alexey Kuznetsov , Hideaki YOSHIFUJI , Eric Dumazet , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, linux-sctp@vger.kernel.org, linux-hams@vger.kernel.org, linux-bluetooth@vger.kernel.org, bridge@lists.linux-foundation.org, linux-can@vger.kernel.org, dccp@vger.kernel.org, linux-decnet-user@lists.sourceforge.net, linux-wpan@vger.kernel.org, linux-s390@vger.kernel.org, mptcp@lists.01.org, lvs-devel@vger.kernel.org, rds-devel@oss.oracle.com, linux-afs@lists.infradead.org, tipc-discussion@lists.sourceforge.net, linux-x25@vger.kernel.org On Thu, Jul 23, 2020 at 08:09:01AM +0200, Christoph Hellwig wrote: > Pass a sockptr_t to prepare for set_fs-less handling of the kernel > pointer from bpf-cgroup. > > Note that the get case is pretty weird in that it actually copies data > back to userspace from setsockopt. > > Signed-off-by: Christoph Hellwig > --- > include/net/ipv6.h | 2 +- > net/ipv6/ip6_flowlabel.c | 16 +++++++++------- > net/ipv6/ipv6_sockglue.c | 2 +- > 3 files changed, 11 insertions(+), 9 deletions(-) > > diff --git a/include/net/ipv6.h b/include/net/ipv6.h > index 262fc88dbd7e2f..4c9d89b5d73268 100644 > --- a/include/net/ipv6.h > +++ b/include/net/ipv6.h > @@ -406,7 +406,7 @@ struct ipv6_txoptions *fl6_merge_options(struct ipv6_txoptions *opt_space, > struct ip6_flowlabel *fl, > struct ipv6_txoptions *fopt); > void fl6_free_socklist(struct sock *sk); > -int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen); > +int ipv6_flowlabel_opt(struct sock *sk, sockptr_t optval, int optlen); > int ipv6_flowlabel_opt_get(struct sock *sk, struct in6_flowlabel_req *freq, > int flags); > int ip6_flowlabel_init(void); > diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c > index 27ee6de9beffc4..6b3c315f3d461a 100644 > --- a/net/ipv6/ip6_flowlabel.c > +++ b/net/ipv6/ip6_flowlabel.c > @@ -371,7 +371,7 @@ static int fl6_renew(struct ip6_flowlabel *fl, unsigned long linger, unsigned lo > > static struct ip6_flowlabel * > fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq, > - char __user *optval, int optlen, int *err_p) > + sockptr_t optval, int optlen, int *err_p) > { > struct ip6_flowlabel *fl = NULL; > int olen; > @@ -401,7 +401,8 @@ fl_create(struct net *net, struct sock *sk, struct in6_flowlabel_req *freq, > memset(fl->opt, 0, sizeof(*fl->opt)); > fl->opt->tot_len = sizeof(*fl->opt) + olen; > err = -EFAULT; > - if (copy_from_user(fl->opt+1, optval+CMSG_ALIGN(sizeof(*freq)), olen)) > + sockptr_advance(optval, CMSG_ALIGN(sizeof(*freq))); > + if (copy_from_sockptr(fl->opt + 1, optval, olen)) > goto done; > > msg.msg_controllen = olen; > @@ -604,7 +605,7 @@ static int ipv6_flowlabel_renew(struct sock *sk, struct in6_flowlabel_req *freq) > } > > static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq, > - void __user *optval, int optlen) > + sockptr_t optval, int optlen) > { > struct ipv6_fl_socklist *sfl, *sfl1 = NULL; > struct ip6_flowlabel *fl, *fl1 = NULL; > @@ -702,8 +703,9 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq, > goto recheck; > > if (!freq->flr_label) { > - if (copy_to_user(&((struct in6_flowlabel_req __user *) optval)->flr_label, > - &fl->label, sizeof(fl->label))) { > + sockptr_advance(optval, > + offsetof(struct in6_flowlabel_req, flr_label)); Christoph, I see a regression with IPv6 flowlabel that I bisected to this patch. When passing '-F 0' to 'ping' the flow label should be random, yet it's the same every time after this patch. It seems that the pointer is never advanced after the call to sockptr_advance() because it is passed by value and not by reference. Even if you were to pass it by reference I think you would later need to call sockptr_decrease() or something similar. Otherwise it is very error-prone. Maybe adding an offset to copy_to_sockptr() and copy_from_sockptr() is better? Thanks > + if (copy_to_sockptr(optval, &fl->label, sizeof(fl->label))) { > /* Intentionally ignore fault. */ > } > } > @@ -716,13 +718,13 @@ static int ipv6_flowlabel_get(struct sock *sk, struct in6_flowlabel_req *freq, > return err; > } > > -int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen) > +int ipv6_flowlabel_opt(struct sock *sk, sockptr_t optval, int optlen) > { > struct in6_flowlabel_req freq; > > if (optlen < sizeof(freq)) > return -EINVAL; > - if (copy_from_user(&freq, optval, sizeof(freq))) > + if (copy_from_sockptr(&freq, optval, sizeof(freq))) > return -EFAULT; > > switch (freq.flr_action) { > diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c > index 119dfaf5f4bb26..3897fb55372d38 100644 > --- a/net/ipv6/ipv6_sockglue.c > +++ b/net/ipv6/ipv6_sockglue.c > @@ -929,7 +929,7 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname, > retv = 0; > break; > case IPV6_FLOWLABEL_MGR: > - retv = ipv6_flowlabel_opt(sk, optval, optlen); > + retv = ipv6_flowlabel_opt(sk, USER_SOCKPTR(optval), optlen); > break; > case IPV6_IPSEC_POLICY: > case IPV6_XFRM_POLICY: > -- > 2.27.0 >