Hi Christoph,
On Thu, Jul 23, 2020 at 08:08:54AM +0200, Christoph Hellwig wrote:
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index da933f99b5d517..42befbf12846c0 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -1422,7 +1422,8 @@ int ip_setsockopt(struct sock *sk, int level,
> optname != IP_IPSEC_POLICY &&
> optname != IP_XFRM_POLICY &&
> !ip_mroute_opt(optname))
> - err = nf_setsockopt(sk, PF_INET, optname, optval, optlen);
> + err = nf_setsockopt(sk, PF_INET, optname, USER_SOCKPTR(optval),
> + optlen);
> #endif
> return err;
> }
> diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
> index 4697d09c98dc3e..f2a9680303d8c0 100644
> --- a/net/ipv4/netfilter/ip_tables.c
> +++ b/net/ipv4/netfilter/ip_tables.c
> @@ -1102,7 +1102,7 @@ __do_replace(struct net *net, const char *name, unsigned int valid_hooks,
> }
>
> static int
> -do_replace(struct net *net, const void __user *user, unsigned int len)
> +do_replace(struct net *net, sockptr_t arg, unsigned int len)
> {
> int ret;
> struct ipt_replace tmp;
> @@ -1110,7 +1110,7 @@ do_replace(struct net *net, const void __user *user, unsigned int len)
> void *loc_cpu_entry;
> struct ipt_entry *iter;
>
> - if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
> + if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
> return -EFAULT;
>
> /* overflow check */
> @@ -1126,8 +1126,8 @@ do_replace(struct net *net, const void __user *user, unsigned int len)
> return -ENOMEM;
>
> loc_cpu_entry = newinfo->entries;
> - if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
> - tmp.size) != 0) {
> + sockptr_advance(arg, sizeof(tmp));
> + if (copy_from_sockptr(loc_cpu_entry, arg, tmp.size) != 0) {
> ret = -EFAULT;
> goto free_newinfo;
> }
Something along this path seems to have broken with this patch. An
invocation of `iptables -A INPUT -m length --length 1360 -j DROP` now
fails, with
nf_setsockopt->do_replace->translate_table->check_entry_size_and_hooks:
(unsigned char *)e + e->next_offset > limit ==> TRUE
resulting in the whole call chain returning -EINVAL. It bisects back to
this commit. This is on net-next.
Jason
