userns xt_recent: Specify the owner/group of ip_list_perms in the initial user namespace

xt_recent creates a bunch of proc files and initializes their uid
and gids to the values of ip_list_uid and ip_list_gid.  When
initialize those proc files convert those values to kuids so they
can continue to reside on the /proc inode.

Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Jan Engelhardt <jengelh@medozas.de>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

2 files changed, 11 insertions, 3 deletions

diff --git a/init/Kconfig b/init/Kconfig
index c8911eb6d500..40f50204dddb 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -944,7 +944,6 @@ config UIDGID_CONVERTED
         # Networking
         depends on NET_9P = n
         depends on NETFILTER_XT_MATCH_OWNER = n
-        depends on NETFILTER_XT_MATCH_RECENT = n
         depends on AF_RXRPC = n
         depends on NET_KEY = n
         depends on DNS_RESOLVER = n
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c
index ae2ad1eec8d0..4635c9b00459 100644
--- a/net/netfilter/xt_recent.c
+++ b/net/netfilter/xt_recent.c
@@ -317,6 +317,8 @@ static int recent_mt_check(const struct xt_mtchk_param *par,
         struct recent_table *t;
 #ifdef CONFIG_PROC_FS
         struct proc_dir_entry *pde;
+        kuid_t uid;
+        kgid_t gid;
 #endif
         unsigned int i;
         int ret = -EINVAL;
@@ -372,6 +374,13 @@ static int recent_mt_check(const struct xt_mtchk_param *par,
         for (i = 0; i < ip_list_hash_size; i++)
                 INIT_LIST_HEAD(&t->iphash[i]);
 #ifdef CONFIG_PROC_FS
+        uid = make_kuid(&init_user_ns, ip_list_uid);
+        gid = make_kgid(&init_user_ns, ip_list_gid);
+        if (!uid_valid(uid) || !gid_valid(gid)) {
+                kfree(t);
+                ret = -EINVAL;
+                goto out;
+        }
         pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
                   &recent_mt_fops, t);
         if (pde == NULL) {
@@ -379,8 +388,8 @@ static int recent_mt_check(const struct xt_mtchk_param *par,
                 ret = -ENOMEM;
                 goto out;
         }
-        pde->uid = ip_list_uid;
-        pde->gid = ip_list_gid;
+        pde->uid = uid;
+        pde->gid = gid;
 #endif
         spin_lock_bh(&recent_lock);
         list_add_tail(&t->list, &recent_net->tables);