[NETFILTER] nfnetlink: unconditionally require CAP_NET_ADMIN

This patch unconditionally requires CAP_NET_ADMIN for all nfnetlink
messages.  It also removes the per-message cap_required field, since all
existing subsystems use CAP_NET_ADMIN for all their messages anyway.

Patrick McHardy owes me a beer if we ever need to re-introduce this.

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 24 insertions, 41 deletions

diff --git a/include/linux/netfilter/nfnetlink.h b/include/linux/netfilter/nfnetlink.h
index 8be2f840a557..934a2479f160 100644
--- a/include/linux/netfilter/nfnetlink.h
+++ b/include/linux/netfilter/nfnetlink.h
@@ -112,7 +112,6 @@ struct nfnl_callback
 {
         int (*call)(struct sock *nl, struct sk_buff *skb, 
                 struct nlmsghdr *nlh, struct nfattr *cda[], int *errp);
-        kernel_cap_t cap_required; /* capabilities required for this msg */
         u_int16_t attr_count;   /* number of nfattr's */
 };
 
diff --git a/net/ipv4/netfilter/ip_conntrack_netlink.c b/net/ipv4/netfilter/ip_conntrack_netlink.c
index f5e5e3158670..de9f4464438d 100644
--- a/net/ipv4/netfilter/ip_conntrack_netlink.c
+++ b/net/ipv4/netfilter/ip_conntrack_netlink.c
@@ -1543,29 +1543,22 @@ static struct notifier_block ctnl_notifier_exp = {
 
 static struct nfnl_callback ctnl_cb[IPCTNL_MSG_MAX] = {
         [IPCTNL_MSG_CT_NEW]             = { .call = ctnetlink_new_conntrack,
-                                            .attr_count = CTA_MAX,
-                                            .cap_required = CAP_NET_ADMIN },
+                                            .attr_count = CTA_MAX, },
         [IPCTNL_MSG_CT_GET]             = { .call = ctnetlink_get_conntrack,
-                                            .attr_count = CTA_MAX,
-                                            .cap_required = CAP_NET_ADMIN },
+                                            .attr_count = CTA_MAX, },
         [IPCTNL_MSG_CT_DELETE]          = { .call = ctnetlink_del_conntrack,
-                                            .attr_count = CTA_MAX,
-                                            .cap_required = CAP_NET_ADMIN },
+                                            .attr_count = CTA_MAX, },
         [IPCTNL_MSG_CT_GET_CTRZERO]     = { .call = ctnetlink_get_conntrack,
-                                            .attr_count = CTA_MAX,
-                                            .cap_required = CAP_NET_ADMIN },
+                                            .attr_count = CTA_MAX, },
 };
 
 static struct nfnl_callback ctnl_exp_cb[IPCTNL_MSG_EXP_MAX] = {
         [IPCTNL_MSG_EXP_GET]            = { .call = ctnetlink_get_expect,
-                                            .attr_count = CTA_EXPECT_MAX,
-                                            .cap_required = CAP_NET_ADMIN },
+                                            .attr_count = CTA_EXPECT_MAX, },
         [IPCTNL_MSG_EXP_NEW]            = { .call = ctnetlink_new_expect,
-                                            .attr_count = CTA_EXPECT_MAX,
-                                            .cap_required = CAP_NET_ADMIN },
+                                            .attr_count = CTA_EXPECT_MAX, },
         [IPCTNL_MSG_EXP_DELETE]         = { .call = ctnetlink_del_expect,
-                                            .attr_count = CTA_EXPECT_MAX,
-                                            .cap_required = CAP_NET_ADMIN },
+                                            .attr_count = CTA_EXPECT_MAX, },
 };
 
 static struct nfnetlink_subsystem ctnl_subsys = {
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 83f4c53030fc..a60c59b97631 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -223,6 +223,12 @@ static inline int nfnetlink_rcv_msg(struct sk_buff *skb,
                  NFNL_SUBSYS_ID(nlh->nlmsg_type),
                  NFNL_MSG_TYPE(nlh->nlmsg_type));
 
+        if (!cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN)) {
+                DEBUGP("missing CAP_NET_ADMIN\n");
+                *errp = -EPERM;
+                return -1;
+        }
+
         /* Only requests are handled by kernel now. */
         if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) {
                 DEBUGP("received non-request message\n");
@@ -240,15 +246,12 @@ static inline int nfnetlink_rcv_msg(struct sk_buff *skb,
         ss = nfnetlink_get_subsys(type);
         if (!ss) {
 #ifdef CONFIG_KMOD
-                if (cap_raised(NETLINK_CB(skb).eff_cap, CAP_NET_ADMIN)) {
-                        /* don't call nfnl_shunlock, since it would reenter
-                         * with further packet processing */
-                        up(&nfnl_sem);
-                        request_module("nfnetlink-subsys-%d",
-                                        NFNL_SUBSYS_ID(type));
-                        nfnl_shlock();
-                        ss = nfnetlink_get_subsys(type);
-                }
+                /* don't call nfnl_shunlock, since it would reenter
+                 * with further packet processing */
+                up(&nfnl_sem);
+                request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type));
+                nfnl_shlock();
+                ss = nfnetlink_get_subsys(type);
                 if (!ss)
 #endif
                         goto err_inval;
@@ -260,13 +263,6 @@ static inline int nfnetlink_rcv_msg(struct sk_buff *skb,
                 goto err_inval;
         }
 
-        if (nc->cap_required && 
-            !cap_raised(NETLINK_CB(skb).eff_cap, nc->cap_required)) {
-                DEBUGP("permission denied for type %d\n", type);
-                *errp = -EPERM;
-                return -1;
-        }
-
         {
                 u_int16_t attr_count = 
                         ss->cb[NFNL_MSG_TYPE(nlh->nlmsg_type)].attr_count;
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index d194676f3655..cba63729313d 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -862,11 +862,9 @@ out_put:
 
 static struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
-                                    .attr_count = NFULA_MAX,
-                                    .cap_required = CAP_NET_ADMIN, },
+                                    .attr_count = NFULA_MAX, },
         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
-                                    .attr_count = NFULA_CFG_MAX,
-                                    .cap_required = CAP_NET_ADMIN },
+                                    .attr_count = NFULA_CFG_MAX, },
 };
 
 static struct nfnetlink_subsystem nfulnl_subsys = {
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index f065a6c94953..f28460b61e47 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -931,14 +931,11 @@ out_put:
 
 static struct nfnl_callback nfqnl_cb[NFQNL_MSG_MAX] = {
         [NFQNL_MSG_PACKET]      = { .call = nfqnl_recv_unsupp,
-                                    .attr_count = NFQA_MAX,
-                                    .cap_required = CAP_NET_ADMIN },
+                                    .attr_count = NFQA_MAX, },
         [NFQNL_MSG_VERDICT]     = { .call = nfqnl_recv_verdict,
-                                    .attr_count = NFQA_MAX,
-                                    .cap_required = CAP_NET_ADMIN },
+                                    .attr_count = NFQA_MAX, },
         [NFQNL_MSG_CONFIG]      = { .call = nfqnl_recv_config,
-                                    .attr_count = NFQA_CFG_MAX,
-                                    .cap_required = CAP_NET_ADMIN },
+                                    .attr_count = NFQA_CFG_MAX, },
 };
 
 static struct nfnetlink_subsystem nfqnl_subsys = {