[PATCH net-next v6 6/8] netfilter: Remove the now superfluous sentinel elements from ctl_table array

Joel Granados via B4 Relay
2024-05-01T09:30:09Z

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

* Remove sentinel elements from ctl_table structs
* Remove instances where an array element is zeroed out to make it look
like a sentinel. This is not longer needed and is safe after commit
c899710fe7f9 ("networking: Update to register_net_sysctl_sz") added
the array size to the ctl_table registration
* Remove the need for having __NF_SYSCTL_CT_LAST_SYSCTL as the
sysctl array size is now in NF_SYSCTL_CT_LAST_SYSCTL
* Remove extra element in ctl_table arrays declarations

Acked-by: Kees Cook <keescook@chromium.org> # loadpin & yama
Signed-off-by: Joel Granados <j.granados@samsung.com>
---
net/bridge/br_netfilter_hooks.c | 1 -
net/ipv6/netfilter/nf_conntrack_reasm.c | 1 -
net/netfilter/ipvs/ip_vs_ctl.c | 5 +----
net/netfilter/ipvs/ip_vs_lblc.c | 5 +----
net/netfilter/ipvs/ip_vs_lblcr.c | 5 +----
net/netfilter/nf_conntrack_standalone.c | 6 +-----
net/netfilter/nf_log.c | 3 +--
7 files changed, 5 insertions(+), 21 deletions(-)

diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 7948a9e7542c..bf30c50b5689 100644
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -1226,7 +1226,6 @@ static struct ctl_table brnf_table[] = {
.mode = 0644,
.proc_handler = brnf_sysctl_call_tables,
},
- { }
};

static inline void br_netfilter_sysctl_default(struct brnf_net *brnf)
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index ce8c14d8aff5..5e1b50c6a44d 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -62,7 +62,6 @@ static struct ctl_table nf_ct_frag6_sysctl_table[] = {
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
- { }
};

static int nf_ct_frag6_sysctl_register(struct net *net)
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 143a341bbc0a..50b5dbe40eb8 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2263,7 +2263,6 @@ static struct ctl_table vs_vars[] = {
.proc_handler = proc_dointvec,
},
#endif
- { }
};

#endif
@@ -4286,10 +4285,8 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
return -ENOMEM;

/* Don't export sysctls to unprivileged users */
- if (net->user_ns != &init_user_ns) {
- tbl[0].procname = NULL;
+ if (net->user_ns != &init_user_ns)
ctl_table_size = 0;
- }
} else
tbl = vs_vars;
/* Initialize sysctl defaults */
diff --git a/net/netfilter/ipvs/ip_vs_lblc.c b/net/netfilter/ipvs/ip_vs_lblc.c
index 8ceec7a2fa8f..2423513d701d 100644
--- a/net/netfilter/ipvs/ip_vs_lblc.c
+++ b/net/netfilter/ipvs/ip_vs_lblc.c
@@ -123,7 +123,6 @@ static struct ctl_table vs_vars_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
- { }
};
#endif

@@ -563,10 +562,8 @@ static int __net_init __ip_vs_lblc_init(struct net *net)
return -ENOMEM;

/* Don't export sysctls to unprivileged users */
- if (net->user_ns != &init_user_ns) {
- ipvs->lblc_ctl_table[0].procname = NULL;
+ if (net->user_ns != &init_user_ns)
vars_table_size = 0;
- }

} else
ipvs->lblc_ctl_table = vs_vars_table;
diff --git a/net/netfilter/ipvs/ip_vs_lblcr.c b/net/netfilter/ipvs/ip_vs_lblcr.c
index 0fb64707213f..cdb1d4bf6761 100644
--- a/net/netfilter/ipvs/ip_vs_lblcr.c
+++ b/net/netfilter/ipvs/ip_vs_lblcr.c
@@ -294,7 +294,6 @@ static struct ctl_table vs_vars_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
- { }
};
#endif

@@ -749,10 +748,8 @@ static int __net_init __ip_vs_lblcr_init(struct net *net)
return -ENOMEM;

/* Don't export sysctls to unprivileged users */
- if (net->user_ns != &init_user_ns) {
- ipvs->lblcr_ctl_table[0].procname = NULL;
+ if (net->user_ns != &init_user_ns)
vars_table_size = 0;
- }
} else
ipvs->lblcr_ctl_table = vs_vars_table;
ipvs->sysctl_lblcr_expiration = DEFAULT_EXPIRATION;
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index bb9dea676ec1..74112e9c5dab 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -616,11 +616,9 @@ enum nf_ct_sysctl_index {
NF_SYSCTL_CT_LWTUNNEL,
#endif

- __NF_SYSCTL_CT_LAST_SYSCTL,
+ NF_SYSCTL_CT_LAST_SYSCTL,
};

-#define NF_SYSCTL_CT_LAST_SYSCTL (__NF_SYSCTL_CT_LAST_SYSCTL + 1)
-
static struct ctl_table nf_ct_sysctl_table[] = {
[NF_SYSCTL_CT_MAX] = {
.procname = "nf_conntrack_max",
@@ -957,7 +955,6 @@ static struct ctl_table nf_ct_sysctl_table[] = {
.proc_handler = nf_hooks_lwtunnel_sysctl_handler,
},
#endif
- {}
};

static struct ctl_table nf_ct_netfilter_table[] = {
@@ -968,7 +965,6 @@ static struct ctl_table nf_ct_netfilter_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
- { }
};

static void nf_conntrack_standalone_init_tcp_sysctl(struct net *net,
diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c
index efedd2f13ac7..769fd7680fac 100644
--- a/net/netfilter/nf_log.c
+++ b/net/netfilter/nf_log.c
@@ -395,7 +395,7 @@ static const struct seq_operations nflog_seq_ops = {

#ifdef CONFIG_SYSCTL
static char nf_log_sysctl_fnames[NFPROTO_NUMPROTO-NFPROTO_UNSPEC][3];
-static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO+1];
+static struct ctl_table nf_log_sysctl_table[NFPROTO_NUMPROTO];
static struct ctl_table_header *nf_log_sysctl_fhdr;

static struct ctl_table nf_log_sysctl_ftable[] = {
@@ -406,7 +406,6 @@ static struct ctl_table nf_log_sysctl_ftable[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
- { }
};

static int nf_log_proc_dostring(struct ctl_table *table, int write,

--
2.43.0