[PATCH v2 10/14] netfilter: Update to register_net_sysctl_sz

Joel Granados
2023-07-31T07:20:38Z

Move from register_net_sysctl to register_net_sysctl_sz for all the
netfilter related files. Do this while making sure to mirror the NULL
assignments with a table_size of zero for the unprivileged users.

We need to move to the new function in preparation for when we change
SIZE_MAX to ARRAY_SIZE() in the register_net_sysctl macro. Failing to do
so would erroneously allow ARRAY_SIZE() to be called on a pointer. We
hold off the SIZE_MAX to ARRAY_SIZE change until we have migrated all
the relevant net sysctl registering functions to register_net_sysctl_sz
in subsequent commits.

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
net/bridge/br_netfilter_hooks.c | 3 ++-
net/ipv6/netfilter/nf_conntrack_reasm.c | 3 ++-
net/netfilter/ipvs/ip_vs_ctl.c | 8 ++++++--
net/netfilter/ipvs/ip_vs_lblc.c | 10 +++++++---
net/netfilter/ipvs/ip_vs_lblcr.c | 10 +++++++---
net/netfilter/nf_conntrack_standalone.c | 4 +++-
net/netfilter/nf_log.c | 7 ++++---
7 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 1a801fab9543..15186247b59a 100644
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -1135,7 +1135,8 @@ static int br_netfilter_sysctl_init_net(struct net *net)

br_netfilter_sysctl_default(brnet);

- brnet->ctl_hdr = register_net_sysctl(net, "net/bridge", table);
+ brnet->ctl_hdr = register_net_sysctl_sz(net, "net/bridge", table,
+ ARRAY_SIZE(brnf_table));
if (!brnet->ctl_hdr) {
if (!net_eq(net, &init_net))
kfree(table);
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index d13240f13607..b2dd48911c8d 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -87,7 +87,8 @@ static int nf_ct_frag6_sysctl_register(struct net *net)
table[2].data = &nf_frag->fqdir->high_thresh;
table[2].extra1 = &nf_frag->fqdir->low_thresh;

- hdr = register_net_sysctl(net, "net/netfilter", table);
+ hdr = register_net_sysctl_sz(net, "net/netfilter", table,
+ ARRAY_SIZE(nf_ct_frag6_sysctl_table));
if (hdr == NULL)
goto err_reg;

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 62606fb44d02..8d69e4c2d822 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -4266,6 +4266,7 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
struct net *net = ipvs->net;
struct ctl_table *tbl;
int idx, ret;
+ size_t ctl_table_size = ARRAY_SIZE(vs_vars);

atomic_set(&ipvs->dropentry, 0);
spin_lock_init(&ipvs->dropentry_lock);
@@ -4282,8 +4283,10 @@ 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)
+ if (net->user_ns != &init_user_ns) {
tbl[0].procname = NULL;
+ ctl_table_size = 0;
+ }
} else
tbl = vs_vars;
/* Initialize sysctl defaults */
@@ -4353,7 +4356,8 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
#endif

ret = -ENOMEM;
- ipvs->sysctl_hdr = register_net_sysctl(net, "net/ipv4/vs", tbl);
+ ipvs->sysctl_hdr = register_net_sysctl_sz(net, "net/ipv4/vs", tbl,
+ ctl_table_size);
if (!ipvs->sysctl_hdr)
goto err;
ipvs->sysctl_tbl = tbl;
diff --git a/net/netfilter/ipvs/ip_vs_lblc.c b/net/netfilter/ipvs/ip_vs_lblc.c
index 1b87214d385e..cf78ba4ce5ff 100644
--- a/net/netfilter/ipvs/ip_vs_lblc.c
+++ b/net/netfilter/ipvs/ip_vs_lblc.c
@@ -550,6 +550,7 @@ static struct ip_vs_scheduler ip_vs_lblc_scheduler = {
static int __net_init __ip_vs_lblc_init(struct net *net)
{
struct netns_ipvs *ipvs = net_ipvs(net);
+ size_t vars_table_size = ARRAY_SIZE(vs_vars_table);

if (!ipvs)
return -ENOENT;
@@ -562,16 +563,19 @@ 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)
+ if (net->user_ns != &init_user_ns) {
ipvs->lblc_ctl_table[0].procname = NULL;
+ vars_table_size = 0;
+ }

} else
ipvs->lblc_ctl_table = vs_vars_table;
ipvs->sysctl_lblc_expiration = DEFAULT_EXPIRATION;
ipvs->lblc_ctl_table[0].data = &ipvs->sysctl_lblc_expiration;

- ipvs->lblc_ctl_header =
- register_net_sysctl(net, "net/ipv4/vs", ipvs->lblc_ctl_table);
+ ipvs->lblc_ctl_header = register_net_sysctl_sz(net, "net/ipv4/vs",
+ ipvs->lblc_ctl_table,
+ vars_table_size);
if (!ipvs->lblc_ctl_header) {
if (!net_eq(net, &init_net))
kfree(ipvs->lblc_ctl_table);
diff --git a/net/netfilter/ipvs/ip_vs_lblcr.c b/net/netfilter/ipvs/ip_vs_lblcr.c
index ad8f5fea6d3a..9eddf118b40e 100644
--- a/net/netfilter/ipvs/ip_vs_lblcr.c
+++ b/net/netfilter/ipvs/ip_vs_lblcr.c
@@ -736,6 +736,7 @@ static struct ip_vs_scheduler ip_vs_lblcr_scheduler =
static int __net_init __ip_vs_lblcr_init(struct net *net)
{
struct netns_ipvs *ipvs = net_ipvs(net);
+ size_t vars_table_size = ARRAY_SIZE(vs_vars_table);

if (!ipvs)
return -ENOENT;
@@ -748,15 +749,18 @@ 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)
+ if (net->user_ns != &init_user_ns) {
ipvs->lblcr_ctl_table[0].procname = NULL;
+ vars_table_size = 0;
+ }
} else
ipvs->lblcr_ctl_table = vs_vars_table;
ipvs->sysctl_lblcr_expiration = DEFAULT_EXPIRATION;
ipvs->lblcr_ctl_table[0].data = &ipvs->sysctl_lblcr_expiration;

- ipvs->lblcr_ctl_header =
- register_net_sysctl(net, "net/ipv4/vs", ipvs->lblcr_ctl_table);
+ ipvs->lblcr_ctl_header = register_net_sysctl_sz(net, "net/ipv4/vs",
+ ipvs->lblcr_ctl_table,
+ vars_table_size);
if (!ipvs->lblcr_ctl_header) {
if (!net_eq(net, &init_net))
kfree(ipvs->lblcr_ctl_table);
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 169e16fc2bce..0ee98ce5b816 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -1106,7 +1106,9 @@ static int nf_conntrack_standalone_init_sysctl(struct net *net)
table[NF_SYSCTL_CT_BUCKETS].mode = 0444;
}

- cnet->sysctl_header = register_net_sysctl(net, "net/netfilter", table);
+ cnet->sysctl_header = register_net_sysctl_sz(net, "net/netfilter",
+ table,
+ ARRAY_SIZE(nf_ct_sysctl_table));
if (!cnet->sysctl_header)
goto out_unregister_netfilter;

diff --git a/net/netfilter/nf_log.c b/net/netfilter/nf_log.c
index 8a29290149bd..8cc52d2bd31b 100644
--- a/net/netfilter/nf_log.c
+++ b/net/netfilter/nf_log.c
@@ -487,9 +487,10 @@ static int netfilter_log_sysctl_init(struct net *net)
for (i = NFPROTO_UNSPEC; i < NFPROTO_NUMPROTO; i++)
table[i].extra2 = net;

- net->nf.nf_log_dir_header = register_net_sysctl(net,
- "net/netfilter/nf_log",
- table);
+ net->nf.nf_log_dir_header = register_net_sysctl_sz(net,
+ "net/netfilter/nf_log",
+ table,
+ ARRAY_SIZE(nf_log_sysctl_table));
if (!net->nf.nf_log_dir_header)
goto err_reg;

--
2.30.2