Support table replacement from userspace. Currently without
returning counters.
Signed-off-by: Jan Engelhardt <jengelh@xxxxxxxxxx>
---
include/linux/netfilter/x_tables.h | 3 ++
net/ipv6/netfilter/ip6_tables.c | 9 ++++++
net/netfilter/x_tables.c | 3 +-
net/netfilter/xt1_support.c | 32 +++++++++++++++++++++
net/netfilter/xt1_translat.c | 53 ++++++++++++++++++++++++++++++++++++
5 files changed, 99 insertions(+), 1 deletions(-)
diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index 3d33a06..d905a44 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -577,6 +577,8 @@ struct xt2_table_link {
struct xt2_table *table;
};
+extern const char *const xt_prefix[NFPROTO_NUMPROTO];
+
#define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
+ nr_cpu_ids * sizeof(char *))
extern int xt_register_target(struct xt_target *target);
@@ -735,6 +737,7 @@ extern int xts_starget_to_xt1(void __user **, int *, unsigned int *,
const struct xt1_xlat_info *);
extern int xts_target_to_xt1(void __user **, int *, unsigned int *,
const struct xt2_entry_target *);
+extern int xts_table_replace(struct net *, struct xt2_table *);
extern struct xt2_rule *xt2_rule_new(struct xt2_chain *);
extern int xt2_rule_add_match(struct xt2_rule *, const char *, uint8_t,
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index ddc0313..78dca6f 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -69,6 +69,7 @@ static int mark_source_chains(const struct xt_table_info *,
#define xtsub_entry ip6t_entry
#define xtsub_replace ip6t_replace
#define xtsub_error_target ip6t_error_target
+#define XTSUB_NFPROTO NFPROTO_IPV6
#define XTSUB_NFPROTO_IPV6 1
#define XTSUB(x) ip6t_ ## x
#define XTSUB2(x) ip6t2_ ## x
@@ -1421,6 +1422,14 @@ do_replace(struct net *net, const void __user *user, unsigned int len)
if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
return -EFAULT;
+ /*
+ * If the table goes away just moments later, no problem.
+ * Just dispatching here.
+ */
+ if (xt2_table_lookup(net, tmp.name,
+ NFPROTO_IPV6, XT2_STD_RCULOCK) != NULL)
+ return ip6t2_do_replace(net, user, len);
+
/* overflow check */
if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
return -ENOMEM;
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index f4794db..5303ae3 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -67,13 +67,14 @@ enum {
/* XT_CONTINUE = 0xFFFFFFFF, */ /* reminder (x_tables.h) */
};
-static const char *const xt_prefix[NFPROTO_NUMPROTO] = {
+const char *const xt_prefix[NFPROTO_NUMPROTO] = {
[NFPROTO_UNSPEC] = "x",
[NFPROTO_IPV4] = "ip",
[NFPROTO_ARP] = "arp",
[NFPROTO_BRIDGE] = "eb",
[NFPROTO_IPV6] = "ip6",
};
+EXPORT_SYMBOL_GPL(xt_prefix);
/* Allow this many total (re)entries. */
static const unsigned int xt_jumpstack_multiplier = 2;
diff --git a/net/netfilter/xt1_support.c b/net/netfilter/xt1_support.c
index af58cff..04126d0 100644
--- a/net/netfilter/xt1_support.c
+++ b/net/netfilter/xt1_support.c
@@ -240,4 +240,36 @@ int xts_target_to_xt1(void __user **user_ptr, int *len, unsigned int *z,
}
EXPORT_SYMBOL_GPL(xts_target_to_xt1);
+/**
+ * Load table module, check hook masks, replace table.
+ */
+int xts_table_replace(struct net *net, struct xt2_table *table)
+{
+ struct xt2_table *old_table;
+
+ old_table = try_then_request_module(xt2_table_lookup(net,
+ table->name,
+ table->nfproto,
+ XT2_KEEP_RCULOCK),
+ "%stable_%s",
+ xt_prefix[table->nfproto],
+ table->name);
+ if (old_table == NULL)
+ return -ENOENT;
+ if (table->valid_hooks != old_table->valid_hooks) {
+ pr_err("Invalid hook mix: 0x%x (old) vs 0x%x (new)\n",
+ old_table->valid_hooks, table->valid_hooks);
+ rcu_read_unlock();
+ return -EINVAL;
+ }
+ rcu_read_unlock();
+
+ old_table = xt2_table_replace(net, table);
+ if (IS_ERR(old_table))
+ return PTR_ERR(old_table);
+ xt2_table_destroy(NULL, old_table);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xts_table_replace);
+
MODULE_LICENSE("GPL");
diff --git a/net/netfilter/xt1_translat.c b/net/netfilter/xt1_translat.c
index bff55fc..669b2b2 100644
--- a/net/netfilter/xt1_translat.c
+++ b/net/netfilter/xt1_translat.c
@@ -434,3 +434,56 @@ XTSUB2(table_to_xt1)(void __user *user_ptr, int len, struct xt2_table *table,
mutex_unlock(&table->xt1_lock);
return ret;
}
+
+static int
+XTSUB2(do_replace)(struct net *net, const void __user *user, unsigned int len)
+{
+ struct xtsub_replace repl;
+ struct xt2_table *table;
+ void *blob;
+ int ret;
+
+ if (copy_from_user(&repl, user, sizeof(repl)) != 0)
+ return -EFAULT;
+
+ /* overflow check */
+ if (repl.num_counters >= INT_MAX / sizeof(struct xt_counters))
+ return -ENOMEM;
+
+#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
+ /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
+ if ((SMP_ALIGN(repl.size) >> PAGE_SHIFT) + 2 > num_physpages)
+ return -ENOMEM;
+#undef SMP_ALIGN
+
+ table = xt2_table_new();
+ if (table == NULL)
+ return -ENOMEM;
+ table->net = net;
+ /* Need a writable copy for check_entry_and_size_hooks. */
+ ret = -ENOMEM;
+ blob = vmalloc(repl.size);
+ if (blob == NULL)
+ goto out;
+ if (copy_from_user(blob, user + sizeof(repl), repl.size) != 0) {
+ ret = -EFAULT;
+ goto out;
+ }
+ strncpy(table->name, repl.name, sizeof(table->name));
+ table->name[sizeof(table->name)-1] = '\0';
+ table->valid_hooks = repl.valid_hooks;
+ table->nfproto = XTSUB_NFPROTO;
+
+ ret = XTSUB2(table_to_xt2)(table, blob, &repl);
+ vfree(blob);
+ if (ret < 0)
+ goto out;
+ ret = xts_table_replace(net, table);
+ if (ret < 0)
+ goto out;
+ return 0;
+
+ out:
+ xt2_table_destroy(NULL, table);
+ return ret;
+}
--
1.7.1
--
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