netfilter: x_tables: validate e->target_offset early

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / ipv4 / netfilter / arp_tables.c

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 85a4f21aac1ad117f740d40da7123a663fdfefa8..269759dd96f4f83a34516f7dceb7d532a2d54f53 100644 (file)
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -465,14 +465,12 @@ static int mark_source_chains(const struct xt_table_info *newinfo,
        return 1;
 }
 
-static inline int check_entry(const struct arpt_entry *e, const char *name)
+static inline int check_entry(const struct arpt_entry *e)
 {
        const struct xt_entry_target *t;
 
-       if (!arp_checkentry(&e->arp)) {
-               duprintf("arp_tables: arp check failed %p %s.\n", e, name);
+       if (!arp_checkentry(&e->arp))
                return -EINVAL;
-       }
 
        if (e->target_offset + sizeof(struct xt_entry_target) > e->next_offset)
                return -EINVAL;
@@ -513,10 +511,6 @@ find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
        struct xt_target *target;
        int ret;
 
-       ret = check_entry(e, name);
-       if (ret)
-               return ret;
-
        t = arpt_get_target(e);
        target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
                                        t->u.user.revision);
@@ -561,6 +555,7 @@ static inline int check_entry_size_and_hooks(struct arpt_entry *e,
                                             unsigned int valid_hooks)
 {
        unsigned int h;
+       int err;
 
        if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
            (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
@@ -575,6 +570,10 @@ static inline int check_entry_size_and_hooks(struct arpt_entry *e,
                return -EINVAL;
        }
 
+       err = check_entry(e);
+       if (err)
+               return err;
+
        /* Check hooks & underflows */
        for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
                if (!(valid_hooks & (1 << h)))
@@ -1039,8 +1038,10 @@ static int __do_replace(struct net *net, const char *name,
 
        xt_free_table_info(oldinfo);
        if (copy_to_user(counters_ptr, counters,
-                        sizeof(struct xt_counters) * num_counters) != 0)
-               ret = -EFAULT;
+                        sizeof(struct xt_counters) * num_counters) != 0) {
+               /* Silent error, can't fail, new table is already in place */
+               net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n");
+       }
        vfree(counters);
        xt_table_unlock(t);
        return ret;
@@ -1230,7 +1231,7 @@ check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
        }
 
        /* For purposes of check_entry casting the compat entry is fine */
-       ret = check_entry((struct arpt_entry *)e, name);
+       ret = check_entry((struct arpt_entry *)e);
        if (ret)
                return ret;