netfilter: x_tables: validate e->target_offset early

We should check that e->target_offset is sane before
mark_source_chains gets called since it will fetch the target entry
for loop detection.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index bf081927e06bed507d2ee798eb5bdd21d4d8d761..830bbe8ec13dd854467f496734fa5cba7c7cbbf2 100644 (file)
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -474,14 +474,12 @@ next:
        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;
@@ -522,10 +520,6 @@ 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;
-
        e->counters.pcnt = xt_percpu_counter_alloc();
        if (IS_ERR_VALUE(e->counters.pcnt))
                return -ENOMEM;
@@ -576,6 +570,7 @@ 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) {
@@ -590,6 +585,10 @@ 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)))
@@ -1246,7 +1245,7 @@ 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;
 

diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index e53f8d6f326d835eca7a5f9ada7c52f477962679..1d72a3c4a7e75775167ab1b014a4fe5e426ac810 100644 (file)
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -569,14 +569,12 @@ static void cleanup_match(struct xt_entry_match *m, struct net *net)
 }
 
 static int
-check_entry(const struct ipt_entry *e, const char *name)
+check_entry(const struct ipt_entry *e)
 {
        const struct xt_entry_target *t;
 
-       if (!ip_checkentry(&e->ip)) {
-               duprintf("ip check failed %p %s.\n", e, name);
+       if (!ip_checkentry(&e->ip))
                return -EINVAL;
-       }
 
        if (e->target_offset + sizeof(struct xt_entry_target) >
            e->next_offset)
@@ -666,10 +664,6 @@ find_check_entry(struct ipt_entry *e, struct net *net, const char *name,
        struct xt_mtchk_param mtpar;
        struct xt_entry_match *ematch;
 
-       ret = check_entry(e, name);
-       if (ret)
-               return ret;
-
        e->counters.pcnt = xt_percpu_counter_alloc();
        if (IS_ERR_VALUE(e->counters.pcnt))
                return -ENOMEM;
@@ -741,6 +735,7 @@ check_entry_size_and_hooks(struct ipt_entry *e,
                           unsigned int valid_hooks)
 {
        unsigned int h;
+       int err;
 
        if ((unsigned long)e % __alignof__(struct ipt_entry) != 0 ||
            (unsigned char *)e + sizeof(struct ipt_entry) >= limit) {
@@ -755,6 +750,10 @@ check_entry_size_and_hooks(struct ipt_entry *e,
                return -EINVAL;
        }
 
+       err = check_entry(e);
+       if (err)
+               return err;
+
        /* Check hooks & underflows */
        for (h = 0; h < NF_INET_NUMHOOKS; h++) {
                if (!(valid_hooks & (1 << h)))
@@ -1506,7 +1505,7 @@ check_compat_entry_size_and_hooks(struct compat_ipt_entry *e,
        }
 
        /* For purposes of check_entry casting the compat entry is fine */
-       ret = check_entry((struct ipt_entry *)e, name);
+       ret = check_entry((struct ipt_entry *)e);
        if (ret)
                return ret;
 

diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 84f9baf7aee83c018ac3a50c14417bef10df6030..26a5ad1cc4fd742180257a60b887a0fac93095c5 100644 (file)
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -581,14 +581,12 @@ static void cleanup_match(struct xt_entry_match *m, struct net *net)
 }
 
 static int
-check_entry(const struct ip6t_entry *e, const char *name)
+check_entry(const struct ip6t_entry *e)
 {
        const struct xt_entry_target *t;
 
-       if (!ip6_checkentry(&e->ipv6)) {
-               duprintf("ip_tables: ip check failed %p %s.\n", e, name);
+       if (!ip6_checkentry(&e->ipv6))
                return -EINVAL;
-       }
 
        if (e->target_offset + sizeof(struct xt_entry_target) >
            e->next_offset)
@@ -679,10 +677,6 @@ find_check_entry(struct ip6t_entry *e, struct net *net, const char *name,
        struct xt_mtchk_param mtpar;
        struct xt_entry_match *ematch;
 
-       ret = check_entry(e, name);
-       if (ret)
-               return ret;
-
        e->counters.pcnt = xt_percpu_counter_alloc();
        if (IS_ERR_VALUE(e->counters.pcnt))
                return -ENOMEM;
@@ -753,6 +747,7 @@ check_entry_size_and_hooks(struct ip6t_entry *e,
                           unsigned int valid_hooks)
 {
        unsigned int h;
+       int err;
 
        if ((unsigned long)e % __alignof__(struct ip6t_entry) != 0 ||
            (unsigned char *)e + sizeof(struct ip6t_entry) >= limit) {
@@ -767,6 +762,10 @@ check_entry_size_and_hooks(struct ip6t_entry *e,
                return -EINVAL;
        }
 
+       err = check_entry(e);
+       if (err)
+               return err;
+
        /* Check hooks & underflows */
        for (h = 0; h < NF_INET_NUMHOOKS; h++) {
                if (!(valid_hooks & (1 << h)))
@@ -1518,7 +1517,7 @@ check_compat_entry_size_and_hooks(struct compat_ip6t_entry *e,
        }
 
        /* For purposes of check_entry casting the compat entry is fine */
-       ret = check_entry((struct ip6t_entry *)e, name);
+       ret = check_entry((struct ip6t_entry *)e);
        if (ret)
                return ret;