diff options
| -rw-r--r-- | include/linux/netfilter/x_tables.h | 4 | ||||
| -rw-r--r-- | net/ipv4/netfilter/arp_tables.c | 11 | ||||
| -rw-r--r-- | net/ipv4/netfilter/ip_tables.c | 12 | ||||
| -rw-r--r-- | net/ipv6/netfilter/ip6_tables.c | 12 | ||||
| -rw-r--r-- | net/netfilter/x_tables.c | 34 |
5 files changed, 41 insertions, 32 deletions
diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index 80a305b85323..0de0862897a4 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -242,6 +242,10 @@ void xt_unregister_match(struct xt_match *target); int xt_register_matches(struct xt_match *match, unsigned int n); void xt_unregister_matches(struct xt_match *match, unsigned int n); +int xt_check_entry_offsets(const void *base, + unsigned int target_offset, + unsigned int next_offset); + int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto, bool inv_proto); int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto, diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index ec37f7c3a033..74668c1d3243 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -496,19 +496,10 @@ next: static inline int check_entry(const struct arpt_entry *e) { - const struct xt_entry_target *t; - if (!arp_checkentry(&e->arp)) return -EINVAL; - if (e->target_offset + sizeof(struct xt_entry_target) > e->next_offset) - return -EINVAL; - - t = arpt_get_target_c(e); - if (e->target_offset + t->u.target_size > e->next_offset) - return -EINVAL; - - return 0; + return xt_check_entry_offsets(e, e->target_offset, e->next_offset); } static inline int check_target(struct arpt_entry *e, const char *name) diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 503038ea7735..71c204d4ca5f 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -590,20 +590,10 @@ static void cleanup_match(struct xt_entry_match *m, struct net *net) static int check_entry(const struct ipt_entry *e) { - const struct xt_entry_target *t; - if (!ip_checkentry(&e->ip)) return -EINVAL; - if (e->target_offset + sizeof(struct xt_entry_target) > - e->next_offset) - return -EINVAL; - - t = ipt_get_target_c(e); - if (e->target_offset + t->u.target_size > e->next_offset) - return -EINVAL; - - return 0; + return xt_check_entry_offsets(e, e->target_offset, e->next_offset); } static int diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 126f2a0f006a..24ae7f458b3b 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -602,20 +602,10 @@ static void cleanup_match(struct xt_entry_match *m, struct net *net) static int check_entry(const struct ip6t_entry *e) { - const struct xt_entry_target *t; - if (!ip6_checkentry(&e->ipv6)) return -EINVAL; - if (e->target_offset + sizeof(struct xt_entry_target) > - e->next_offset) - return -EINVAL; - - t = ip6t_get_target_c(e); - if (e->target_offset + t->u.target_size > e->next_offset) - return -EINVAL; - - return 0; + return xt_check_entry_offsets(e, e->target_offset, e->next_offset); } static int check_match(struct xt_entry_match *m, struct xt_mtchk_param *par) diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 582c9cfd6567..1f44bfa8dd94 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -541,6 +541,40 @@ int xt_compat_match_to_user(const struct xt_entry_match *m, EXPORT_SYMBOL_GPL(xt_compat_match_to_user); #endif /* CONFIG_COMPAT */ +/** + * xt_check_entry_offsets - validate arp/ip/ip6t_entry + * + * @base: pointer to arp/ip/ip6t_entry + * @target_offset: the arp/ip/ip6_t->target_offset + * @next_offset: the arp/ip/ip6_t->next_offset + * + * validates that target_offset and next_offset are sane. + * + * The arp/ip/ip6t_entry structure @base must have passed following tests: + * - it must point to a valid memory location + * - base to base + next_offset must be accessible, i.e. not exceed allocated + * length. + * + * Return: 0 on success, negative errno on failure. + */ +int xt_check_entry_offsets(const void *base, + unsigned int target_offset, + unsigned int next_offset) +{ + const struct xt_entry_target *t; + const char *e = base; + + if (target_offset + sizeof(*t) > next_offset) + return -EINVAL; + + t = (void *)(e + target_offset); + if (target_offset + t->u.target_size > next_offset) + return -EINVAL; + + return 0; +} +EXPORT_SYMBOL(xt_check_entry_offsets); + int xt_check_target(struct xt_tgchk_param *par, unsigned int size, u_int8_t proto, bool inv_proto) { |