From bdf533de6968e9686df777dc178486f600c6e617 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 22 Mar 2016 18:02:49 +0100 Subject: [PATCH] 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 Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/arp_tables.c | 17 ++++++++--------- net/ipv4/netfilter/ip_tables.c | 17 ++++++++--------- net/ipv6/netfilter/ip6_tables.c | 17 ++++++++--------- 3 files changed, 24 insertions(+), 27 deletions(-) diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index bf081927e06b..830bbe8ec13d 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -474,14 +474,12 @@ 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; @@ -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 e53f8d6f326d..1d72a3c4a7e7 100644 --- 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 84f9baf7aee8..26a5ad1cc4fd 100644 --- 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;