diff options
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/netfilter/arp_tables.c | 21 | ||||
| -rw-r--r-- | net/ipv4/netfilter/ip_tables.c | 21 |
2 files changed, 38 insertions, 4 deletions
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 064082dffaf..7bc11ffbb84 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -533,6 +533,21 @@ out: return ret; } +static bool check_underflow(struct arpt_entry *e) +{ + const struct arpt_entry_target *t; + unsigned int verdict; + + if (!unconditional(&e->arp)) + return false; + t = arpt_get_target(e); + if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0) + return false; + verdict = ((struct arpt_standard_target *)t)->verdict; + verdict = -verdict - 1; + return verdict == NF_DROP || verdict == NF_ACCEPT; +} + static inline int check_entry_size_and_hooks(struct arpt_entry *e, struct xt_table_info *newinfo, unsigned char *base, @@ -564,8 +579,10 @@ static inline int check_entry_size_and_hooks(struct arpt_entry *e, if ((unsigned char *)e - base == hook_entries[h]) newinfo->hook_entry[h] = hook_entries[h]; if ((unsigned char *)e - base == underflows[h]) { - if (!unconditional(&e->arp)) { - pr_err("Underflows must be unconditional\n"); + if (!check_underflow(e)) { + pr_err("Underflows must be unconditional and " + "use the STANDARD target with " + "ACCEPT/DROP\n"); return -EINVAL; } newinfo->underflow[h] = underflows[h]; diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 6e546d573d9..0b43fd7ca04 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -708,6 +708,21 @@ find_check_entry(struct ipt_entry *e, const char *name, unsigned int size, return ret; } +static bool check_underflow(struct ipt_entry *e) +{ + const struct ipt_entry_target *t; + unsigned int verdict; + + if (!unconditional(&e->ip)) + return false; + t = ipt_get_target(e); + if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0) + return false; + verdict = ((struct ipt_standard_target *)t)->verdict; + verdict = -verdict - 1; + return verdict == NF_DROP || verdict == NF_ACCEPT; +} + static int check_entry_size_and_hooks(struct ipt_entry *e, struct xt_table_info *newinfo, @@ -740,8 +755,10 @@ check_entry_size_and_hooks(struct ipt_entry *e, if ((unsigned char *)e - base == hook_entries[h]) newinfo->hook_entry[h] = hook_entries[h]; if ((unsigned char *)e - base == underflows[h]) { - if (!unconditional(&e->ip)) { - pr_err("Underflows must be unconditional\n"); + if (!check_underflow(e)) { + pr_err("Underflows must be unconditional and " + "use the STANDARD target with " + "ACCEPT/DROP\n"); return -EINVAL; } newinfo->underflow[h] = underflows[h]; |