diff options
Diffstat (limited to 'net/ipv4/netfilter/arp_tables.c')
-rw-r--r-- | net/ipv4/netfilter/arp_tables.c | 44 |
1 files changed, 31 insertions, 13 deletions
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 7505dff4ffd..7bc11ffbb84 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -8,7 +8,7 @@ * Copyright (C) 2002 David S. Miller (davem@redhat.com) * */ - +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/kernel.h> #include <linux/skbuff.h> #include <linux/netdevice.h> @@ -341,15 +341,11 @@ unsigned int arpt_do_table(struct sk_buff *skb, } /* All zeroes == unconditional rule. */ -static inline int unconditional(const struct arpt_arp *arp) +static inline bool unconditional(const struct arpt_arp *arp) { - unsigned int i; + static const struct arpt_arp uncond; - for (i = 0; i < sizeof(*arp)/sizeof(__u32); i++) - if (((__u32 *)arp)[i]) - return 0; - - return 1; + return memcmp(arp, &uncond, sizeof(uncond)) == 0; } /* Figures out from what hook each rule can be called: returns 0 if @@ -537,12 +533,28 @@ 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, unsigned char *limit, const unsigned int *hook_entries, const unsigned int *underflows, + unsigned int valid_hooks, unsigned int *i) { unsigned int h; @@ -562,15 +574,21 @@ static inline int check_entry_size_and_hooks(struct arpt_entry *e, /* Check hooks & underflows */ for (h = 0; h < NF_ARP_NUMHOOKS; h++) { + if (!(valid_hooks & (1 << h))) + continue; if ((unsigned char *)e - base == hook_entries[h]) newinfo->hook_entry[h] = hook_entries[h]; - if ((unsigned char *)e - base == underflows[h]) + if ((unsigned char *)e - base == underflows[h]) { + 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]; + } } - /* FIXME: underflows must be unconditional, standard verdicts - < 0 (not ARPT_RETURN). --RR */ - /* Clear counters and comefrom */ e->counters = ((struct xt_counters) { 0, 0 }); e->comefrom = 0; @@ -630,7 +648,7 @@ static int translate_table(const char *name, newinfo, entry0, entry0 + size, - hook_entries, underflows, &i); + hook_entries, underflows, valid_hooks, &i); duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret); if (ret != 0) return ret; |