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[NETFILTER]: xt_tables: add centralized error checking

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Introduce new functions for common match/target checks (private data
size, valid hooks, valid tables and valid protocols) to get more consistent
error reporting and to avoid each module duplicating them.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McHardy 2006-03-20 17:59:06 -08:00 committed by David S. Miller
parent 6ea46c9c12
commit 37f9f7334b
2 changed files with 84 additions and 11 deletions
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23
include/linux/netfilter/x_tables.h
View file

@ -92,8 +92,6 @@ struct xt_match
const char name[XT_FUNCTION_MAXNAMELEN-1];
u_int8_t revision;
/* Return true or false: return FALSE and set *hotdrop = 1 to
force immediate packet drop. */
/* Arguments changed since 2.6.9, as this must now handle
@ -120,6 +118,12 @@ struct xt_match
/* Set this to THIS_MODULE if you are a module, otherwise NULL */
struct module *me;
char *table;
unsigned int matchsize;
unsigned int hooks;
unsigned short proto;
u_int8_t revision;
};
/* Registration hooks for targets. */
@ -129,8 +133,6 @@ struct xt_target
const char name[XT_FUNCTION_MAXNAMELEN-1];
u_int8_t revision;
/* Returns verdict. Argument order changed since 2.6.9, as this
must now handle non-linear skbs, using skb_copy_bits and
skb_ip_make_writable. */
@ -156,6 +158,12 @@ struct xt_target
/* Set this to THIS_MODULE if you are a module, otherwise NULL */
struct module *me;
char *table;
unsigned int targetsize;
unsigned int hooks;
unsigned short proto;
u_int8_t revision;
};
/* Furniture shopping... */
@ -207,6 +215,13 @@ extern void xt_unregister_target(int af, struct xt_target *target);
extern int xt_register_match(int af, struct xt_match *target);
extern void xt_unregister_match(int af, struct xt_match *target);
extern int xt_check_match(const struct xt_match *match, unsigned short family,
unsigned int size, const char *table, unsigned int hook,
unsigned short proto, int inv_proto);
extern int xt_check_target(const struct xt_target *target, unsigned short family,
unsigned int size, const char *table, unsigned int hook,
unsigned short proto, int inv_proto);
extern int xt_register_table(struct xt_table *table,
struct xt_table_info *bootstrap,
struct xt_table_info *newinfo);

72
net/netfilter/x_tables.c
View file

@ -52,6 +52,12 @@ enum {
MATCH,
};
static const char *xt_prefix[NPROTO] = {
[AF_INET] = "ip",
[AF_INET6] = "ip6",
[NF_ARP] = "arp",
};
/* Registration hooks for targets. */
int
xt_register_target(int af, struct xt_target *target)
@ -158,18 +164,12 @@ struct xt_target *xt_find_target(int af, const char *name, u8 revision)
}
EXPORT_SYMBOL(xt_find_target);
static const char *xt_prefix[NPROTO] = {
[AF_INET] = "ipt_%s",
[AF_INET6] = "ip6t_%s",
[NF_ARP] = "arpt_%s",
};
struct xt_target *xt_request_find_target(int af, const char *name, u8 revision)
{
struct xt_target *target;
target = try_then_request_module(xt_find_target(af, name, revision),
xt_prefix[af], name);
"%st_%s", xt_prefix[af], name);
if (IS_ERR(target) || !target)
return NULL;
return target;
@ -237,6 +237,64 @@ int xt_find_revision(int af, const char *name, u8 revision, int target,
}
EXPORT_SYMBOL_GPL(xt_find_revision);
int xt_check_match(const struct xt_match *match, unsigned short family,
unsigned int size, const char *table, unsigned int hook_mask,
unsigned short proto, int inv_proto)
{
if (XT_ALIGN(match->matchsize) != size) {
printk("%s_tables: %s match: invalid size %Zu != %u\n",
xt_prefix[family], match->name,
XT_ALIGN(match->matchsize), size);
return -EINVAL;
}
if (match->table && strcmp(match->table, table)) {
printk("%s_tables: %s match: only valid in %s table, not %s\n",
xt_prefix[family], match->name, match->table, table);
return -EINVAL;
}
if (match->hooks && (hook_mask & ~match->hooks) != 0) {
printk("%s_tables: %s match: bad hook_mask %u\n",
xt_prefix[family], match->name, hook_mask);
return -EINVAL;
}
if (match->proto && (match->proto != proto || inv_proto)) {
printk("%s_tables: %s match: only valid for protocol %u\n",
xt_prefix[family], match->name, match->proto);
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL_GPL(xt_check_match);
int xt_check_target(const struct xt_target *target, unsigned short family,
unsigned int size, const char *table, unsigned int hook_mask,
unsigned short proto, int inv_proto)
{
if (XT_ALIGN(target->targetsize) != size) {
printk("%s_tables: %s target: invalid size %Zu != %u\n",
xt_prefix[family], target->name,
XT_ALIGN(target->targetsize), size);
return -EINVAL;
}
if (target->table && strcmp(target->table, table)) {
printk("%s_tables: %s target: only valid in %s table, not %s\n",
xt_prefix[family], target->name, target->table, table);
return -EINVAL;
}
if (target->hooks && (hook_mask & ~target->hooks) != 0) {
printk("%s_tables: %s target: bad hook_mask %u\n",
xt_prefix[family], target->name, hook_mask);
return -EINVAL;
}
if (target->proto && (target->proto != proto || inv_proto)) {
printk("%s_tables: %s target: only valid for protocol %u\n",
xt_prefix[family], target->name, target->proto);
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL_GPL(xt_check_target);
struct xt_table_info *xt_alloc_table_info(unsigned int size)
{
struct xt_table_info *newinfo;