[NETFILTER]: x_tables: simplify compat API

Split the xt_compat_match/xt_compat_target into smaller type-safe functions
performing just one operation. Handle all alignment and size-related
conversions centrally in these function instead of requiring each module to
implement a full-blown conversion function. Replace ->compat callback by
->compat_from_user and ->compat_to_user callbacks, responsible for
converting just a single private structure.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 11 deletions

diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index c832295dbf61..739a98eebe2c 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -138,12 +138,6 @@ struct xt_counters_info
 
 #include <linux/netdevice.h>
 
-#ifdef CONFIG_COMPAT
-#define COMPAT_TO_USER          1
-#define COMPAT_FROM_USER        -1
-#define COMPAT_CALC_SIZE        0
-#endif
-
 struct xt_match
 {
         struct list_head list;
@@ -176,7 +170,8 @@ struct xt_match
         void (*destroy)(const struct xt_match *match, void *matchinfo);
 
         /* Called when userspace align differs from kernel space one */
-        int (*compat)(void *match, void **dstptr, int *size, int convert);
+        void (*compat_from_user)(void *dst, void *src);
+        int (*compat_to_user)(void __user *dst, void *src);
 
         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
         struct module *me;
@@ -186,6 +181,7 @@ struct xt_match
 
         char *table;
         unsigned int matchsize;
+        unsigned int compatsize;
         unsigned int hooks;
         unsigned short proto;
 
@@ -224,13 +220,15 @@ struct xt_target
         void (*destroy)(const struct xt_target *target, void *targinfo);
 
         /* Called when userspace align differs from kernel space one */
-        int (*compat)(void *target, void **dstptr, int *size, int convert);
+        void (*compat_from_user)(void *dst, void *src);
+        int (*compat_to_user)(void __user *dst, void *src);
 
         /* Set this to THIS_MODULE if you are a module, otherwise NULL */
         struct module *me;
 
         char *table;
         unsigned int targetsize;
+        unsigned int compatsize;
         unsigned int hooks;
         unsigned short proto;
 
@@ -387,9 +385,18 @@ struct compat_xt_counters_info
 
 extern void xt_compat_lock(int af);
 extern void xt_compat_unlock(int af);
-extern int xt_compat_match(void *match, void **dstptr, int *size, int convert);
-extern int xt_compat_target(void *target, void **dstptr, int *size,
-                int convert);
+
+extern int xt_compat_match_offset(struct xt_match *match);
+extern void xt_compat_match_from_user(struct xt_entry_match *m,
+                                      void **dstptr, int *size);
+extern int xt_compat_match_to_user(struct xt_entry_match *m,
+                                   void * __user *dstptr, int *size);
+
+extern int xt_compat_target_offset(struct xt_target *target);
+extern void xt_compat_target_from_user(struct xt_entry_target *t,
+                                       void **dstptr, int *size);
+extern int xt_compat_target_to_user(struct xt_entry_target *t,
+                                    void * __user *dstptr, int *size);
 
 #endif /* CONFIG_COMPAT */
 #endif /* __KERNEL__ */