netfilter: xtables: fix build failure from COMPAT_XT_ALIGN outside CONFIG_COMPAT

The patch in the Fixes references COMPAT_XT_ALIGN in the definition
of XT_DATA_TO_USER, outside an #ifdef CONFIG_COMPAT block.

Split XT_DATA_TO_USER into separate compat and non compat variants and
define the first inside an CONFIG_COMPAT block.

This simplifies both variants by removing branches inside the macro.

Fixes: 324318f0248c ("netfilter: xtables: zero padding in data_to_user")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index d17769599c101e261a643df84c02444fbd043d38..1770c1d9b37fc14be9d9d8cf4721d21c745826ad 100644 (file)
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -296,18 +296,17 @@ int xt_data_to_user(void __user *dst, const void *src,
 }
 EXPORT_SYMBOL_GPL(xt_data_to_user);
 
-#define XT_DATA_TO_USER(U, K, TYPE, C_SIZE)                            \
+#define XT_DATA_TO_USER(U, K, TYPE)                                    \
        xt_data_to_user(U->data, K->data,                               \
                        K->u.kernel.TYPE->usersize,                     \
-                       C_SIZE ? : K->u.kernel.TYPE->TYPE##size,        \
-                       C_SIZE ? COMPAT_XT_ALIGN(C_SIZE) :              \
-                                XT_ALIGN(K->u.kernel.TYPE->TYPE##size))
+                       K->u.kernel.TYPE->TYPE##size,                   \
+                       XT_ALIGN(K->u.kernel.TYPE->TYPE##size))
 
 int xt_match_to_user(const struct xt_entry_match *m,
                     struct xt_entry_match __user *u)
 {
        return XT_OBJ_TO_USER(u, m, match, 0) ||
-              XT_DATA_TO_USER(u, m, match, 0);
+              XT_DATA_TO_USER(u, m, match);
 }
 EXPORT_SYMBOL_GPL(xt_match_to_user);
 
@@ -315,7 +314,7 @@ int xt_target_to_user(const struct xt_entry_target *t,
                      struct xt_entry_target __user *u)
 {
        return XT_OBJ_TO_USER(u, t, target, 0) ||
-              XT_DATA_TO_USER(u, t, target, 0);
+              XT_DATA_TO_USER(u, t, target);
 }
 EXPORT_SYMBOL_GPL(xt_target_to_user);
 
@@ -614,6 +613,12 @@ void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
 }
 EXPORT_SYMBOL_GPL(xt_compat_match_from_user);
 
+#define COMPAT_XT_DATA_TO_USER(U, K, TYPE, C_SIZE)                     \
+       xt_data_to_user(U->data, K->data,                               \
+                       K->u.kernel.TYPE->usersize,                     \
+                       C_SIZE,                                         \
+                       COMPAT_XT_ALIGN(C_SIZE))
+
 int xt_compat_match_to_user(const struct xt_entry_match *m,
                            void __user **dstptr, unsigned int *size)
 {
@@ -629,7 +634,7 @@ int xt_compat_match_to_user(const struct xt_entry_match *m,
                if (match->compat_to_user((void __user *)cm->data, m->data))
                        return -EFAULT;
        } else {
-               if (XT_DATA_TO_USER(cm, m, match, msize - sizeof(*cm)))
+               if (COMPAT_XT_DATA_TO_USER(cm, m, match, msize - sizeof(*cm)))
                        return -EFAULT;
        }
 
@@ -975,7 +980,7 @@ int xt_compat_target_to_user(const struct xt_entry_target *t,
                if (target->compat_to_user((void __user *)ct->data, t->data))
                        return -EFAULT;
        } else {
-               if (XT_DATA_TO_USER(ct, t, target, tsize - sizeof(*ct)))
+               if (COMPAT_XT_DATA_TO_USER(ct, t, target, tsize - sizeof(*ct)))
                        return -EFAULT;
        }