On Tue, May 16, 2017 at 11:45 PM, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
> Hi all,
>
> After merging the netfilter tree, today's linux-next build (i386
> defconfig) failed like this:
>
> net/netfilter/x_tables.c: In function 'xt_match_to_user':
> net/netfilter/x_tables.c:303:13: error: implicit declaration of function 'COMPAT_XT_ALIGN' [-Werror=implicit-function-declaration]
> C_SIZE ? COMPAT_XT_ALIGN(C_SIZE) : \
> ^
> net/netfilter/x_tables.c:310:9: note: in expansion of macro 'XT_DATA_TO_USER'
> XT_DATA_TO_USER(u, m, match, 0);
> ^
>
> Caused by commit
>
> 324318f0248c ("netfilter: xtables: zero padding in data_to_user")
>
> In the !CONFIG_COMPAT case C_SIZE will always be zero, but the compiler
> is still looking for the macro :-(
Apologies for the breakage.
> I added this cludge patch (I am sure it can be done better):
>
> From: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Date: Wed, 17 May 2017 13:36:26 +1000
> Subject: [PATCH] netfilter: xtables: fix for zero padding in data_to_user
>
> Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> ---
> net/netfilter/x_tables.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
> index d17769599c10..2b1785993a92 100644
> --- a/net/netfilter/x_tables.c
> +++ b/net/netfilter/x_tables.c
> @@ -296,12 +296,20 @@ int xt_data_to_user(void __user *dst, const void *src,
> }
> EXPORT_SYMBOL_GPL(xt_data_to_user);
>
> +#ifdef CONFIG_COMPAT
> #define XT_DATA_TO_USER(U, K, TYPE, C_SIZE) \
> 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))
> +#else
> +#define XT_DATA_TO_USER(U, K, TYPE, C_SIZE) \
> + xt_data_to_user(U->data, K->data, \
> + K->u.kernel.TYPE->usersize, \
> + C_SIZE ? : K->u.kernel.TYPE->TYPE##size, \
> + C_SIZE ? : XT_ALIGN(K->u.kernel.TYPE->TYPE##size))
> +#endif
>
I will send a patch to the netfilter to define a separate
COMPAT_XT_DATA_TO_USER inside the CONFIG_COMPAT region further down
the file. This also allows simplifying XT_DATA_TO_USER by removing
those ternary statements.
-#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))
and
+#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))
+
--
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